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Was my fatehr's homebrew double conversion SW receiver a HBR?
Looking thru a friend's Feb 2009 QST, saw an article on the W6TC "HBR"
double conversion homebrew radio. Which my father may have built a copy of. I no longer have that radio, but looking at the pictures of teh sets in the QST article, it looks very similar to what my father built. I do remember that he used a 1.8MHz crystal for what might have been the 1st IF to 2nd IF conversion mixer. I also remember, in the mid 60's (I was in grammar school) getting this crystal for my father as an Xmas gift (well, I gave him money that he used to order the crystal, I would not have been old enough to know how to mail order stuff myself yet). Anyway, did the HBR use a crystal of a frequency like this as a conversion local osc mixer? Or maybe the crystal wasn't in an oscillator circuit, but maybe as a bandpass filter? |
Was my fatehr's homebrew double conversion SW receiver a HBR?
On Mar 18, 1:12*am, Robert casey wrote:
Looking thru a friend's Feb 2009 QST, saw an article on the W6TC "HBR" double conversion homebrew radio. *Which my father may have built a copy of. *I no longer have that radio, but looking at the pictures of teh sets in the QST article, it looks very similar to what my father built. *I do remember that he used a 1.8MHz crystal for what might have been the 1st IF to 2nd IF conversion mixer. *I also remember, in the mid 60's (I was in grammar school) getting this crystal for my father as an Xmas gift (well, I gave him money that he used to order the crystal, I would not have been old enough to know how to mail order stuff myself yet). * Anyway, did the HBR use a crystal of a frequency like this as a conversion local osc mixer? *Or maybe the crystal wasn't in an oscillator circuit, but maybe as a bandpass filter? * I dont know about HBR but Bill Orr published plans for a radio like that. The radio was intended to be use with external down converter to cover all the ham bands.I think it was a pretty popular construction project for a lot of hams. pmillet has copies of old copyright expired books and I think they have a copy of Bill Orr"s handbook that will have the plans I am talking about. You can download the books for free. Jimmie |
Was my fatehr's homebrew double conversion SW receiver a HBR?
The HBRs were a series of receivers designed by the late
Ted Crosby, W6TC and published in QST during the late 50s and early 60s. The design used plug-in coils for the osc and rf stages, and they were double conversion designs, with a first IF of 1600 kc and a second IF of either 100 kc or 85 kc (when using surplus ARC-5 IFTs.) The 1800 mc xtal you bought your dad was used for the second coversion osc. to convert the 1600 kc IF down to 100 kc. Many hams deviated from the exact original IF frequencies (i.e. strong local BC station on 1600 kc) which might explain why the xtal was chosen for 1800 kc instead of 1500 or 1700. I'm gathering parts to build a more updated version, using half-lattice filters salvaged from Heath HR-10 receivers for a first IF at 1682 kc. Pete |
Was my father's homebrew double conversion SW receiver a HBR?
The design used plug-in coils for the osc and rf stages, and they were double conversion designs, with a first IF of 1600 kc and a second IF of either 100 kc or 85 kc (when using surplus ARC-5 IFTs.) The 1800 mc xtal you bought your dad was used for the second coversion osc. to convert the 1600 kc IF down to 100 kc. Many hams deviated from the exact original IF frequencies (i.e. strong local BC station on 1600 kc) which might explain why the xtal was chosen for 1800 kc instead of 1500 or 1700. We have a local mid power station at 1600KHz, WWRL, at my parents' house, so my father might have wanted to avoid problems with it. His radio had a bandswitch instead of plug in coils, and he'd receive various broadcast SW stations. He wasn't a ham at the time just yet. |
Was my father's homebrew double conversion SW receiver a HBR?
On Mar 18, 9:24*pm, Robert casey wrote:
The design used plug-in coils for the osc and rf stages, and *they were double conversion designs, with a first IF of *1600 kc and a second IF of either 100 kc or 85 kc (when *using surplus ARC-5 IFTs.) *The 1800 mc xtal you bought *your dad was used for the second coversion osc. to convert *the 1600 kc IF down to 100 kc. *Many hams deviated from *the exact original IF frequencies (i.e. strong local BC *station on 1600 kc) which might explain why the xtal was chosen for 1800 kc instead of 1500 or 1700. We have a local mid power station at 1600KHz, WWRL, at my parents' house, so my father might have wanted to avoid problems with it. His radio had a bandswitch instead of plug in coils, and he'd receive various broadcast SW stations. *He wasn't a ham at the time just yet. * I had a friend who was a retired engineer with GE turned TV tech who built one with a band switch and he later modified it to be more of a general purpose SW receiver. His name was Olin Griggs. Jimmie. |
Was my father's homebrew double conversion SW receiver a HBR?
JIMMIE wrote:
On Mar 18, 9:24 pm, Robert casey wrote: The design used plug-in coils for the osc and rf stages, and they were double conversion designs, with a first IF of 1600 kc and a second IF of either 100 kc or 85 kc (when using surplus ARC-5 IFTs.) The 1800 mc xtal you bought your dad was used for the second coversion osc. to convert the 1600 kc IF down to 100 kc. Many hams deviated from the exact original IF frequencies (i.e. strong local BC station on 1600 kc) which might explain why the xtal was chosen for 1800 kc instead of 1500 or 1700. We have a local mid power station at 1600KHz, WWRL, at my parents' house, so my father might have wanted to avoid problems with it. His radio had a bandswitch instead of plug in coils, and he'd receive various broadcast SW stations. He wasn't a ham at the time just yet. I had a friend who was a retired engineer with GE turned TV tech who built one with a band switch and he later modified it to be more of a general purpose SW receiver. His name was Olin Griggs. Jimmie. I once saw an article in 73 magazine showing a HB receiver that used a re-worked turret tv tuner as a band switch. The coils were re-wound onto the original forms, but some have just replaced the forms with some of the smaller sized toroid cores. I have a bunch of old tv tuners in the junk box, but over the years the contacts have gone bad and now show a high resistance. Maybe they could be cleaned up, but it no longer seems worth the effort. My new idea is to use miniature relays to switch the circuits. I recently found nearly a gross of small relays for free so why not? |
Was my father's homebrew double conversion SW receiver a HBR?
ken scharf wrote:
JIMMIE wrote: On Mar 18, 9:24 pm, Robert casey wrote: The design used plug-in coils for the osc and rf stages, and they were double conversion designs, with a first IF of 1600 kc and a second IF of either 100 kc or 85 kc (when using surplus ARC-5 IFTs.) The 1800 mc xtal you bought your dad was used for the second coversion osc. to convert the 1600 kc IF down to 100 kc. Many hams deviated from the exact original IF frequencies (i.e. strong local BC station on 1600 kc) which might explain why the xtal was chosen for 1800 kc instead of 1500 or 1700. We have a local mid power station at 1600KHz, WWRL, at my parents' house, so my father might have wanted to avoid problems with it. His radio had a bandswitch instead of plug in coils, and he'd receive various broadcast SW stations. He wasn't a ham at the time just yet. I had a friend who was a retired engineer with GE turned TV tech who built one with a band switch and he later modified it to be more of a general purpose SW receiver. His name was Olin Griggs. Jimmie. I once saw an article in 73 magazine showing a HB receiver that used a re-worked turret tv tuner as a band switch. The coils were re-wound onto the original forms, but some have just replaced the forms with some of the smaller sized toroid cores. I have a bunch of old tv tuners in the junk box, but over the years the contacts have gone bad and now show a high resistance. Maybe they could be cleaned up, but it no longer seems worth the effort. My new idea is to use miniature relays to switch the circuits. I recently found nearly a gross of small relays for free so why not? Relays will most likely bring some grief over the years with contacts not conducting 100% and such. Better use band switching diodes or PIN diodes. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. |
Was my father's homebrew double conversion SW receiver a HBR?
Joerg wrote:
ken scharf wrote: JIMMIE wrote: On Mar 18, 9:24 pm, Robert casey wrote: The design used plug-in coils for the osc and rf stages, and they were double conversion designs, with a first IF of 1600 kc and a second IF of either 100 kc or 85 kc (when using surplus ARC-5 IFTs.) The 1800 mc xtal you bought your dad was used for the second coversion osc. to convert the 1600 kc IF down to 100 kc. Many hams deviated from the exact original IF frequencies (i.e. strong local BC station on 1600 kc) which might explain why the xtal was chosen for 1800 kc instead of 1500 or 1700. We have a local mid power station at 1600KHz, WWRL, at my parents' house, so my father might have wanted to avoid problems with it. His radio had a bandswitch instead of plug in coils, and he'd receive various broadcast SW stations. He wasn't a ham at the time just yet. I had a friend who was a retired engineer with GE turned TV tech who built one with a band switch and he later modified it to be more of a general purpose SW receiver. His name was Olin Griggs. Jimmie. I once saw an article in 73 magazine showing a HB receiver that used a re-worked turret tv tuner as a band switch. The coils were re-wound onto the original forms, but some have just replaced the forms with some of the smaller sized toroid cores. I have a bunch of old tv tuners in the junk box, but over the years the contacts have gone bad and now show a high resistance. Maybe they could be cleaned up, but it no longer seems worth the effort. My new idea is to use miniature relays to switch the circuits. I recently found nearly a gross of small relays for free so why not? Relays will most likely bring some grief over the years with contacts not conducting 100% and such. Better use band switching diodes or PIN diodes. There is a trick with relays, they must conduct a minimum amount of current or the contacts won't self clean. Using relays to switch receiver input circuits that are only passing micro amps will eventually cause problems. But, if you bias the circuits with some resistors so the relay must switch at least a few milliamps they will last longer. Another idea if the relays are computer controlled would be to switch in a high current source (few hundred ma) before opening or closing the desired relays, then switch off the high current source. Relays should not be any worse than switches as far as contacts go, however rotary switches would tend to be self cleaning due to the wiping action. Relays are often used in switching low pass filers used after solid state finals. Here they ARE carrying high current (rf output) but not switching it. |
Was my father's homebrew double conversion SW receiver a HBR?
Relays will most likely bring some grief over the years with contacts
not conducting 100% and such. Better use band switching diodes or PIN diodes. There is a trick with relays, they must conduct a minimum amount of current or the contacts won't self clean. Using relays to switch receiver input circuits that are only passing micro amps will eventually cause problems. But, if you bias the circuits with some resistors so the relay must switch at least a few milliamps they will last longer. Another idea if the relays are computer controlled would be to switch in a high current source (few hundred ma) before opening or closing the desired relays, then switch off the high current source. Relays should not be any worse than switches as far as contacts go, however rotary switches would tend to be self cleaning due to the wiping action. Relays are often used in switching low pass filers used after solid state finals. Here they ARE carrying high current (rf output) but not switching it. ============================================= Had this relay switching problem with my (almost vintage) Ten Tec Paragon trx (AD 1988) a few years ago and ordered a relay from TenTec , but never had to change ,because the original relay cleared itself. Would suggest to operate an 'ailing' rx relay a number of times ,eg 10-20 times within a short period ; its contact(s) might then clear itself. Frank GM0CSZ / KN6WH |
Was my father's homebrew double conversion SW receiver a HBR?
ken scharf wrote:
Joerg wrote: ken scharf wrote: JIMMIE wrote: On Mar 18, 9:24 pm, Robert casey wrote: The design used plug-in coils for the osc and rf stages, and they were double conversion designs, with a first IF of 1600 kc and a second IF of either 100 kc or 85 kc (when using surplus ARC-5 IFTs.) The 1800 mc xtal you bought your dad was used for the second coversion osc. to convert the 1600 kc IF down to 100 kc. Many hams deviated from the exact original IF frequencies (i.e. strong local BC station on 1600 kc) which might explain why the xtal was chosen for 1800 kc instead of 1500 or 1700. We have a local mid power station at 1600KHz, WWRL, at my parents' house, so my father might have wanted to avoid problems with it. His radio had a bandswitch instead of plug in coils, and he'd receive various broadcast SW stations. He wasn't a ham at the time just yet. I had a friend who was a retired engineer with GE turned TV tech who built one with a band switch and he later modified it to be more of a general purpose SW receiver. His name was Olin Griggs. Jimmie. I once saw an article in 73 magazine showing a HB receiver that used a re-worked turret tv tuner as a band switch. The coils were re-wound onto the original forms, but some have just replaced the forms with some of the smaller sized toroid cores. I have a bunch of old tv tuners in the junk box, but over the years the contacts have gone bad and now show a high resistance. Maybe they could be cleaned up, but it no longer seems worth the effort. My new idea is to use miniature relays to switch the circuits. I recently found nearly a gross of small relays for free so why not? Relays will most likely bring some grief over the years with contacts not conducting 100% and such. Better use band switching diodes or PIN diodes. There is a trick with relays, they must conduct a minimum amount of current or the contacts won't self clean. Using relays to switch receiver input circuits that are only passing micro amps will eventually cause problems. But, if you bias the circuits with some resistors so the relay must switch at least a few milliamps they will last longer. Another idea if the relays are computer controlled would be to switch in a high current source (few hundred ma) before opening or closing the desired relays, then switch off the high current source. Relays should not be any worse than switches as far as contacts go, however rotary switches would tend to be self cleaning due to the wiping action. Relays are often used in switching low pass filers used after solid state finals. Here they ARE carrying high current (rf output) but not switching it. Yeah, I wish the designers of the NRD-515 here had known that as well. Every few months a relay will become "sticky". The S-meter drops to zilch, rock the attenuator switch 5-10 times, and it's back :-( Relays with some current are ok but I prefer the electronic method. PIN diodes with lots of current and plenty of carrier lifetime usually work. One just has to make sure there aren't any rectification effects that can cause IM or harmonics in the presence of strong signals. FET switches are sometimes a good deal as well but since the SD5000 and SD5400 have gone towards high-priced boutique status not so much anymore. -- 73, Joerg |
Was my father's homebrew double conversion SW receiver a HBR?
On Mar 20, 6:47*pm, ken scharf wrote:
JIMMIE wrote: On Mar 18, 9:24 pm, Robert casey wrote: The design used plug-in coils for the osc and rf stages, and *they were double conversion designs, with a first IF of *1600 kc and a second IF of either 100 kc or 85 kc (when *using surplus ARC-5 IFTs.) *The 1800 mc xtal you bought *your dad was used for the second coversion osc. to convert *the 1600 kc IF down to 100 kc. *Many hams deviated from *the exact original IF frequencies (i.e. strong local BC *station on 1600 kc) which might explain why the xtal was chosen for 1800 kc instead of 1500 or 1700. We have a local mid power station at 1600KHz, WWRL, at my parents' house, so my father might have wanted to avoid problems with it. His radio had a bandswitch instead of plug in coils, and he'd receive various broadcast SW stations. *He wasn't a ham at the time just yet.. * I had a friend who was a retired engineer with GE turned TV tech who built one with a band switch and he later modified it to be more of a general purpose SW receiver. His name was Olin Griggs. Jimmie. I once saw an article in 73 magazine showing a HB receiver that used a re-worked turret tv tuner as a band switch. *The coils were re-wound onto the original forms, but some have just replaced the forms with some of the smaller sized toroid cores. *I have a bunch of old tv tuners in the junk box, but over the years the contacts have gone bad and now show a high resistance. * Maybe they could be cleaned up, but it no longer seems worth the effort. *My new idea is to use miniature relays to switch the circuits. *I recently found nearly a gross of small relays for free so why not?- Hide quoted text - - Show quoted text - I tried the TV tuner trick one time and it didnt work well at all. Most tuners are tossed because the contacts fail. Various contact cleaners will only help for a while because wor out is worn out and there is not a long term fix you can do for them. The exception to this was a very old one I found that was at least as big or bigger than a shoe box. Shame on me but I used one like this to build my own CB radio tx. I was using it to switch crystals and trimmer caps for the osc. Jimmie |
Was my father's homebrew double conversion SW receiver a HBR?
JIMMIE wrote:
On Mar 20, 6:47 pm, ken scharf wrote: JIMMIE wrote: On Mar 18, 9:24 pm, Robert casey wrote: The design used plug-in coils for the osc and rf stages, and they were double conversion designs, with a first IF of 1600 kc and a second IF of either 100 kc or 85 kc (when using surplus ARC-5 IFTs.) The 1800 mc xtal you bought your dad was used for the second coversion osc. to convert the 1600 kc IF down to 100 kc. Many hams deviated from the exact original IF frequencies (i.e. strong local BC station on 1600 kc) which might explain why the xtal was chosen for 1800 kc instead of 1500 or 1700. We have a local mid power station at 1600KHz, WWRL, at my parents' house, so my father might have wanted to avoid problems with it. His radio had a bandswitch instead of plug in coils, and he'd receive various broadcast SW stations. He wasn't a ham at the time just yet. I had a friend who was a retired engineer with GE turned TV tech who built one with a band switch and he later modified it to be more of a general purpose SW receiver. His name was Olin Griggs. Jimmie. I once saw an article in 73 magazine showing a HB receiver that used a re-worked turret tv tuner as a band switch. The coils were re-wound onto the original forms, but some have just replaced the forms with some of the smaller sized toroid cores. I have a bunch of old tv tuners in the junk box, but over the years the contacts have gone bad and now show a high resistance. Maybe they could be cleaned up, but it no longer seems worth the effort. My new idea is to use miniature relays to switch the circuits. I recently found nearly a gross of small relays for free so why not?- Hide quoted text - - Show quoted text - I tried the TV tuner trick one time and it didnt work well at all. Most tuners are tossed because the contacts fail. ... Not really. Back then TVs were often tossed because the flyback xfmr had blown and repair was deemed uneconomical. Or someone said that because in reality they wanted that brand spanking new set that was one sale. But this is so long ago that if there's any left the contacts will have corrodes away. [...] -- 73, Joerg |
Was my fatehr's homebrew double conversion SW receiver a HBR?
On Mar 17, 10:12�pm, Robert casey wrote:
Looking thru a friend's Feb 2009 QST, saw an article on the W6TC "HBR" double conversion homebrew radio. �Which my father may have built a copy of. �I no longer have that radio, but looking at the pictures of teh sets in the QST article, it looks very similar to what my father built. �I do remember that he used a 1.8MHz crystal for what might have been the 1st IF to 2nd IF conversion mixer. �I also remember, in the mid 60's (I was in grammar school) getting this crystal for my father as an Xmas gift (well, I gave him money that he used to order the crystal, I would not have been old enough to know how to mail order stuff myself yet). � Anyway, did the HBR use a crystal of a frequency like this as a conversion local osc mixer? �Or maybe the crystal wasn't in an oscillator circuit, but maybe as a bandpass filter? � Bob, try www.qsl.net/k5bcq/HBR/hbr.html for a rather complete collection of Home Brew Receiver photos, schematics, details, hints&kinks, etc., which is Kees Talen's website. It isn't as squashed together as QST articles (which don't cover all the HBR versions) nor does it have the extra 450 KB warning page present with QST article downloads. 73, Len AF6AY |
Was my father's homebrew double conversion SW receiver a HBR?
AF6AY wrote:
"Joerg" posted on Fri, Mar 20 2009 6:06 pm ken scharf wrote: JIMMIE wrote: On Mar 18, 9:24 pm, Robert casey wrote: I once saw an article in 73 magazine showing a HB receiver that used a re-worked turret tv tuner as a band switch. The coils were re-wound onto the original forms, but some have just replaced the forms with some of the smaller sized toroid cores. I have a bunch of old tv tuners in the junk box, but over the years the contacts have gone bad and now show a high resistance. Maybe they could be cleaned up, but it no longer seems worth the effort. My new idea is to use miniature relays to switch the circuits. I recently found nearly a gross of small relays for free so why not? Relays will most likely bring some grief over the years with contacts not conducting 100% and such. Better use band switching diodes or PIN diodes. I disagree based on some experience in environmentally testing relays ranging from high-power to low-power to 'choppers' in so-called stabilized (DC) amplifiers for military avionics, then doing comparative testing against the cheaper commercial relay designs on the market over 50 years ago. About the only "grief" is one can get is failure to wire it correctly or not understanding what relay contacts acually do or how to power their actuating coils. Power relays CAN result in contact pitting and poor resistance as a result of many multiple activations while carrying inductive loads of many Amperes of current with resulting very high voltage back-EMF ('flyback') conditions on contact separation. That is NOT the case with receiver bandswitching applications. Not even close. There are some unusual contact effects in so-called "dry" circuits carrying femtoAmpere currents or less but those won't affect high- impedance input and output circuits common to vacuum tubes. One of the better choices for no-nonsense, easier to implement bandswitch conversions without much cost is to use modern, easy-to-get small relays requiring only 100 to 150 mW coil powers, available in coil operating voltage increments of 6, 12, 18, 24 VDC...or, if salvaging older tube equipment, the "plate relays" of a half century ago designed for higher 12 to 30 VDC, comparable powers for a few mA of plate current in coils. [much harder to get now given all electronics is firmly in the solid- state era starting over 40 years ago] Some relay makers, such as Omron, are widely used in electronics, especially for automotive applications and are found listed in all major distributor catalogs. Relay contacts can easily withstand 200 to 400 VDC stock of now v. old (half-century ago). The make or break contacts do NOT involve any unusual RF impedance characteristics other than a few pFd of capacitance equivalent to ordinary point-to-point wiring or the lead-length inductance of some short point-to-point wire inductance in the low nanoHy range. It has an excellent open or closed contact condition with excellent isolation between actuating coil and contact set. By contrast, conventional rotary bandswitch structures designed around 60 to 70 years ago, are open to all sorts of contamination, including OXIDATION of contacts plus wear of typically cheap contact construction of a bygone era. Sealed or semi-sealed rotary switch wafers of the post-WWII era have much longer life than the old open-to-everything wafer designs that may look good in their first half decade, then degrade from oxidation after that, before normal wear effects show up. Based on over a decade of using the TV channel "turret tuner" (such as the cheap products of Standard Coil tuners of long ago) types just for TV channel selection, I wouldn't try to convert those to anything else than scrap. I'm being kind on that evaluation. The MECHANICS of such turret tuners may look good, but VHF-UHF circuits don't work on either mechanics or appearance. HF circuits might squeak by, but the typical contact set of turret tuners was never optimized for either wear or contact resistance. It was 'optimized' entirely for maximum profit from lowest-possible cost of components in a highly-competitive TV market of long ago. Today there are a number of inexpensive small relays used in HF radio equipment, especially in automatic antenna tuners (used for switching banks of binary-progression-values of inductors and capacitors) from direct microcontroller control of actuating coils. Those work very well and show no degredation running with 100 W of RF or more at 50 Ohm impedances. Millions of automobiles on the road today are tooling around with little packages of relays controlling everything from headlights to sensor selection in adverse temperature ranges and high vibration, no real problems from those relays. In short, small semi-sealed low-power relays are FINE for vacuum tube circuit switching in homebrew electronics, properly applied. They can easily replace most rotary bandswitching applications in layout with less stray circuit series-inductance and parallel-to-ground capacitance than with point-to-point wiring. Relays are ok in those applications, where there are actual currents flowing. What I meant was pure signal switching with no DC currents. Sealed relays, Reeds, mercury-wetted and such work quite well there. But non-sealed versions have issues and a snap-on plastic cap ain't a seal. Those problems became really nasty after we moved across an ocean and all this stuff was in a sea container for two months. After that almost all the band switching relays had problems, had to clean all of them. Now I am down to one sticky relay every couple month or so. Some I have replaced with PIN diode circuits and that, of course, made the issues completely go away. But it's always a hassle to do in an exisitng circuit. -- 73, Joerg |
Was my father's homebrew double conversion SW receiver a HBR?
"Joerg" wrote in message Yeah, I wish the designers of the NRD-515 here had known that as well. Every few months a relay will become "sticky". The S-meter drops to zilch, rock the attenuator switch 5-10 times, and it's back :-( Relays with some current are ok but I prefer the electronic method. PIN diodes with lots of current and plenty of carrier lifetime usually work. One just has to make sure there aren't any rectification effects that can cause IM or harmonics in the presence of strong signals. FET switches are sometimes a good deal as well but since the SD5000 and SD5400 have gone towards high-priced boutique status not so much anymore. -- 73, Joerg Hello Joerg Odd you're having that problem with the NRD-515. So far mine has been rock solid, except for the rotting foam disease in the mechanical filters... But... I do have constant problems with the relay that selects the external VFO in the NSD-515 transmitter! It always needs attention and cleaning. Its the odd-ball relay that was added on the bottom of the mother board. I'm wondering if you have had the same problem with the transmitter (assuming you own the pair) and what you did to fix it. 73 Peter k1zjh |
Was my father's homebrew double conversion SW receiver a HBR?
Unca Pete wrote:
"Joerg" wrote in message Yeah, I wish the designers of the NRD-515 here had known that as well. Every few months a relay will become "sticky". The S-meter drops to zilch, rock the attenuator switch 5-10 times, and it's back :-( Relays with some current are ok but I prefer the electronic method. PIN diodes with lots of current and plenty of carrier lifetime usually work. One just has to make sure there aren't any rectification effects that can cause IM or harmonics in the presence of strong signals. FET switches are sometimes a good deal as well but since the SD5000 and SD5400 have gone towards high-priced boutique status not so much anymore. -- 73, Joerg Hello Joerg Odd you're having that problem with the NRD-515. So far mine has been rock solid, except for the rotting foam disease in the mechanical filters... But... I do have constant problems with the relay that selects the external VFO in the NSD-515 transmitter! It always needs attention and cleaning. Its the odd-ball relay that was added on the bottom of the mother board. I'm wondering if you have had the same problem with the transmitter (assuming you own the pair) and what you did to fix it. Actually I only have the receiver. Besides relays there is one other serious problem: The bearings of the tune encoder are seriously worn, the shaft sloshes around. I am not looking forward to the day when I have to disect that thing. Rotting foam in filters? Whoops, I've got to watch out for that. As for relays, my problem really got worse after all this was in a sea container for a while and crossed an ocean. -- 73, Joerg |
Was my father's homebrew double conversion SW receiver a HBR?
On Mar 21, 5:11*pm, Joerg
wrote: JIMMIE wrote: On Mar 20, 6:47 pm, ken scharf wrote: JIMMIE wrote: On Mar 18, 9:24 pm, Robert casey wrote: The design used plug-in coils for the osc and rf stages, and *they were double conversion designs, with a first IF of *1600 kc and a second IF of either 100 kc or 85 kc (when *using surplus ARC-5 IFTs.) *The 1800 mc xtal you bought *your dad was used for the second coversion osc. to convert *the 1600 kc IF down to 100 kc. *Many hams deviated from *the exact original IF frequencies (i.e. strong local BC *station on 1600 kc) which might explain why the xtal was chosen for 1800 kc instead of 1500 or 1700. We have a local mid power station at 1600KHz, WWRL, at my parents' house, so my father might have wanted to avoid problems with it. His radio had a bandswitch instead of plug in coils, and he'd receive various broadcast SW stations. *He wasn't a ham at the time just yet. * I had a friend who was a retired engineer with GE turned TV tech who built one with a band switch and he later modified it to be more of a general purpose SW receiver. His name was Olin Griggs. Jimmie. I once saw an article in 73 magazine showing a HB receiver that used a re-worked turret tv tuner as a band switch. *The coils were re-wound onto the original forms, but some have just replaced the forms with some of the smaller sized toroid cores. *I have a bunch of old tv tuners in the junk box, but over the years the contacts have gone bad and now show a high resistance. * Maybe they could be cleaned up, but it no longer seems worth the effort. *My new idea is to use miniature relays to switch the circuits. *I recently found nearly a gross of small relays for free so why not?- Hide quoted text - - Show quoted text - I tried the TV tuner trick one time and it didnt work well at all. Most tuners are tossed because the contacts fail. ... Not really. Back then TVs were often tossed because the flyback xfmr had blown and repair was deemed uneconomical. Or someone said that because in reality they wanted that brand spanking new set that was one sale. But this is so long ago that if there's any left the contacts will have corrodes away. [...] -- 73, Joerg- Hide quoted text - - Show quoted text - You must be younger than me, Ive replaced a lot of TV tuners and flybacks. It was in the early 80s that i first noticed TVs becoming diposable and quit working on them. Luckily for me there was still a lot of other electtronic repair work needed to be done. Most of the local industry was becoming more electronic oriented in their equipment and needed someone to maintain their equipment but did not want to hire a full time tech. The sawmills, textile plants, food processing plants kept me pretty busy aand i enjoyed the work much more not having to deal with the usual customers. Jimme |
Was my father's homebrew double conversion SW receiver a HBR?
JIMMIE wrote:
On Mar 21, 5:11 pm, Joerg wrote: JIMMIE wrote: On Mar 20, 6:47 pm, ken scharf wrote: JIMMIE wrote: On Mar 18, 9:24 pm, Robert casey wrote: The design used plug-in coils for the osc and rf stages, and they were double conversion designs, with a first IF of 1600 kc and a second IF of either 100 kc or 85 kc (when using surplus ARC-5 IFTs.) The 1800 mc xtal you bought your dad was used for the second coversion osc. to convert the 1600 kc IF down to 100 kc. Many hams deviated from the exact original IF frequencies (i.e. strong local BC station on 1600 kc) which might explain why the xtal was chosen for 1800 kc instead of 1500 or 1700. We have a local mid power station at 1600KHz, WWRL, at my parents' house, so my father might have wanted to avoid problems with it. His radio had a bandswitch instead of plug in coils, and he'd receive various broadcast SW stations. He wasn't a ham at the time just yet. I had a friend who was a retired engineer with GE turned TV tech who built one with a band switch and he later modified it to be more of a general purpose SW receiver. His name was Olin Griggs. Jimmie. I once saw an article in 73 magazine showing a HB receiver that used a re-worked turret tv tuner as a band switch. The coils were re-wound onto the original forms, but some have just replaced the forms with some of the smaller sized toroid cores. I have a bunch of old tv tuners in the junk box, but over the years the contacts have gone bad and now show a high resistance. Maybe they could be cleaned up, but it no longer seems worth the effort. My new idea is to use miniature relays to switch the circuits. I recently found nearly a gross of small relays for free so why not?- Hide quoted text - - Show quoted text - I tried the TV tuner trick one time and it didnt work well at all. Most tuners are tossed because the contacts fail. ... Not really. Back then TVs were often tossed because the flyback xfmr had blown and repair was deemed uneconomical. Or someone said that because in reality they wanted that brand spanking new set that was one sale. But this is so long ago that if there's any left the contacts will have corrodes away. [...] -- 73, Joerg- Hide quoted text - - Show quoted text - You must be younger than me, Ive replaced a lot of TV tuners and flybacks. It was in the early 80s that i first noticed TVs becoming diposable and quit working on them. Luckily for me there was still a lot of other electtronic repair work needed to be done. Most of the local industry was becoming more electronic oriented in their equipment and needed someone to maintain their equipment but did not want to hire a full time tech. The sawmills, textile plants, food processing plants kept me pretty busy aand i enjoyed the work much more not having to deal with the usual customers. Same here, in the early 80's I began to refuse fixing TVs and stuff. But even before that, I remember the flyback transformers for some sets being so outrageously expensive that a repair plain didn't make sense. Especially if it had taken out the H-deflection tube and some other stuff with it or the set itself had already been quite tired at the time it hissed its good-bye. This was in Europe. -- 73, Joerg |
Was my father's homebrew double conversion SW receiver a HBR?
On Mar 21, 4:31�pm, Joerg
wrote: AF6AY wrote: "Joerg" posted on Fri, Mar 20 2009 6:06 pm ken scharf wrote: JIMMIE wrote: Relays are ok in those applications, where there are actual currents flowing. What I meant was pure signal switching with no DC currents. That's called "dry" switching in the electronics industry, has been called that for over a half century. Sealed relays, Reeds, mercury-wetted and such work quite well there. But non-sealed versions have issues and a snap-on plastic cap ain't a seal. Didn't say that that it was a seal. But...there are many kinds of 'seals' and there are many kinds of contact alloys which few hobbyists investigate. Those problems became really nasty after we moved across an ocean and all this stuff was in a sea container for two months. After that almost all the band switching relays had problems, had to clean all of them. Now I am down to one sticky relay every couple month or so. My wife and I own a nice 2005 model Chevrolet Malibu MAXX that we've driven in both driving rain with some intermittent ice to Wisconsin from California and back, to Washington state from California and back. It has two little boxes of many small-signal relays, only a very few qualifying for large-signal types. Never a problem since we got it in late June of 2005. Those relay boxes all have lids and the small relays have little covers and that auto has definitely been exposed to the environment many times in the last 4 years. I can sympathize with your bad sea container shipping experience but consumer-grade radios (such as for amateur radio) were never designed to be exposed to sea evnvironments. Ask yourself how all those off- shore made radios made it to the USA? Inside standardized container boxes. I didn't make my comment lightly or pretend that I know everything there is to electronics. I do know, by a rather large set of experiences that 'dry' circuit relays (hermetically sealed OR by reasonably-good individual covers) will work without having to be 'operated many times' in order to 'clean their contacts.' I'll cite one application that is military, the US AN/PRC-104 manpack HF transceiver. About one-third of that backpack radio is an automatic antenna tuner so that one whip length can be optimized for best electrical characteristics. It does that with a rather conventional microprocessor control driving two banks of binary- sequence inductance and capacitance values switched by relays. It has been in operational status with the US Army since around 1984 and is expected to be phased out soon in favor of more modern HF-to-UHF transceiver designs. It's been a while since I've seen the guts of it but I don't recall that it had any hermetically-sealed relays in it. Right now I'm beginning to start cutting holes for a rebuild of an 'ancient' HF receiver once made for my late father wanting to tune to some SW BC stations, principally Radio Sweden back in 1964. I've been fortunate to get a large collection of North Electric small sealed relays dating back to about 1955 production which I've already breadboarded for bandswitching use. Very familiar with relay testing, I found NO problems from 'dry' contact switching. The low capacitance to ground and minimal series inductance from the contact set do NOT upset any of the L-C circuits being switched. replaced with PIN diode circuits and that, of course, made the issues completely go away. But it's always a hassle to do in an exisitng circuit.. Yes, I have that in the filter board of my two decade old Icom IC-R70, all switched with 'RF switch' diodes (no registry number). If needs be, that entire filter board could be enclosed to prevent any problems from the environment. Icom used that sort of semi-conductor switching for ease of overall parts cost along with reduced labor costs to Icom. Such work fine at the LOW impedances involved (50 to 75 Ohms) but I've tried to duplicate that at 10 KOhms on a breadboard and have run into problems with diodes' own impedances affecting circuit operation. Those could be solved, I'm sure, but I didn't care to spend weeks fiddling with them for my rebuild project. The relay contact set had only the shunt capacity and series inductance to contend with and those were very low values and easily compensated for alignment. 73, Len AF6AY |
Was my father's homebrew double conversion SW receiver a HBR?
AF6AY wrote:
On Mar 21, 4:31�pm, Joerg wrote: AF6AY wrote: "Joerg" posted on Fri, Mar 20 2009 6:06 pm ken scharf wrote: JIMMIE wrote: Relays are ok in those applications, where there are actual currents flowing. What I meant was pure signal switching with no DC currents. That's called "dry" switching in the electronics industry, has been called that for over a half century. Sealed relays, Reeds, mercury-wetted and such work quite well there. But non-sealed versions have issues and a snap-on plastic cap ain't a seal. Didn't say that that it was a seal. But...there are many kinds of 'seals' and there are many kinds of contact alloys which few hobbyists investigate. Most must make do with whatever places such as Digikey offer at affordable cost. Those problems became really nasty after we moved across an ocean and all this stuff was in a sea container for two months. After that almost all the band switching relays had problems, had to clean all of them. Now I am down to one sticky relay every couple month or so. My wife and I own a nice 2005 model Chevrolet Malibu MAXX that we've driven in both driving rain with some intermittent ice to Wisconsin from California and back, to Washington state from California and back. It has two little boxes of many small-signal relays, only a very few qualifying for large-signal types. Never a problem since we got it in late June of 2005. Those relay boxes all have lids and the small relays have little covers and that auto has definitely been exposed to the environment many times in the last 4 years. Sure, but in a car relays always switch something that draws a serious current, more than a few milliamps. That works for a long time. Well, until a "weld wart" shows up, like it did on a relay in out Genie garage door opener. I can sympathize with your bad sea container shipping experience but consumer-grade radios (such as for amateur radio) were never designed to be exposed to sea evnvironments. Ask yourself how all those off- shore made radios made it to the USA? Inside standardized container boxes. Usually they are carefully packaged and silica gel is included. When you move that usually ain't the case. Plus the radio was quite old by that time. I didn't make my comment lightly or pretend that I know everything there is to electronics. I do know, by a rather large set of experiences that 'dry' circuit relays (hermetically sealed OR by reasonably-good individual covers) will work without having to be 'operated many times' in order to 'clean their contacts.' Hmm, I've had that happen even in $xxxxx lab gear, not quite consumer-grade. Never really with mil gear though but those guys can often design to "the sky's the limit" cost goals. I'll cite one application that is military, the US AN/PRC-104 manpack HF transceiver. About one-third of that backpack radio is an automatic antenna tuner so that one whip length can be optimized for best electrical characteristics. It does that with a rather conventional microprocessor control driving two banks of binary- sequence inductance and capacitance values switched by relays. It has been in operational status with the US Army since around 1984 and is expected to be phased out soon in favor of more modern HF-to-UHF transceiver designs. It's been a while since I've seen the guts of it but I don't recall that it had any hermetically-sealed relays in it. But I bet no expense was spared to pick the very best parts for that radio. Right now I'm beginning to start cutting holes for a rebuild of an 'ancient' HF receiver once made for my late father wanting to tune to some SW BC stations, principally Radio Sweden back in 1964. I've been fortunate to get a large collection of North Electric small sealed relays dating back to about 1955 production which I've already breadboarded for bandswitching use. Very familiar with relay testing, I found NO problems from 'dry' contact switching. The low capacitance to ground and minimal series inductance from the contact set do NOT upset any of the L-C circuits being switched. Sealed relays are ok. I also have a few really old ones here and so far they have never let me down. But I don't have enough to equip a filter bank with 15-20 in- and outputs. For that I've got a stash of HSMP-3810 PIN diodes. replaced with PIN diode circuits and that, of course, made the issues completely go away. But it's always a hassle to do in an exisitng circuit. Yes, I have that in the filter board of my two decade old Icom IC-R70, all switched with 'RF switch' diodes (no registry number). If needs be, that entire filter board could be enclosed to prevent any problems from the environment. Icom used that sort of semi-conductor switching for ease of overall parts cost along with reduced labor costs to Icom. Such work fine at the LOW impedances involved (50 to 75 Ohms) but I've tried to duplicate that at 10 KOhms on a breadboard and have run into problems with diodes' own impedances affecting circuit operation. Those could be solved, I'm sure, but I didn't care to spend weeks fiddling with them for my rebuild project. The relay contact set had only the shunt capacity and series inductance to contend with and those were very low values and easily compensated for alignment. Yeah, anything above 1K or so is less suitable for diodes. That's where JFETs come in which, in turn, are not so hot for anything low impedance. Unless you use the fat expensive kind and they've got too high capacitances. Many fine FETs like the P8000 have gone over the rainbow bridge by now. I guess they only found homes in ham gear and that wasn't a large enough market. -- 73, Joerg |
Was my father's homebrew double conversion SW receiver a HBR?
On Mar 23, 3:32�pm, Joerg
wrote: AF6AY wrote: On Mar 21, 4:31 pm, Joerg wrote: AF6AY wrote: "Joerg" posted on Fri, Mar 20 2009 6:06 pm ken scharf wrote: JIMMIE wrote: Relays are ok in those applications, where there are actual currents flowing. What I meant was pure signal switching with no DC currents. That's called "dry" switching in the electronics industry, has been called that for over a half century. Sealed relays, Reeds, mercury-wetted and such work quite well there. But non-sealed versions have issues and a snap-on plastic cap ain't a seal.. Didn't say that that it was a seal. �But...there are many kinds of 'seals' and there are many kinds of contact alloys which few hobbyists investigate. Most must make do with whatever places such as Digikey offer at affordable cost. I disagree considering that Digikey is one of the largest distributors in the world of electronics and offers so many different models AND price ranges. Then there is Mouser, and Newark, and Allied, and Jameco, and Ocean State, and Futurlec, and....a whole bunch of them. None of those are 'giving away' anything. Sure, but in a car relays always switch something that draws a serious current, more than a few milliamps. That works for a long time. Well, until a "weld wart" shows up, like it did on a relay in out Genie garage door opener. I will disagree again, but not on our particular Chevrolet...I only got a glance at the electronics wiring manual at a local dealership service shop and NOT all the controlled circuits were "serious current" ones. But, if you are convinced that they ALL are, I can't convince you... Hmm, I've had that happen even in $xxxxx lab gear, not quite consumer-grade. Never really with mil gear though but those guys can often design to "the sky's the limit" cost goals. Sorry, but that is URBAN MYTH among amateurs. What amateurs don't realize is that components are elevated in cost by EXTREME ENVIRONMENTS required. Sure, everything at room temperature works dandy and one can use any kind of schlock parts and get away with it. Freeze it below brass-monkey temps or heat it more than boiling water, drop-kick it across the room, run it under extreme vibration, it MUST WORK. Put most ham gear through that and you won't have enough left to sell anything but its manuals on e-bay. Been there, done that for years...its what I did for a living. ----------------on the AN/PRC-104 HF transceiver But I bet no expense was spared to pick the very best parts for that radio. I'll bet you've never seen the inside of it, let alone talk with any of the staff at Hughes Ground Systems that designed it. If you want to investigate it, the TMs (user to depot level) are available on the 'Web. Hard to find and you may need special clearance to access some military sites nowadays, but it is available for nothing. If you want to pay money for such a manual, fine, those are easier to get. Sealed relays are ok. Thank you for such permission. I was using salvaged components from junkyard electronics a half-century old and know how to test things that are salvaged. Note: I'm not just making conversation here, I'm trying to point out a few things which defy Urban Myth and what the ARRL deems 'useful' for amateurs. I also have a few really old ones here and so far they have never let me down. But I don't have enough to equip a filter bank with 15-20 in- and outputs. For that I've got a stash of HSMP-3810 PIN diodes. I'm not swayed or impressed by a bunch of house numbers. Neither do I need over a dozen different things switching in/out. For that matter, I've tried out 3-penny-apiece 1N4148 diodes (100-lot price), plain old ordinary old-fashioned silicon switching diodes and they could work just fine for 4 different HF circuits...but NOT easily for B+ at 100 VDC...and they need more circuitry for controlling them than just relay coils needing only a back- EMF clamp diode. But, what the hey, if you are convinced in only your way of doing things, fine, go do it. Excuse me, I'm going off-line and spend some quality workshop time putting some hardware together. QRT. 73, Len AF6AY |
Was my father's homebrew double conversion SW receiver a HBR?
AF6AY wrote:
On Mar 23, 3:32�pm, Joerg wrote: AF6AY wrote: On Mar 21, 4:31 pm, Joerg wrote: AF6AY wrote: "Joerg" posted on Fri, Mar 20 2009 6:06 pm ken scharf wrote: JIMMIE wrote: Relays are ok in those applications, where there are actual currents flowing. What I meant was pure signal switching with no DC currents. That's called "dry" switching in the electronics industry, has been called that for over a half century. Sealed relays, Reeds, mercury-wetted and such work quite well there. But non-sealed versions have issues and a snap-on plastic cap ain't a seal. Didn't say that that it was a seal. �But...there are many kinds of 'seals' and there are many kinds of contact alloys which few hobbyists investigate. Most must make do with whatever places such as Digikey offer at affordable cost. I disagree considering that Digikey is one of the largest distributors in the world of electronics and offers so many different models AND price ranges. Then there is Mouser, and Newark, and Allied, and Jameco, and Ocean State, and Futurlec, and....a whole bunch of them. None of those are 'giving away' anything. Sorry, maybe I didn't express it well enough. My point was that not everyone has a mil budget or a Rockefeller-sized bank account ;-) Sure, but in a car relays always switch something that draws a serious current, more than a few milliamps. That works for a long time. Well, until a "weld wart" shows up, like it did on a relay in out Genie garage door opener. I will disagree again, but not on our particular Chevrolet...I only got a glance at the electronics wiring manual at a local dealership service shop and NOT all the controlled circuits were "serious current" ones. But, if you are convinced that they ALL are, I can't convince you... Interesting, my car doesn't have that. Now I am curious. What are they switching in a car where there is no DC current? Hmm, I've had that happen even in $xxxxx lab gear, not quite consumer-grade. Never really with mil gear though but those guys can often design to "the sky's the limit" cost goals. Sorry, but that is URBAN MYTH among amateurs. What amateurs don't realize is that components are elevated in cost by EXTREME ENVIRONMENTS required. Sure, everything at room temperature works dandy and one can use any kind of schlock parts and get away with it. Freeze it below brass-monkey temps or heat it more than boiling water, drop-kick it across the room, run it under extreme vibration, it MUST WORK. Put most ham gear through that and you won't have enough left to sell anything but its manuals on e-bay. Been there, done that for years...its what I did for a living. As I said this was high-Dollar lab gear. The kind where they don't even flinch when an engineer says "this needs a piece of rigid coax". ----------------on the AN/PRC-104 HF transceiver But I bet no expense was spared to pick the very best parts for that radio. I'll bet you've never seen the inside of it, let alone talk with any of the staff at Hughes Ground Systems that designed it. If you want to investigate it, the TMs (user to depot level) are available on the 'Web. I've served (army), had to deal with radio/telco equipment. Cleaned many relays there with Emery paper and alcohol. There is a reason for instructions like this: http://www.ansaldo-sts.com/EN/Ansald...y_Cleaning.pdf Hard to find and you may need special clearance to access some military sites nowadays, but it is available for nothing. If you want to pay money for such a manual, fine, those are easier to get. Sealed relays are ok. Thank you for such permission. I was using salvaged components from junkyard electronics a half-century old and know how to test things that are salvaged. Note: I'm not just making conversation here, I'm trying to point out a few things which defy Urban Myth and what the ARRL deems 'useful' for amateurs. I also have a few really old ones here and so far they have never let me down. But I don't have enough to equip a filter bank with 15-20 in- and outputs. For that I've got a stash of HSMP-3810 PIN diodes. I'm not swayed or impressed by a bunch of house numbers. Neither do I need over a dozen different things switching in/out. For that matter, I've tried out 3-penny-apiece 1N4148 diodes (100-lot price), plain old ordinary old-fashioned silicon switching diodes and they could work just fine for 4 different HF circuits...but NOT easily for B+ at 100 VDC...and they need more circuitry for controlling them than just relay coils needing only a back- EMF clamp diode. Yep, usually a resistor plus on occasion a choke in series with it, and enough voltage to be able to be able to reverse the diodes far enough. But, what the hey, if you are convinced in only your way of doing things, fine, go do it. Excuse me, I'm going off-line and spend some quality workshop time putting some hardware together. QRT. Have fun :-) I am going to have to repair a bench supply that blew its power transistors way down in there. Not much fun. -- 73, Joerg |
Was my father's homebrew double conversion SW receiver a HBR?
Joerg wrote:
JIMMIE wrote: On Mar 21, 5:11 pm, Joerg wrote: JIMMIE wrote: On Mar 20, 6:47 pm, ken scharf wrote: JIMMIE wrote: On Mar 18, 9:24 pm, Robert casey wrote: The design used plug-in coils for the osc and rf stages, and they were double conversion designs, with a first IF of 1600 kc and a second IF of either 100 kc or 85 kc (when using surplus ARC-5 IFTs.) The 1800 mc xtal you bought your dad was used for the second coversion osc. to convert the 1600 kc IF down to 100 kc. Many hams deviated from the exact original IF frequencies (i.e. strong local BC station on 1600 kc) which might explain why the xtal was chosen for 1800 kc instead of 1500 or 1700. We have a local mid power station at 1600KHz, WWRL, at my parents' house, so my father might have wanted to avoid problems with it. His radio had a bandswitch instead of plug in coils, and he'd receive various broadcast SW stations. He wasn't a ham at the time just yet. I had a friend who was a retired engineer with GE turned TV tech who built one with a band switch and he later modified it to be more of a general purpose SW receiver. His name was Olin Griggs. Jimmie. I once saw an article in 73 magazine showing a HB receiver that used a re-worked turret tv tuner as a band switch. The coils were re-wound onto the original forms, but some have just replaced the forms with some of the smaller sized toroid cores. I have a bunch of old tv tuners in the junk box, but over the years the contacts have gone bad and now show a high resistance. Maybe they could be cleaned up, but it no longer seems worth the effort. My new idea is to use miniature relays to switch the circuits. I recently found nearly a gross of small relays for free so why not?- Hide quoted text - - Show quoted text - I tried the TV tuner trick one time and it didnt work well at all. Most tuners are tossed because the contacts fail. ... Not really. Back then TVs were often tossed because the flyback xfmr had blown and repair was deemed uneconomical. Or someone said that because in reality they wanted that brand spanking new set that was one sale. But this is so long ago that if there's any left the contacts will have corrodes away. [...] -- 73, Joerg- Hide quoted text - - Show quoted text - You must be younger than me, Ive replaced a lot of TV tuners and flybacks. It was in the early 80s that i first noticed TVs becoming diposable and quit working on them. Luckily for me there was still a lot of other electtronic repair work needed to be done. Most of the local industry was becoming more electronic oriented in their equipment and needed someone to maintain their equipment but did not want to hire a full time tech. The sawmills, textile plants, food processing plants kept me pretty busy aand i enjoyed the work much more not having to deal with the usual customers. Same here, in the early 80's I began to refuse fixing TVs and stuff. But even before that, I remember the flyback transformers for some sets being so outrageously expensive that a repair plain didn't make sense. Especially if it had taken out the H-deflection tube and some other stuff with it or the set itself had already been quite tired at the time it hissed its good-bye. This was in Europe. I once fixed my parents tv by replacing the yoke, and I more recently fixed my wife's tv set by replacing the flyback (AND the horizontal output transistor). The first set was a tube type Zenith B&W 19" portable. The second was a Trinitron color portable. I think you still can get replacement yokes, flybacks, and even CRT's for recent tv's. Good luck getting anything else! |
Was my father's homebrew double conversion SW receiver a HBR?
ken scharf wrote:
Joerg wrote: JIMMIE wrote: On Mar 21, 5:11 pm, Joerg wrote: JIMMIE wrote: On Mar 20, 6:47 pm, ken scharf wrote: JIMMIE wrote: On Mar 18, 9:24 pm, Robert casey wrote: The design used plug-in coils for the osc and rf stages, and they were double conversion designs, with a first IF of 1600 kc and a second IF of either 100 kc or 85 kc (when using surplus ARC-5 IFTs.) The 1800 mc xtal you bought your dad was used for the second coversion osc. to convert the 1600 kc IF down to 100 kc. Many hams deviated from the exact original IF frequencies (i.e. strong local BC station on 1600 kc) which might explain why the xtal was chosen for 1800 kc instead of 1500 or 1700. We have a local mid power station at 1600KHz, WWRL, at my parents' house, so my father might have wanted to avoid problems with it. His radio had a bandswitch instead of plug in coils, and he'd receive various broadcast SW stations. He wasn't a ham at the time just yet. I had a friend who was a retired engineer with GE turned TV tech who built one with a band switch and he later modified it to be more of a general purpose SW receiver. His name was Olin Griggs. Jimmie. I once saw an article in 73 magazine showing a HB receiver that used a re-worked turret tv tuner as a band switch. The coils were re-wound onto the original forms, but some have just replaced the forms with some of the smaller sized toroid cores. I have a bunch of old tv tuners in the junk box, but over the years the contacts have gone bad and now show a high resistance. Maybe they could be cleaned up, but it no longer seems worth the effort. My new idea is to use miniature relays to switch the circuits. I recently found nearly a gross of small relays for free so why not?- Hide quoted text - - Show quoted text - I tried the TV tuner trick one time and it didnt work well at all. Most tuners are tossed because the contacts fail. ... Not really. Back then TVs were often tossed because the flyback xfmr had blown and repair was deemed uneconomical. Or someone said that because in reality they wanted that brand spanking new set that was one sale. But this is so long ago that if there's any left the contacts will have corrodes away. [...] -- 73, Joerg- Hide quoted text - - Show quoted text - You must be younger than me, Ive replaced a lot of TV tuners and flybacks. It was in the early 80s that i first noticed TVs becoming diposable and quit working on them. Luckily for me there was still a lot of other electtronic repair work needed to be done. Most of the local industry was becoming more electronic oriented in their equipment and needed someone to maintain their equipment but did not want to hire a full time tech. The sawmills, textile plants, food processing plants kept me pretty busy aand i enjoyed the work much more not having to deal with the usual customers. Same here, in the early 80's I began to refuse fixing TVs and stuff. But even before that, I remember the flyback transformers for some sets being so outrageously expensive that a repair plain didn't make sense. Especially if it had taken out the H-deflection tube and some other stuff with it or the set itself had already been quite tired at the time it hissed its good-bye. This was in Europe. I once fixed my parents tv by replacing the yoke, and I more recently fixed my wife's tv set by replacing the flyback (AND the horizontal output transistor). The first set was a tube type Zenith B&W 19" portable. The second was a Trinitron color portable. I think you still can get replacement yokes, flybacks, and even CRT's for recent tv's. Good luck getting anything else! I think the real challenge will come when one of those monstrous LCD TV sets goes on the fritz and it's anything other than the backlight inverter that died. -- 73, Joerg |
Was my father's homebrew double conversion SW receiver a HBR?
Joerg wrote:
ken scharf wrote: Joerg wrote: JIMMIE wrote: On Mar 21, 5:11 pm, Joerg wrote: JIMMIE wrote: On Mar 20, 6:47 pm, ken scharf wrote: JIMMIE wrote: On Mar 18, 9:24 pm, Robert casey wrote: The design used plug-in coils for the osc and rf stages, and they were double conversion designs, with a first IF of 1600 kc and a second IF of either 100 kc or 85 kc (when using surplus ARC-5 IFTs.) The 1800 mc xtal you bought your dad was used for the second coversion osc. to convert the 1600 kc IF down to 100 kc. Many hams deviated from the exact original IF frequencies (i.e. strong local BC station on 1600 kc) which might explain why the xtal was chosen for 1800 kc instead of 1500 or 1700. We have a local mid power station at 1600KHz, WWRL, at my parents' house, so my father might have wanted to avoid problems with it. His radio had a bandswitch instead of plug in coils, and he'd receive various broadcast SW stations. He wasn't a ham at the time just yet. I had a friend who was a retired engineer with GE turned TV tech who built one with a band switch and he later modified it to be more of a general purpose SW receiver. His name was Olin Griggs. Jimmie. I once saw an article in 73 magazine showing a HB receiver that used a re-worked turret tv tuner as a band switch. The coils were re-wound onto the original forms, but some have just replaced the forms with some of the smaller sized toroid cores. I have a bunch of old tv tuners in the junk box, but over the years the contacts have gone bad and now show a high resistance. Maybe they could be cleaned up, but it no longer seems worth the effort. My new idea is to use miniature relays to switch the circuits. I recently found nearly a gross of small relays for free so why not?- Hide quoted text - - Show quoted text - I tried the TV tuner trick one time and it didnt work well at all. Most tuners are tossed because the contacts fail. ... Not really. Back then TVs were often tossed because the flyback xfmr had blown and repair was deemed uneconomical. Or someone said that because in reality they wanted that brand spanking new set that was one sale. But this is so long ago that if there's any left the contacts will have corrodes away. [...] -- 73, Joerg- Hide quoted text - - Show quoted text - You must be younger than me, Ive replaced a lot of TV tuners and flybacks. It was in the early 80s that i first noticed TVs becoming diposable and quit working on them. Luckily for me there was still a lot of other electtronic repair work needed to be done. Most of the local industry was becoming more electronic oriented in their equipment and needed someone to maintain their equipment but did not want to hire a full time tech. The sawmills, textile plants, food processing plants kept me pretty busy aand i enjoyed the work much more not having to deal with the usual customers. Same here, in the early 80's I began to refuse fixing TVs and stuff. But even before that, I remember the flyback transformers for some sets being so outrageously expensive that a repair plain didn't make sense. Especially if it had taken out the H-deflection tube and some other stuff with it or the set itself had already been quite tired at the time it hissed its good-bye. This was in Europe. I once fixed my parents tv by replacing the yoke, and I more recently fixed my wife's tv set by replacing the flyback (AND the horizontal output transistor). The first set was a tube type Zenith B&W 19" portable. The second was a Trinitron color portable. I think you still can get replacement yokes, flybacks, and even CRT's for recent tv's. Good luck getting anything else! I think the real challenge will come when one of those monstrous LCD TV sets goes on the fritz and it's anything other than the backlight inverter that died. The backlight itself is actually part of the LCD panel in most cases, so when that dies, you need to replace the panel, which means the tv is toast. Most of the other parts are low power, except for the panel drivers, which themselves may be part of the panel! |
Was my father's homebrew double conversion SW receiver a HBR?
ken scharf wrote:
Joerg wrote: ken scharf wrote: Joerg wrote: JIMMIE wrote: On Mar 21, 5:11 pm, Joerg wrote: JIMMIE wrote: On Mar 20, 6:47 pm, ken scharf wrote: JIMMIE wrote: On Mar 18, 9:24 pm, Robert casey wrote: The design used plug-in coils for the osc and rf stages, and they were double conversion designs, with a first IF of 1600 kc and a second IF of either 100 kc or 85 kc (when using surplus ARC-5 IFTs.) The 1800 mc xtal you bought your dad was used for the second coversion osc. to convert the 1600 kc IF down to 100 kc. Many hams deviated from the exact original IF frequencies (i.e. strong local BC station on 1600 kc) which might explain why the xtal was chosen for 1800 kc instead of 1500 or 1700. We have a local mid power station at 1600KHz, WWRL, at my parents' house, so my father might have wanted to avoid problems with it. His radio had a bandswitch instead of plug in coils, and he'd receive various broadcast SW stations. He wasn't a ham at the time just yet. I had a friend who was a retired engineer with GE turned TV tech who built one with a band switch and he later modified it to be more of a general purpose SW receiver. His name was Olin Griggs. Jimmie. I once saw an article in 73 magazine showing a HB receiver that used a re-worked turret tv tuner as a band switch. The coils were re-wound onto the original forms, but some have just replaced the forms with some of the smaller sized toroid cores. I have a bunch of old tv tuners in the junk box, but over the years the contacts have gone bad and now show a high resistance. Maybe they could be cleaned up, but it no longer seems worth the effort. My new idea is to use miniature relays to switch the circuits. I recently found nearly a gross of small relays for free so why not?- Hide quoted text - - Show quoted text - I tried the TV tuner trick one time and it didnt work well at all. Most tuners are tossed because the contacts fail. ... Not really. Back then TVs were often tossed because the flyback xfmr had blown and repair was deemed uneconomical. Or someone said that because in reality they wanted that brand spanking new set that was one sale. But this is so long ago that if there's any left the contacts will have corrodes away. [...] -- 73, Joerg- Hide quoted text - - Show quoted text - You must be younger than me, Ive replaced a lot of TV tuners and flybacks. It was in the early 80s that i first noticed TVs becoming diposable and quit working on them. Luckily for me there was still a lot of other electtronic repair work needed to be done. Most of the local industry was becoming more electronic oriented in their equipment and needed someone to maintain their equipment but did not want to hire a full time tech. The sawmills, textile plants, food processing plants kept me pretty busy aand i enjoyed the work much more not having to deal with the usual customers. Same here, in the early 80's I began to refuse fixing TVs and stuff. But even before that, I remember the flyback transformers for some sets being so outrageously expensive that a repair plain didn't make sense. Especially if it had taken out the H-deflection tube and some other stuff with it or the set itself had already been quite tired at the time it hissed its good-bye. This was in Europe. I once fixed my parents tv by replacing the yoke, and I more recently fixed my wife's tv set by replacing the flyback (AND the horizontal output transistor). The first set was a tube type Zenith B&W 19" portable. The second was a Trinitron color portable. I think you still can get replacement yokes, flybacks, and even CRT's for recent tv's. Good luck getting anything else! I think the real challenge will come when one of those monstrous LCD TV sets goes on the fritz and it's anything other than the backlight inverter that died. The backlight itself is actually part of the LCD panel in most cases, so when that dies, you need to replace the panel, which means the tv is toast. Often you can get to that inverter. Then if you are lucky it's the two transistors. If not it's usually the transformer and then the catalog chase begins. Most of the other parts are low power, except for the panel drivers, which themselves may be part of the panel! Got to be careful. I've designed a HV generator with CCFL transformers for a client last year. Guess who was the first one it bit? The remainder of those TVs is often largely high integration. DSPs, special video chips, memory, FPGA, ASICs. Very hard to debug because they won't give you any technical documents, usually. -- 73, Joerg |
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