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ARC 5 Transmitter
Someone gave me an old ARC 5 (7-9.1) transmitter found at the county
dump. I would like to see if I can get it going on 40 meter CW. I have found some information online, namely a schematic and an article for "converting to Amateur use". I realize this is a crap shoot, but I think it would be fun trying. I am trying to verify the wiring according to this old schematic knowing that so many units have been hacked into over the years. I have put together a power supply along the lines of the reprinted "converting" article available at the ARRL website. The Xtal in this unit is 8870 KC. Is this OK? How does this Xtal function in this otherwise VFO unit, and what determines the frequency that was chosen for this xtal? Other information or sources of information would be welcome. Anyone else have any luck with these things? Any recommendations? Bill K6TAJ |
Bill posted:
Someone gave me an old ARC 5 (7-9.1) transmitter found at the county dump. I would like to see if I can get it going on 40 meter CW. I have found some information online, namely a schematic and an article for "converting to Amateur use". I realize this is a crap shoot, but I think it would be fun trying. I am trying to verify the wiring according to this old schematic knowing that so many units have been hacked into over the years. I have put together a power supply along the lines of the reprinted "converting" article available at the ARRL website. The Xtal in this unit is 8870 KC. Is this OK? How does this Xtal function in this otherwise VFO unit, and what determines the frequency that was chosen for this xtal? Other information or sources of information would be welcome. Anyone else have any luck with these things? Any recommendations? You should not have any strange problems getting it running. The xtal was selected for each mission. The crystal is used as a reference for setting the VFO frequency. In the check position, the VFO and crystal oscillator are both on, and when the vfo comes close to the crystal freq you will see the affect on the tuning eye. Have a ball. Don |
Bill posted:
Someone gave me an old ARC 5 (7-9.1) transmitter found at the county dump. I would like to see if I can get it going on 40 meter CW. I have found some information online, namely a schematic and an article for "converting to Amateur use". I realize this is a crap shoot, but I think it would be fun trying. I am trying to verify the wiring according to this old schematic knowing that so many units have been hacked into over the years. I have put together a power supply along the lines of the reprinted "converting" article available at the ARRL website. The Xtal in this unit is 8870 KC. Is this OK? How does this Xtal function in this otherwise VFO unit, and what determines the frequency that was chosen for this xtal? Other information or sources of information would be welcome. Anyone else have any luck with these things? Any recommendations? You should not have any strange problems getting it running. The xtal was selected for each mission. The crystal is used as a reference for setting the VFO frequency. In the check position, the VFO and crystal oscillator are both on, and when the vfo comes close to the crystal freq you will see the affect on the tuning eye. Have a ball. Don |
Tnx, Oh, I see, you calibrate the tuning dial by using the Xtal as a reference
knowing it is at the stated Xtal frequency when the magic eye peaks. I assume you use the little knob next to the dial for this tweaking? or do you loosen the dial and re-set it according to this calibration? Bill K6TAJ Dbowey wrote: Bill posted: Someone gave me an old ARC 5 (7-9.1) transmitter found at the county dump. I would like to see if I can get it going on 40 meter CW. I have found some information online, namely a schematic and an article for "converting to Amateur use". I realize this is a crap shoot, but I think it would be fun trying. I am trying to verify the wiring according to this old schematic knowing that so many units have been hacked into over the years. I have put together a power supply along the lines of the reprinted "converting" article available at the ARRL website. The Xtal in this unit is 8870 KC. Is this OK? How does this Xtal function in this otherwise VFO unit, and what determines the frequency that was chosen for this xtal? Other information or sources of information would be welcome. Anyone else have any luck with these things? Any recommendations? You should not have any strange problems getting it running. The xtal was selected for each mission. The crystal is used as a reference for setting the VFO frequency. In the check position, the VFO and crystal oscillator are both on, and when the vfo comes close to the crystal freq you will see the affect on the tuning eye. Have a ball. Don |
Tnx, Oh, I see, you calibrate the tuning dial by using the Xtal as a reference
knowing it is at the stated Xtal frequency when the magic eye peaks. I assume you use the little knob next to the dial for this tweaking? or do you loosen the dial and re-set it according to this calibration? Bill K6TAJ Dbowey wrote: Bill posted: Someone gave me an old ARC 5 (7-9.1) transmitter found at the county dump. I would like to see if I can get it going on 40 meter CW. I have found some information online, namely a schematic and an article for "converting to Amateur use". I realize this is a crap shoot, but I think it would be fun trying. I am trying to verify the wiring according to this old schematic knowing that so many units have been hacked into over the years. I have put together a power supply along the lines of the reprinted "converting" article available at the ARRL website. The Xtal in this unit is 8870 KC. Is this OK? How does this Xtal function in this otherwise VFO unit, and what determines the frequency that was chosen for this xtal? Other information or sources of information would be welcome. Anyone else have any luck with these things? Any recommendations? You should not have any strange problems getting it running. The xtal was selected for each mission. The crystal is used as a reference for setting the VFO frequency. In the check position, the VFO and crystal oscillator are both on, and when the vfo comes close to the crystal freq you will see the affect on the tuning eye. Have a ball. Don |
Tnx, Oh, I see, you calibrate the tuning dial by using the Xtal as a reference knowing it is at the stated Xtal frequency when the magic eye peaks. I assume you use the little knob next to the dial for this tweaking? or do you loosen the dial and re-set it according to this calibration? Just turn the vfo freqency knob to see the zero beat, then lock it. In ham use you would not usually use the crystal check/set feature, but you could. The crystal's socket probably would accept an FT243 mounted crystal. Don |
Tnx, Oh, I see, you calibrate the tuning dial by using the Xtal as a reference knowing it is at the stated Xtal frequency when the magic eye peaks. I assume you use the little knob next to the dial for this tweaking? or do you loosen the dial and re-set it according to this calibration? Just turn the vfo freqency knob to see the zero beat, then lock it. In ham use you would not usually use the crystal check/set feature, but you could. The crystal's socket probably would accept an FT243 mounted crystal. Don |
Bill, There is also a tuning eye tube in back of xmtr , the Xtal and
tuning eye is used to calibrate the VFO .You won`t need the Xtal or eye tube for ham use.. I used an Arc 5 about 60 years ago on 40 mtrs. I had pretty good output BUT it chirped like all crazy..there were several schemes to get the chirp out, none of them worked very well..If you can get the VFO to key without chirping it will be all OK. Good luck 73 Harold W4PQW |
Bill, There is also a tuning eye tube in back of xmtr , the Xtal and
tuning eye is used to calibrate the VFO .You won`t need the Xtal or eye tube for ham use.. I used an Arc 5 about 60 years ago on 40 mtrs. I had pretty good output BUT it chirped like all crazy..there were several schemes to get the chirp out, none of them worked very well..If you can get the VFO to key without chirping it will be all OK. Good luck 73 Harold W4PQW |
The ARC-5 transmitter is one of the great piece of electronics out of WWII.
As a kid, my first transmitter was an ARC-5 bought from JJ Glass of Los Angeles for about $5.95. It was brand new and a beauty to behold. Getting it working right will teach you everything that you need to know about electronics (well as of 1957 anyway). I was able to get mine to key nicely with no chirp at all. I still have a wall full of them, they are nice to look at. You should be able to find a schematic on the internet. I found that adjusting the oscillator plate voltage to the individual transmitter could help solve a lot of problems and regulated dc on the filaments does wonders, too. They will run 100 watts without too much strain, although the power supplyis often twice the size of the transmitter. But, they also run qrp on a much smaller supply and lower voltage. Have fun, Colin K7FM --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04 |
The ARC-5 transmitter is one of the great piece of electronics out of WWII.
As a kid, my first transmitter was an ARC-5 bought from JJ Glass of Los Angeles for about $5.95. It was brand new and a beauty to behold. Getting it working right will teach you everything that you need to know about electronics (well as of 1957 anyway). I was able to get mine to key nicely with no chirp at all. I still have a wall full of them, they are nice to look at. You should be able to find a schematic on the internet. I found that adjusting the oscillator plate voltage to the individual transmitter could help solve a lot of problems and regulated dc on the filaments does wonders, too. They will run 100 watts without too much strain, although the power supplyis often twice the size of the transmitter. But, they also run qrp on a much smaller supply and lower voltage. Have fun, Colin K7FM --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04 |
Thanks to everyone for the encouragement. Next step is to make the conversion
to this little power supply, then tweak that oscillator plate voltage etc. and see if I can get it on the air. I have already decided not to worry about keeping this thing "original", eg. will be putting in a new power plug, key jack, and coax connector etc. I am sure I will have many more questions as I proceed and will keep you posted with the progress and inevitable mysteries that will need solving.... Why do you think the regulated dc on the filaments makes such a difference? Closer to the original battery powered situation? Would that be true for any old tube transmitter? Or because these particularly were originally designed to run on 28 volt DC. Bill, K6TAJ COLIN LAMB wrote: The ARC-5 transmitter is one of the great piece of electronics out of WWII. As a kid, my first transmitter was an ARC-5 bought from JJ Glass of Los Angeles for about $5.95. It was brand new and a beauty to behold. Getting it working right will teach you everything that you need to know about electronics (well as of 1957 anyway). I was able to get mine to key nicely with no chirp at all. I still have a wall full of them, they are nice to look at. You should be able to find a schematic on the internet. I found that adjusting the oscillator plate voltage to the individual transmitter could help solve a lot of problems and regulated dc on the filaments does wonders, too. They will run 100 watts without too much strain, although the power supplyis often twice the size of the transmitter. But, they also run qrp on a much smaller supply and lower voltage. Have fun, Colin K7FM --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04 |
Thanks to everyone for the encouragement. Next step is to make the conversion
to this little power supply, then tweak that oscillator plate voltage etc. and see if I can get it on the air. I have already decided not to worry about keeping this thing "original", eg. will be putting in a new power plug, key jack, and coax connector etc. I am sure I will have many more questions as I proceed and will keep you posted with the progress and inevitable mysteries that will need solving.... Why do you think the regulated dc on the filaments makes such a difference? Closer to the original battery powered situation? Would that be true for any old tube transmitter? Or because these particularly were originally designed to run on 28 volt DC. Bill, K6TAJ COLIN LAMB wrote: The ARC-5 transmitter is one of the great piece of electronics out of WWII. As a kid, my first transmitter was an ARC-5 bought from JJ Glass of Los Angeles for about $5.95. It was brand new and a beauty to behold. Getting it working right will teach you everything that you need to know about electronics (well as of 1957 anyway). I was able to get mine to key nicely with no chirp at all. I still have a wall full of them, they are nice to look at. You should be able to find a schematic on the internet. I found that adjusting the oscillator plate voltage to the individual transmitter could help solve a lot of problems and regulated dc on the filaments does wonders, too. They will run 100 watts without too much strain, although the power supplyis often twice the size of the transmitter. But, they also run qrp on a much smaller supply and lower voltage. Have fun, Colin K7FM --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04 |
why would you not need to use the Xtal to calibrate the VFO for ham use?
Bill K6TAJ wrote: Bill, There is also a tuning eye tube in back of xmtr , the Xtal and tuning eye is used to calibrate the VFO .You won`t need the Xtal or eye tube for ham use.. I used an Arc 5 about 60 years ago on 40 mtrs. I had pretty good output BUT it chirped like all crazy..there were several schemes to get the chirp out, none of them worked very well..If you can get the VFO to key without chirping it will be all OK. Good luck 73 Harold W4PQW |
why would you not need to use the Xtal to calibrate the VFO for ham use?
Bill K6TAJ wrote: Bill, There is also a tuning eye tube in back of xmtr , the Xtal and tuning eye is used to calibrate the VFO .You won`t need the Xtal or eye tube for ham use.. I used an Arc 5 about 60 years ago on 40 mtrs. I had pretty good output BUT it chirped like all crazy..there were several schemes to get the chirp out, none of them worked very well..If you can get the VFO to key without chirping it will be all OK. Good luck 73 Harold W4PQW |
zeno wrote:
why would you not need to use the Xtal to calibrate the VFO for ham use? Bill K6TAJ On the 6-9MHz one I had many moons ago the xtal cal point was up at the top end, close to 9 MHz and didn't serve much of a purpose for exact 7 MHz calibration. Of course I was *supposed* to be using xtals as a Novice :-) It would be preferable just to accurately set the dial at 7MHz. Once its set its very accurate. Its will be as exact as you can interpolate across the little swath of the 40 CW band. -Bill |
zeno wrote:
why would you not need to use the Xtal to calibrate the VFO for ham use? Bill K6TAJ On the 6-9MHz one I had many moons ago the xtal cal point was up at the top end, close to 9 MHz and didn't serve much of a purpose for exact 7 MHz calibration. Of course I was *supposed* to be using xtals as a Novice :-) It would be preferable just to accurately set the dial at 7MHz. Once its set its very accurate. Its will be as exact as you can interpolate across the little swath of the 40 CW band. -Bill |
Question: "Why do you think the regulated dc on the filaments makes such a
difference? Closer to the original battery powered situation? Would that be true for any old tube transmitter? Or because these particularly were originally designed to run on 28 volt DC." The oscillator obtains feedback by tapping the cathode up on the coil. This allows the ac on the filaments to modulate the oscillator slightly. A filament winding was added to reduce this effect, but it does not. Some ARC-5s have hum modulation - especially when multiplying to 10 meters. Also, a change in filament voltage causes drift of the vfo. When we were converting these rigs 50 years ago, it was difficult to get 24 volts regulated. Today it is a snap. It may be easier to get a regulated 13.8 volts (or 12 volts or anything in between). In my early hamshack, the test for stability was to switch on the heater and listen for drift about 30 seconds later. Even the heralded SX-101 would drift mightily on 10 meters when I did that trick - until I regulated the filament voltage on the oscillator using the separate transformer that always kept the heater on. 73, Colin K7FM --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04 |
Question: "Why do you think the regulated dc on the filaments makes such a
difference? Closer to the original battery powered situation? Would that be true for any old tube transmitter? Or because these particularly were originally designed to run on 28 volt DC." The oscillator obtains feedback by tapping the cathode up on the coil. This allows the ac on the filaments to modulate the oscillator slightly. A filament winding was added to reduce this effect, but it does not. Some ARC-5s have hum modulation - especially when multiplying to 10 meters. Also, a change in filament voltage causes drift of the vfo. When we were converting these rigs 50 years ago, it was difficult to get 24 volts regulated. Today it is a snap. It may be easier to get a regulated 13.8 volts (or 12 volts or anything in between). In my early hamshack, the test for stability was to switch on the heater and listen for drift about 30 seconds later. Even the heralded SX-101 would drift mightily on 10 meters when I did that trick - until I regulated the filament voltage on the oscillator using the separate transformer that always kept the heater on. 73, Colin K7FM --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/04 |
Nostalgia. When drafted into the Navy is 1943
my first job was setting up ARC-5 transmitters and receivers in 336 SNJ (AT-6) aircraft. (among other things) Later after the war when there wasn't much money around, I would rewind ARC-5 receivers and use them for ten-meter converters. In those days tapping on the case of just about any transmitter or receiver would produce some modulation. Except for Collins equipment. The ARC-5 VHF transmitters were truly awe inspiring when they arrived. 73s W6BWY |
Nostalgia. When drafted into the Navy is 1943
my first job was setting up ARC-5 transmitters and receivers in 336 SNJ (AT-6) aircraft. (among other things) Later after the war when there wasn't much money around, I would rewind ARC-5 receivers and use them for ten-meter converters. In those days tapping on the case of just about any transmitter or receiver would produce some modulation. Except for Collins equipment. The ARC-5 VHF transmitters were truly awe inspiring when they arrived. 73s W6BWY |
zeno wrote: I have already decided not to worry about keeping this thing "original", eg. will be putting in a new power plug, key jack, and coax connector etc.... It is certainly your radio and you can do as you wish, but I urge you to reconsider; this isn't a old Craig CB rig or and Eico 753. This radio has historic significance. Extensive modification is needless and will turn your historic relic into a junkbox nothing. You can get the rig on the air with a good signal without drilling a single hole or chopping out anything. It's as simple as disconnecting one wire and adjusting one relay contact. If you need pins to fit the power connector on the back, send me your address and I'll send you some. Moreover, if you do the butchery to put the filiments on 12 volts AC, you are defeating part of the engineering solution designed to keep the rigs stable. My rigs are original design and work great with good power out and little or no chirp. First- throw out ALL those "conversion" articles from the 50s, 60s and 70s. The first ones were written by people who knew nothing about getting these rigs going and the rest just parroted what the first wrote. I can't tell you how many rigs went from "war relic" to "trash can" because of some conversion "author." The rigs are NOT TVI machines, chirp factories, harmonic generators or any of the other myths you've heard. These were born out of people flailing around blindly without any understanding of how the rig was designed to work. I have lots of information on how to get these going with little work and no irreversable mods. I'm headed to work. If anyone cares to read them, I will post them when I get home this evening. 73 DE Dave Stinson AB5S |
zeno wrote: I have already decided not to worry about keeping this thing "original", eg. will be putting in a new power plug, key jack, and coax connector etc.... It is certainly your radio and you can do as you wish, but I urge you to reconsider; this isn't a old Craig CB rig or and Eico 753. This radio has historic significance. Extensive modification is needless and will turn your historic relic into a junkbox nothing. You can get the rig on the air with a good signal without drilling a single hole or chopping out anything. It's as simple as disconnecting one wire and adjusting one relay contact. If you need pins to fit the power connector on the back, send me your address and I'll send you some. Moreover, if you do the butchery to put the filiments on 12 volts AC, you are defeating part of the engineering solution designed to keep the rigs stable. My rigs are original design and work great with good power out and little or no chirp. First- throw out ALL those "conversion" articles from the 50s, 60s and 70s. The first ones were written by people who knew nothing about getting these rigs going and the rest just parroted what the first wrote. I can't tell you how many rigs went from "war relic" to "trash can" because of some conversion "author." The rigs are NOT TVI machines, chirp factories, harmonic generators or any of the other myths you've heard. These were born out of people flailing around blindly without any understanding of how the rig was designed to work. I have lots of information on how to get these going with little work and no irreversable mods. I'm headed to work. If anyone cares to read them, I will post them when I get home this evening. 73 DE Dave Stinson AB5S |
God bless you; you're just the man I'm looking for.
Do you have any idea what the MF ARC-5 transmitters were for? These are the rare : T-15, 500-800 KC T-16, 800-1300 KC T-17, 1300-2100 KC The latest theory is that they were used in joint maneuvers with third-world allied navies, where were still using the 1920s-agreed navy frequencies below 2 MC. There so much I would love to ask you about these sets, if you don't mind the trouble. I'm a serious historian of the Command Set series and gentlemen like yourself are a treasure to find. 73 DE Dave Stinson AB5S Spike wrote: Nostalgia. When drafted into the Navy is 1943 my first job was setting up ARC-5 transmitters and receivers in 336 SNJ (AT-6) aircraft. (among other things) Later after the war when there wasn't much money around, I would rewind ARC-5 receivers and use them for ten-meter converters. In those days tapping on the case of just about any transmitter or receiver would produce some modulation. Except for Collins equipment. The ARC-5 VHF transmitters were truly awe inspiring when they arrived. 73s W6BWY |
God bless you; you're just the man I'm looking for.
Do you have any idea what the MF ARC-5 transmitters were for? These are the rare : T-15, 500-800 KC T-16, 800-1300 KC T-17, 1300-2100 KC The latest theory is that they were used in joint maneuvers with third-world allied navies, where were still using the 1920s-agreed navy frequencies below 2 MC. There so much I would love to ask you about these sets, if you don't mind the trouble. I'm a serious historian of the Command Set series and gentlemen like yourself are a treasure to find. 73 DE Dave Stinson AB5S Spike wrote: Nostalgia. When drafted into the Navy is 1943 my first job was setting up ARC-5 transmitters and receivers in 336 SNJ (AT-6) aircraft. (among other things) Later after the war when there wasn't much money around, I would rewind ARC-5 receivers and use them for ten-meter converters. In those days tapping on the case of just about any transmitter or receiver would produce some modulation. Except for Collins equipment. The ARC-5 VHF transmitters were truly awe inspiring when they arrived. 73s W6BWY |
In article , zeno writes:
you calibrate the tuning dial by using the Xtal as a reference knowing it is at the stated Xtal frequency when the magic eye peaks. I assume you use the little knob next to the dial for this tweaking? or do you loosen the dial and re-set it according to this calibration? All the xtal tells you is whether the dial is close or not. Recalibration is a shop procedure. The dial is pinned - don't try to change it. The little knobs next to each control are locks to prevent the settings from changing in flight. 73 de Jim, N2EY |
In article , zeno writes:
you calibrate the tuning dial by using the Xtal as a reference knowing it is at the stated Xtal frequency when the magic eye peaks. I assume you use the little knob next to the dial for this tweaking? or do you loosen the dial and re-set it according to this calibration? All the xtal tells you is whether the dial is close or not. Recalibration is a shop procedure. The dial is pinned - don't try to change it. The little knobs next to each control are locks to prevent the settings from changing in flight. 73 de Jim, N2EY |
In article , zeno writes:
Someone gave me an old ARC 5 (7-9.1) transmitter found at the county dump. I would like to see if I can get it going on 40 meter CW. First question is: What condition is it in? If it's in original unmodified condition, or close to it, please don't hack it up. Unmodified ARC-5s *used to be* all over the place for low prices, and were often subjected to all sorts of modifications. Some mods were pretty good, most really weren't. IMHO, one that's survived this long in unmodified shape deserves to be preserved. If you don't want to keep it historically accurate, sell it to someone who does. There are plenty of hacked-up ones around to experiment with. OTOH, if it's been through the mods already (power socket changed, lots of extra holes, coils rewound, paint largely gone, etc.) it might be OK to mod it or use it as a parts source. I have found some information online, namely a schematic and an article for "converting to Amateur use". I realize this is a crap shoot, but I think it would be fun trying. I am trying to verify the wiring according to this old schematic knowing that so many units have been hacked into over the years. I have put together a power supply along the lines of the reprinted "converting" article available at the ARRL website. What does that conversion article show? There was an article in the ARRL Handbooks for years that involved building an external crystal oscillator in a minibox, using a 6AG7. Most of that article was pretty good because it didn't hack up the ARC-5 too much (but it did recommend destroying the power socket, unfortunately). The Xtal in this unit is 8870 KC. Is this OK? Not for ham operation! How does this Xtal function in this otherwise VFO unit, and what determines the frequency that was chosen for this xtal? It allowed the dial to be checked against one known point, using the 1629 magic-eye tube. This was a simple check that could be done in the plane to be sure that things weren't way off. ARC-5 transmitters (when used in small planes) were usually meant to be adjusted on the ground by a technician, who would then lock all the settings and the pilot would simply choose which transmitter to use. Other information or sources of information would be welcome. KG7BZ website, if it's still operational Anyone else have any luck with these things? Any recommendations? They are an excellent example of 1930s radio engineering at its very best. They did the job with a maximum of efficiency and a minimum of size, weight, complexity and cost. The receivers are even better. 73 de Jim, N2EY btw, about 12 years or so ago, a local ham showed me an intact BC-459. A little dusty but completely untouched. He found it on someone's trash, wanted to know if it was worth carting to the upcoming hamfest and if so, how much to ask. I said $25 and he thought I was nuts. It was the first thing he sold. |
In article , zeno writes:
Someone gave me an old ARC 5 (7-9.1) transmitter found at the county dump. I would like to see if I can get it going on 40 meter CW. First question is: What condition is it in? If it's in original unmodified condition, or close to it, please don't hack it up. Unmodified ARC-5s *used to be* all over the place for low prices, and were often subjected to all sorts of modifications. Some mods were pretty good, most really weren't. IMHO, one that's survived this long in unmodified shape deserves to be preserved. If you don't want to keep it historically accurate, sell it to someone who does. There are plenty of hacked-up ones around to experiment with. OTOH, if it's been through the mods already (power socket changed, lots of extra holes, coils rewound, paint largely gone, etc.) it might be OK to mod it or use it as a parts source. I have found some information online, namely a schematic and an article for "converting to Amateur use". I realize this is a crap shoot, but I think it would be fun trying. I am trying to verify the wiring according to this old schematic knowing that so many units have been hacked into over the years. I have put together a power supply along the lines of the reprinted "converting" article available at the ARRL website. What does that conversion article show? There was an article in the ARRL Handbooks for years that involved building an external crystal oscillator in a minibox, using a 6AG7. Most of that article was pretty good because it didn't hack up the ARC-5 too much (but it did recommend destroying the power socket, unfortunately). The Xtal in this unit is 8870 KC. Is this OK? Not for ham operation! How does this Xtal function in this otherwise VFO unit, and what determines the frequency that was chosen for this xtal? It allowed the dial to be checked against one known point, using the 1629 magic-eye tube. This was a simple check that could be done in the plane to be sure that things weren't way off. ARC-5 transmitters (when used in small planes) were usually meant to be adjusted on the ground by a technician, who would then lock all the settings and the pilot would simply choose which transmitter to use. Other information or sources of information would be welcome. KG7BZ website, if it's still operational Anyone else have any luck with these things? Any recommendations? They are an excellent example of 1930s radio engineering at its very best. They did the job with a maximum of efficiency and a minimum of size, weight, complexity and cost. The receivers are even better. 73 de Jim, N2EY btw, about 12 years or so ago, a local ham showed me an intact BC-459. A little dusty but completely untouched. He found it on someone's trash, wanted to know if it was worth carting to the upcoming hamfest and if so, how much to ask. I said $25 and he thought I was nuts. It was the first thing he sold. |
The BC-459-A found at the dump, is a bare aluminum Western Electric. It has been
already modified, the plug was already changed, a key jack put in the back, and a bunch of wiring mods which are incomprehensible to me. It is missing the 1629, the 1626, and the Xtal. I have since picked up another BC-459 (black) which seems to be internally unmodified and complete with all tubes and Xtal (8870 KC), although it is missing the bottom plate and the cover. It is a black, but It notice the case parts from the bare aluminum one would fit to this black one. I was also given an old homebrew power supply which still works and was apparently built to the specs that are described in the ARRL article about converting the Arc 5 for Novice use. This power supply has a male octal plug with wiring that exactly corresponds to this article, eg. it has the 12.6 V filament and a 6.3 V filament as well as all the B+ voltages as per the article. Yes this is the article which describes how to make an outboard crystal controlled oscillator with 6AG7 tube and which then plugs into the Xtal socket of the Arc 5. The modification is such that the Arc 5 can be put back to VFO operation simply by removing this outboard novice xtal unit and putting back the original Xtal. The wiring in this first BC-459 is a mess and has been hacked up, It was going to use this unit for parts, at least use the bottom plate and the case, even though it is bare aluminum and the better unit I have is black. The better unit, as stated, seems to be internally unmodified, so doing the mods in this article would be more straight forward. However, having now posted to this forum and having received the various suggestions, I am wondering what the best path might be here. First off, I do not understand how one would use the original plug in the back since I have never seen an original male fitting available anywhere. Secondly, I am wondering what kind of other power supply one would use to keep everything in its original context. In short I am wondering what is the best, and most practical way to get this thing operating. The only information on converstion that I have at this point is the the article which appears on the ARRL site "Coverting Surplus Transmitter for Novice Use" even though I was not going to build the outboard xtal unit as suggested. I would be interested in seeing other, perhaps superior, methods for putting this gear to use. Really, how bad is this particular article and its mod suggestions? It has been suggested that the addition of some regulation on the oscillator voltage would solve the problem of chirp/drift etc. I would be interested in the type of mods and power supplies that you are all using which have proven successful before I proceed any further. I am assuming there are plenty of these units preserved as museum pieces already, I was more interested in using it without necessarily turning the shack into a complete ww2 cockpit. Bill, K6TAJ David Stinson wrote: zeno wrote: I have already decided not to worry about keeping this thing "original", eg. will be putting in a new power plug, key jack, and coax connector etc.... It is certainly your radio and you can do as you wish, but I urge you to reconsider; this isn't a old Craig CB rig or and Eico 753. This radio has historic significance. Extensive modification is needless and will turn your historic relic into a junkbox nothing. You can get the rig on the air with a good signal without drilling a single hole or chopping out anything. It's as simple as disconnecting one wire and adjusting one relay contact. If you need pins to fit the power connector on the back, send me your address and I'll send you some. Moreover, if you do the butchery to put the filiments on 12 volts AC, you are defeating part of the engineering solution designed to keep the rigs stable. My rigs are original design and work great with good power out and little or no chirp. First- throw out ALL those "conversion" articles from the 50s, 60s and 70s. The first ones were written by people who knew nothing about getting these rigs going and the rest just parroted what the first wrote. I can't tell you how many rigs went from "war relic" to "trash can" because of some conversion "author." The rigs are NOT TVI machines, chirp factories, harmonic generators or any of the other myths you've heard. These were born out of people flailing around blindly without any understanding of how the rig was designed to work. I have lots of information on how to get these going with little work and no irreversable mods. I'm headed to work. If anyone cares to read them, I will post them when I get home this evening. 73 DE Dave Stinson AB5S |
The BC-459-A found at the dump, is a bare aluminum Western Electric. It has been
already modified, the plug was already changed, a key jack put in the back, and a bunch of wiring mods which are incomprehensible to me. It is missing the 1629, the 1626, and the Xtal. I have since picked up another BC-459 (black) which seems to be internally unmodified and complete with all tubes and Xtal (8870 KC), although it is missing the bottom plate and the cover. It is a black, but It notice the case parts from the bare aluminum one would fit to this black one. I was also given an old homebrew power supply which still works and was apparently built to the specs that are described in the ARRL article about converting the Arc 5 for Novice use. This power supply has a male octal plug with wiring that exactly corresponds to this article, eg. it has the 12.6 V filament and a 6.3 V filament as well as all the B+ voltages as per the article. Yes this is the article which describes how to make an outboard crystal controlled oscillator with 6AG7 tube and which then plugs into the Xtal socket of the Arc 5. The modification is such that the Arc 5 can be put back to VFO operation simply by removing this outboard novice xtal unit and putting back the original Xtal. The wiring in this first BC-459 is a mess and has been hacked up, It was going to use this unit for parts, at least use the bottom plate and the case, even though it is bare aluminum and the better unit I have is black. The better unit, as stated, seems to be internally unmodified, so doing the mods in this article would be more straight forward. However, having now posted to this forum and having received the various suggestions, I am wondering what the best path might be here. First off, I do not understand how one would use the original plug in the back since I have never seen an original male fitting available anywhere. Secondly, I am wondering what kind of other power supply one would use to keep everything in its original context. In short I am wondering what is the best, and most practical way to get this thing operating. The only information on converstion that I have at this point is the the article which appears on the ARRL site "Coverting Surplus Transmitter for Novice Use" even though I was not going to build the outboard xtal unit as suggested. I would be interested in seeing other, perhaps superior, methods for putting this gear to use. Really, how bad is this particular article and its mod suggestions? It has been suggested that the addition of some regulation on the oscillator voltage would solve the problem of chirp/drift etc. I would be interested in the type of mods and power supplies that you are all using which have proven successful before I proceed any further. I am assuming there are plenty of these units preserved as museum pieces already, I was more interested in using it without necessarily turning the shack into a complete ww2 cockpit. Bill, K6TAJ David Stinson wrote: zeno wrote: I have already decided not to worry about keeping this thing "original", eg. will be putting in a new power plug, key jack, and coax connector etc.... It is certainly your radio and you can do as you wish, but I urge you to reconsider; this isn't a old Craig CB rig or and Eico 753. This radio has historic significance. Extensive modification is needless and will turn your historic relic into a junkbox nothing. You can get the rig on the air with a good signal without drilling a single hole or chopping out anything. It's as simple as disconnecting one wire and adjusting one relay contact. If you need pins to fit the power connector on the back, send me your address and I'll send you some. Moreover, if you do the butchery to put the filiments on 12 volts AC, you are defeating part of the engineering solution designed to keep the rigs stable. My rigs are original design and work great with good power out and little or no chirp. First- throw out ALL those "conversion" articles from the 50s, 60s and 70s. The first ones were written by people who knew nothing about getting these rigs going and the rest just parroted what the first wrote. I can't tell you how many rigs went from "war relic" to "trash can" because of some conversion "author." The rigs are NOT TVI machines, chirp factories, harmonic generators or any of the other myths you've heard. These were born out of people flailing around blindly without any understanding of how the rig was designed to work. I have lots of information on how to get these going with little work and no irreversable mods. I'm headed to work. If anyone cares to read them, I will post them when I get home this evening. 73 DE Dave Stinson AB5S |
N2EY wrote: In article , zeno writes: Someone gave me an old ARC 5 (7-9.1) transmitter found at the county dump. I would like to see if I can get it going on 40 meter CW. First question is: What condition is it in? The one has already been modified, the other is relatively unmodified, but missing the bottom and the top case. What does that conversion article show? There was an article in the ARRL Handbooks for years that involved building an external crystal oscillator in a minibox, using a 6AG7. Most of that article was pretty good because it didn't hack up the ARC-5 too much (but it did recommend destroying the power socket, unfortunately). Yes, that is the article. I also have a power supply that works and has an octal male plug as described in that article. I would have to add an octal female socket on the back of the unmodified unit to receive this power supply plug. If I were to attempt to put the modified unit back together I would need way more information than I have at this point. For example the unmodified unit has an RF choke next to the large vertical coil in from of the 1625s, on the modified unit, it looks like it never had this rf choke installed. There are little wiring differences like this in these two units which I do not understand. The vertical coil in the unmodified unit has the red number 9295 printing on its edge, the modified unit has the number 7250 on it. I do not know what this number means (?). What (where would I get) information would I need to rebuild a totally modified unit, to make it into some kind of an operating transmitter? The Xtal in this unit is 8870 KC. Is this OK? Not for ham operation! The way I understand it, this is just for calibration of the VFO, so it is OK. My original intention was to recreate a 50's style conversion of one of these transmitters, however, I am not wondering if there is not a better way to go. Bill k6TAJ |
N2EY wrote: In article , zeno writes: Someone gave me an old ARC 5 (7-9.1) transmitter found at the county dump. I would like to see if I can get it going on 40 meter CW. First question is: What condition is it in? The one has already been modified, the other is relatively unmodified, but missing the bottom and the top case. What does that conversion article show? There was an article in the ARRL Handbooks for years that involved building an external crystal oscillator in a minibox, using a 6AG7. Most of that article was pretty good because it didn't hack up the ARC-5 too much (but it did recommend destroying the power socket, unfortunately). Yes, that is the article. I also have a power supply that works and has an octal male plug as described in that article. I would have to add an octal female socket on the back of the unmodified unit to receive this power supply plug. If I were to attempt to put the modified unit back together I would need way more information than I have at this point. For example the unmodified unit has an RF choke next to the large vertical coil in from of the 1625s, on the modified unit, it looks like it never had this rf choke installed. There are little wiring differences like this in these two units which I do not understand. The vertical coil in the unmodified unit has the red number 9295 printing on its edge, the modified unit has the number 7250 on it. I do not know what this number means (?). What (where would I get) information would I need to rebuild a totally modified unit, to make it into some kind of an operating transmitter? The Xtal in this unit is 8870 KC. Is this OK? Not for ham operation! The way I understand it, this is just for calibration of the VFO, so it is OK. My original intention was to recreate a 50's style conversion of one of these transmitters, however, I am not wondering if there is not a better way to go. Bill k6TAJ |
zeno wrote: The one has already been modified, the other is relatively unmodified, but missing the bottom and the top case. Send me your mailing address. I'll dig out a bottom and a top for your rig. Concerning the power supply in the ARRL book- It isn't the best design for the rig. I'm putting together a couple of posts about all this and will have them up shortly. 73 Dave S. |
zeno wrote: The one has already been modified, the other is relatively unmodified, but missing the bottom and the top case. Send me your mailing address. I'll dig out a bottom and a top for your rig. Concerning the power supply in the ARRL book- It isn't the best design for the rig. I'm putting together a couple of posts about all this and will have them up shortly. 73 Dave S. |
I have a T-16 NOS in the box. Opened only for inspection. It going to the
'E' place. "David Stinson" wrote in message news:bJDvd.3553$Zn6.2981@trnddc08... God bless you; you're just the man I'm looking for. Do you have any idea what the MF ARC-5 transmitters were for? These are the rare : T-15, 500-800 KC T-16, 800-1300 KC T-17, 1300-2100 KC The latest theory is that they were used in joint maneuvers with third-world allied navies, where were still using the 1920s-agreed navy frequencies below 2 MC. There so much I would love to ask you about these sets, if you don't mind the trouble. I'm a serious historian of the Command Set series and gentlemen like yourself are a treasure to find. 73 DE Dave Stinson AB5S Spike wrote: Nostalgia. When drafted into the Navy is 1943 my first job was setting up ARC-5 transmitters and receivers in 336 SNJ (AT-6) aircraft. (among other things) Later after the war when there wasn't much money around, I would rewind ARC-5 receivers and use them for ten-meter converters. In those days tapping on the case of just about any transmitter or receiver would produce some modulation. Except for Collins equipment. The ARC-5 VHF transmitters were truly awe inspiring when they arrived. 73s W6BWY |
I have a T-16 NOS in the box. Opened only for inspection. It going to the
'E' place. "David Stinson" wrote in message news:bJDvd.3553$Zn6.2981@trnddc08... God bless you; you're just the man I'm looking for. Do you have any idea what the MF ARC-5 transmitters were for? These are the rare : T-15, 500-800 KC T-16, 800-1300 KC T-17, 1300-2100 KC The latest theory is that they were used in joint maneuvers with third-world allied navies, where were still using the 1920s-agreed navy frequencies below 2 MC. There so much I would love to ask you about these sets, if you don't mind the trouble. I'm a serious historian of the Command Set series and gentlemen like yourself are a treasure to find. 73 DE Dave Stinson AB5S Spike wrote: Nostalgia. When drafted into the Navy is 1943 my first job was setting up ARC-5 transmitters and receivers in 336 SNJ (AT-6) aircraft. (among other things) Later after the war when there wasn't much money around, I would rewind ARC-5 receivers and use them for ten-meter converters. In those days tapping on the case of just about any transmitter or receiver would produce some modulation. Except for Collins equipment. The ARC-5 VHF transmitters were truly awe inspiring when they arrived. 73s W6BWY |
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