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"Pete KE9OA" wrote:
Hey Eric................anytime you have any questions, feel free to shout me down, and I will be glad to answer them as clearly as I know how! The coolest thing about knowledge it that it can be shared. Someday, I will write a comprehensive book all about radio design...............I just need to learn more than the .00000000000000000000000001% that I know right now! Pete, Thanks for the offer! We've talked in the past, but I must say that part of the problem is being able to frame the question coherently. Take care, Eric Pete "Eric F. Richards" wrote in message ... "phil :)" wrote: hi Eric: i am responding here as my reader ate the thread... Quite true, but that's not what you said -- you said it was "resonant." A nit-pick, perhaps, at 3/4 wavelenghts resonance is at 736-kHz. as a 2 wavelengths beverage: 1.9-MHz. your antenna is quite capable on MW. Oh, I don't argue *that*, I just argue that it wasn't resonant. Not that it matters, really, my WR-G303i reports its signal strength as 30 mV 120 miles away on a 400 foot wire broadside to the antenna. Flamethrower, indeed. As for the "flamethrower" at the end of the wire, they are in violation of 47 CFR 22.369, which explicitly lays out the field strength limits on Table Mountain. They may get grandfathered in, but now that the feds are reopening Table Mountain for NIST projects, the local HDTV wannabes are chafing at the restrictions -- even though their antennas would be about 40 miles away. what frequency are they on? Dunno. I don't keep up with the local doings of the broadcasters much. I assume they are in the old standard TV UHF band; 47 CFR 369 says that from 470 to 890 MHz, field strength on Table Mountain must be less than 30 mV/m. radios are black boxes: feed them signals within specs and they perform predictably. ICOM probably left off the LW BPF to save $1. companies are cheap. Actually I got word from someone who said that the '75 was considered a work in progress that never progressed. i know what the R75 is and is not. Then all I ask is that you remember that when you brag on it. Good bargain? definitely. Ultimate radio? No. i am lucky to have Pete as a mentor. That you are. I wish I was fluent enough in electronics to be able to speak the same language as Pete. if you gain access to that antenna try your RX340 and bring along a 7030 owner. No radio is perfect; the '7030 wouldn't hold up out there... To me the question would be whether or not the '340 would. Eric -- Eric F. Richards, "Nature abhors a vacuum tube." -- J. R. Pierce, Bell Labs, c. 1940 -- Eric F. Richards, "Don't destroy the Earth! That's where I keep all of my stuff!" - Squidd on www.fark.com |
Pete KE9OA wrote:
The only way that this should happen is if either the receiver is very conservatively rated (do we know exactly what method was use to make this measurement?), or if the measurements were incorrectly done. I am not sure that real world performance would reflect those measurements, unless you are in an area where there are several strong signals that are only 5kHz apart. When I am measuring the overload point on the receiver that I am developing, it is very easy to drive the system into overload with a signal generator, yet with a 100 foot longwire in the presence of three 50kW MW broadcasters, no overload is present. I think that specs do tell the story, if the measurement system is properly set up. As an example, on one project, I needed to make some desense measurements from 5kHz to several hundred MHz away from the desired signal. The desired signal level was -140dBm. Using an HP8657 or an 8640B, the broadband noise from these two units was so high, even a 300MHz away from the desired signal, that I had to run the generators through a K&L tunable filter. The only generator that was slightly usable was an HP8642B. This is the one that uses the Modulated Fractional Divider, with the Sigma-Delta modulation. In reference to you statement about the receiver working better than its rated specs, I just don't think so, unless as I said earlier, the measurements were done incorrectly. The only way to really to a close-in IP3 measurement is to run the interfering signal through a very selective, deep skirted crystal filter. You need the interfering signal to have almost non-existant close-in phase noise; otherwise, the measurement is meaningless. Pete, As you know the receiver testing for 'Passport' is done by Sherwood Engineering. Do you know anything about the equipment they use and how the test specs are generated? -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
hi Telamon:
Actually I got word from someone who said that the '75 was considered a work in progress that never progressed. That's an understatement if I ever heard one! Welcome to the real world. Engineers will play with a design until they are happy with it but management runs the show. As soon as the pointy haired boss thinks that the design has met its goals the effort ends. sounds like the voice of experience. regards, phil :) |
hi starman:
As you know the receiver testing for 'Passport' is done by Sherwood Engineering. Do you know anything about the equipment they use and how the test specs are generated? go he http://www.mini-circuits.com/application.html regards, phil |
hi Telamon:
You can mark the group unread or un-subscribe and re-subscribe to the group to get all messages on the news server. thanks, i tried. the HDD has errors. Blindly reading specifications can lead you astray on how the radio will perform. Some measurements require the radio be in a non-optimum reception state. there is also creative spec writing. i'd rather view a schematic, do you have the RX340's? I'm going to play devil's advocate and ask the question "why do some radios work much better than the IP3 @ 5KHz measurement would indicate?" during usage, antenna can help: if we use a LW loop and that station 5 kHz away is being nulled by 50 dB because of its direction then we've solved the problem before it got inside the radio. regards, phil :) |
hi Eric:
Oh, I don't argue *that*, I just argue that it wasn't resonant. if you knew that then why use this antenna for LW? Not that it matters, really, my WR-G303i reports its signal strength as 30 mV 120 miles away on a 400 foot wire broadside to the antenna. Flamethrower, indeed. 30mV at what frequency? can you fault the R8B and R75 for overloading? Dunno. I don't keep up with the local doings of the broadcasters much. I assume they are in the old standard TV UHF band; 47 CFR 369 says that from 470 to 890 MHz, field strength on Table Mountain must be less than 30 mV/m. that PAR LPF should severely attenuate UHF. spectral analysis of that wire is needed. low frequencies or potent RF energy can cause PIN diodes to rectify. No radio is perfect; the '7030 wouldn't hold up out there... To me the question would be whether or not the '340 would. the 7030 uses an SD5400 first mixer and has 40 dB of attenuation on tap... add a $50 homebrew LW BPF: your RX340 will overload first. either way an R75 hooked to a LW loop will hear more NDBs. Eric, you remind me of Captain Ahab, fighting that whale of an antenna, Moby Dick. man versus nature, a classic... but the SOB already bit off your leg. shake the obsession... build a LW loop. regards, phil :) |
"phil :)" wrote:
hi Eric: Oh, I don't argue *that*, I just argue that it wasn't resonant. if you knew that then why use this antenna for LW? Sigh... round and round we go... because it was very effective for my needs, specifically picking up NDBs east of the site. Which it did very well. Not that it matters, really, my WR-G303i reports its signal strength as 30 mV 120 miles away on a 400 foot wire broadside to the antenna. Flamethrower, indeed. 30mV at what frequency? can you fault the R8B and R75 for overloading? ....what are you, totally thick or what? The MW station that was causing the problems. Dunno. I don't keep up with the local doings of the broadcasters much. I assume they are in the old standard TV UHF band; 47 CFR 369 says that from 470 to 890 MHz, field strength on Table Mountain must be less than 30 mV/m. that PAR LPF should severely attenuate UHF. spectral analysis of that wire is needed. low frequencies or potent RF energy can cause PIN diodes to rectify. The PAR LPF has no relevence to the federal regulations regarding Table Mountain. What's your point? HDTV broadcasters at Lookout Mountain are griping about the regs. My point, in case you missed it, again, is that the flamethrower is in violation of the regs in 47 CFR 369. No radio is perfect; the '7030 wouldn't hold up out there... To me the question would be whether or not the '340 would. the 7030 uses an SD5400 first mixer and has 40 dB of attenuation on tap... add a $50 homebrew LW BPF: your RX340 will overload first. either way an R75 hooked to a LW loop will hear more NDBs. Of course. The R75 solves all. Can't imagine that if you use your LW loop with another radio, that it'll outperform that R75, can you? Come on, this is really simple. Take whatever crutches you add to your R75, apply them to nearly ANY other radio on the market, and it'll leave your R75 in the dust. (Notably, your dream radio, the Racal 6790, would be left in the dust as well. What's your affinity to radios with crappy front-ends?) Eric, you remind me of Captain Ahab, fighting that whale of an antenna, Moby Dick. man versus nature, a classic... but the SOB already bit off your leg. shake the obsession... build a LW loop. Actually I'll probably purchase what Pete comes up with, since his loop probably will have a low NF and resistance to overload. Just a guess. We'll see. regards, phil :) So, what's the deal with the R75 schematic on Yahoo? I've been trying to retrieve it for a week and the server acts dead. Is Yahoo that lax in running their servers? -- Eric F. Richards, "The most likely way for the world to be destroyed, most experts agree, is by accident. That's where we come in; we're computer professionals. We cause accidents." - Nathaniel S. Borenstein |
Eric F. Richards wrote:
[...] Dunno. I don't keep up with the local doings of the broadcasters much. I assume they are in the old standard TV UHF band; 47 CFR 369 says that from 470 to 890 MHz, field strength on Table Mountain must be less than 30 mV/m. that PAR LPF should severely attenuate UHF. spectral analysis of that wire is needed. low frequencies or potent RF energy can cause PIN diodes to rectify. The PAR LPF has no relevence to the federal regulations regarding Table Mountain. What's your point? HDTV broadcasters at Lookout Mountain are griping about the regs. My point, in case you missed it, again, is that the flamethrower is in violation of the regs in 47 CFR 369. Ack! phil completely drives me to distraction. The above two entries should read 47 CFR 22.369 Part 22, 369. I should've kept my R75 and put a "Hello, my name is phil" tag on it so I could give it a good kick every time he posts more pro-R75 drivel... |
hi Eric:
...what are you, totally thick or what? The MW station that was causing the problems. at what *frequency* is that MW station transmitting? Of course. The R75 solves all. Can't imagine that if you use your LW loop with another radio, that it'll outperform that R75, can you? Come on, this is really simple. Take whatever crutches you add to your R75, apply them to nearly ANY other radio on the market, and it'll leave your R75 in the dust. (Notably, your dream radio, the Racal 6790, would be left in the dust as well. What's your affinity to radios with crappy front-ends?) the R75 was used to drive home a point: ANY tabletop using the LW loop i suggested will outperform your antenna. only you cannot admit you were wrong. thinking is a crutch! rip on the 7030 and Racal all you want genius. who could not figure out that a simple $50 homebrew LW BPF in front of either will smoke your $4000 RX340 in terms of IP3, dynamic range, phase noise, ultimate rejection, etc. explain how your radio will leave any tabletop "in the dust" when both are hooked to a LW loop? quote specs. regards, phil :) |
I should've kept my R75 and put a "Hello, my name is phil" tag on it so I could give it a good kick every time he posts more pro-R75 drivel... pandering Captain Ahab? when Moby Dick overloaded an R8B and R75 you just blamed the radios: "Get a real radio, and notice the difference. And if you can't afford a real radio, get a Drake." so Steve, Les, Ken, me, and others told you to stick it. instead of building a LW loop you went out and "showed all us idiots" by buying a $4k radio LOL. what did you ask those TenTec engineers Eric? directions to the bathroom? in the words of President Bush: "THE GAME IS OVER" regards, phil :) |
I thought you sounded familiar. I also need to keep things clear on my end,
so I don't start speaking in Greek! Anyway, you and the other folks on the NG are welcome to shout me down anytime! Pete Gianakopoulos KE9OA "Eric F. Richards" wrote in message ... "Pete KE9OA" wrote: Hey Eric................anytime you have any questions, feel free to shout me down, and I will be glad to answer them as clearly as I know how! The coolest thing about knowledge it that it can be shared. Someday, I will write a comprehensive book all about radio design...............I just need to learn more than the .00000000000000000000000001% that I know right now! Pete, Thanks for the offer! We've talked in the past, but I must say that part of the problem is being able to frame the question coherently. Take care, Eric Pete "Eric F. Richards" wrote in message ... "phil :)" wrote: hi Eric: i am responding here as my reader ate the thread... Quite true, but that's not what you said -- you said it was "resonant." A nit-pick, perhaps, at 3/4 wavelenghts resonance is at 736-kHz. as a 2 wavelengths beverage: 1.9-MHz. your antenna is quite capable on MW. Oh, I don't argue *that*, I just argue that it wasn't resonant. Not that it matters, really, my WR-G303i reports its signal strength as 30 mV 120 miles away on a 400 foot wire broadside to the antenna. Flamethrower, indeed. As for the "flamethrower" at the end of the wire, they are in violation of 47 CFR 22.369, which explicitly lays out the field strength limits on Table Mountain. They may get grandfathered in, but now that the feds are reopening Table Mountain for NIST projects, the local HDTV wannabes are chafing at the restrictions -- even though their antennas would be about 40 miles away. what frequency are they on? Dunno. I don't keep up with the local doings of the broadcasters much. I assume they are in the old standard TV UHF band; 47 CFR 369 says that from 470 to 890 MHz, field strength on Table Mountain must be less than 30 mV/m. radios are black boxes: feed them signals within specs and they perform predictably. ICOM probably left off the LW BPF to save $1. companies are cheap. Actually I got word from someone who said that the '75 was considered a work in progress that never progressed. i know what the R75 is and is not. Then all I ask is that you remember that when you brag on it. Good bargain? definitely. Ultimate radio? No. i am lucky to have Pete as a mentor. That you are. I wish I was fluent enough in electronics to be able to speak the same language as Pete. if you gain access to that antenna try your RX340 and bring along a 7030 owner. No radio is perfect; the '7030 wouldn't hold up out there... To me the question would be whether or not the '340 would. Eric -- Eric F. Richards, "Nature abhors a vacuum tube." -- J. R. Pierce, Bell Labs, c. 1940 -- Eric F. Richards, "Don't destroy the Earth! That's where I keep all of my stuff!" - Squidd on www.fark.com |
It should be good..............I am shooting for a +40dBm IP3 on the loop
amplifier. About that 6790, the IP3 on that unit is rated at +30dBm, which isn't bad, but they do have a wide open front end. Still, I haven't had any overload problems with mine. It is my favorite receiver, but it so is BIGGGGGGGGGGGGGGG. Maybe, when I buy a house, I will build a nice deep night table to keep it on. When you open up the 6790, you see that the construction is very good. All of the RF modules are enclosed in a die-cast "egg crate construction" style of assembly. The 45MHz I.F. filter is at least 8 poles, so the 2nd mixer is protected quite well from out of bandpass stations. I got mine from Ken G. down in St Louis. He is a great person to deal with. Pete "Eric F. Richards" wrote in message ... "phil :)" wrote: hi Eric: Oh, I don't argue *that*, I just argue that it wasn't resonant. if you knew that then why use this antenna for LW? Sigh... round and round we go... because it was very effective for my needs, specifically picking up NDBs east of the site. Which it did very well. Not that it matters, really, my WR-G303i reports its signal strength as 30 mV 120 miles away on a 400 foot wire broadside to the antenna. Flamethrower, indeed. 30mV at what frequency? can you fault the R8B and R75 for overloading? ...what are you, totally thick or what? The MW station that was causing the problems. Dunno. I don't keep up with the local doings of the broadcasters much. I assume they are in the old standard TV UHF band; 47 CFR 369 says that from 470 to 890 MHz, field strength on Table Mountain must be less than 30 mV/m. that PAR LPF should severely attenuate UHF. spectral analysis of that wire is needed. low frequencies or potent RF energy can cause PIN diodes to rectify. The PAR LPF has no relevence to the federal regulations regarding Table Mountain. What's your point? HDTV broadcasters at Lookout Mountain are griping about the regs. My point, in case you missed it, again, is that the flamethrower is in violation of the regs in 47 CFR 369. No radio is perfect; the '7030 wouldn't hold up out there... To me the question would be whether or not the '340 would. the 7030 uses an SD5400 first mixer and has 40 dB of attenuation on tap... add a $50 homebrew LW BPF: your RX340 will overload first. either way an R75 hooked to a LW loop will hear more NDBs. Of course. The R75 solves all. Can't imagine that if you use your LW loop with another radio, that it'll outperform that R75, can you? Come on, this is really simple. Take whatever crutches you add to your R75, apply them to nearly ANY other radio on the market, and it'll leave your R75 in the dust. (Notably, your dream radio, the Racal 6790, would be left in the dust as well. What's your affinity to radios with crappy front-ends?) Eric, you remind me of Captain Ahab, fighting that whale of an antenna, Moby Dick. man versus nature, a classic... but the SOB already bit off your leg. shake the obsession... build a LW loop. Actually I'll probably purchase what Pete comes up with, since his loop probably will have a low NF and resistance to overload. Just a guess. We'll see. regards, phil :) So, what's the deal with the R75 schematic on Yahoo? I've been trying to retrieve it for a week and the server acts dead. Is Yahoo that lax in running their servers? -- Eric F. Richards, "The most likely way for the world to be destroyed, most experts agree, is by accident. That's where we come in; we're computer professionals. We cause accidents." - Nathaniel S. Borenstein |
"Pete KE9OA" wrote:
It should be good..............I am shooting for a +40dBm IP3 on the loop amplifier. Cool! About that 6790, the IP3 on that unit is rated at +30dBm, which isn't bad, but they do have a wide open front end. Yeah. I know it has a pretty solid front end, but no preselector. I'm just returning the favor for phil needling me. The only real problem with that receiver is that it generally is bare-bones when you get it and you have to fill out all the filter options. Eric Still, I haven't had any overload problems with mine. It is my favorite receiver, but it so is BIGGGGGGGGGGGGGGG. Maybe, when I buy a house, I will build a nice deep night table to keep it on. When you open up the 6790, you see that the construction is very good. All of the RF modules are enclosed in a die-cast "egg crate construction" style of assembly. The 45MHz I.F. filter is at least 8 poles, so the 2nd mixer is protected quite well from out of bandpass stations. I got mine from Ken G. down in St Louis. He is a great person to deal with. Pete -- Eric F. Richards "The weird part is that I can feel productive even when I'm doomed." - Dilbert |
"phil :)" wrote:
hi Eric: ...what are you, totally thick or what? The MW station that was causing the problems. at what *frequency* is that MW station transmitting? 670 kHz. KLTT. "The nations most powerful Christian voice." For someone who keeps track of all the flaws in my past statements, you should remember that one. Of course. The R75 solves all. Can't imagine that if you use your LW loop with another radio, that it'll outperform that R75, can you? Come on, this is really simple. Take whatever crutches you add to your R75, apply them to nearly ANY other radio on the market, and it'll leave your R75 in the dust. (Notably, your dream radio, the Racal 6790, would be left in the dust as well. What's your affinity to radios with crappy front-ends?) the R75 was used to drive home a point: ANY tabletop using the LW loop i suggested will outperform your antenna. We'll see. I have no argument with using an LW loop, only with using the R75. only you cannot admit you were wrong. thinking is a crutch! rip on the 7030 and Racal all you want genius. Thank you, I think I will. who could not figure out that a simple $50 homebrew LW BPF in front of either will smoke your $4000 RX340 in terms of IP3, dynamic range, phase noise, ultimate rejection, etc. explain how your radio will leave any tabletop "in the dust" when both are hooked to a LW loop? quote specs. Tell me, phil, what's the hyping on the price of the '340? The half-octave BPFs in the front end were only one reason I got it. Most of the reasons I bought it were based on operating it and getting a feel for how capable it was. Specs? You can look them up yourself. I'm not a walking calculator. We can argue about 1, 3, 10 or 20 dB of dynamic range for close-in spacing, but that isn't the issue. You know that. regards, phil :) -- Eric F. Richards, "Nature abhors a vacuum tube." -- J. R. Pierce, Bell Labs, c. 1940 |
hi Eric:
honestly i was trying to help. if you hook a large air-core air-cap [high- Q] tuned loop to your RX340 you should be very happy with the results on LW. you are correct, DR is not a big issue with this setup. if you hate the R75 that is fine. one of the best out of the box units is the R8B. people who say one cannot program listen or DX with the [insert tabletop name here] are full of it. i've done experiments bearing this out. the tabletops are more similar than they are different. buy whatever suits your fancy and use the best antenna possible. i will call a spade a spade. the 7030 and 6790 have high IP3 mixers. AFA that 1000' antenna: 670-kHz is 3/4 wavelengths resonant at 1099'. radios are going to suffer from overload. i suggest trying a series-resonant trap that: this should dump much of that 670-kHz energy to ground before it enters the radio. regards, phil :) |
I know that...............I think that both of you are good guys. Radio fun!
Pete "Eric F. Richards" wrote in message ... "Pete KE9OA" wrote: It should be good..............I am shooting for a +40dBm IP3 on the loop amplifier. Cool! About that 6790, the IP3 on that unit is rated at +30dBm, which isn't bad, but they do have a wide open front end. Yeah. I know it has a pretty solid front end, but no preselector. I'm just returning the favor for phil needling me. The only real problem with that receiver is that it generally is bare-bones when you get it and you have to fill out all the filter options. Eric Still, I haven't had any overload problems with mine. It is my favorite receiver, but it so is BIGGGGGGGGGGGGGGG. Maybe, when I buy a house, I will build a nice deep night table to keep it on. When you open up the 6790, you see that the construction is very good. All of the RF modules are enclosed in a die-cast "egg crate construction" style of assembly. The 45MHz I.F. filter is at least 8 poles, so the 2nd mixer is protected quite well from out of bandpass stations. I got mine from Ken G. down in St Louis. He is a great person to deal with. Pete -- Eric F. Richards "The weird part is that I can feel productive even when I'm doomed." - Dilbert |
"Pete KE9OA" wrote:
I know that...............I think that both of you are good guys. Radio fun! Pete anyone else belive that? (crickets chirping) Hmpf. Thought so. :-) Thanks for the vote of confidence, Pete! Eric "Eric F. Richards" wrote in message ... "Pete KE9OA" wrote: It should be good..............I am shooting for a +40dBm IP3 on the loop amplifier. Cool! About that 6790, the IP3 on that unit is rated at +30dBm, which isn't bad, but they do have a wide open front end. Yeah. I know it has a pretty solid front end, but no preselector. I'm just returning the favor for phil needling me. The only real problem with that receiver is that it generally is bare-bones when you get it and you have to fill out all the filter options. Eric Still, I haven't had any overload problems with mine. It is my favorite receiver, but it so is BIGGGGGGGGGGGGGGG. Maybe, when I buy a house, I will build a nice deep night table to keep it on. When you open up the 6790, you see that the construction is very good. All of the RF modules are enclosed in a die-cast "egg crate construction" style of assembly. The 45MHz I.F. filter is at least 8 poles, so the 2nd mixer is protected quite well from out of bandpass stations. I got mine from Ken G. down in St Louis. He is a great person to deal with. Pete -- Eric F. Richards "The weird part is that I can feel productive even when I'm doomed." - Dilbert -- Eric F. Richards, "Nature abhors a vacuum tube." -- J. R. Pierce, Bell Labs, c. 1940 |
EFR,
OMG - You almost paid the Icom IC-R75 a 'backhanded' Compliment. tdsgdih ~ RHF = = = This Day Shall Go Down In History :o) .. .. = = = Eric F. Richards = = = wrote in message . .. - - - S N I P - - - Yeah. I know it has a pretty solid front end, but no preselector. I'm just returning the favor for phil needling me. The only real problem with that receiver is that it generally is bare-bones when you get it and you have to fill out all the filter options. Eric - - - S N I P - - - |
In article ,
"Pete KE9OA" wrote: They might be able to fix that problem in the RX340 if they use a longer time constant in the loop filter. They could even use a dual time constant loop filter, they way it is done in fast lock time synthesizers. The Sync is executed is DSP so that would take a software change and if that is the case you would think it would be fixed but since it is not the problem must be more complicated. Like you I suspected that the problem might be loop timing since it was improved with a software revision and that the sync has another interesting aspect to it and that is a narrow lock range compared to other analog radios I own. The RX340 will lock more consistently when tuned right on a stations frequency. Since most stations are on channel this normally requires no additional action in operating the radio. A more complex reason for the RX340 non-lock is that the radio has a front-end analog RF AGC followed by a DSP AGC. The locking problem could be related to the way the two loops interact in various reception situations. "Telamon" wrote in message ... In article , (Kenneth) wrote: Telamon wrote in message What quotes this quotes from passport to world band radio?: The Ten Tec RX340 [$3,999]test findings:The sync selectable sideband lose look relatively easily,Passport recomend an external Sherwood SE-3 [500.00],poor dynamic range,static crashes sound harsher than on analog receivers.Spurious signal noted around 6MHZ segment,notch filter does not work in AM,Sync selectable sideband or ISB modes,Noise blanker not effective ect, ect, ect, You play fast and loose with the facts, misstating or exaggerating them. I used to think that you were just confused but you continue although corrected so I can only conclude that your thoughts are completely prejudicial whatever your motivation. You have no credibility. What the problem? Do you don't like this passport RX 340 flaws report? This is NOT MY OPPINION but the "con" part of the passport to world band radio magazine review.Do you think they are "prejudiced whatever their motivations"?.Then why you not call them and protest? You are making a ridiculous ninny paper prattling "You have no credibility" "you have not credibility" but this is only your nonsense oppinion because you want to deflect the attention and hide the passport report about your expensive receiver.Why don't accept it or complain with the right people [passport reviewers staff]about the review and stop this nonsense? This sample of the report [the flaws part] is an accurate quote of what the passport reviewer wrote and NOT MY OPPINION.I don't add anything or exaggerate anything.You are the only one confused and with credibility deficiency here. Ken You have no credibility. You may have copied what is written in Passport and twisted it for your own evil ends but that does not constitute a quote. Here is the way to do it. In the 2004 Passport RX340 review I read "Noise blanker not effective at some locations; for example, other receivers (but not the POS IC-R75) work better in reducing noise from electric fences." This means it is effective against some noise types but not all. This entire quote about the noise blanker reads differently from your writing (sic) "Noise blanker not effective ect, ect, ect," as an example of your bias. I think Passport had their hands on a bum unit. I have not had the problems they describe in my RX340 with one exception and that is it does lose sync lock on rapid and deep fading signals. The signal can be very weak or deeply fading and it is not a problem unless the fade is rapid. The fading can be rapid without a locking problem as long as it is not deep. The radio will lose lock if both conditions exist at the same time to a great enough extent. It is one area of the radios performance I whish was better. The other cons as I've told you several times are not evident in my unit and I would expect other people that own this radio to come back and post that their unit does have the other problems but you don't see those posts do you? What you do see is Kenneth flapping in the breeze trying to justify his decisions by knocking other people. -- Telamon Ventura, California -- Telamon Ventura, California |
hi Telamon:
A more complex reason for the RX340 non-lock is that the radio has a front-end analog RF AGC followed by a DSP AGC. The locking problem could be related to the way the two loops interact in various reception situations. the RX340's 16-bit ADC is not ideal as this limits AGC inside the DSP. the "software" AGC must keep altering [via DAC] the analog gain during fades. new ham gear uses 24-bit ADCs. regards, phil :) |
On Sun, 25 Jan 2004 01:50:53 -0500, "phil :)"
wrote: hi Telamon: A more complex reason for the RX340 non-lock is that the radio has a front-end analog RF AGC followed by a DSP AGC. The locking problem could be related to the way the two loops interact in various reception situations. the RX340's 16-bit ADC is not ideal as this limits AGC inside the DSP. the "software" AGC must keep altering [via DAC] the analog gain during fades. new ham gear uses 24-bit ADCs. regards, phil :) Right on, Phil. 2nd generation (16-bit) DSP IF receivers (RX331/340, WJ8711A/HF1000) with this architecture have this problem. (The first generation Collins HF2050 only had 7-bit A/D, but also a different architecture.) I find that by using the IF gain control to place the signal amplitude in the sweet spot where its variations stay within the 16-bit range of the 3rd IF I very seldom have unlock/relock problems. However, if I get fading so great that it requires the outer loop to adjust that IF gain to keep the signal in the DSP range, if the fade's rate-of-change is sufficiently high the old unlock/relocks reappear. If you need 8-bit "telephone quality" dynamic range for the modulation, the carrier can only have 8 bits. Even with the more reasonable assumption of 6 bits for program content, you still only have 10 bits - or 60dB. On the other hand, with 24 bits you'd have 96dB even with 8-bit audio (to maintain full fidelity of all the static and crud on MF/HFg). Even with this limitation, however, my RX340s totally outclass my Harris, Cubic and Icom receivers. Cost-reducing $10k (or more) surveillance receivers to $4k is difficult enough, and I have a lot of respect for Ten-Tec's engineers. The addition of SAM was designed for the "human-friendly" RX340 and then back-fitted into the RX331, since it was IF-software-only. Now if the spooks would just order a next-generation to the 331/340 with 24-bit A/D.......g This is where someone like Winradio who uses your PC's soundcard for the last IF could perhaps have a software/hardware verison that exploited 24-bit soundcards. Unfortunately, unless I'm mistaken, their software runs the same on any "compatible" (with SB16) soundcard. Probably a wise business decision due to the much more limited market of folks with 24 bit soundcards. Oh well, they'd probably have to spend more on the front end stuff, anyway. Good listening, Al ================================================= Location: 42N39, 71W09 (Near Boston, MA) HF Antennas: 65ft TFD, 45ft T2FD, 28ft vertical, 65ft doublet HF Receivers: Ten-Tec RX340, RX320, Harris R2368, Cubic R3030A Decoders: Code300-32, Universal M-8000, PK-232MBX/DSP ================================================= |
In article , "phil :)"
wrote: hi Telamon: A more complex reason for the RX340 non-lock is that the radio has a front-end analog RF AGC followed by a DSP AGC. The locking problem could be related to the way the two loops interact in various reception situations. the RX340's 16-bit ADC is not ideal as this limits AGC inside the DSP. the "software" AGC must keep altering [via DAC] the analog gain during fades. new ham gear uses 24-bit ADCs. Yes. And then the lost lock arises due to how they interact. The dual loop response probably isn't fast enough to correct for rapid and deep fading. -- Telamon Ventura, California |
hi Albert and Telamon:
thank you both for the replies. maybe TenTec has a 24-bit ADC version in store? regards, phil :) |
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