NGEN - is it working?
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Hopefully not a silly question...
If I connect NGEN to my K2 but leave it switched off, I have a certain level of background noise. If I turn NGEN on, there's no noticeable increase in background noise. Have I missed something? Is AGC compensating for the increase in noise? ... or is my NGEN broken? I built it over Christmas and I've never actually noticed it working. The lights "do the right thing", but apart from a very brief "chuff" when I switch it on, I'm not convinced it's producing any actual output. -- "Nosey" Nick Waterman, G7RZQ, K2 #5209. use Std::Disclaimer; [hidden email] Actions speak louder than words. The pen is mightier than the sword. _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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I would expect a noticeable increase in noise. Try this: see if you can tune
in some signal with the NGEN connected (perhaps connect a clip lead to the antenna terminal as well if needed). Listen to the signal with the NGEN on and off. There should be a difference, even if the AGC is coming into play. 73 - Mike WA8BXN _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Nick Waterman
Better yet, turn off AGC. You must turn off AGC to get much meaningful out
of s'gram anyhow. Dan / WG4S / K2 #2456 PS: Off is PRE/ATT & AGC together. <snip> I would expect a noticeable increase in noise. Try this: see if you can tune in some signal with the NGEN connected (perhaps connect a clip lead to the antenna terminal as well if needed). Listen to the signal with the NGEN on and off. There should be a difference, even if the AGC is coming into play. </snip> _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Nick Waterman
Noise increase should be unmistakable. Make sure the MMIC isn't in
backwards :) If you have a key attached, and happened to transmit into it, just order replacement MMIC (get 3, about $10 delivered :) from Elecraft. de john/w1rt On 1/29/06, Nick Waterman <[hidden email]> wrote: > Hopefully not a silly question... > > If I connect NGEN to my K2 but leave it switched off, I have a certain > level of background noise. If I turn NGEN on, there's no noticeable > increase in background noise. > > Have I missed something? Is AGC compensating for the increase in noise? > ... or is my NGEN broken? I built it over Christmas and I've never > actually noticed it working. The lights "do the right thing", but apart > from a very brief "chuff" when I switch it on, I'm not convinced it's > producing any actual output. > > -- > "Nosey" Nick Waterman, G7RZQ, K2 #5209. > use Std::Disclaimer; [hidden email] > Actions speak louder than words. The pen is mightier than the sword. > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Nick Waterman
Hi
First make sure your 9 volt battery is good. It should measure at least 8 volts or higher. My N-Gen did not work also when I built it. The problem was the Zener diode was not producing noise. This sometimes happens with a particularly "good" diode. Remember this noise is normally an undesirable quality of a zener diode. I replaced the diode with a 2N3904 transistor using only the base and emitter leads. 2N3904 and 2N2222 transistors make fairly good noise sources used this way. Just connect the emitter-base junction so it is reversed biased and it will break over at around 5 volts just like a zener diode. If you have several transistors select one with the best noise output. Don Brown ----- Original Message ----- From: "Nick Waterman" <[hidden email]> To: "Elecraft Reflector" <[hidden email]> Sent: Sunday, January 29, 2006 9:23 AM Subject: [Elecraft] NGEN - is it working? > Hopefully not a silly question... > > If I connect NGEN to my K2 but leave it switched off, I have a certain > level of background noise. If I turn NGEN on, there's no noticeable > increase in background noise. > > Have I missed something? Is AGC compensating for the increase in noise? > ... or is my NGEN broken? I built it over Christmas and I've never > actually noticed it working. The lights "do the right thing", but apart > from a very brief "chuff" when I switch it on, I'm not convinced it's > producing any actual output. > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by zeke7237
John D'Ausilio wrote:
> Noise increase should be unmistakable. Make sure the MMIC isn't in > backwards :) I was wondering if I'd mounted it "upside down", but as both the top and bottom leads are grounded, it looks as though, as long as the slanted lead is towards the centre of the board, I can't realistically get it wrong. > If you have a key attached and happened to transmit > into it, just order replacement MMIC (get 3, about $10 delivered :) > from Elecraft. I'm an SSB guy, don't know CW YET. I don't have a key, I do have a PTT switch, but only recently... Basically... I built NGEN, XG1, DL1 without being able to test them. I built the K2 and had no PTT or key connected. I transmitted into DL1 for the bandpass filter tweaking, but did no other transmitting until after building KSB2. I can be just about positive I've never transmitted into NGEN... And even if I had, it definitely wouldn't have been the FIRST thing I'd done to it, and as far as I can tell, NGEN has never worked, or at least not noticably. I'll try testing with AGC off, NGEN connected, and XG1 sat nearby on the bench so I have a signal to compare with my noise or lack thereof. If it still doesn't work, can I be fairly confident that it's the MMIC, or might it be the Zenner D2? Or indeed anything else? There's no "cheap and dirty signal tracing" or table of voltages for NGEN, is there? -- "Nosey" Nick Waterman, G7RZQ, K2 #5209. use Std::Disclaimer; [hidden email] Half the people you know are below average. _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Hi
You can use your K2 as a tester for the N-gen. Just use a probe made up of some RG58 connected to the antenna input of the K2 and install a small capacitor (around .01) in series with the probe end. You can then touch the probe to the zener diode cathode. You should hear an increase in the noise level on the K2. If that is good then move on the the MMIC the output there should increase on the S-meter of the K2. The circuit is so simple it just about has to be the battery the zener diode or the MMIC in that order Don Brown ----- Original Message ----- From: "Nick Waterman" <[hidden email]> To: "Elecraft Reflector" <[hidden email]> Sent: Sunday, January 29, 2006 11:23 AM Subject: Re: [Elecraft] NGEN - is it working? > John D'Ausilio wrote: > > Noise increase should be unmistakable. Make sure the MMIC isn't in > > backwards :) > > I was wondering if I'd mounted it "upside down", but as both the top and > bottom leads are grounded, it looks as though, as long as the slanted > lead is towards the centre of the board, I can't realistically get it > wrong. > > > If you have a key attached and happened to transmit > > into it, just order replacement MMIC (get 3, about $10 delivered :) > > from Elecraft. > > I'm an SSB guy, don't know CW YET. I don't have a key, I do have a PTT > switch, but only recently... Basically... > > I built NGEN, XG1, DL1 without being able to test them. I built the K2 > and had no PTT or key connected. I transmitted into DL1 for the bandpass > filter tweaking, but did no other transmitting until after building > KSB2. I can be just about positive I've never transmitted into NGEN... > And even if I had, it definitely wouldn't have been the FIRST thing I'd > done to it, and as far as I can tell, NGEN has never worked, or at least > not noticably. > > I'll try testing with AGC off, NGEN connected, and XG1 sat nearby on the > bench so I have a signal to compare with my noise or lack thereof. > > If it still doesn't work, can I be fairly confident that it's the MMIC, > or might it be the Zenner D2? Or indeed anything else? There's no "cheap > and dirty signal tracing" or table of voltages for NGEN, is there? > > -- > "Nosey" Nick Waterman, G7RZQ, K2 #5209. > use Std::Disclaimer; [hidden email] > Half the people you know are below average. > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Nick Waterman
Nick Waterman wrote:
> If I connect NGEN to my K2 but leave it switched off, I have a certain > level of background noise. If I turn NGEN on, there's no noticeable > increase in background noise. Hi Nick, Your N-gen should definitely provide an audible increase in noise when connected to the K2. The noise level is very well-controlled; there are radio astronomers in Japan using N-gens instead of HP-346 noise sources to calibrate their radio telescopes. If you can't hear the increase, it's likely that you have a defective component or a cold solder joint somewhere. Regarding the zener diode, there should never be one that is "too good," unless it is actually bad. Noise production is an inherent characteristic of the avalanche breakdown (a.k.a. "zener") process. When we designed the N-gen, we tested 20 diodes of different types, and they all put out the same noise level within a dB or so. If you discover that your zener is not producing noise (by substituting one that does), please send the old one to us so we can test it. We'll send a replacement free of charge. 73, Wayne N6KR --- http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Don Brown-4
For the short period I had an HP 141T spectrum analyzer, I played
around with my noise gen a bit, and I was able to get a view showing the noise of the N-Gen over a wide range, it looked like a fuzzy little catarpillar, I should have taken a pic. You should be able to test your N-Gen on any VHF radio including an FM broadcast or aircraft reciever, any HF radio including some cheap "shortwave", a Radio Shack Weather Cube, just about anything. The signal shows on up a good oscilloscope but just barely, a radio is a sensitive thing! 73 de Alex nS6y On Jan 29, 2006, at 9:35 AM, Don Brown wrote: > Hi > > You can use your K2 as a tester for the N-gen. Just use a probe made > up of > some RG58 connected to the antenna input of the K2 and install a small > capacitor (around .01) in series with the probe end. You can then > touch the > probe to the zener diode cathode. You should hear an increase in the > noise > level on the K2. If that is good then move on the the MMIC the output > there > should increase on the S-meter of the K2. The circuit is so simple it > just > about has to be the battery the zener diode or the MMIC in that order > > Don Brown > > > > > ----- Original Message ----- > From: "Nick Waterman" <[hidden email]> > To: "Elecraft Reflector" <[hidden email]> > Sent: Sunday, January 29, 2006 11:23 AM > Subject: Re: [Elecraft] NGEN - is it working? > > >> John D'Ausilio wrote: >>> Noise increase should be unmistakable. Make sure the MMIC isn't in >>> backwards :) >> >> I was wondering if I'd mounted it "upside down", but as both the top >> and >> bottom leads are grounded, it looks as though, as long as the slanted >> lead is towards the centre of the board, I can't realistically get it >> wrong. >> >>> If you have a key attached and happened to transmit >>> into it, just order replacement MMIC (get 3, about $10 delivered :) >>> from Elecraft. >> >> I'm an SSB guy, don't know CW YET. I don't have a key, I do have a PTT >> switch, but only recently... Basically... >> >> I built NGEN, XG1, DL1 without being able to test them. I built the K2 >> and had no PTT or key connected. I transmitted into DL1 for the >> bandpass >> filter tweaking, but did no other transmitting until after building >> KSB2. I can be just about positive I've never transmitted into NGEN... >> And even if I had, it definitely wouldn't have been the FIRST thing >> I'd >> done to it, and as far as I can tell, NGEN has never worked, or at >> least >> not noticably. >> >> I'll try testing with AGC off, NGEN connected, and XG1 sat nearby on >> the >> bench so I have a signal to compare with my noise or lack thereof. >> >> If it still doesn't work, can I be fairly confident that it's the >> MMIC, >> or might it be the Zenner D2? Or indeed anything else? There's no >> "cheap >> and dirty signal tracing" or table of voltages for NGEN, is there? >> >> -- >> "Nosey" Nick Waterman, G7RZQ, K2 #5209. >> use Std::Disclaimer; [hidden email] >> Half the people you know are below average. >> _______________________________________________ >> Elecraft mailing list >> Post to: [hidden email] >> You must be a subscriber to post to the list. >> Subscriber Info (Addr. Change, sub, unsub etc.): >> http://mailman.qth.net/mailman/listinfo/elecraft >> >> Help: http://mailman.qth.net/subscribers.htm >> Elecraft web page: http://www.elecraft.com >> > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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