> Chris > TP4 is not all that helpful its a control signal. > So let me back up for a minute. What are we troubleshooting? > I was thinking band 2 was semi working and you still had a totally dead > band 3. > My comments have been around trying to see what was going on with 3. > Other comment. > I think we should take this offline. Most likely driving time-nuts nuts. :-) > Do you use skype? > Regards > Paul
> On Sun, Dec 9, 2012 at 11:29 AM, paul swed <paulsw...@gmail.com> wrote: >> Didier is 100% correct though I use a 10 db pad for exactly the same >> purpose. You have to be careful. In your case there is a +28 db power amp >> that feeds the yig mixer in the 545. That would destroy the spectrum >> analyzer frontend. In fact if measuring that component you would want 30 db >> of loss using a 2 watt pad. Most spectrum analyzers run in the 0 to +5 or >> so db range. >> >> All of that said I actually have to look at your other comments to make >> some sense of what you are seeing. >> Regards >> Paul >> WB8TSL >> >> >> On Sun, Dec 9, 2012 at 7:22 AM, <shali...@gmail.com> wrote: >> >>> Good practice with a spectrum analyzer is to put a 20 dB pad at the input >>> all the time unless you are sure you don't need it for a particular >>> measurement. >>> >>> It has saved my bacon many times. >>> >>> It also protects the input connector from excessive wear. >>> >>> Didier KO4BB >>> >>> >>> Sent from my Droid Razr 4G LTE wireless tracker. >>> >>> >>> >>> -----Original Message----- >>> From: Chris Wilson <ch...@chriswilson.tv> >>> To: Chris Wilson <ch...@chriswilson.tv>, Discussion of precise time and >>> frequency measurement <time-nuts@febo.com> >>> Sent: Sun, 09 Dec 2012 5:54 AM >>> Subject: Re: [time-nuts] EIP545A 18GHz counter query >>> >>> >>> >>> > Did do some more reading and I think what I suggest is the right >>> approach. >>> > Band 2 and 3 use the same VCO. So if band 2 is generally working >>> > then its possibly the rf multiplier yig filter mixer diodes etc. But >>> > if the RF detectors show RF then its going to be a much more >>> interesting issue. >>> > I do not know what sort of test equipment you might have. I have >>> > spectrum analyzers and such. And do agree without extenders that I >>> don't have its a royal pain. >>> > Regards >>> > Paul. >>> >>> >>> 09/12/2012 11:45 >>> >>> Thanks very much for your input with this, much appreciated. I do have >>> a spectrum analyser, but it's a bit like having a set of surgeons >>> implements. Interesting to have, but needing the requisite skill to >>> use safely :) I can do only the most basic stuff, to be frank I am >>> very wary of blowing the input stage up by doing something daft! >>> >>> I think I follow your train of thought here Paul. But, before seeing >>> your post I did some tests at TP4, to see if the unit was constantly >>> scanning for a signal when on Band 2. here is what I found and saw: >>> >>> I have now refitted the new Q12, and removed the test 1k resistor. >>> >>> OK, the trace from TP4 does different things depending what band it is >>> on. Bands 1 and 3 it just sits there, #1. On Band 2 it gives what appears >>> to be two traces, #2. Changing the timebase gives the other trace I show >>> linked, #3. On bands 1 and 3 only a single trace appears. So Band 2 is >>> doing something different at TP4, with no input signal. Warm Q12 with >>> an input signal to Band 2 and the two traces change to a single trace, >>> #4. >>> >>> Once it cools again the two traces return. >>> >>> Traces: >>> >>> #1 http://www.gatesgarth.com/scope/TP4-band1.jpg >>> >>> #2 http://www.gatesgarth.com/scope/TP4-band2.jpg >>> >>> #3 http://www.gatesgarth.com/scope/TP4-...t-timebase.jpg >>> >>> #4 http://www.gatesgarth.com/scope/TP4-...put-signal.jpg >>> >>> I would need explicit instruction to poke about using the SA. It's an >>> HP 8568B. Thanks again Paul :) >>> >>> >>> >>> -- >>> Best Regards, >>> Chris Wilson. >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> >> > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. 09/12/2012 19:53 Will send direct e-mail thanks for everyone's he;p and patience. -- Best Regards, Chris Wilson. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.