The S-meter only reads the strength of the signals falling within the DSP passband. There may be other strong signals hitting the ADC outside the DSP passband, and these won't show on your S-meter.
73, Matt VK2ACL On 22/09/2012, at 3:18 AM, Edward R Cole <kl...@acsalaska.net> wrote: > At 01:09 AM 9/21/2012, Josh Lehan wrote: >> On 09/21/2012 12:23 AM, Edward R Cole wrote: >>> I have been running my KX3 as 28-MHz IF for my 144-28 transverter and >>> the transverter is a little gain deficient in Rx so I turn on the >>> preamp in the KX3 too boost the level a tad. Unfortunately after a >>> few minutes the preamp shuts off by itself. KX3 is sitting in Rx >>> monitoring a 2m FM frequency (29.210+116=145.210). >>> >>> I had the preamp set to 30-dB gain so thought maybe that was >>> overloading the receiver and the radio automatically adjusted for >>> overdriving. So I set the preamp to 10-dB gain. It still shuts off >>> by itself after a few minutes. >>> >>> Anyone see this happening? >>> 73, Ed - KL7UW >> >> I've seen that happen as well. If I have the preamp on, and tune a >> strong nearby station in the AM broadcast band, a little message like >> "HI SIGNAL" (I forgot the exact wording) will appear, and the preamp >> will turn itself off. Good thing, IMO, if it protects against >> overloading the receiver. It's easy to turn back on again, simply hit PRE. >> >> The message only flashes for a few seconds, so it's easy to miss. I >> kind of wish that alerts/warnings like this would stay on the screen >> longer, or at least until a control is pressed, so that they're not >> missed if the radio isn't actively being looked at right at that moment. >> >> Josh >> KJ6PVN > > > Josh if the signal were s9+40 I would agree with that, but the signal > just barely shows S1 flickering and not full quieting. The preamp > should not trip in that condition else it is not usable for any > signal. Use on 10m and 6m is necessary for good sensitivity. BTW > when I run the transverter on my K3 I see a signal of S9, so the KX3 > appears considerably less sensitive on 28-MHz. This is comparing by > looking the same IRLP node only 15-miles away which exhibits a stable > FM signal. That is why I wish to run the preamp. Monitoring a FM > channel should not require the operator to stare at the radio with > finger poised to push the PRE button. > > I'll run a comparative test using -107 dBm from my XG3. It shows S4 > when using the 144-28 transverter with the K3 (28-MHz with no preamp engaged). > > 73, Ed- KL7UW > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
