No I didn't have to narrow the span to 2 kHz to see the -127 dBm signal. Anything less than about 30 kHz was sufficient.
Also, remember I had the K3 preamp off and the attenuator on. With the attenuator off, the -127 dBm signal is visible all the way up to 200 kHz span. With the K3 preamp turned on I can see a -135 dB signal, even at 200 kHz span. (I had to use a 10 dB attenuator to get the signal generator to go that low.) Alan N1AL On Tue, 2010-09-14 at 07:51 -1000, Merv Schweigert wrote: > For some reason that goes against what I think many are looking for in the > P3, if one has to narrow the span to 2khz, then I see no use for the P3 > at all, I need > to see what is on the band at -127DBm at 30 to 50khz or more span. If > the signal is > only seen at 2KHZ, I can hear that by ear and dont need the P3. I > think VHF > operators are saying the same thing, they need to look over a larger > portion of the > band and spot weak signals and move to them, not narrow to 2KHZ and sit > there > and tune the radio hoping to find a weak signal, thats what you do > without a P3. > Does the LP Pan also work that poorly that you cannot see weak signals > 30KHZ > away? > I do notice that with all the P3 sales, you do not see many LP Pans for > sale, so either > people who buy the P3 are just buying it to have another Elecraft > product, or they are > keeping both and not sure yet which is the best? > Most of my operation will be low band, 160 meters, and if I cannot see > the weak > signals on the band and cover at least 30 KHZ then the P3 is of no use > at all. > Bill W4ZV are you seeing the weak signals on 160 that are 20 or 30KHZ away? > Or do you have to narrow the span down to see a signal that is barely > audible? > 160 ops would like to know. > 73 Merv K9FD / KH7C > > > > Hi Larry, > > > > It depends on the span. Unlike some other panadapters, the P3 > > automatically reduces the sample rate as you narrow the span, which > > improves the sensitivity. > > > > For example, I have my HP8656B signal generator set to 3640 kHz with the > > amplitude as low as it will go (-127 dBm). The K3 has the preamp off, > > the attenuator on, and default CW shift and width. Under those > > conditions I can just barely hear the carrier. It's weak enough that if > > it were a modulated CW signal I don't think I could copy it. > > > > However the carrier is clearly visible on the waterfall if I set the P3 > > span to 2 kHz. As I increase the span the signal gradually gets harder > > and harder to see. Above about 30 kHz or so the signal disappears into > > the noise. > > > > So that's the trick. Narrow the span to make those signals pop out of > > the noise. > > > > 73, > > > > Alan N1AL > > > > > > On Tue, 2010-09-14 at 06:03 -0700, Larry K1UO wrote: > > > >> Bill, > >> > >> I can tell you that just last night, on 160 meters, I copied 2 very weak > >> stations perfectly Q5 that did not show on the P3 waterfall. Now, Its > >> entirely possible its my adjustment skills but I dont think so. Yes..the > >> K3 > >> IF Mod was factory installed. This has happened more than once. For > >> some reason I was expecting the P3 to show these very weak signals better > >> than I could find them myself while tuning but no amount of adjustment so > >> far will do this. I may be expecting too much? > >> Just so you know what anothers experience has been so far. > >> 73 > >> > >> > >> > >> > >> I too would like to see details of the improvement over LPan etc. I am a > >> long time user of SDR/computer panadapters for use in detecting very weak > >> signals at UHF/VHF/microwave. I use a Softrock on the K3 IF port since I > >> got > >> my K3 a year ago. I have yet to see one report regarding weak sig > >> detection > >> with the P3 after many requests to the initial testers of the P3. ANYONE > >> out > >> there looking for weak weak sigs with a P3?? > >> > >> 73 Bill K0AWU EN37ed > >> > >> > >> > > > > > > ______________________________________________________________ > > Elecraft mailing list > > Home: http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto:[email protected] > > > > 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:[email protected] > > 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
