Might be both. matt
On Thu, 13 Sep 2012 08:41:20 -0400, you wrote: >Very interesting. I was operating at our local submarine for Museum Ships >Day, using my K2 in the field about 200 yards away from the sub from which >they were operating SSB on 20 meters. I tried to operate 20m CW but the >"whooshing" on the band anywhere in the CW segment was just too much. I >thought it was just blow-by of the K2's xtal filters, but I think now I'm >learning it was the dirty transmitter they were using - not sure which one. > >Chip >AE5KA > >On Thu, Sep 13, 2012 at 12:18 AM, Matt Zilmer <[email protected]> wrote: > >> My case study may not be any less interesting than others you've >> heard. During Field Day, 2011 K3 #24 (mine) was the centerpiece of >> our group's CW effort. The group was a number of aligned clubs, and >> we operated 12F (emergency operations center, 12 stations). You can >> imagine the HF overlap involved, since there were nearly always two >> stations on one band but on different modes. Our site was about 350 >> meters in diameter with stations around the outside edges and a couple >> on VHF/UHF in the middle. >> >> Dave, W3DMA, is also a K3 owner. He and I were partnered on the CW >> station. We operated 19 hours out of the 24 allowed, for about 800 >> contacts. This isn't awful, but it should have been better. The main >> cause of our CW count being so low was phase noise from other stations >> on the same band at our site. Many were running > 100W too. That >> WHOOSH Wayne mentioned wiped out a lot of received transmissions on >> our end, and we had to constantly ask for AGNs due to a transient high >> noise floor. We could see that 15-20 dB rise of the floor on the P3 >> quite easily. The screen went mostly white during those times. >> >> Now - I KNEW better, but I went around to the other stations when they >> were operating on same bands as the CW station (Dave at the key, were >> at the computer). They weren't hearing us AT ALL and didn't even know >> we were on the same band! Except for our roving spotter with a >> broadband panadapter who could see my K3 but not hear it. No key >> clicks from us, but of course you could hear them all over the band(s) >> from remote stations. >> >> Phase noise and key clicks are the enemy. I respectfully suggest that >> Wayne emphasize (as well) that designing a transceiver to >> intentionally not produce either of these is a worthy objective more >> on a moral plane than an operating advantage. Tactically, having >> clicks and wideband noise could be put to advantage against other FD >> groups. As Wayne pointed out, phase noise may limit receiver >> sensitivity (if it's not limited first by other factors), but most >> hams have never thought about it that way. I suspect, in practice, >> that in other transceivers phase noise is not the limiting factor in >> sensitivity - mainly because the front end design is shoddy compared >> to the K3. Front end noise figure is perhaps a larger factor in many >> cases. >> >> The main real-world problem is that the K3 is a minority in the >> general ham rig population. Maybe someday, the K3 penetration rate >> will be high enough that we can hear it in how quiet the bands are. >> Crowded but quiet between signals that is. >> >> 73, >> Matt Zilmer, W6NIA / NNN0UET / NNN0GAF THREE >> NMCM RMS Winmor: NNU9ET-5: Upland, CA. >> NAQCC: 6081, 10-10: 10413, KX3 #6/FT >> >> ______________________________________________________________ >> 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
