Re: [Elecraft] K3 audio output v headphone sensitiviy
I've been using a Heil headset for many years with my FT 1000D, and now also the K3. I have never felt there is inadequate volume from either rig through the headphones. Using narrow filters on CW, the volume settings are about 60 per cent of full volume. And often I have to back off from that. Bob N7UA Bill W4ZV wrote: K7TV wrote: What is adequate headphone sensitivity may be highly dependent on operating mode and rig selectivity. Case in point: Many years ago I ordered an FT-1000 and a Heil headset (forget which model). Headset volume was fine for voice, and for CW using a wide filter. But the FT-1000, like the K3, can be set to very narrow CW filtering. This brings down the noise to far below what you have at more normal bandwidth. On a quiet band one can then work CW stations that are extremely weak. In my case, that is where the Heil headset became unuseable, because of inadequate volume. In my opinion, when trying to copy the weakest possible CW signal for a given bandwidth, the gain needs to be high enough that the noise level is quite loud. I sent the Heil headset back to the store. This episode begs the question: The K3 being famous for its quiet receiver, does it have enough rx audio gain to provide a loud background noise level in CW mode using the 50 Hz bandwidth, for an average speaker or for a reasonable headset (not Heil!)? I don't agree that's the best way to copy weak signals...but that's another issue in itself. http://www.eham.net/articles/9982 (A few days I broke that record at 26 uW). The sticker on my BM-10 states IMP 32 OHM, which is what I measure for each side. Using it: 50 Hz BW, max RF Gain, AGC-Fast and CONFIG: AF GAIN HI (default setting). AF GAIN is set to 12 o'clock for a comfortable level listening to a dummy load (i.e. strictly RX background noise). With any sort of band noise I would need even less AF GAIN. The 1 uV output (-107 dBm) from an XG1 is uncomfortably high and I backed off AF GAIN to ~10 o'clock for that. Both of my Heil ProSet headsets measure 200 ohms per side and they also have plenty of output with the K3. BTW I normally have CONFIG: AF GAIN set to LO for all my headphones. I can't explain others' problems but all 3 of my Heil headsets have plenty of AF gain with the K3...even for very weak signals buried in noise. 73, Bill ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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] K3 Filters
The K3 description mentions variable XTAL filters (up to three) in the front end, prior to the DSP. My question is: are these filters variable band width (similar to the K2, which used a filter whose BW could be changed as a function of voltage applied ) or are the filters variable in that multiple filters are switched to track with the DSP setting. IOW, if one has just the 500 Hz filter for the front end, can the BW of that filter be narrowed if one sets a tighter BW overall? Or does one need a narrower roofing filter to narrow the roofing filter stage BW? Thanks, Bob, N7UA ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
Re: [Elecraft] RF build up
It's a little known aspect of special relativity which was in fact predicted by Einstein's equations. That coupled with the Heisenberg Uncertainty Principle implies that as you approach a certin limiting speed in CW, the actual transmission speed will slow down and one will no longer be able to distinguish dots from dashes. - Original Message - From: Tom Mc [EMAIL PROTECTED] To: Thom R. Lacosta [EMAIL PROTECTED]; David A. Belsley [EMAIL PROTECTED] Cc: Elecraft Reflector elecraft@mailman.qth.net Sent: Tuesday, December 21, 2004 9:47 AM Subject: Re: [Elecraft] RF build up It's my understanding (from reading another list which is addressing this problem) that some of the RF will, in fact radiate, but that it slows down the speed of the signal. For example, one guy reports sending 27 WPM from his K2 but by the time it gets through the frozen RF build-up on his antenna, it was only 18 WPM. With this in mind, it might be a good time for me to go for the ARRL high speed endorsements on my code copying certificate. Just a thought... Happy Holidays Tom, WB2QDG K2 #1103 -Original Message- From: Thom R. Lacosta [EMAIL PROTECTED] To: David A. Belsley [EMAIL PROTECTED] Cc: Elecraft Reflector elecraft@mailman.qth.net Date: Tuesday, December 21, 2004 10:28 AM Subject: Re: [Elecraft] RF build up On Tue, 21 Dec 2004, David A. Belsley wrote: Does anyone know of a good way to remove frozen RF from an antenna? Considering the season, you might want to find some eggnog and see if it helps the RF escape. Even if it doesn't, if you drink enough, you may no longer be aware of/plagued by the frozen RF. 73,Thom-k3hrn www.zerobeat.net Home of QRP Web Ring, Drakelist home page, Free Classified Ads for amateur radio, QRP IRC channel Elecraft Owners Database www.tlchost.net/ Web Hosting as low as 3.49/month ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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: Elecraft@mailman.qth.net 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: Elecraft@mailman.qth.net 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] K2 Phase Noise
Has anyone come up with a mod that reduces phase noise on the K2? Thanks, Bob ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
