Re: [Elecraft] K3 Dual Receive Surprise
It is not unusual for me to hear some sort of multipath propagation on 20m late in the afternoon here in Arizona when beaming to Japan (single receiver and 4 element yagi with a good F/B ratio). The disparity in arrival time is often enough to make signals totally unreadable at CW speeds of roughly 25 WPM. The middle of a character or even a word sometimes just sounds like a continuous carrier. This might go on for an hour or more until one of the paths disappears. I have on two occasions this winter even heard three different arrival times for the same signal, which was very weird and I wish I had recorded it. Given the differences in path length necessary to generate that kind of delay I make no claim regarding the cause ... only that I have clearly heard it several times. In any case, if such delays are enough to blur 25 WPM CW, they would be enough to be easily noticed in static crashes. Of course, that still requires some sort of polarity disparity to create the effect observed by Mr. Zilmer.73,Dave AB7EStephen W. Kercel wrote:Recall that radio waves move at 3 x 10^8 meters per second. If you look at multi path propagation at HF radio waves over intercontinental distances, and suppose that your two receivers were responding to two different signals taking two different paths, the differences in time of arrival of the different signals would be 1/1 second or less the delay is many orders of magnitude too short for your internal cognitive processes to detect the difference in arrival time of RF wave fronts. ___ 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] AGC Setting for PSK-31
One of the premium PCI sound cards highly recommended by N8LP (the M-Audio Audiophile 2496) for use with LP-PAN, albeit with a 90 KHz display limitation, is currently available for $85 at Amazon.com, and it might be found even cheaper elsewhere. http://www.amazon.com/gp/product/B6I5H5 73, Dave AB7E Original Message Subject: Re: [Elecraft] AGC Setting for PSK-31 From: "Simon \(HB9DRV\)" Date: Thu, January 22, 2009 11:16 am A *very* good reason for using a second soundcard is that Windows will not use it for send the clicks, clacks and beeps you hear while playing with your PC. On SSTV it's easy to see when someone is using the internal soundcard instead of second card. A good soundcard will not suffer from intermod - just like a good radio. So even if you don't want to shell out for a microHam spend $50 and get a second soundcard anyway and use this for your radio. Simon Brown, HB9DRV www.ham-radio-deluxe.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
Re: [Elecraft] Digital mode Identification
I've searched around for similar information and so far this is the best I've found: http://www.w1hkj.com/FldigiHelp/Modes/index.htm It shows waterfall, spectrum, and audio samples of most of the common digital modes (listed at the left of the page). The comparison comments at the bottom left link are interesting as well.. 73, Dave AB7E Original Message Subject: [Elecraft] Digital mode Identification From: "Frank MacDonell" Date: Thu, January 15, 2009 4:54 pm To: Elecraft How can a newbie to digital modes identify signal types on the waterfall? Tnx. Frank KD8FIP ___ 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] Using K3's Pre-amp
Adam,If you suspect a local source for the noise, you might consider making an mp3 recording of it. There are some hams out there who have a LOT of painful experience chasing down noise sources and have become pretty good at identifying the sounds. I'm sure there are some of those experts here on the Elecraft reflector, as well as on the Contesting reflector. You could upload the mp3 file to your website and forward the links. 73, Dave AB7E Original Message Subject: Re: [Elecraft] Using K3's Pre-amp From: "Adam Koczarski" Date: Mon, January 12, 2009 8:47 am To: I just ran a noise experiment at my QTH yesterday. My typical noise is s7.0 S6.5 s7.5 on 80m, 40m & 20m respectively. With every circuit in the house off, except the one the radio is on, and with only the power supply and the radio on that one circuit the noise is s4.0 S4.75 s5.0. I turned on circuits one at a time and recorded to S level jump for each. The 'home entertainment center' seems to be the biggest contributor so I'll start there. Now I just need to figure out how the switch off the neighborhood transformers and silence my neighbors! :) I have some fairly large power lines across the street. Are they usually strong contributors to noise? You can see the resulting data here: http://www.ka7ark.com/20080111QTHnoise/pics.html Adam - ka7ark ___ 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
