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21. Re: Topband: Re: eliminating radio hum/hiss (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Fri, 06 Feb 2004 22:46:42 -0500
Well, manufacturers frequently produce "quiet" receivers by filtering out most of [noise AND signal] energy above ~1 kHz. Typical cutoff starts at 1 kHz with ~15 dB attenuation at 2.7 kHz. This remov
/archives//html/Topband/2004-02/msg00122.html (7,273 bytes)

22. Re: Topband: Re: eliminating radio hum/hiss (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Sun, 08 Feb 2004 09:24:04 -0500
Please read "higher speech frequencies" as 1000-2700 Hz. Removing them is quite wrong for SSB, although it's very good for CW. 73, Sinisa YT1NT, VA3TTN _______________________________________________
/archives//html/Topband/2004-02/msg00126.html (7,287 bytes)

23. Re: Topband: Input Impedance of the FT1000/S-Meter Calibration issues (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Tue, 10 Feb 2004 04:09:32 -0500
Mismatch loss doesn't apply to this case. The variation was observed with a constant current source, not 50 Ohm source. Power delivered to FT1000 input is R * I ^ 2, where R is the real part of input
/archives//html/Topband/2004-02/msg00142.html (8,278 bytes)

24. Re: Topband: Input Impedance of the FT1000/S-Meter Calibration issues (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Tue, 10 Feb 2004 18:25:23 -0500
Hi Tod, Thank you. It certainly cannot be fixed that way, although its external manifestation can be masked out. In theory, it could be fixed by redesigning some of input circuits, but I don't think
/archives//html/Topband/2004-02/msg00150.html (10,698 bytes)

25. Re: Topband: FEEDING AN END-FED LONGWIRE (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Wed, 03 Mar 2004 21:12:38 -0500
Of course that it is a myth that an antenna can be end-fed, but that fact does not prevent your antenna to work in some other way and serve your needs so well. Your antenna is as much center-fed as a
/archives//html/Topband/2004-03/msg00018.html (7,702 bytes)

26. Re: Topband: FEEDING AN END-FED LONGWIRE (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Thu, 04 Mar 2004 08:04:18 -0500
Well, the radiation may or may not be as described, but one thing is for sure: common mode feeder current is exactly equal to the current feeding the "antenna". That's physics. 73, Sinisa YT1NT, VA3T
/archives//html/Topband/2004-03/msg00025.html (7,928 bytes)

27. Re: Topband: FEEDING AN END-FED LONGWIRE (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Wed, 10 Mar 2004 13:21:39 -0500
The ratio of 81:1 would be quite an accomplishment. Did you perform any impedance measurements? 73, Sinisa YT1NT, VA3TTN _______________________________________________ Topband mailing list Topband@c
/archives//html/Topband/2004-03/msg00133.html (8,470 bytes)

28. Re: Topband: FEEDING AN END-FED LONGWIRE (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Wed, 10 Mar 2004 22:01:27 -0500
No, there isn't a myth than such an antenna is no good. But there is a myth about how such an antenna actually works. This has been explained decades ago, and one reference springs to mind: The Black
/archives//html/Topband/2004-03/msg00145.html (9,057 bytes)

29. Re: Topband: Help needed: Windom & MFJ-259B measurements (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Fri, 23 Jul 2004 08:50:38 -0400
It is very difficult to do it correctly. Due to highly assymetric construction, common mode voltage is very high at the feedpoint, possibly exceeding driving voltage. A balun with exceptionally high
/archives//html/Topband/2004-07/msg00050.html (8,013 bytes)

30. Re: Topband: Adding radials, a question (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Thu, 02 Sep 2004 03:23:05 -0400
... Please describe your measurement setup and procedure. Assuming that nothing went wrong with measurements, there are two possible explanations of your findings. The first (and more probable, I'd g
/archives//html/Topband/2004-09/msg00001.html (8,150 bytes)

31. Re: Topband: Adding radials, a question (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Thu, 02 Sep 2004 06:39:53 -0400
... After a second thougth, I'm less sure about what actually happens. Although the ground loss resistance can be higher with 1/2 wl radials than with 1/4 wl radials (as described), it should nevert
/archives//html/Topband/2004-09/msg00002.html (6,999 bytes)

32. Re: Topband: 160m noise (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Wed, 10 Nov 2004 20:03:11 -0500
Although it's a good idea to dissipate the incident RF power, a choke can be very effective if designed with parallel resonance at RF frequency. Series impedance will be very high (many tens of kOhms
/archives//html/Topband/2004-11/msg00073.html (10,092 bytes)

33. Re: Topband: 160m noise (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Wed, 10 Nov 2004 20:03:47 -0500
With high imepdance antennas one needs much better chokes than with 50-Ohm antennas. I would recommend winding RG174 (or even smaller coax) on FT240-43. You must wind enough turns to position the par
/archives//html/Topband/2004-11/msg00074.html (8,529 bytes)

34. Re: Topband: Close to earth Beverage. (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Fri, 19 Nov 2004 22:28:35 -0500
Have you tried the same test with sloping wires? 73, Sinisa YT1NT, VE3EA _______________________________________________ Topband mailing list Topband@contesting.com http://lists.contesting.com/mailma
/archives//html/Topband/2004-11/msg00201.html (8,501 bytes)

35. Re: Topband: Close to earth Beverage. (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Sat, 20 Nov 2004 15:45:40 -0500
Sounds logical to me, but that would invalidate any advantage of using sloping vs. vertical terminations. I think Tom W8JI noted earlier that there is actually no advantage at all, and I was just cur
/archives//html/Topband/2004-11/msg00204.html (8,589 bytes)

36. Re: Topband: buried radial problems. (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Thu, 23 Dec 2004 09:21:50 -0500
Just had a quick look at http://www.kintronic.com/site/techpapers/KTL_NAB_Paper.pdf Must admit that I failed to see anything new, let alone revolutionary in the design shown on Figure 1. I can only
/archives//html/Topband/2004-12/msg00289.html (9,116 bytes)

37. Re: Topband: "Is your feedline also an antenna?" (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Mon, 10 Oct 2005 17:16:58 -0400
Could you estimate how many dB's are represented by "TOTALLY "? 6, 16, 26? 73, Sinisa _______________________________________________ Topband mailing list Topband@contesting.com http://lists.contesti
/archives//html/Topband/2005-10/msg00055.html (9,261 bytes)

38. Re: Topband: Antenna Impedance vs efficiency (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Wed, 23 Nov 2005 09:21:10 -0500
It is the ratio of electric intensity to magnetic intensity, in the "far" or "radiation" field. No, there isn't. No. 73, Sinisa YT1NT, VE3EA _______________________________________________ Topband ma
/archives//html/Topband/2005-11/msg00283.html (7,150 bytes)

39. Re: Topband: Horizontal antennas (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Mon, 09 Jan 2006 19:57:00 -0500
Could you recommend some introductory reading on the interaction between Earth's magnetic field orientation and wave polarization? 73, Sinisa YT1NT, VE3EA ____________________________________________
/archives//html/Topband/2006-01/msg00117.html (7,052 bytes)

40. Re: Topband: 1/4 versus 1/2 wave vert. (score: 1)
Author: Sinisa Hristov <shristov@ptt.yu>
Date: Fri, 13 Jan 2006 21:51:44 -0500
Unfortunately, it will not work that well. Progressing from base, the ground current will increase, reaching significant values rather quickly. 73, Sinisa YT1NT, VE3EA _______________________________
/archives//html/Topband/2006-01/msg00218.html (8,090 bytes)


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