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Total 37 documents matching your query.

1. Re: Topband: FT1000 MKV Filters (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Fri, 25 Jul 2008 13:37:26 +0200
For weak signal work with no strong signals capable of overloading RX stages, there is no advantage in installing 250 Hz at 8215 kHz IF. Operating comfort may be increased slightly by a narrow filter
/archives//html/Topband/2008-07/msg00087.html (7,808 bytes)

2. Re: Topband: FT1000 MKV Filters (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Fri, 25 Jul 2008 14:48:40 +0200
My mistake, NOT is missing, should read as follows: Operating comfort may be increased slightly by a narrow filter, such as Inrad's 125 Hz at 455 kHz IF, or the built-in 60 Hz DSP APF. They will NOT
/archives//html/Topband/2008-07/msg00088.html (7,794 bytes)

3. Re: Topband: Wideband x-former... (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Tue, 31 Mar 2009 04:09:54 +0200
You need a trifilar winding, i.e. wind it using three parallel wires. Then connect wires in series, just as if you had three separate windings. To match 50 Ohm to 22 Ohm proceed as following. Let the
/archives//html/Topband/2009-03/msg00118.html (7,810 bytes)

4. Re: Topband: Ground Radials & Multi-Element Antennas (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Thu, 05 Nov 2009 15:14:29 +0100
I've seen such an advice, but no explanation was given. In absence of some good reason to pass an electric current from wire A to wire B, I'd rather keep those wires unconnected. 73, Sinisa YT1NT, V
/archives//html/Topband/2009-11/msg00167.html (7,719 bytes)

5. Re: Topband: Elevated Radials (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Thu, 21 Oct 2010 18:20:54 +0200
5 x 100 ft, or even 6 x 83 ft will do better than just a few longer ones. 73, Sinisa YT1NT, VE3EA _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
/archives//html/Topband/2010-10/msg00108.html (7,320 bytes)

6. Re: Topband: SDR/DSP pulls out signals HOW FAR down in the noise? (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Mon, 20 Dec 2010 18:08:40 +0100
Those two files are completely unrelated, even the duration is not the same. The file http://www.sdrham.com/bin/cq_unfiltered.mp3 has a very weak signal on 650 Hz. The file http://www.sdrham.com/bin/
/archives//html/Topband/2010-12/msg00084.html (7,720 bytes)

7. Re: Topband: 160 metre vertical with 'top loading' (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Mon, 25 Apr 2011 15:55:00 +0200
Perfectly true. Wait a minute, a piece of coiled wire is not a perfect inductor! It's a completely different beast: the perfect inductor has zero length, but a piece of coiled wire almost always has
/archives//html/Topband/2011-04/msg00121.html (7,949 bytes)

8. Re: Topband: 160 metre vertical with 'top loading' (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Wed, 27 Apr 2011 12:36:04 +0200
A current decrease (meaning less current at one end that at the other) is not a loss, and it's far from being unexplained. It's caused by the standing wave, just like the current decrease on a straig
/archives//html/Topband/2011-04/msg00145.html (9,477 bytes)

9. Re: Topband: question about RX splitter (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Tue, 18 Oct 2011 05:25:07 +0200
Capacitance from primary to secondary will degrade common mode isolation on higher frequencies. Depending on your needs, it may still be sufficient. The splitting and matching function is fine. The n
/archives//html/Topband/2011-10/msg00142.html (9,136 bytes)

10. Re: Topband: Ground loss query (re inverted L, antenna radiation resistance, & Jerry Sevick) (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Wed, 19 Oct 2011 20:28:56 +0200
... ... Folding has nothing to do with either radiation resistance or ground losses. It is impedance-transforming device only. You've just performed 1:4 impedance transformation, nothing else. 73, Si
/archives//html/Topband/2011-10/msg00156.html (8,470 bytes)

11. Re: Topband: More Amplifier info (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Sun, 08 Jul 2012 17:17:29 +0200
I did a detailed study of this device last year, and can confirm that the marketing story of being able to handle SWR of 65:1 is an absolute nonsense. 73, Sinisa YT1NT, VE3EA ________________________
/archives//html/Topband/2012-07/msg00111.html (7,377 bytes)

12. Re: Topband: S21 impedance measurements (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Sat, 14 Jul 2012 22:16:04 +0200
If one wishes to look at this as a simple voltage divider, then the end of the souce cable should be terminated in 50 Ohms, assuming that the unknown impedance is substantially higher. If there is a
/archives//html/Topband/2012-07/msg00195.html (8,054 bytes)

13. Re: Topband: Vertical Array Over Uneven Ground (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Thu, 15 Nov 2012 12:39:59 +0100
It's fun to learn that Dr. Maxwell, the inventor of electromagnetic waves, had used metric units exclusively 200 years ago. So, why we cannot do the same today? 73, Sinisa YT1NT, VE3EA ______________
/archives//html/Topband/2012-11/msg00223.html (7,820 bytes)

14. Re: Topband: Lab style comparison results on 160m small lot antenna changes. (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Fri, 21 Dec 2012 16:07:55 +0100
The question of correlation with reality must be answered for each particular sumulation. NEC works most accurately with straight thin wire antennas. It leaves much to be desired with telescopic tub
/archives//html/Topband/2012-12/msg00559.html (8,956 bytes)

15. Re: Topband: Hairpin Matching Coil Questions (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Sat, 14 Sep 2013 18:47:41 +0200
A hairpin or a parallel matching inductor should be adjusted this way: 1. select inductance (hairpin length); 2. adjust wire length for the desired resonant frequency. Repeat 1 and 2 until you get SW
/archives//html/Topband/2013-09/msg00202.html (6,951 bytes)

16. Re: Topband: Ferrites and verticals (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Wed, 13 Aug 2014 12:38:27 +0200
The purpose of a choke is to prevent the coax shield from becoming a part of your antenna. Do you want to connect directly to your antenna a long conductor with random length and position, connected
/archives//html/Topband/2014-08/msg00106.html (8,613 bytes)

17. Re: Topband: 160M loading coil mounting/orientation (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Mon, 08 Sep 2014 15:06:59 +0200
Orientation doesn't matter. Place it as you would place any other inductor, i.e. 1-2 coil diameters away from other metallic objects, and from soil. Protect it from elements, and that's it. 73, Sinis
/archives//html/Topband/2014-09/msg00074.html (7,451 bytes)

18. Re: Topband: TX relays (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Thu, 09 Oct 2014 19:20:20 +0200
10 kV between contacts, or 10 kV between a contact and the coil? 73, Sinisa YT1NT, VE3EA _________________ Topband Reflector Archives - http://www.contesting.com/_topband
/archives//html/Topband/2014-10/msg00037.html (8,859 bytes)

19. Re: Topband: Modeling "Ground" (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Tue, 24 Feb 2015 17:41:47 +0100
Sommerfeld integral is not an approximation, has not been tuned, and has no provision for tuning. Sommerfeld integral is an exact solution of Maxwell equations for the case of infinite, plane and hom
/archives//html/Topband/2015-02/msg00605.html (8,343 bytes)

20. Re: Topband: Modeling "Ground" (score: 1)
Author: shristov <shristov@ptt.rs>
Date: Tue, 24 Feb 2015 18:49:47 +0100
This is interesting. Where in those 10,000+ lines is the tuning hack? 73, Sinisa _________________ Topband Reflector Archives - http://www.contesting.com/_topband
/archives//html/Topband/2015-02/msg00609.html (7,762 bytes)


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