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Total 82 documents matching your query.

1. TopBand: Capacitors for Shunt Feed (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Sat, 1 Nov 1997 20:37:12 +0000; Hi Guys, The problem is ESR (equiv series resistance), not voltage. Ceramic single layer caps (especially HV types) have high series resistance and also have poor temperature stability so they drift.; /archives//html/Topband/1997-11/msg00018.html (7,809 bytes)
2. TopBand: Vertical Matching (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Tue, 4 Nov 1997 22:43:27 +0000; Hi Mike, Yes,why not use surplus CATV cable? Tune it for the middle of the contest area, a 1/4 marconi (even one made from wire) is TWICE as broad as a half wave antenna. That because the L/D ratio; /archives//html/Topband/1997-11/msg00051.html (9,300 bytes)
3. TopBand: Beverage baluns/transformers de W0AH (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Thu, 6 Nov 1997 09:19:21 +0000; While that does test the balun for impedance, it does NOT test it for loss. Many books recommend the WRONG core material for baluns, The cores have too high an initial permeability, some as high as; /archives//html/Topband/1997-11/msg00077.html (10,101 bytes)
4. TopBand: Beverage baluns/transformers de W0AH (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Fri, 7 Nov 1997 00:35:46 +0000; Hi All, To further complicate the problem, the type of transformer or balun and the power level also affects core selection. Carl is certainly correct, but another important fact is permeability of a; /archives//html/Topband/1997-11/msg00092.html (10,068 bytes)
5. TopBand: Beverage terminating resistor (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Sat, 8 Nov 1997 08:38:57 +0000; The usual procedure is to get the terminating impedance right (for maximum F/B, and then adjust the input transformer. Remember some transformer can be so crummy (especially ones with needlessly high; /archives//html/Topband/1997-11/msg00112.html (12,373 bytes)
6. TopBand: Beverage terminating resistor (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Sun, 9 Nov 1997 17:55:53 +0000; Good point Bill. What I've found in real life is the resistor doesn't "steer" the null much, it just makes it deeper. Does it work differently with virtual reality antennas? 73, Tom W8JI -- FAQ on W; /archives//html/Topband/1997-11/msg00128.html (9,291 bytes)
7. TopBand: polarization (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Mon, 10 Nov 1997 07:18:29 +0000; Hi Carl, I'd like to remember that, but I don't understand why that would be true. I do understand the part about the polarity not being dependent on the transmitters polarity, but not why the polar; /archives//html/Topband/1997-11/msg00134.html (7,689 bytes)
8. TopBand: Beverage terminating resistor (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Tue, 11 Nov 1997 06:56:09 +0000; Hi Bill, Any way we slice it, that is a 12% pattern null change that probably amount to a fraction of a dB directivity. In my experience, termination adjustmet changes null depth much more rapidly t; /archives//html/Topband/1997-11/msg00149.html (9,173 bytes)
9. TopBand: annoying 800 hz tone on 1840 (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Thu, 13 Nov 1997 07:41:44 +0000; To: <topband@contesting.com> 800 hz Any digital device. My Panasonic FAX machine can be heard for about two blocks, and I've had problems with everything from burglar alarms on up. Good luck Dennis,; /archives//html/Topband/1997-11/msg00175.html (7,658 bytes)
10. TopBand: Skewed propagation, TX RX angles (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Fri, 14 Nov 1997 07:20:05 +0000; To: <topband@contesting.com> It sure opened my eye Yuri (I only have one I). The question I have is how do you "see" it?? How large and high are your antenna arrays on 160 through 40? What chart rec; /archives//html/Topband/1997-11/msg00189.html (15,463 bytes)
11. TopBand: Stealth Wire Vertical (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Mon, 17 Nov 1997 06:56:30 +0000; The biggest problem is usually corona, and of course the very poor mechanical strength. If you have too much corna, you will curse because the antenna will slowly melt. This was discussed at length; /archives//html/Topband/1997-11/msg00230.html (7,343 bytes)
12. TopBand: Re: [AMPS] USE OF AUTO TRANSFORMER (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Mon, 17 Nov 1997 08:58:36 +0000; Hi Bob, You can run into several problems. First, all steel cores saturate at some flux level. When that happens, any additional primary voltage no longer adds core flux at the same rate. The result; /archives//html/Topband/1997-11/msg00232.html (8,536 bytes)
13. TopBand: Re: [AMPS] AMPLIFIER QUESTIONS? (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Mon, 17 Nov 1997 08:58:36 +0000; Your reply is incorrect Rich. True directional couplers, such as used in the Bird wattmeter, remain calibrated very well in spite of impedance excursions. The method of subtracing reflected power fr; /archives//html/Topband/1997-11/msg00233.html (8,127 bytes)
14. TopBand: Skewed propagation, TX RX angles (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Mon, 17 Nov 1997 08:58:36 +0000; Same observations here Bill. When the signal is near the geomagnetic pole, the path often skews 30 or so degrees. In Ohio, I noticed that with VS6DO morning after morning. VU, JT1 and others were th; /archives//html/Topband/1997-11/msg00234.html (9,375 bytes)
15. TopBand: skewed paths (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Tue, 18 Nov 1997 09:11:45 +0000; Hi Peter, (Woops, I changed software and I had my amps icon posting to topband! But that's ok, my topband was going to my sister. I guess I'll get a lump of coal for Christmas since I used to keep h; /archives//html/Topband/1997-11/msg00249.html (8,960 bytes)
16. TopBand: Skewed propagation, TX RX angles (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Tue, 18 Nov 1997 09:11:46 +0000; You are correct Carl, and I was wrong. I do recall skewing of signals during disturbed conditions. I was focused on NORMAL conditions, and should have been more clear. I also posted a post for amps; /archives//html/Topband/1997-11/msg00250.html (8,857 bytes)
17. TopBand: qso ?? (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Wed, 26 Nov 1997 10:34:18 +0000; Hi Glen, Please don't take this personal, but you struck a nerve with me. If you didn't copy the confirmation, technically you have NO contact even if he did come back. Stu Perry worked every station; /archives//html/Topband/1997-11/msg00387.html (7,571 bytes)
18. TopBand: UNI-HAT vs. GAP vs. GLADIATOR (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Fri, 3 Oct 1997 12:35:24 +0000; To: <topband@contesting.com> Most likely not Lane, if the antennas were the same height and had the same ground systems the antenna's performance would be about the same on 160. The Uni-hat is a good; /archives//html/Topband/1997-10/msg00027.html (8,889 bytes)
19. TopBand: Autek RF-1 Antenna Analyzer (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Mon, 6 Oct 1997 22:39:19 +0000; A bandpass or band reject filter would be the way to NOT go. The best device is a high Q parallel LC circuit right at the analyzer's terminals. By adjusting the parallel circuit for maximum impedanc; /archives//html/Topband/1997-10/msg00075.html (8,838 bytes)
20. TopBand: Folded unipoles (score: 1): Author: w8jitom@postoffice.worldnet.att.net (w8jitom@postoffice.worldnet.att.net); Date: Mon, 6 Oct 1997 22:39:19 +0000; You can find that in Electromagnetic Waves and Radiating Systems, Jordan-Balmain, on page 403 in "Antenna Fundamentals". The radiation resistance of a thin freespace folded dipole of any number of w; /archives//html/Topband/1997-10/msg00076.html (13,291 bytes)

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