Search String: Display: Description: Sort:

Results:

References: [ +from:W8JI@contesting.com: 1348 ]

Total 1348 documents matching your query.

141. Topband: A wee bit more on power coupling (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Wed, 8 May 2002 22:17:36 -0400
Horizontal dipoles (and Inverted Vee Dipoles also) only have a perfectly horizontal polarization directly broadside to the antenna. The polarization gradually tilts, and reaches vertical directly of
/archives//html/Topband/2002-05/msg00077.html (8,167 bytes)

142. Topband: DSP and Digital Filter Effectiveness for (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Thu, 9 May 2002 23:03:45 -0400
The wide filter or a wider filter works best with the 1000D and all of my other receivers. The reason a DSP system works poorly on the audio line is the DSP system looks at wave shape. Noise normall
/archives//html/Topband/2002-05/msg00091.html (8,192 bytes)

143. Topband: A wee bit more on power coupling (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Thu, 9 May 2002 23:03:44 -0400
Hi Bob I asked: Then what are you saying? Below it sounds like you are saying the coupling would be worse, and so the dipole would have added attenuation to the tune of almost 24dB compared to a vert
/archives//html/Topband/2002-05/msg00092.html (8,424 bytes)

144. Topband: Comparing antennas (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Fri, 10 May 2002 00:03:21 -0400
Bill, Pete, and others, 24dB is significant loss, and vertically polarized losses were near zero dB. That should be very easy to see, since it is a profound difference in level. Some SSB transmitters
/archives//html/Topband/2002-05/msg00094.html (7,041 bytes)

145. Topband: More on 160 dipoles (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Fri, 10 May 2002 20:40:52 -0400
Typically I see large repeatable differences ONLY when comparing a low dipole (around 100 feet or less high) with a high dipole or vertical over a path several hundred miles long or longer. The aver
/archives//html/Topband/2002-05/msg00104.html (8,790 bytes)

146. Topband: Noise, DSP and Receivers (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Fri, 10 May 2002 20:40:52 -0400
DSP can work very well with impulse noise, just as well as a conventional blanker system, if bandwidth of the system before the DSP processing is wide and does not overload. The same is true with an
/archives//html/Topband/2002-05/msg00105.html (8,359 bytes)

147. Topband: Polarisation Coupling Loss - a broadcasters perspective (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Mon, 13 May 2002 09:01:04 -0400
Hi Bob, Some key elements appear to be missing in all of this. Were there ever any A-B tests made to confirm the predictions? Can you point me to descriptions of those tests? Is 20dB the maximum pos
/archives//html/Topband/2002-05/msg00115.html (7,922 bytes)

148. Topband: inveted L 3/8 (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Fri, 17 May 2002 21:45:41 -0400
While almost anything will radiate...with a short vertical section Inverted L making the antenna longer decreases the useful low-angle radiation. It also does not necessarily decrease ground losses
/archives//html/Topband/2002-05/msg00131.html (7,622 bytes)

149. Topband: tower resonance (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Tue, 21 May 2002 20:09:10 -0400
I generally use a field strength meter with a built-in loop antenna. I do a skeleton proof whenever anything is changed to be sure my vertical patterns are OK. It is possible to find inexpensive sel
/archives//html/Topband/2002-05/msg00150.html (7,791 bytes)

150. Topband: Shunt feeding a tower with side mounted yagi (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Tue, 28 May 2002 10:26:40 -0400
While "shield" may be a poor choice of words, a large yagi or yagis mounted low on a shunt-fed tower can have a detrimental effect on system efficiency if they are large enough or enough of them. I
/archives//html/Topband/2002-05/msg00185.html (9,834 bytes)

151. Topband: Re: Vactrols and Flag (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Sun, 14 Apr 2002 07:05:24 -0400
Hi Don, The impedance of the antenna is fairly low. A metallic mast won't make any difference as long as it is more than a fraction of an inch from the wire. 73, Tom W8JI W8JI@contesting.com
/archives//html/Topband/2002-04/msg00022.html (7,550 bytes)

152. Topband: Lightning and Beverages (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Mon, 29 Apr 2002 08:44:10 -0400
Having over 30 antennas is a good test bed for proving reliability of a system. I can't afford to constantly check and replace resistors after storms. Despite being in Georgia, with frequent afterno
/archives//html/Topband/2002-04/msg00063.html (9,652 bytes)

153. Topband: Lightning and Beverages (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Tue, 30 Apr 2002 07:48:48 -0400
Use a reasonably close-spaced spark gap across the resistors (making absolutely sure you use composition resistors of course). Same at the transformer end. One simple way to do that at the resistor
/archives//html/Topband/2002-04/msg00073.html (8,539 bytes)

154. Topband: Geomagnetic absorption of horizontally polarized antenna signals? (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Tue, 30 Apr 2002 07:48:49 -0400
I think the biggest problem for an absolute answer is a lack of reliable verification data. Very few amateurs have enough room to install a textbook perfect vertical, let alone a horizontal at a few
/archives//html/Topband/2002-04/msg00074.html (9,434 bytes)

155. Topband: Re: DX Pileup Practices (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Sat, 2 Mar 2002 07:50:58 -0500
What is defined as a "tail-ender"? I assume you mean calling **before** the DX station has sent "TU" or whatever the final close of a contact is? I agree with UVZ George's comments. Spreading people
/archives//html/Topband/2002-03/msg00024.html (8,105 bytes)

156. Topband: 160M coaxial loop (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Sun, 3 Mar 2002 16:21:45 -0500
Hi Frank, Most people incorrectly assume the shield "filters" electric fields, and allows magnetic fields to pass to what they assume is the "antenna" inside the shield. That concept is totally wrong
/archives//html/Topband/2002-03/msg00039.html (7,892 bytes)

157. Topband: Re: DX Pileup Practices (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Sun, 3 Mar 2002 16:21:45 -0500
Hi Robin, OK that makes sense. The moment you say "TU" or whatever you closing sequence is, then all is open. Before that, just be patient shutup and listen. 73, Tom W8JI W8JI@contesting.com
/archives//html/Topband/2002-03/msg00040.html (8,211 bytes)

158. Topband: Reactance problem (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Thu, 14 Mar 2002 05:59:15 -0500
An open shield connection or water in the cable can cause reactance to appear over a wide frequency range. Additional problems are dc or low frequency AC getting into the meter input, or the unit is
/archives//html/Topband/2002-03/msg00132.html (8,114 bytes)

159. Topband: Number of radials - elevated vs grounded (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Thu, 14 Mar 2002 05:59:15 -0500
Hi Don, That was a well thought-out post but I'd like to clarify one thing: That depends on how you define "enough" and what else you do at the feedpoint. With only three or four radials, there will
/archives//html/Topband/2002-03/msg00133.html (7,710 bytes)

160. Topband: Tunable External Preselector for better Beverage S/N? (score: 1)
Author: W8JI@contesting.com (Tom Rauch)
Date: Thu, 14 Mar 2002 22:02:50 -0500
That is a common assumption, but almost never true. Unless out-of-band signals or noise are actually overloading the receiver front end or mixers (which would indicate a VERY poor receiver), it will
/archives//html/Topband/2002-03/msg00141.html (7,303 bytes)


This search system is powered by Namazu