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101. [TowerTalk] vertical mast calculations (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Sun Mar 23 14:29:38 2003
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA.
/archives//html/Towertalk/2003-03/msg00306.html (9,093 bytes)

102. base insulator ideas was Re: [TowerTalk] vertical mast calculations (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Sun Mar 23 21:18:21 2003
One can get structural fiberglass shapes fairly inexpensively. Cost wise, it's about the same as aluminum in the same size, and the strength is, to a first order, the same as aluminum. It's twice as
/archives//html/Towertalk/2003-03/msg00314.html (8,348 bytes)

103. [TowerTalk] High tension power lines ? (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Mon Mar 31 12:20:11 2003
Fascinating question... First question for you: What kind of power lines? LV feeders (240V), MV distribution stuff (14-30 kV) or HV transmission lines (100 kV+). They'll all have different kinds of i
/archives//html/Towertalk/2003-03/msg00432.html (9,292 bytes)

104. [TowerTalk] Tower-shack Grounds (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Mon Mar 31 18:12:48 2003
You need to separate "grounding for lightning protection", "RF grounding", and "safety ground" as concepts. If you're driving the tower as a radiator, then the ground at the tower is the "RF ground".
/archives//html/Towertalk/2003-03/msg00444.html (9,559 bytes)

105. [TowerTalk] Idea Hamshack (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Mon Mar 31 23:08:16 2003
But NEC is reallly addressing the safety ground, not coax ground, which can (and might) be different. I've just been going through the IEEE Emerald Book (IEEE std 1100) parsing it out, and it has muc
/archives//html/Towertalk/2003-03/msg00453.html (9,486 bytes)

106. location of magnetic north pole Re: [TowerTalk] compass question (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Mon Feb 10 19:57:40 2003
I misstated the approximate location of the Magnetic North pole as 70N,100W. As everyone knows, it does move, and one can probably identify the age of the reference by the latitude they cite. In 2002
/archives//html/Towertalk/2003-02/msg00237.html (9,211 bytes)

107. [TowerTalk] compass question (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Mon Feb 10 19:58:23 2003
To: <towertalk@contesting.com>
/archives//html/Towertalk/2003-02/msg00238.html (9,837 bytes)

108. [TowerTalk] Magnetic North Info & Map (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Tue Feb 11 12:42:12 2003
The Canadian site is actually fascinating... Lots of stuff there about how the magnetic field is NOT adequately represented by a dipole (What, no bar magnet in the middle of the earth?)... This is on
/archives//html/Towertalk/2003-02/msg00260.html (9,968 bytes)

109. time from cell phone was Re: [TowerTalk] Magnetic North Info & Map (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Wed Feb 12 12:58:13 2003
Indeed, while the various TDMA cell phone systems use GPS clocks for sync (such as the Z3801s you see available surplus), I don't know that the average phone actually gets a time message. Certainly,
/archives//html/Towertalk/2003-02/msg00292.html (8,719 bytes)

110. Fw: [TowerTalk] RE: Compass question (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Wed Feb 12 23:01:47 2003
any
/archives//html/Towertalk/2003-02/msg00312.html (9,558 bytes)

111. [TowerTalk] Driving Point Impedance (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Wed Feb 12 23:11:11 2003
What element currents did you assume for driving point Z? Phased 90 degrees each step? Apparent driving point Z changes with element currents, of course. I've been looking at phased arrays a lot, and
/archives//html/Towertalk/2003-02/msg00313.html (9,108 bytes)

112. [TowerTalk] Driving Point Impedance (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Wed Feb 12 23:18:00 2003
Just to check ballpark Mutual Z numbers.. for dipoles in free space for halfwave dipoles in free space .25 lambda R21= 40.9 .5 lambda , -12.7 .75 lambda, -24.8 (@ 0.7 lambda) to -18.6 (@0.8 lambda) R
/archives//html/Towertalk/2003-02/msg00314.html (8,740 bytes)

113. [TowerTalk] RE: Compass question (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Thu Feb 13 09:47:07 2003
The GPS receiver doesn't measure any bearings... it measures distance to the satellites, and does "tri-lateration" not "tri-angulation"
/archives//html/Towertalk/2003-02/msg00318.html (7,665 bytes)

114. [TowerTalk] Need engineering calcs for Tri-Ex W-67 (or W-51) (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Thu Feb 13 12:17:57 2003
Or, your local PE, after reviewing the old calcs, might find that the design meets the new standards, as well as the older ones. Or, for instance, you might find that the maximum antenna area might n
/archives//html/Towertalk/2003-02/msg00324.html (8,896 bytes)

115. [TowerTalk] RE: Compass question (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Thu Feb 13 12:35:19 2003
hmmm.. it used to be (pre 1970s) that you could approximate the change in deviation by 1/2 degree per decade (in California). But now that the magnetic north pole seems to be moving quite rapidly (40
/archives//html/Towertalk/2003-02/msg00325.html (9,898 bytes)

116. [TowerTalk] Digging the hole (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Thu Feb 20 12:41:13 2003
While not denying the putative benefits of healthy exercise in the outdoors (at least, that's what I tell the kids), a trip to the local equipment rental place might turn up some things that will mak
/archives//html/Towertalk/2003-02/msg00372.html (10,799 bytes)

117. [TowerTalk] Digging the hole...after the "dig" (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Thu Feb 20 14:34:23 2003
If you had to get a building permit for the tower base, it's unlikely that the "mix in the hole" approach will meet the inspector's approval. Not enough process control to ensure that the structural
/archives//html/Towertalk/2003-02/msg00380.html (9,061 bytes)

118. [TowerTalk] 80m 3element (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Sun Feb 23 19:24:59 2003
SNR usually applies to a link (i.e. transmitter to receiver) Are you assuming that the noise distribution is uniform around the antenna? Then the SNR would be the incoming signal power density, times
/archives//html/Towertalk/2003-02/msg00435.html (8,377 bytes)

119. [TowerTalk] Relays (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Tue Feb 25 13:09:40 2003
This brings up an interesting question... has anyone ever done some reasonable quantitative performance measurements on "non-RF" relays. Sure, they aren't nice vacuum relays, and they probably have a
/archives//html/Towertalk/2003-02/msg00470.html (10,029 bytes)

120. [TowerTalk] Clever Solution for moving a tower (score: 1)
Author: jimlux@earthlink.net (Jim Lux)
Date: Wed Feb 26 10:25:20 2003
Or, a 4 horse or stock trailer.. certainly it will take the weight.. might be a challenge getting it in the door of the trailer. Almost any tractor or front end loader can pick it up. MA-550 I'm it.
/archives//html/Towertalk/2003-02/msg00497.html (11,036 bytes)


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