To: | towertalk@contesting.com |
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Subject: | Re: [TowerTalk] 80 mts four square or yagi? |
From: | Pete Smith N4ZR <n4zr@contesting.com> |
Date: | Tue, 10 Mar 2015 09:19:55 -0400 |
List-post: | <towertalk@contesting.com">mailto:towertalk@contesting.com> |
The *magic* of 1X/2X spacing is that it tends to cancel the second
vertical lobe. Depending on your takeoff angle needs, this might not be
a good thing, but on the other hand if you can switch to use just the
lower antenna you'll find that it emphasizes the same angles that the
stack cancels. You might look at 50/100 ft spacing too. HFTA's problems
with close spacing begin *much* closer than that - IIRC, <10 ft.
73, Pete N4ZR Check out the Reverse Beacon Network at http://reversebeacon.net, blog at reversebeacon.blogspot.com. For spots, please go to your favorite ARC V6 or VE7CC DX cluster node. On 3/9/2015 9:11 PM, W0MU Mike Fatchett wrote: What values did you get using HFTA. HFTA has some issues with very close spaced stacks. The numbers are wrong.Mike W0MU On 3/9/2015 7:09 PM, Jorge Diez - CX6VM wrote:Thanks Jim Sorry for the delay, just returning from along trip after ARRLDX SSB Is curious HFTA. It stopped my project for a two stack for 20 mts yagís.Since many contesters told me to put it at 69/139 ft, HFTA told me that thisis not the best distances.OK about your document, will read it, but here we don´t have such facilities than in USA to know ho´w the ground conductivity, the terrain data, etc, etc73, Jorge -----Mensaje original----- De: TowerTalk [mailto:towertalk-bounces@contesting.com] En nombre de Jim Brown Enviado el: domingo, 08 de marzo de 2015 02:44 p.m. Para: towertalk@contesting.com Asunto: Re: [TowerTalk] 80 mts four square or yagi? On Sun,3/8/2015 10:06 AM, Jorge Diez CX6VM wrote:Wish someone have some analysis or field test to compare a 4SQ with sixty 1/4 WL radials each vertical and a 3 element wire yagi with boom at 115ftThis is not exactly the answer, but it should help you think about it. http://k9yc.com/VertOrHorizontal-Slides.pdf Also, if the land around you is not flat, you also need to study and useHFTA extensively. It comes on the CD with the ARRL Antenna Book. HFTA tellsonly about horizontally polarized antennas, NOT verticals, because theyinteract with the earth very differently. The slides tell a big part of thatstory. 73, Jim K9YC _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ---El software de antivirus Avast ha analizado este correo electrónico en busca de virus.http://www.avast.com _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk_______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk |
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