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Inertia520
New member
Username: Inertia520
Post Number: 2
Registered: 9-2012
| | Posted on Wednesday, March 20, 2013 - 5:28 pm: | 
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Hey guys I know you guys have done a lot of field testing on all the alum ground plane ant.P500,10k,coily,etc..Just curious if anyone has done any experimenting with adding a tophat to the Maco v58.I have talked on these antennas for years and am going to be taking it down to install on a permanent tower since I recently moved and put it up to fast.Any info would be great curious to see if this would be an improvement or just a bunch of jazz on the other ground planes |
Tech833
Moderator
Username: Tech833
Post Number: 2247
Registered: 8-2002
| | Posted on Sunday, March 24, 2013 - 2:20 pm: |
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A top hat on a 5/8 wave antenna serves no electrical purpose, except some believe it reduces static. The same effect could be achieved by putting something round on top.
The original purpose for the top hat on 5/8 wave antennas was to physically shorten them. In the past, the part 95 rules were strictly adhered to, and for those whom were mounting their antennas atop a structure taller than 40 feet (thus staying under the 60 foot to ground level rule), they needed to stay under 20 feet above the mounting structure. A 22.5 foot tall antenna would have exceeded that and thus been against the rules.
I've run 5/8 wave antennas on various bands and saw no benefit to the top hat. Since many of my installations are on mountaintops where wind is a concern, I remove the top hats to reduce wind resistance and whipping action of the vertical element. After removing the top hat, simply add some length to the vertical radiator to retune the antenna to the desired frequency range. In the case of the Maco, simply don't add a top hat at all.
Your radio 'Mythbuster' since 1998
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