Re: Mobile antenna placement and patterns


stan W9SMR
 

Wow, Peter!

That was a very comprehensive exercise. Well done and thanks for sharing it.

73,
Stan
W9SMR

________________________________________
From: main@070Club.groups.io <main@070Club.groups.io> on behalf of Peter, NN9K #2629 <nn9k.peter@gmail.com>
Sent: Thursday, April 22, 2021 10:25 AM
To: main@070Club.groups.io
Subject: [070Club] Mobile antenna placement and patterns

I just uploaded a file -- 2007_MARAC_Bakeoff_Results.pdf<https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2F070club.groups.io%2Fg%2Fmain%2Ffiles%2F2007_MARAC_Bakeoff_Results.pdf&data=04%7C01%7C%7Ca9284d7b30d849fb277e08d9059a6e51%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637546983089346176%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=uSGr9DgRJUOWAJouk8yyabGHVABahDtHdMFXlMuz3II%3D&reserved=0> and although it is "old" data it is still relevant today. It was probably the most comprehensive mobile antenna testing I have seen and participated in. Take your time reading it and hopefully it will help you make informed mobile antenna decisions.

RF problems during mobile operation. The Icom 7000 was very prone to RF problems even to the point of shutting of shutting down the radio. A simple torrid choke on the antenna lead would solve the problem. And I suspect the newer Icoms may also be a bit sensitive to RF on the feedline also and possibly any device attached to the radio could be affected also.

One more comment -- mag-mounts need to be grounded! A separate ground strap from the mount to a good ground point on the vehicle will make a difference in SWR and radiation pattern. Use good heavy braid and if done carefully will help keep the mount in the vehicle during sudden stops.
--
Peter, NN9K

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