Do you have to tune a UHF Antenna?

Submitted: Sunday, Nov 03, 2002 at 01:00
ThreadID: 2277 Views:2057 Replies:3 FollowUps:1
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I installed myself a new GME 3200 with a 4.5 colinear Antenna and get great reception from a repeater some 60km away, I was going to buy/borrow a SWR metre to check that the antenna was 1-1.5 as recommended and have been told by two radio Tecs that you DON'T need to SWR a UHF antenna as they are pre tuned 1-1.5 when made at the factory. Is this correct? Please note that I am talking only UHF not 27meg!
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Reply By: Member - Nigel - Sunday, Nov 03, 2002 at 01:00

Sunday, Nov 03, 2002 at 01:00
UHF antenna's are designed so that they will achieve a SWR of 1:1.5 or less in most situations, and therefore are not really tunable.

An insufficient ground plane may give greater SWR, but the solution is to put the antenna in a position where there is more ground plane, or use a special ground plane base (elevated feed).
AnswerID: 8146

Reply By: Member - Nigel - Sunday, Nov 03, 2002 at 01:00

Sunday, Nov 03, 2002 at 01:00
Oh by the way, I forgot to mention that if you can talk (transmit) to a repeater 60km away then your SWR is more than likely ok. Get a friend to listen and see how your signal sounds coming back from the repeater.
AnswerID: 8148

Reply By: Mike - Sunday, Nov 03, 2002 at 01:00

Sunday, Nov 03, 2002 at 01:00
Thanks Nigel, I do have an elevated Ground plain antenna, Would I notice much difference in going from a elevated ground plain 4.5bd to a elevated ground plain 6.5 antenna. Mike
AnswerID: 8151

Follow Up By: Member - Nigel - Monday, Nov 04, 2002 at 01:00

Monday, Nov 04, 2002 at 01:00
depends on your terrain.

I have both on different vehicles and have been meaning to swap the whips to test the difference on my car. Been too busy with work to try it yet.
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