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huffhuff



Member Since: 05 May 2016
Location: Home Counties
Posts: 379
United Kingdom 2001 Defender 90 Td5 HT Java Black
High CB SWR after fitting patriot roof rack...
Hi all,

My CB was working fine with my old roof rack, about 2/2.5 SWR across the range (meter permanently fitted inline). After installing the new roof rack (much more aluminium) the SWR now goes quite far into the red on all channels, low or high.

What do I need to do to bring it down to a more acceptable level? It's a mini-orbiter fitted above the rear offside window/quarter light.

Cheers

Ben TD5 Defender 90
Discovery 3 HSE
Post #638438 19th Jul 2017 11:08am
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ChrisCM



Member Since: 10 Jun 2013
Location: Cornwall uk
Posts: 572
United Kingdom 2010 Defender 110 Puma 2.4 SW Santorini Black
Even 2/2.5 seems a bit high, for my Ham Radio I wouldn't want to go above 1.5:1. You certainly won't be getting anything like the full output from your radio with an SWR that high!

Not familiar with your antenna, can you alter its length? Is there a there a loading coil which can be slid up and down the antenna mast or has it some sort of adjustment collar if the loading coil is located at the base?

It may be possible to get hold of a mini antenna tuner which works on 27Mhz, you can then tune the antenna remotely but this is not as efficient as getting the length right.

If you know a friendly radio Ham he/she may have an antenna Analyzer which would tell you the resonant frequency of your antenna and whether it's too long/short on the CB bands, there is no way of knowing with just an SWR meter, just that it's not right.

Chris 2010 Defender 110 Station Wagon, Santorini Black.
Post #638455 19th Jul 2017 12:38pm
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dorsetsmith



Member Since: 30 Oct 2011
Location: South West
Posts: 4554
You changed your ground plan i.e. patriot roof rack

1. try grounding roof rack to the antenna mount

2. re setup antenna
Post #638460 19th Jul 2017 1:08pm
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huffhuff



Member Since: 05 May 2016
Location: Home Counties
Posts: 379
United Kingdom 2001 Defender 90 Td5 HT Java Black
Okey dokey, will give grounding rack to mount. Annoying as that will need a cable going from inside to outside.

D'oh

Cheers TD5 Defender 90
Discovery 3 HSE
Post #638462 19th Jul 2017 1:38pm
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