UHF vs VHF antenna cable & mounts
Submitted: Thursday, Dec 18, 2008 at 11:28
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wortgames
Hi everyone,
What would be the effect of using a VHF cable and base for a UHF antenna?
I have a Uniden UH090 (UHF/VHF combo) with currently just a UHF antenna mounted on the fender. I want to mount another antenna base in an existing hole in the roof before I finish retrimming the roof lining.
I have a spare, unused Benelec 10106F 'Standard' (VHF) cable and base, and the right-angle fitting of the base would better suit the location in the roof. However, it seems a shame to use the prime roof mount for 27meg which I'll only use rarely (eg if a travelling buddy only has a VHF CB). Around town / low carparks the fender mount UHF is probably better, but it's tempting to move it up to the roof for country driving.
So should I go out and buy and fit the more awkward, UHF mount and have 2 UHF bases, borrowing one for VHF when required - or will I still get decent results if I whack the UHF antenna on the VHF base on the roof?
Reply By: Robin Miller - Thursday, Dec 18, 2008 at 11:53
Thursday, Dec 18, 2008 at 11:53
Theres not really enough info in your post about the antenna types Wortgames
as ground independant antenna's will give a different reaction than say a 1/4 wave
vertical mounted on a ground plane (centre of car roof).
Generally speaking you will have a bit more loss in the VHF cable but by itself you will probably not notice this, just keep connections very short (1cm).
I'd buy UHf but only if fitted in accordance with antenna type.
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Follow Up By: wortgames - Thursday, Dec 18, 2008 at 12:27
Thursday, Dec 18, 2008 at 12:27
Hi Robin, I guess I'm talking in general terms really. ATM I have a 67cm centre-coil whip, I think it's about a 3db or something, just a cheapie but it does the job.
I'd probably use the fender mount for 27meg when required. My roof is ali and I don't think it would handle the extra leverage of a VHF antenna too
well without some reinforcement.
Having said that, I'd prefer not to go off and shell out for a new UHF base and lead which will be more awkward to mount and hardly ever used, if the difference between that and a VHF setup is minimal. I'm mostly just pluggng the hole but thinking about some flexibility too.
I'm mostly on the highway and I'll be adding a bullbar and better ants before we do the big trip in a couple of years, so it's not that critical - just wondering how the VHF mount would fare as a temporary UHF setup when required.
Of course, it seems a bit odd to be talking about using a VHF ant on a UHF base and a UHF ant on a VHF base, but there you go... ;o)
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Reply By: Member - Olcoolone (S.A) The O - Thursday, Dec 18, 2008 at 12:28
Thursday, Dec 18, 2008 at 12:28
Yes that will work fine, as long as the UHF antenna and antenna base is used for the UHF side of the radio.
The down side is the Benelec base you are mounting into the roof can ONLY be used for the 27 Mhz HF side of the radio.
The better option is to go and buy another UHF base and mount it in the roof, this way if anything happens to the UHF antenna or base mounted on your fender you can swap plugs at the back of the radio and remove the 27 Mhz antenna on the roof and replace it with a UHF antenna and your back in business.
There is not much action on 27 Mhz AM these days.
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Follow Up By: wortgames - Thursday, Dec 18, 2008 at 12:37
Thursday, Dec 18, 2008 at 12:37
Sorry O, I must have posted while you were composing your reply.
What will happen if I use the Benelec base for the UHF side?
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Follow Up By: Member - Olcoolone (S.A) The O - Thursday, Dec 18, 2008 at 12:46
Thursday, Dec 18, 2008 at 12:46
You will get a fair bit of signal lose on transmit, you may also find they use lower grade coax cable on the VHF base compared to the proper UHF base.
A UHF base has better shielding and lower signal lose the a VHF base.
I would go the right way the first time and have peace of mind.
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Follow Up By: wortgames - Thursday, Dec 18, 2008 at 13:01
Thursday, Dec 18, 2008 at 13:01
You might be right, maybe I should just spring the extra $30 now and then have better options.
I'm curious though - if the only difference between a UHF and VHF base is that the UHF base is 'better' - why do they still bother to make and sell separate VHF bases? Wouldn't the 'better' design just dominate?
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Follow Up By: Member - Olcoolone (S.A) The O - Thursday, Dec 18, 2008 at 17:12
Thursday, Dec 18, 2008 at 17:12
The VHF base is a cheaper design as there is less machining.
You would think they would scrap the old design and just stay with the newer type.
We always use the UHF design.
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