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 TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10 
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Post TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10
Please bare with me as its the first time i have tried a wire antenna. Today i fitted the above antenna (really a posh title for a half size g5rv), i only really want this to cover 40m as my hexbeam does the other bands. The problem i have is the swr is high (cannot get below 2). Now the mast i fitted it on is a carp pole which was kindly donated free of charge by my workmate. Would the fact that the pole is carbon fibre and not fibreglass cause the high swr reading. It is up about 22ft in the centre and the ends come down to approx 6ft . Cheers in advance Colin


Sat Jul 30, 2016 7:00 pm
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 TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10 
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Post Re: TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10
Yes.

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Sat Jul 30, 2016 7:19 pm
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 TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10 
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Post Re: TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10
ei9ju wrote:
Yes.

Thanks Gerry, did not realise until i had put the ruddy thing up as i thought it was fibreglass. Would insulating the top of the pole where the antenna is fixed onto work for now until i can get another suitable pole.


Sat Jul 30, 2016 7:26 pm
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 TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10 
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Post Re: TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10
Insulating may work, can you sleeve it a piece non-conductive material something like a short length of electrical conduit.

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Sat Jul 30, 2016 7:31 pm
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 TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10 
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Post Re: TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10
ei9ju wrote:
Insulating may work, can you sleeve it a piece non-conductive material something like a short length of electrical conduit.


I will look in the garage tomorrow and see what i can find. Good idea about the conduit as we have lots of that in work. Thanks for your replies Gerry, I'm sure i will get there in the end.


Sat Jul 30, 2016 7:37 pm
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 TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10 
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Post Re: TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10
Firstly going back to my earlier post i did insulate the carbon fibre pole but it did not help at all. Now where i stand now is i need a bit of advice on this antenna. I have my mates antenna analyzer attached and i now have the antenna up on a 8m fibreglass pole and have both ends coming down and attached with kevlar rope on the dogbones to the garden shed roof (about 3m) and the front fence (about 6m) as garden drops away the other side of the fence. The swr on 7.170 is 2.0 and it is resonant on 6.720 where the swr is 1.1. I only bought this antenna for 40m so if i can get it to tune in on 40m without the antenna tuner it would be great. Do you think the antenna wires will need altering to get the swr right for 40m....Cheers Colin


Wed Aug 10, 2016 8:12 pm
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 TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10 
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Post Re: TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10
Its too long, using an antenna calculator work out what length is resonant at 6.720 mhz then do the same for 7.100 take one figure away from the other, divide by 2 then shorten each leg by that amonunt DONT cut it just fold back and wrap the wires around each other and take another analyser reading,
is it fed with 300ohm ribbon? you may need to alter this as well.

I was bored so 6.720mhz = 21.23metres
7.100mhz=20.09 metres
=1.14metres
=0.570metres per leg

seems a lot but try it if you dont cut the wires you can adjust to suit remember when you lift it clear of ground/structures it will change resonance higher..surely making a 40 metre dipole would be simpler if you just want 40 metres.

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Last edited by G0JUR on Wed Aug 10, 2016 9:20 pm, edited 1 time in total.



Wed Aug 10, 2016 9:09 pm
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 TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10 
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Post Re: TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10
Neill wrote:
Its too long, using an antenna calculator work out what length is resonant at 6.720 mhz then do the same for 7.100 take one figure away from the other, divide by 2 then shorten each leg by that amonunt DONT cut it just fold back and wrap the wires around each other and take another analyser reading,
is it fed with 300ohm ribbon? you may need to alter this as well.

I was bored so 6.720mhz = 21.23metres
7.100mhz=20.09 metres
=1.14metres
=0.570metres per leg

seems a lot but try it if you dont cut the wires you can adjust to suit remember when you lift it clear of ground/structures it will change resonance higher.


Thanks Neill your help is much appreciated. Will try tomorrow if this rain ever stops.


Wed Aug 10, 2016 9:18 pm
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 TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10 
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Post Re: TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10
making a 40 metre dipole would be a lot simpler,

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Wed Aug 10, 2016 9:21 pm
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 TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10 
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Post Re: TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10
Neill wrote:
making a 40 metre dipole would be a lot simpler,

Only bought this as it was cheap and only wanted it for 40m as use my hexbeam for the other bands. It would not bother me at all if it was only a 40m antenna as that is all it will get used for.


Wed Aug 10, 2016 9:31 pm
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 TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10 
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Post Re: TAYLOR MADE RF LIMITED LONG WIRE-DIPOLE TMRF-40-10
just had a look at the specs for that antenna, the legs are 26 odd foot and the twin 15 foot it may need a bit more fiddling than just shortening the legs, but its still worth a bit of trimming to see if you can change resonance.

Me I would get 2 lengths of wire 10.5 metres long and a dipole centre then just trim to resonance where you want it.

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Its not the class of licence the amateur holds thats important but the class of bias the prat applies to his amplifier


Wed Aug 10, 2016 10:21 pm
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