Shortening Antenna Cables

[Daisy Burnett]

Hi Guys
Trying to continue to improve radio workability. I know that years ago when you shortened the antenna cable for a radio you had adjust things using an SWR meter. I have been led to believe that this is no longer the case with advent of better technology. What I would like to do is shorten the cables on both my 27 meg and VHF radio's to get rid of that coiled up coaxial cable. Can I do this without effecting the performance of the radio's?

Thanks
Daisy

[Taylor2]

Re: Shortening Antenna Cables

Yep for sure. Shouldn't be a problem, as long as you are confident reterminating the plug on the back of the radio. Its not the best option to shorten the cable by cutting the coax and then rejoining it half way along the run, you really need to retierminate at the plug. Extra cable is handy if you ever want to move your radios or antenna in the future. Cheers

[TheRealAndy]

Re: Shortening Antenna Cables

Depends on the antenna. With certain GME 27mhz antennas you CANNOT shorten the coax. From memory, with pacific antennas you can shorten the coax. BEst to check with the manufacturer first.

[lethal098]

Re: Shortening Antenna Cables

It is reccomended to not change the length of tha cable as they are a tuned length, however left over cable should not be coiled up, it should be laid out in a straight line where possible, i have run mine down the side under the gunwhale and then back up to the radio.

Cheers Lee

[murf]

Re: Shortening Antenna Cables

instead of coiling would figure eighting work better? I have never delved right into radio gear

cheers Murf

[ifish86]

Re: Shortening Antenna Cables

i didnt think coiling coaxial cable would matter to much as it extremely low v

[Taylor2]

Re: Shortening Antenna Cables

Shortening the cable will not affect the transmitt receive side of your radio. Shortening the cable will actually improve its efficiency, marginally. Changing the length of the antenna WILL affect the tx/rx of your set.

Coiling coaxial cable should not be a problem as long as the bend radius is not small enough to damage the centre conductor. The shielding on the coax is to reduce interference. You shouldn't get inducatance, not on a set like that.

[ShaneJ]

Re: Shortening Antenna Cables

Some poor information here.

GME antennas are not to have the coax shortened at all. The coax is a tuned length to match the impedance of the radio to the antenna itself as these antennas have no loading coil/balun etc

[oldboot]

Re: Shortening Antenna Cables

We had a serious go at this one a little while back.

Some of the ground independent areials......that is an aerial that does not have a metal base and requires a ground connection.......use a specific length of cable as part of the hokus pokus they have to do to make a single stick work ground independent.

I made enquiries of a mate who used to work for GME as a technician, and he pressed one of his mates that used to work for GME as an engineer.

It seems they use something more modern but similar to a grid dip occilator to sweep tune the aerials for an optimum cable length.....this is why different model aerials have different cable lengths.

If you measuer one with an SWR meter it won't look good...if you try to tune it by SWR you will make it worse.

The newer GME areials that come as a base and a seperately selected areial may be different, but anything GME and white and over 12 months old will be cable length critical.

You can probaly get away with chopping of a plug and reterminating...if carefull but that is about it for shortening.

As far as coiling up the excess.....at this frequency, as long as the coils are bigger than 3 or 4 inches diameter it should make very little difference...what you do not want to do is kink the coax.

A mates boat had the excess bound up in a longshank of tied up tight with cable ties and stuffed in somewhere......this ment it had a bout half a dozen tight kinks in the cable.

If it is a GME or any other older style ground independent aerial DO NOT shorten the cable.

cheers

[Daisy Burnett]

Re: Shortening Antenna Cables

Thanks guys. A few mixed signals here so I might give GME a call and see what they have to say. I know in the past there was a problem in changing lengths but I heard someone say that it was no longer a problem. I will post the info after I ahve spoken the GME and let you know the good oil for GME antenna's at least.

Cheers Daisy

[oldboot]

Re: Shortening Antenna Cables

Mate... been there and done that.

Unless the aerial in question was baught in the last 12 months AND it is the new range where the masts are interchangable, ( they screw into the a universal base) you are wasting your time.

YOU can not shorten the cable on any of the older GME white aerials...full stop........end story.

The reason I asked some ex GME mates was because I did not get any explanation as to the "why and how" from anybody at GME.

cheers

[ahamay]

Re: Shortening Antenna Cables

Some poor information here.

LOL... cracks me up...everyone's a friggin expert. Maybe there should have been a poll as well then he could have gone with the majority

[TheRealAndy]

Re: Shortening Antenna Cables

I also had a crack at contacting GME (same thread that oldboot is referring too) to find out why you cant shorten cables, but I never got a technical answer.

[Marlin_Mike]

Re: Shortening Antenna Cables

LOL... cracks me up...everyone's a friggin expert. Maybe there should have been a poll as well then he could have gone with the majority

No expert here ahamay..................LOL

But ask your self one question Daisy Burnett: Is the radio working fine??? Yes??? Then if it aint broke why try to fix it?????????????????????????

Mike

[Spin]

Re: Shortening Antenna Cables

I have an SwR meter here
Who wants to donate there antenna for the test .