Antron 99 TVI Issue

[3pinplug]

Useful info adrian about the correct way to do the choke, learnt something myself there, as i say wrapping the coax round the base pole worked for me, the pole wasnt that long as it just went betqeen the T &K mounting brackets.
If the poster trys both hopefully he will be up and DXing in no time.
All the best
Mark

[Transwarp]

The A99 always seemed to make TVI apparent when it wasn't before with another ant. When my GP27 broke and I replaced it with an A99 TVI showed it's head (fairly new coax and 12ft pole) I bought another GP (they were cheap back then) fitted that and the problem was gone.

I always put it down to the dial-a-match type rings on the A99 being a possible source of giving jip.

[Adriano9966]

I used an A99 on cb and later on 10 metre ham radio for a long time and I never had any issue. Its a good antenna in my view despite it's high price and the hype that once surrounded it.There is a lot to like. The light weight construction ,The fact that you can break it down into 3 sections for portable use etc .In my opinion this problem is not caused by the antenna but by direct RF breakthrough! The fact that the guy is using an amp will not help as this will render the problem worse.

I suspect a distribution Tv amp as a possible cause or if not poor quality cable or ancient tv aerial .Whatever the cause this is my opinion as modern TV sets should now be better designed in respect of screening against RFI.

common mode currents spring to mind as well hence my air choke advice

(:) BTW thanks for the comment Mark. For me every day is a school day I have some experience but I'm by no means an expert so just like you I'm learning new stuff all the time )

Perhaps Wayne might like to come back and explain how the TV is set up,How long his feeder is and how it runs back to his shack,type of feeder etc? Just a bit more information please Wayne so that we can provide the correct advice ! Kind regards Adrian

[PoisoN]

I always make a ugly balun to put below mine never have tvi problems, It shouldnt be much of an issue these days anyway with new type tv's if anything they give off interference.

[pc1mh]

Had the same thing here on all bands on the Solarcon A99 (using 50 to 160 Watt). Your radio, antenna and amp are doing great, don't change anything on it. I build a choke (As said in this thread and its the only good solution.) and all TVI problems are gone even with 200 Watt SSB. Here is a picture of my choke: http://pc1mh.blogspot.nl/2013/07/to-cho ... mains.html

A choke is good for any antenna. Don't worry about your signal going to the antenna as there is no effect on the outgoing signal. The TVI problem is caused by the RF field around your antenna picked up by the coax mantle. The choke stops the signal going any further inside your house.

There is much more info on this subject on my site. The link is: http://pc1mh.blogspot.nl/2013/07/to-cho ... mains.html

[LondonCbRadio]

You need to use a choke at the antenna feedpoint to stop the coax from radiating, that would be the first step . If it's still happening after doing that then make or buy a braid braker that will stop it. I know it's an old thread but this info will help others looking in. I built a braid braker and tested the antenna next to my tv antenna and my freeview don't freeze even using 100 watts. Also if using cb amps it will be a good idea to use a low pass filter. Choking at the antenna feedpoint also lowers the noise you pick up.

[ch25]

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