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TVI cure found

loosecannon

loosecannon

Sr. Member
Mar 9, 2006
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hi all, i am posting this here because i feel that TVI is a problem that alot of CB'ers contend with, and hams do not as much since they dont do much AMing.

hope thats ok.

i have been having issues with one neighbor in particular, where i am coming through their TV and phone.
my stuff is grounded and my AMC is intact.
i have no problems with other neighbors; its just their cheapo electronics that are the problem. (try telling them that!LOL)

anyway, i found some ferrite snap on chokes on ebay and bought five of them.
i snapped them onto the coax (LMR400) at the feedpoint of the antenna, and voila!
no more interference, confirmed by the neighbor!

not sure if posting links is ok or not but here is a link to the ones i bought.
if the link doesnt show up, try searching for "tvi rfi emi filter"

http://cgi.ebay.com/EMI-RFI-TVI-fil...ryZ48692QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
 

i buy mine at radio shack. you can also make a 4-6 in coil (7 or more wraps) at the antenna feedpoint to reduce some
 
$5.29 at the shack. i bought a mine when one of the stores was closing (90% off). they were in the parts drawers, i think all shacks have them but these days you never know. it seems the people that work there only try to sell you a cell phone or plan. long gone are the days that all they sold was commercial and ham radio equiptment (1920's - 1970's).

http://www.radioshack.com/product/i...1&origkw=ferrite&kw=ferrite&parentPage=search
 
Thanks for the link and part number.. I will check and see if the local Radio Shack has them, but I doubt it because like you said, it's more cell phones and Ipods rather than electronic stuff now days.

I'm intersted in trying a couple out just to see if they really work..
 
OK Flame all you want, but this is a question that I would really like answered.

Why does the choke have to be at the base of the antenna and not closer to the device, as between the radio and amp or between the device and meter etc?
 
At the base of the antenna works because a lot of times there is current flowing down the shield of the coax. The choke, a snap on or bead type, or even a coil of coax at the base of the antenna, stops the flow down the outside of the coax, and keeps it from radiating the signal.
You want the antenna to radiate, not the coax.

73
Jeff
 
karo said:
I might give that a try and how many watts are you using to cause tvi with the neighbors?
Click to expand...

It sure doesn't take many watts to cause interference with a neighbors Baby Monitors. I found that out first hand.
 
I've bought snapons at RS that would easily fit 1/2" coax such as RG8. You mean they don't carry that size any more?

Jeff's right on. Keep what's supposed to squirt out of the antenna AT the antenna and not insinuating itself closer to the ground (and susceptible electronics) (and your microphone: OUCH!).
 
Not sure what the "mix" is with RS ferrites, but whatever it is, it won't affect what's inside the coax; just what might be trying to get back down the outside of the shield. In other words, it can't hurt to try one or two - however many come in a package. Hold them in place with a black (UV resistant) ty-rap or some UV-resistant tape.
 
hey karo, the ones i bought were for RG8 sized coax.
i run LMR 400 which is the same .405" diameter.

they fit just loose enough to slide so i used a couple of cable ties to hold them in place.

i also saw an auction for the same thing for RG58 etc...
loosecannon

PS- i usually run about 350 PEP, but the interference would happen when barefoot also.
now nothing even when amp is on.
 
Ferrite chokes of several different sized can be purchased from MFJ as well.

I kept locking up my mouse and keyboard with stray rf. Put two snap on ferrites on the cords right at the computer and the problem was solved.

One cheapo TV had interference - put 4 1/4 snap ons on the TV coax right by the TV - problem solved.


Here you can get them 6 for $9.99 - these are 1/4 inch ones, perfect for TV coax.

click
 
loosecannon said:
hi all, i am posting this here because i feel that TVI is a problem that alot of CB'ers contend with, and hams do not as much since they dont do much AMing.

hope thats ok.

i have been having issues with one neighbor in particular, where i am coming through their TV and phone.
my stuff is grounded and my AMC is intact.
i have no problems with other neighbors; its just their cheapo electronics that are the problem. (try telling them that!LOL)

anyway, i found some ferrite snap on chokes on ebay and bought five of them.
i snapped them onto the coax (LMR400) at the feedpoint of the antenna, and voila!
no more interference, confirmed by the neighbor!

not sure if posting links is ok or not but here is a link to the ones i bought.
if the link doesnt show up, try searching for "tvi rfi emi filter"

http://cgi.ebay.com/EMI-RFI-TVI-fil...ryZ48692QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Click to expand...

How many did you put on the coax, all five? This would be helpful for the folks suffering with TVI.
 
yes, i put on all five.

i have heard of people using between 3 and 10.

i would figure that if 10 didnt work; you should try something else.
 

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