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BAD TVI with thunderbolt 305

J

JustinDePolis2

Guest
Do away with whatever coax you're using, and switch to Belden 9913. Not RG-8, or "the good stuff" RG-213 no matter what anyone tells you. Only Belden 9913. Then get an Interceptor I-10K from Jay. His web site is: www.a1antennas.com The problem will either be gone, or so very slight that it won't bother anyone.


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Don't forget to make sure you have your station equipment properly grounded with a single bus ground system. Also with your A-99, how much higher is "put higher"? The interference from their TV could very well be coming in throught the electrical wiring. Buy them a good RF attenuating power strip to put by their TV and see if that makes a difference. I also suggest buying the ARRL RFI book. It has TONS of useful information on how to cure this. The suggestion about using the Interceptor 10K isn't a bad one either. Simply put, it will change the angle of radiation of your station so that more RF is put out on the horizon, instead of right down into you and your neighbors house.



Moleculo


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Maybe the fact that it's shielded 6 times as well as typical RG-213 made by S.I.W. We're not talking about attenuation, that's a different subject all together.<img src=http://users.joplin.com/dutch64804/posticon34.gif ALT=":34">


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Most computer speakers are un-shielded, you would have to be lucky not to get "bleedover" no matter what you do. I just turn my speakers off when transmitting, also warn the neighbors before a CDX DX contest.


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Do yourself a BIG favor and go buy the ARRL RFI book. You CAN cure even the computer speakers. In the book it will show you how to wind the speaker wire around a torroid or even use a capacitor (probably a .01 uF) to get rid of the RFI. The parts are only a few dollars and once you solve one simple problem, you'll know how to solve more complicated ones.





Moleculo


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Very good point, Frank, although I don't think it has to do with the "cleanliness" of the equipment, as long as it's getting into phones, stereos, etc. If he's getting into Televisions on channel 2, 5, or possible 7-8, then I would say it's the equipment. The reasoning behind this is that those channels are harmonically related to 27Mhz. Example, TV channel 2 is right around 54Mhz, 27.205 X 2 = 54.410, and the additional harmonics that are created on both sides of the sidebands of the origional carrier frequency due to A.F. modulating it, and being harmonically related to the modulating A.F. as well(27.205) now creates 54.410, +/- 4 - 10Khz in either direction. All equipment does this to some extent, ham equipment much much much less! Although, if "cleanliness" was the problem, a simple low pass filter would be adequate, and therefore cure all of the problems. I really think the problem is the cheap coax that alot of people use, alot of it, particularly the S.I.W generic brand coax cables have sometimes as little as 75% shielding... not too good when you concider that Belden 9913 has a foil shield along with a 99% braid. Another problem is the antenna systems installation. Alot of the CB antennas seem to have a habit for making the feedline radiate as well. Then the radio operator has neighbor problems and tries to ground their equipment through 20 feet of #10 solid copper wire, and well, that can make the whole situation worse, especially if they try to use a cold water pipe. A good R.F. ground needs to be at least one 8ft. ground rod, then preferable less than 3ft of 2" wide braid going to a localised grounding "bus" bar, then separate grounds going from there, Improper grounds can make things worse! Think about it, if you have a telephone in the near field of radiation, it doesn't care what frequency it is on, it does it's job, and rectify an amplitude modulated signal on the line, and turn it into A.F. and there you have it...your echo box all over the neighbors phone. The Antron 99 seems to have a strange take-off angle, and throw R.F all over the place. (if someone more experienced in antenna design has a reason for this, please feel free to step in at any time) I've personally used a Icom 737 and a Yaesu FL-2100B into an Antron 99, and cheap coax and had people all over my block getting driven nuts. I then had some friends come out a week later to my house and help me put up a Maco V 5/8 antenna (which actually has a ground plane) and some good 9913 coax that I had ran before. Same radio, and amplifier, no problems at all, no even a hint of RFI on my own telephones, televisions, etc. to go even farther, scrap the Maco, and get an I-10K from Jay, it will at least cut the problem in half, if not eliminate it.


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any body know a good way to cut down on killing my other home owners. I have a antron 99 i know thats a problem but it was put higher . But i put a goot tvi filter on and still getting there tv's a bit and the computer speakers.


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A friend down the street was having problems with me getting in his computer speakers. A clam shell ferrite core on each speaker wire close to the speaker solved this. Also a few loops in the coax by antenna and a ferrite core near antenna helps also.
 
Mr Clean said:
A friend down the street was having problems with me getting in his computer speakers. A clam shell ferrite core on each speaker wire close to the speaker solved this. Also a few loops in the coax by antenna and a ferrite core near antenna helps also.

a choke at feed point without a ground plane will fark up your swr without that groundplane its using the coax as a counter poise or groundplane if you didnt know that.

so if your gona do the air choke on a a99 do it like 9 feet down from feed point.

ya ive had all kinds of trouble with nieghbors and im now using good 213 and a imax with gpk1 kit. no complaints with it not even out the top of tree yet.
 
The 305 amp is a dirty design due to it has no isolation between the tubes and the power supply , no shielding .
 
kc2jgl said:
The 305 amp is a dirty design due to it has no isolation between the tubes and the power supply , no shielding .

Is this where you got your handle at mr 305?
 
jjohnson said:
kc2jgl said:
The 305 amp is a dirty design due to it has no isolation between the tubes and the power supply , no shielding .

Is this where you got your handle at mr 305?
No jj i got it when i got back on the cb someone said to me you dont need your call letters any more ,they said pick a no. so i had a truck that gave me a lot of problems with the computer wiring harness . the motor was a 305 so i said i would never forget that . and i know about the 305 amp i bought one blowed up from candyman and fixed it and found it to be dirty . by the way you joined another fourm and i voted you in . see you later dude .305
 

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