[RFI] N6CW TVI

[Dave Phemister]

-----Original Message-----
From: Dave Phemister [mailto:phemid at qwest.net] 
Sent: Thursday, June 21, 2007 9:12 PM
To: 'ab7rw'
Subject: RE: [RFI] N6CW TVI

Hi all,
If you haven't installed a LOW PASS filter on your radio equipment, now is
the time to do so. Also, you need to investigate your station ground system.

You want to have single point grounding, radio to a grounding bar, tuner to
the same grounding bar, low pass filter to the same grounding bar, any other
equipment in your shack to the same grounding bar. Use stranded copper wire
no smaller than # 10 AWG and as short as possible.
Run a ground wire, minimum #6 AWG to an 8' ground rod directly outside your
shack wall.
Do not rely on the AC ground to be your station ground, it won't work.
Make sure ALL ground connections are tight and the outside connections are
weather proofed.
Check ALL coax connectors that they are installed on the coax correctly and
that their mating connections are clean and protected against weather.
Now, let's look at the TV's. Are they over 7-9 years old and in plastic
box's, It's possible that they don't have proper internal bypassing or
internal shielding. Are you receiving your programming "OFF-THE-AIR"???
Are your Ham Radio antennas in the vicinity of the TV's???
Are you running 100 watts or legal limit???
If any of the TV conditions above exist, you may not be able to correct the
TVI problem. 
At my QTH I can receive TV programming OFF-THE-AIR or from the Dish Network.
While running full legal limit, I have no TVI on any TV in the house or
interference on any wired or wireless phone. I don't get any interference on
my computer which sits about 2 1/2 feet from my linear amp.
This is due to proper filtering and grounding within my station.
73's,
Dave - WB7ESV




-----Original Message-----
From: ab7rw [mailto:pyasson at pacifier.com] 
Sent: Thursday, June 21, 2007 2:35 PM
To: Phemister, Dave
Subject: Fw: [RFI] N6CW TVI


----- Original Message ----- 
From: "Kelly Johnson" <n6kj.kelly at gmail.com>
To: <RFI at contesting.com>
Sent: Thursday, June 21, 2007 12:41 PM
Subject: Re: [RFI] N6CW TVI


> Jim Brown would suggest the bucket treatment: dunk the TV in a bucket
> of water twice; remove once.  I think that's how it goes :-)
>
> I have a similar, impossible to fix problem with my 13 year old
> Mitsubishi.  No amount of toroids, filters, or whatever have been able
> to completely eliminate the TVI on 80m.  I can run QRO on all other
> bands, but on 80m I get TVI with as little as 50W.  No other TV in the
> house has any issues on any band.  I believe that RF is getting into
> the color burst circuitry directly through the case.  One of these
> days I'll replace this TV.  Until then, I use 80m only after everyone
> has gone to bed.
>
>
> On 6/21/07, CatWhiskR at aol.com <CatWhiskR at aol.com> wrote:
>> Guys,
>>
>> Thanks for all the suggestions. To answer some questions: The TV is being

>> fed
>> straight from a splitter direct into the set. I have bypassed the 
>> splitter to
>> no avail. No extra stuff to cause problems. The splitter has been 
>> replaced.
>> >From the splitter one lead goes to the effected TV and the other lead 
>> >goes to
>> the other TV (Panasonic, no problems), downstairs and as far away from 
>> the
>> antenna as it can get, and to the cable network for the computers. No 
>> interference
>> on any of that stuff.
>>
>> I have tried several different types of high pass filters on the TV plus
>> several AC line types besides the toroids. I have plugged the TV into a 
>> different
>> outlet fed from a different circuit. I have done a lot of TVI fixes over 
>> the
>> years but this one seems to be impossible without getting into the TV 
>> itself to
>> do experiments. I am not really interested in doing that. Been there, 
>> done
>> that in the past.
>>
>> I think what points to the deficiency of the TV set itself is when I move

>> the
>> cable or power cord around, I can drastically change the TVI problem. 
>> This is
>> even with my body shielding it or putting the cable cord next to the 
>> power
>> cord. It gets better not worse. But it is a combination of body 
>> capacitance and
>> cord placement. I cannot move away and have it stay good. And no, it does

>> not
>> change the problem by rotating the TV 90 degrees to the antenna. I will 
>> try to
>> move the set to the other side of the room and see if that helps.
>> Unfortunately, that is not a good viewing area.
>>
>> Maybe I just need to buy permanent press clothes and get rid of the iron.
>>
>> Terry/N6CW
>>
>>
>> **************************************
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