[NLRS] VHF low pass filters?

[Jim Klassen]

Just a quick thought.

You said this happened during an Es opening.    Is there a chance that it had nothing to do with you and that he was seeing interference from DX TV stations received over Es (or other enhancement)?  This might be a stretch since there isn't any VHF-L band TV anymore, but there is still VHF-H.

Assuming you are in the twin cities area:
Ch 9.1 and 29.1 are @ 189MHz,
Ch 11.1 and 11.2 are @ 201MHz,
Ch 13 is analog, and
everything else is 520MHz ~ 690MHz.

On Jan 2, 2013, at 9:40 AM, Paul Husby wrote:

> 
> 
> Phil's suggestion of a quarter-wave stub on the receive line is excellent.  Preferably, it would be located before any preamp.  If he is using one of the newer amplified antennas, that won't be possible and the damage may have already been done.  Still worth a try, though.
> 
> 73,
> Paul W0UC
> 
> On 1/2/2013 9:27 AM, Phil Hejtmanek wrote:
>> 
>> 
>> Hi Kirk.
>> 
>> Very interesting problem from my perspective; I've been involved in TV transmission for 35+ years, and I think this is the first TVI complaint I've heard about now that the US has converted to digital TV.  I am curious to know what the nature of the interference is, and the actual RF channel that your neighbor experiences it on.  Has he been able to describe the nature of the interference to you?  Is it picture or sound?  More likely than not, you are either overloading a preamp in his antenna system and desensing his receiver( resulting is loss of everything), or your signal is getting in to his TV audio system somehow (if he has an external surround sound system this is fairly likely) and he's hearing artifacts of your SSB modulation in his speakers.
>> 
>> I doubt the problem is on your end...more likely he needs some grounding help.  If it is an overload problem, maybe you could put a tuned stub on his antenna line to suck out the 50 MHz signal.
>> 
>> Good luck and 73,
>> 
>> Phil   kf9us
>> 
>> 
>> 
>> 
>> 
>>> ________________________________
>>> From: kp hpjr <inservice2him at hotmail.com>
>>> To: "nlrs at mailman.qth.net" <nlrs at mailman.qth.net>
>>> Sent: Wednesday, January 2, 2013 7:03 AM
>>> Subject: [NLRS] VHF low pass filters?
>>> 
>>> 
>>> 
>>> 
>>> Group,
>>> 
>>> Happy New year.
>>> 
>>> A neighbor approached me asking if I was operating the other night. He said that I had been interfering
>>> with his over the air TV signal. He placed the time frames during the MS rally and during this weekend Es opening.
>>> 
>>> I have only been on 6m as of late at times running up to 600w. His home is about 1000' away from me. His setup is a new digital TV with outdoor antenna fed with the typical radio shack type coax. His antenna is basically looking my way.
>>> 
>>> I'm needing some help with this. Are there filters I/he can use?
>>> 
>>> I'm well grounded and use very good hardware...Andrews connectors and feedlines etc.
>>> 
>>> Your input welcome.
>>> 
>>> Kirk, N0KK
>>> 
>>> BTW: 1st RFI complaint in 18 years.
>>> 
>>> 
>>> 
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James Klassen
Graduate Student
University of Minnesota
Natural Resources Science and Management
210 Green Hall
1530 Cleveland Avenue N.
St. Paul, MN, 55108
Email: klas0037 at umn.edu