>>>>>> Today I purchased & installed a new Panasonic  TX-25 CK1  TV  receiver to replace an older one of same make.

To my horror, I found that it radiates a strong rough carrier on 136.1 spreading both up and down several hundred hertz making the band inoperable on all three of my antennas. <<<<<<<<<<

 

The problem has now been solved .

Insertion of a filter (kindly loaned by Steve GW4ALG ) in the mains ( power ) supply was totally ineffective.

Removal of the antenna , with the TV on, also did not remove the interference.

 

Fortunately the dealer who supplied the TV was an independent family type Co. and the salesman was an" old time "repairman.  He went to a great deal of trouble in contacting the Panasonic technical dept. They could offer no help other than suggesting that I "re tune it".

 

The supplier delivered two  further TVs  one the same model as the problem one.  It produced the same qrm.

The second was an entirely different type (widescreen ). Panasonic  TX-28DK1  UK standard..The interference was totally removed & I have been unable to detect any spurious signals in the LF band.

 

Many thanks to all who sent me advice  and suggestions.

 

Regards

 

Mike   GW4HXO.