23c/m BANDPASS FILTER giving a Domestic TV UHF rejection
The cheap 23c/m RX's on the market suffer from cross-modulation with the wanted and unwanted signals such as the Domestic UHF TV stations. The RX units can cover 800 to 1700MHz so there is a problem.
I live over 20 miles away from Winter Hill and while beaming anywhere South I was getting trouble.
I found putting 3db attenuator in the aerial lead cured the problem.
I next measured the max signal on the Spectrum analyzer and found the level was just 10m/V.
I then decided to design some sort of bandpass filter and here are the results todate.
A Better and simpler unit was then Designed below
ALL THE TV INTERFERENCE WENT WITH THIS ONE JUST 0.5db INSERTION LOSS.
-70DB REJECTION @ 500MHz
Size just 50 x 60 mm