UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Improving Selectivity In Vintage Receivers

Bazz4CQJ · 6th Feb 2023, 10:03 am

Yes, Andrew's observation is quite an eye opener, but does fit in with some previous experience. In the days when I used my HRO behind a 2m converter, and tuning 4-6MHz, I was shocked to find it really did interfere with the family (Band 3) TV. Lots of RF came out of the HRO and went straight down the mains and at sufficient strength to affect the TV. I seem to recall there were no decoupling caps on the LT wiring. Adding a few 'changed the picture completely'

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Furthermore, it's certainly the case that the layout of the HRO was not optimised around the position of the RF filter and the mixer and first IF valves.

B

6th Feb 2023, 10:03 am	#125
Bazz4CQJ Dekatron Join Date: Apr 2009 Location: Oxfordshire, UK. Posts: 4,935	Re: Improving Selectivity In Vintage Receivers Yes, Andrew's observation is quite an eye opener, but does fit in with some previous experience. In the days when I used my HRO behind a 2m converter, and tuning 4-6MHz, I was shocked to find it really did interfere with the family (Band 3) TV. Lots of RF came out of the HRO and went straight down the mains and at sufficient strength to affect the TV. I seem to recall there were no decoupling caps on the LT wiring. Adding a few 'changed the picture completely' . Furthermore, it's certainly the case that the layout of the HRO was not optimised around the position of the RF filter and the mixer and first IF valves. B __________________ Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch.