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

Bazz4CQJ · 25th Oct 2022, 11:31 pm

A current thread discussing improving the performance of an Eddystone 840 identified the issue of selectivity as a key specific issue. This applies to many vintage receivers, generally those designed before SSB became a dominant mode.

There does not seem to be a "magic bullet" solution to this problem and various approaches were discussed. These included the possible use of Q multipliers and of the ceramic filters produced for use in various receivers with 455kHz and 10.7MHz IF's.

One member of the forum has already installed a mechanical filter in an HRO with success, but these are hard to find now. He had also tried the ceramic filters (cheap and cheerful, but not intended for use with valves) and was pleased with that outcome also.

Has anyone any thoughts or prior experience with this issue?

B

25th Oct 2022, 11:31 pm	#1
Bazz4CQJ Dekatron Join Date: Apr 2009 Location: Oxfordshire, UK. Posts: 4,934	Improving Selectivity In Vintage Receivers A current thread discussing improving the performance of an Eddystone 840 identified the issue of selectivity as a key specific issue. This applies to many vintage receivers, generally those designed before SSB became a dominant mode. There does not seem to be a "magic bullet" solution to this problem and various approaches were discussed. These included the possible use of Q multipliers and of the ceramic filters produced for use in various receivers with 455kHz and 10.7MHz IF's. One member of the forum has already installed a mechanical filter in an HRO with success, but these are hard to find now. He had also tried the ceramic filters (cheap and cheerful, but not intended for use with valves) and was pleased with that outcome also. Has anyone any thoughts or prior experience with this issue? B __________________ Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch.