12-11-2020, 11:34 AM
Hi Adrian.
There were a number of different IF frequencies used by different manufacturers. In the early days they were low as valves performed better at lower frequencies. I believe the EF50 was a changing point and post war IF frequencies went up into the 30mhz area. The advantage of a higher IF is bandwidth, lower frequency IF and it becomes harder to attain the required bandwidth so often another stage is needed too.
As yet we have no idea of the BHTV frequencies so for me I'd use 34.65 mhz vision and 38.15 mhz sound plus a tunable front end from most likely 46mhz to 66mhz, I belive the old Ch1 won't be used.
There were a number of different IF frequencies used by different manufacturers. In the early days they were low as valves performed better at lower frequencies. I believe the EF50 was a changing point and post war IF frequencies went up into the 30mhz area. The advantage of a higher IF is bandwidth, lower frequency IF and it becomes harder to attain the required bandwidth so often another stage is needed too.
As yet we have no idea of the BHTV frequencies so for me I'd use 34.65 mhz vision and 38.15 mhz sound plus a tunable front end from most likely 46mhz to 66mhz, I belive the old Ch1 won't be used.
