UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

Jon_G4MDC · 1st Oct 2017, 3:52 pm

Thanks for the clear explanation about how the channels work David! That has been mystifying to say the least until now.
Please can you reveal the two RX bandwidths in use? 25kHz PMR sets usually had 15kHz BW IFs - I wonder if Aviation was a bit wider?

The PYE Whitehall also included a sharp low pass in the Rx AF, cut off about 2.5kHz, to remove heterodynes for exactly the same reason. Actually I find that filter helps intelligibility and is nice to listen to whether or not there is staggered carrier working going on.

1st Oct 2017, 3:52 pm	#25
Jon_G4MDC Nonode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 2,015	Re: Why is aeronautical VHF AM? Thanks for the clear explanation about how the channels work David! That has been mystifying to say the least until now. Please can you reveal the two RX bandwidths in use? 25kHz PMR sets usually had 15kHz BW IFs - I wonder if Aviation was a bit wider? The PYE Whitehall also included a sharp low pass in the Rx AF, cut off about 2.5kHz, to remove heterodynes for exactly the same reason. Actually I find that filter helps intelligibility and is nice to listen to whether or not there is staggered carrier working going on.