UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Pye T30FM transmitter and R17/R18 receivers

Jon_G4MDC · 9th Mar 2018, 5:22 pm

You don't say whether they are High band (148-174 mostly) or Low Band (68-88MHz) or could be P Band 79/101MHz?

I know a fair bit about these and have some info - but it is well buried.

T30FM IIRC had a low power PA Box - single output device about 10W-ish to a second square box usually containing a pair of devices to reach 30W. I have seen 45W or more from them.

They had a bit of an issue with power supply dissipation on high duty cycles. The 2N3055 on the heatsink at the rear gets a hard time. Regulator PCBs are often quite crunchy around the driver TR and resistors.

I forget the R17/18 but I think you might be right that one had a front end box with nice helical resonators while the other only had a front end PCB - pretty much stolen from a Westminster.

9th Mar 2018, 5:22 pm	#3
Jon_G4MDC Nonode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 2,015	Re: Pye T30FM transmitter and R17/R18 receivers You don't say whether they are High band (148-174 mostly) or Low Band (68-88MHz) or could be P Band 79/101MHz? I know a fair bit about these and have some info - but it is well buried. T30FM IIRC had a low power PA Box - single output device about 10W-ish to a second square box usually containing a pair of devices to reach 30W. I have seen 45W or more from them. They had a bit of an issue with power supply dissipation on high duty cycles. The 2N3055 on the heatsink at the rear gets a hard time. Regulator PCBs are often quite crunchy around the driver TR and resistors. I forget the R17/18 but I think you might be right that one had a front end box with nice helical resonators while the other only had a front end PCB - pretty much stolen from a Westminster. Last edited by Jon_G4MDC; 9th Mar 2018 at 5:31 pm.