UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Questions on 160/80 metre AM transmitters.

G6Tanuki · 25th Dec 2022, 8:26 pm

There's much to be said in favour of putting the choke on the downstream side of the pi-network - see below.

RFC8 being the 'anode' choke.

This decouples any silly and unpredictable choke self-resonances from the PA valve and means the choke is working at a low RF impedance.

This approach was used in a number of US WWII-era military transmitters, but seems to never have taken hold this side of the pond.

25th Dec 2022, 8:26 pm	#94
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,007	Re: Quick question on the CODAR AT5, if anyone has one to hand. There's much to be said in favour of putting the choke on the downstream side of the pi-network - see below. RFC8 being the 'anode' choke. This decouples any silly and unpredictable choke self-resonances from the PA valve and means the choke is working at a low RF impedance. This approach was used in a number of US WWII-era military transmitters, but seems to never have taken hold this side of the pond. Attached Thumbnails __________________ I'm the Operator of my Pocket Calculator. -Kraftwerk.