12-01-2006, 09:17 PM
Hello Philco radio lovers,
I am new to the group and also new to the TRF radio. I wasn't sure if this Model 20 TRF radio functioned normally. I got this radio recently. The radio worked (it received signals). However, the audio garbbled if the radio received strong signals.
It looked like that there wasn't an AGC circuit in the IF and RF sections. I wonder if this was the reason that caused the distorted audio. Also, I wonder if there are mods (such as adding AVC and diode detector) to improve the receiving performance.
Thank you for your answers.
73,
Jonathan,
AB6LS
I am new to the group and also new to the TRF radio. I wasn't sure if this Model 20 TRF radio functioned normally. I got this radio recently. The radio worked (it received signals). However, the audio garbbled if the radio received strong signals.
It looked like that there wasn't an AGC circuit in the IF and RF sections. I wonder if this was the reason that caused the distorted audio. Also, I wonder if there are mods (such as adding AVC and diode detector) to improve the receiving performance.
Thank you for your answers.
73,
Jonathan,
AB6LS
It amplifies the rf on the whole band through- out the radio to the detector/first audio amplifier. That is why you get "blaring" on strong signals and have to turn up the volume on weak signals (no avc). Have you recaped the radio yet? A good recapping might be in order. You can find the schematic here. 
