UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Mini-Mod 2021!

Ian - G4JQT · 11th Mar 2021, 4:05 pm

Great to see another MiniMod thread!

To answer Paul, the antenna needs to be only about a yard long. Too long and the final tuned circuit will never tune. But remember, this only transmits a signal for few feet. It's meant to be used quite close to the radio.

The capacitor value (C12 in the original article) was 680 nF not uF! 470 nF should be almost as good, but with a theoretical slight drop in bass response.

As for frequency to use, it won't tune the whole MW band and but it tunes about +/- 400 kHz centred on about 900 kHz. I think the Q of the tuned circuits means it has slightly more output at the higher frequency end of the range.

11th Mar 2021, 4:05 pm	#12
Ian - G4JQT Octode Join Date: Jun 2004 Location: Reading/Fakenham, UK. Posts: 1,323	Re: Mini-Mod 2021! Great to see another MiniMod thread! To answer Paul, the antenna needs to be only about a yard long. Too long and the final tuned circuit will never tune. But remember, this only transmits a signal for few feet. It's meant to be used quite close to the radio. The capacitor value (C12 in the original article) was 680 nF not uF! 470 nF should be almost as good, but with a theoretical slight drop in bass response. As for frequency to use, it won't tune the whole MW band and but it tunes about +/- 400 kHz centred on about 900 kHz. I think the Q of the tuned circuits means it has slightly more output at the higher frequency end of the range.