04-02-2025, 07:01 PM
(This post was last modified: 04-02-2025, 07:03 PM by Mike Watterson.)
Certainly many early UK small signal transistors only did to IF frequencies, hence one of the Bush sets having a valve.
Some UK car radios only used the transistors for audio output and ran the valves with 13.8V HT. A few had transistor inverters replacing vibrator packs.
A lot of the Russian transistors even in late 60s & early 70s had terrible RF performance so they used them for an HT inverter and audio, the rest of the military R/T using Rod Pentodes. Only one non-military radio, for forestry work, was produced. They were also in satellites and the Sputnik (but really that was military too, developing ICBMs).
I wonder how feasible it is to add an attenuator and IC buffer amp in front of the transistor base or after the collector? These tend to be low impedance so would work best at which ever side is lower impedance.
I did use a LW loading coil for a MW aerial as low frequency coil on my Ambit FET based "GDO". It certainly extended the range, but useless as a dip meter. I added a J310 FET buffer and an SMA socket to use the Dip meter as small portable signal Generator from 400 kHz to 200 MHz.
In general the design is poorer sensitivity at lower frequencies and there was a revised version with a totally different oscillator that is much more sensitive as a Dip Meter. Handy to adjust "traps" on aerials.
Some UK car radios only used the transistors for audio output and ran the valves with 13.8V HT. A few had transistor inverters replacing vibrator packs.
A lot of the Russian transistors even in late 60s & early 70s had terrible RF performance so they used them for an HT inverter and audio, the rest of the military R/T using Rod Pentodes. Only one non-military radio, for forestry work, was produced. They were also in satellites and the Sputnik (but really that was military too, developing ICBMs).
I wonder how feasible it is to add an attenuator and IC buffer amp in front of the transistor base or after the collector? These tend to be low impedance so would work best at which ever side is lower impedance.
I did use a LW loading coil for a MW aerial as low frequency coil on my Ambit FET based "GDO". It certainly extended the range, but useless as a dip meter. I added a J310 FET buffer and an SMA socket to use the Dip meter as small portable signal Generator from 400 kHz to 200 MHz.
In general the design is poorer sensitivity at lower frequencies and there was a revised version with a totally different oscillator that is much more sensitive as a Dip Meter. Handy to adjust "traps" on aerials.
