01-10-2016, 07:56 AM
Thanks for the info Michael.
My next project will be an FM portable hybrid radio.
I intend to use a TBA820 as an audio output as using the rod valves I'll need more of them for a start and lots of batteries. This would defeat the purpose of the set as it needs to be as compact as possible, light, sensitive, drift free and economic on battery power.
Quite a task TBH but some experiments so far have been successful. I intend to have it crystal controlled with one or possibly two crystals for two stations/frequencies max.
Over the years I've bought countless FM portables for the wife and they either use too many batteries, (rechargeables are short lived before recharge and don't last these days) have poor sensitivity or non PLL sets drift. My wife uses a portable every week day on her rounds and I'm forever fitting batteries.
The idea of one AA driving the filaments and a PP3 for the TBA820 and the dual control filament rod valves sounds good, If necessary half a dozen or more CR2025 could be used for HT, this wouldn't add much weight and the low consumption should give them a long life.
The actual valves I'd use hasn't been marked in stone yet and I'm open to ideas.
My next project will be an FM portable hybrid radio.
I intend to use a TBA820 as an audio output as using the rod valves I'll need more of them for a start and lots of batteries. This would defeat the purpose of the set as it needs to be as compact as possible, light, sensitive, drift free and economic on battery power.
Quite a task TBH but some experiments so far have been successful. I intend to have it crystal controlled with one or possibly two crystals for two stations/frequencies max.
Over the years I've bought countless FM portables for the wife and they either use too many batteries, (rechargeables are short lived before recharge and don't last these days) have poor sensitivity or non PLL sets drift. My wife uses a portable every week day on her rounds and I'm forever fitting batteries.
The idea of one AA driving the filaments and a PP3 for the TBA820 and the dual control filament rod valves sounds good, If necessary half a dozen or more CR2025 could be used for HT, this wouldn't add much weight and the low consumption should give them a long life.
The actual valves I'd use hasn't been marked in stone yet and I'm open to ideas.
