On Jan 28, 1:43*am, (Scott Dorsey) wrote:
VK3XAO wrote:
I'd like to build a simple tube-type FM broadcast tuner. So far it
looks like a 6BA7 is the best bet for oscillator/mixer but I need a
circuit to avoid the pitfalls and/or reinvention of the wheel.

Look in the back of the RCA Receiving Tube Handbook. *There are some
nice designs in there that are pretty bulletproof.

Your problem is going to be finding good IF transformers, more than
anything else.
--scott
--
"C'est un Nagra. *C'est suisse, et tres, tres precis."

Thanks Scott,

The IF transformers was the easy bit, to be scavenged from a piece of
unused tube-type mobile radio gear that got overtaken by technology.
I've looked at the RCA Receiving Tube Handbook (RC35 in my case) but
would prefer a circuit that used more generally available (in
Australia) tubes. There *must* be some commercial FM broadcast
receivers that used a 6BA7 or a triode-pentode converter stage -
Zenith used a 12AT7 twin triode that works well.

All circuit source suggestions appreciated.

John