Tuning Indicators

[pwdrive]

A good intro to the history of radio tuning indicators, with further links/refs etc:

http://www.radiomuseum.org/forum/history...e_led.html

Lawrence.

[AlanBeckett]

The Pye TP/AC uses a a Saturated Reactor Tuning Indicator connected into the Mixer Anode.

Alan.

[pwdrive]

Thanks Alan, I never heard of that system until I came across that article.

Lawrence.

[AlanBeckett]

Herewith the relavant bit of the Schematic - I'd better not Post the whole thing.

   

'A' is the Heater Supply - 4 Volts -and the Bulb is 2V 100mA. The I.F Frequency is 127kHz.
I've got one and it looks to be all there. I'll get to it, honest.

Alan

[pwdrive]

Interesting.

Lawrence.

[Joe]

The Pye TP/AC uses a a Saturated Reactor Tuning Indicator connected into the Mixer Anode.

Alan.

He means a light bulb.

- Joe

[AlanBeckett]

Very droll young Joe

Alan

[pwdrive]

An amature built direct conversion VLF receiver was built using the saturated core principle, it switched (I think) like a Polyakov mixer, if I can find the article I will post it on here.

Lawrence.

[pwdrive]

The VLF job:

http://fhs-consulting.com/aa1tj/vlfrecei...mixer.html

The 80 Meter job:

http://aa1tj.blogspot.co.uk/2011/12/satu...n-80m.html

Both experimental.

Lawrence.

[pwdrive]

And another one (unusual)

http://www.wireless.org.uk/mechrx.htm

Lawrence.