01-09-2021, 09:33 PM
I do have a dual control rod valve but haven't given that option a try. I did start playing with an idea that showed some promise for gain control of the likes of IF amplifiers, that used a FET as a voltage controlled resistor in series with a coupling capacitor grounding the cathode circuit signal, of course, being directly heated valves that would mean in a practical circuit the use of a common mode choke which I haven't got round to yet, but it certainly works with an elevated filament battery, (I think that's the term?).
I would agree that the rod pentodes seem a lower noise option to wound grid types.
Loop aerial...
I read about a type of loop aerial that fascinated me so that I made one. It is tuned by the connected radios own tuning capacitor with a switched RCA phono socket fitted to the set to switch out it's own internal aerial. It uses a toroidal inductance matching transformer. The set I use with it most is an ER Sky King that is an ideal candidate because it has a single coil loop with a loading inductance for lonwave reception... The loop makes the old ER into a very sensitive set indeed.
Here is a link to KR1S webpage description of his Hoop loop.
http://kr1s.kearman.com/html/hooploop.html
Picture of the actual loop.
I would agree that the rod pentodes seem a lower noise option to wound grid types.
Loop aerial...
I read about a type of loop aerial that fascinated me so that I made one. It is tuned by the connected radios own tuning capacitor with a switched RCA phono socket fitted to the set to switch out it's own internal aerial. It uses a toroidal inductance matching transformer. The set I use with it most is an ER Sky King that is an ideal candidate because it has a single coil loop with a loading inductance for lonwave reception... The loop makes the old ER into a very sensitive set indeed.
Here is a link to KR1S webpage description of his Hoop loop.
http://kr1s.kearman.com/html/hooploop.html
Picture of the actual loop.
