09-03-2018, 07:49 PM
Hi.
Well for some time I've been trying some circuits using Super Regeneration. My main idea has been to make a simple FM set and of course I intended at one point was to make a fixed frequency portable for Anne.
Using a 1Ж18Б I found it possible to make a Super Regen but in no way could I coax it to work up at 88mHz or above. I actually got success on the 11 meter CB band and heard a couple of times NBFM from no doubt a local CB station, fairly loud into a pair of headphones with virtually no aerial and just one valve.
Next I tried a 1Ж24Б, with this valve I got very weak results on 89.5mHz BBC R2 but at least it did work to an extent, higher frequency stations didn't come through.
I then though that the 1Ж29Б might be a better bet. All of these little tests were made on double sided laminate board for screening and stability. I have had really good success with the 1Ж29Б all the way up though Band 2 and with a small change to the tuning coil I could receive Prestwick control tower. Take mind I'm not using an external aerial. On FM, volume from one valve is perfectly loud enough on a set of high impedance phones.
The circuit is very simple. I have wired the filaments in series with the centre tap grounded, the Super Regen oscillator coil is 25 turns of litz wire wound round a 1 meg 1 watt resistor and the tuning coil is 4 turns of 14 gauge enamelled copper wire across a beehive trimmer for the tests.
I'll pop up a circuit later.
Well for some time I've been trying some circuits using Super Regeneration. My main idea has been to make a simple FM set and of course I intended at one point was to make a fixed frequency portable for Anne.
Using a 1Ж18Б I found it possible to make a Super Regen but in no way could I coax it to work up at 88mHz or above. I actually got success on the 11 meter CB band and heard a couple of times NBFM from no doubt a local CB station, fairly loud into a pair of headphones with virtually no aerial and just one valve.
Next I tried a 1Ж24Б, with this valve I got very weak results on 89.5mHz BBC R2 but at least it did work to an extent, higher frequency stations didn't come through.
I then though that the 1Ж29Б might be a better bet. All of these little tests were made on double sided laminate board for screening and stability. I have had really good success with the 1Ж29Б all the way up though Band 2 and with a small change to the tuning coil I could receive Prestwick control tower. Take mind I'm not using an external aerial. On FM, volume from one valve is perfectly loud enough on a set of high impedance phones.
The circuit is very simple. I have wired the filaments in series with the centre tap grounded, the Super Regen oscillator coil is 25 turns of litz wire wound round a 1 meg 1 watt resistor and the tuning coil is 4 turns of 14 gauge enamelled copper wire across a beehive trimmer for the tests.
I'll pop up a circuit later.
