31-10-2012, 05:00 PM
Nah - I've checked the wiring, which is fine, and a 1kHz signal injected at the input of the diode comes through loud and clear in the phones, so the diode and transistor stages are working. I therefore think it's most likely the coil because the tuned circuit is just the coil, a tuning cap, the diode and a coupling cap - hardly rocket science. A DRR2 coil will soon be on its way to me from Big Al, so I can give that a spin, and if all's well, can check the inductances of the windings to enable me to hopefully wind a replica or two. I'm quite taken by the simple R.E.P one-valver circuit that Al posted, so I can see me knocking that up ere too long. Yet another diversion from other items on my 'to do' list! 
I have a nostalgic fondness for little TRF valve sets - it was listening to one made by the teenage son of the proprietor of a Bed and Breakfast place we stayed at in Mablethorpe as a ten-yr old in 1949 that was the spark that got me into radio. He'd made what I later discovered was a one-valve TRF. Once he'd helped me master the reaction control, I recall excitedly listening to Morse code, and wondering if it was spies. (Maybe it was?).
Also, we listened to the local Coastguard station ship to shore radio, little realising that some 23 years later, I'd be taking my 12WPM Morse test at that station for my amateur radio licence! From the age of 12, I began building little radios with varying degees of success (or failure!), and when I started a newspaper round, I used to dawdle along scowering the pages of 'Hobbies Weekly' magazine for simple radio circuits before delivering the mag - well thumbed by then - through the letter box of the intended recipent!
Happy days.
I'm not going to be around much this next few days, so I'm afraid that tinkering will have to take a back seat.
I have a nostalgic fondness for little TRF valve sets - it was listening to one made by the teenage son of the proprietor of a Bed and Breakfast place we stayed at in Mablethorpe as a ten-yr old in 1949 that was the spark that got me into radio. He'd made what I later discovered was a one-valve TRF. Once he'd helped me master the reaction control, I recall excitedly listening to Morse code, and wondering if it was spies. (Maybe it was?).
Also, we listened to the local Coastguard station ship to shore radio, little realising that some 23 years later, I'd be taking my 12WPM Morse test at that station for my amateur radio licence! From the age of 12, I began building little radios with varying degees of success (or failure!), and when I started a newspaper round, I used to dawdle along scowering the pages of 'Hobbies Weekly' magazine for simple radio circuits before delivering the mag - well thumbed by then - through the letter box of the intended recipent!
Happy days.
I'm not going to be around much this next few days, so I'm afraid that tinkering will have to take a back seat.
Regards, David.
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
