Just think - you're picking up and decoding SSB signals with three transistors, when even the lowest cost SDR system has three billion. And you're linking back to ideas a hundred years old. I think that's a lot of fun.
Very good point, 3 transistors on a speaker. You get used to the bells and whistles of modern SDR or superheterodyne receivers. Thanks for watching, Daz
A very interesting artefact you have there Daz, the coils appear to be Denco and I may be wrong about this but I always the green coils were for valve use, not transistor?
I wonder Michael if that's why they went for a FET instead of a bipolar transistor. So to use up the stocks they may have had from the hybrid version they made before? I guess they wanted to move towards solid state to keep things fresh. I think FET"s were the in thing too? Thanks for watching. Daz
The tuning capacitor seems quite small, does that mean the inductor is a bit small and doesnt produce as high a voltage. As a kid i made the crude crystal set, a good earth and long wire. I could hear local stations and luxemburg . I had a 500pf variable toaster rack and a toilet roll tube fully wound. Large cap, large inductor. Bloody loud lol.
It's a good point. As it has to cover a wide range. I wonder if some compromise has been made with inductor values. I'm keen to try a crystal set myself as I got some vintage headphones, while we have AM still. Thanks for watching, Daz
Many fets are symmetrical and source/drain not identified by most testers. Unfortunately most of Codar's receivers were quite poor. The best radio equipment they ever made by far was the AT5 transmitter, especially the later ones with the simple band-switch mod and PSU change for better netting signal.
Good morning Darren. I remember seeing the advert for this reciever in PW and EE. As a schoolboy I had a Codar CR70A which was a far better reciever. Thank you for the video. Terry
JFETs can be damaged by static. One of my first jobs was digging out dead 2n3819s potted in araldite and replacing them. I now know that araldite is unsuitable for potting electronic components, maybe that's what did for them , who knows? It was a long time ago. A regenerative receiver, takes me back. Cheers, Steve.
Doesn't sound fun retrieving the FETs. I guess the junction is quite vulnerable to static and impulses. I think plastic packages are not that moisture proof and it creeps up the leads, Steve. Thanks for watching, Daz
Just think - you're picking up and decoding SSB signals with three transistors, when even the lowest cost SDR system has three billion. And you're linking back to ideas a hundred years old. I think that's a lot of fun.
Very good point, 3 transistors on a speaker. You get used to the bells and whistles of modern SDR or superheterodyne receivers. Thanks for watching, Daz
A very interesting artefact you have there Daz, the coils appear to be Denco and I may be wrong about this but I always the green coils were for valve use, not transistor?
I wonder Michael if that's why they went for a FET instead of a bipolar transistor. So to use up the stocks they may have had from the hybrid version they made before? I guess they wanted to move towards solid state to keep things fresh. I think FET"s were the in thing too? Thanks for watching. Daz
The tuning capacitor seems quite small, does that mean the inductor is a bit small and doesnt produce as high a voltage.
As a kid i made the crude crystal set, a good earth and long wire.
I could hear local stations and luxemburg .
I had a 500pf variable toaster rack and a toilet roll tube fully wound.
Large cap, large inductor.
Bloody loud lol.
It's a good point. As it has to cover a wide range. I wonder if some compromise has been made with inductor values. I'm keen to try a crystal set myself as I got some vintage headphones, while we have AM still. Thanks for watching, Daz
Many fets are symmetrical and source/drain not identified by most testers. Unfortunately most of Codar's receivers were quite poor. The best radio equipment they ever made by far was the AT5 transmitter, especially the later ones with the simple band-switch mod and PSU change for better netting signal.
I must admit I have the top band tx but not finished looking at it at the moment. Ah yes that will explain the tester results, thanks for that. Daz
Good regenerative receiver and receiving results.
Thanks, worked not too bad if I remember its only 3 transistors. Thanks for watching, Daz
Good morning Darren. I remember seeing the advert for this reciever in PW and EE. As a schoolboy I had a Codar CR70A which was a far better reciever. Thank you for the video. Terry
Well I've got to confess there are two of those receiver's sitting in my shed so see what I can do with them, Terry. Thanks for watching. Daz
@@darrencoe5795 As well as bringing back old memories that would be brilliant.
JFETs can be damaged by static. One of my first jobs was digging out dead 2n3819s potted in araldite and replacing them. I now know that araldite is unsuitable for potting electronic components, maybe that's what did for them , who knows? It was a long time ago. A regenerative receiver, takes me back. Cheers, Steve.
Doesn't sound fun retrieving the FETs. I guess the junction is quite vulnerable to static and impulses. I think plastic packages are not that moisture proof and it creeps up the leads, Steve. Thanks for watching, Daz