I have uploaded before and after photos as well as my working schematic.
The little radio will be going to the AWA Conference at the end of August where
kit radios are the theme this year. We hope to have kit radio represented from
all of the eras.
Conclusions:
This late 1930's $4.95 entry level Regen kit does not require A or B batteries
and provides modest performance. On local stations with a longwire, it drives a
loudspeaker when connected to a small transformer and an eficient speaker. It
promises multiband performance but it is doubtful that Meissner supplied any
other plug in coils, than the BCB coil provided in the kit. Using 6.3V 300 mA
tubes in a series string on 110 or 220 VAC is decidedly silly and somewhat
dangerous!
The hum is almost intolerable on headphones but not heard on speaker. It has a
nasty habit of blasting you with loud AC hum for 30 seconds after you turn the
unit OFF. Check out the schematic to see why I am getting all that hum...
On a spin and tune with 2000 Ohm headphones, I was able to easily pick up 18 BCB
stations all across the band at 11 AM today. 3 locals were strong enough for
room volume on a speaker.
... That sounds about right. Its not AC after the diode although its 'pulsating' at 60 cycles because of no filtering. The ole .707 number usually works for...
Thanks all for the help on this project! I have uploaded before and after photos as well as my working schematic. The little radio will be going to the AWA...
... It looks like the B+ to the detector is not getting full benefit of the filtering. What about moving R3 to the C9/R7 junction? Also...many of these things...
Thanks Bill, Yes great catch - that schematic has an error in the B+ section. The radio is actually wired as shown in the updated schematic. I uploaded REV2!...
... Really? Meissner was a major player in the coil business (at least in later years), so it seems reasonable that they would offer other coils. – John...
Hi John, There are a few people who have these little receivers; The style of coil form is quite odd with crimped contacts on the outside of the form and a...
I find I have forgotten all my Calculus, (argh!) so not going back to quite to basics, we find: For a familiarity check, for a full-wave rectifier Erms =...
Re: Hum I don't remember a serious hum problem, merely a wee bit when not regenerating. Your description sounds like a sneak circuit/connection. I've lost...
About hum: The power plug needs clarification. The wide blade is the neutral connection, at or near ground potential, and the narrow blade is the hot ...
Mike, interesting report on the Meissner. Now re the other waveband coils, Meissner only supplied the MW BC coils with any regen kit. I just now looked at a...
Oh - looking at the schematic, I see where the hum is coming from: the 1/2 wave heater supply is modulating the electron stream from the cathode. I was always...
There should be no connection from the heater supply and the receiver circuitry. The only way there can be an influence is resistive leakage between the...
More to the point, the thermal lag in the cathode is much too long to be affected by an 8 millisecond gap between current pulses, and could not affect...
Richard, look in the Photos section under WU2D photos. The schematic is in there, not in files section. The filament circuit cannot be 100% isolated from the...
Ah, yes. The only thing I notice is that when the power switch is open, there is ac continuity to ground through the C4 ground bus to chassis capacitor, which...
... the ... This may not be the case with the Meissner, but tapping down the inductor like that can improve selectivity at the expense of sensitivity. It may...
If the capacitor were across the whole coil and the tube tapped down on the coil that would be true, but as drawn the top of the winding is not active, and may...
ac/dc receivers do not have to have inherent hum. I think it's usually common mode currents in the steel chassis. I have an RMCA AR-8506-B ac/dc maritime...
Wow, Thanks guys. Lots of feedback on the hum! The amount of background hum and the ridiculous hum on turning the set off is troublesome. I actually found a...
What you want is a 250 vac motor RUN capacitor. Motor starting capacitors are often back to back electrolytic capacitors, and won't last in continuous...
Richard, I wouldn't dismiss the electron stream modulation quite out of hand. The P-P "AC modulation" is pretty high. I don't offhand know how to calculate the...
I'll bet you it was a capacitor non-polarized, approximately 8uf at 250V. The exact value would be 7.8709198813056379821958456973294uf but 8uf ought to be...
30 watts drop over a 6 foot resistance cord wouldn't burn anything. Possibly the bad reputation these things had was maybe a propensity to break? I don't know....
Hi Hue What you are saying is only partly correct. The 'heat tape' is fine providing it is attached to something that will absorb the heat it produces. If it...
Well, I will have to take your word for it, and maybe ask my brother, who has more experience with it. The 2 or 4 winters I used it, I had it on plastic pipe,...
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