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 Post subject: Re: Build me a Radio
PostPosted: Aug Tue 18, 2020 6:26 pm 
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Location: S. Dartmouth MA 02748-1225 USA
Mr. Highlander wrote:
For the grid leak, I would normally use a mica, but I wanted to use all the parts listed. But for sake of working, cheating would need to be an option.
I think you mean grid condenser (in association with the grid leak resistor) Yes? A mica, yes, for a grid condenser in the detector. A larger value is used for the long waves such as 300pf, for shortwave radios 250pf to as low as 100pf. Over the extent of the BC band changing that value of the grid condenser has no noticeable effect.

IMHO I am not sure Eddies goal was to use all the parts as they were salvaged from the same radio. However, the original radio may have been poorly built or "hacked" in its later life so the parts are not "authentic" to what is/was supposed to be. It is that, the bulk of the components seem to be the Diamond radio build (Bruno coils). I may copy the PDF's for the 4-tube build for myself. I think I have the RF coils as that seems to be the key to identifying the circuit.

The choke you added to the plate circuit of the detector is often used when the particular brand of 1st AF transformer has problems with shunting RF from the tickler. Some circuits do not use/need that component. A .001 to .003 is often used across the primary of the 1st AF to shunt the RF. Even if headphones are the load as in a one tube set.

Many circuits can and will fail because of component placement and poor wiring practice. That is why, if replicating a 20's era build article is is good to at least place the parts as the diagrammatic shows, even if they are not parts made by the manufacturer of the OEM part on the part list. New radio fans would often hack in additional components to solve such problems that could have been prevented by essentially, "following the directions"...

Often, a regenerative radio becomes a control nightmare in that the tuning condenser and any other variables like the regeneration all contribute to both hand capacity and interaction. Not only hard to tune but all those variables interact making even rudimentary calibration impossible. The three circuit tuner is an improvement.

FWIW I am amazed at the number of part makers in Radio World that I am not familiar with as well as the number of unique circuits offered.

Chas

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 Post subject: Re: Build me a Radio
PostPosted: Aug Wed 19, 2020 3:03 am 
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Joined: Feb Tue 05, 2019 1:02 am
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Location: Blackshear ,Georgia
I'm still reading and researching this one , seeing if I might run across another radio using same parts besides the diamonds ,probably gonna be a short night for me tonight though, these midnight and after getting to bed catching up to me ,along with the heat down here . Chas if you get a minute check out this other radio i posted awhile back and see if you may recognize it , or the circuitry , any ideas and info you might share on it ,thanks .viewtopic.php?f=1&t=378275


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 Post subject: Re: Build me a Radio
PostPosted: Aug Wed 19, 2020 4:02 am 
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Location: S. Dartmouth MA 02748-1225 USA
Yes, I know the late stuff, I, too stay up late far too often. Problem is brain gets wired up on research and does not shut off..

I did comment on that 4-tube set, interesting. You do seem to find the weird ones...

Chas

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 Post subject: Re: Build me a Radio
PostPosted: Aug Fri 21, 2020 3:39 am 
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Location: Blackshear ,Georgia
One would think there should be thousands of the diamonds of the air receivers out there with all the advertising on them back then .


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 Post subject: Re: Build me a Radio
PostPosted: Aug Fri 21, 2020 4:29 am 
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Location: S. Dartmouth MA 02748-1225 USA
Eddie,

I would think so too.

I have yet to review the construction article.

The radio may be more pedestrian then I think. Meaning, it's just another regenerative set with no redeeming qualities other than the bragging rights that the radio fan built it from the magazine plans...

I see many Browning-Drakes (regenerative w/RF amp) and have several in my collection, they do work outstanding because of the winding of the detector transformer. They were well advertised, there were even "knock-off" coils...

Chas

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 Post subject: Re: Build me a Radio
PostPosted: Aug Fri 21, 2020 4:57 am 
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Location: Omak,wa,usa
Hello Eddy,
looks like a fun project


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