Signal Flow Transistor AM Radio

[mc68hc000]

Where can i download this picture ?

[AllAmericanFiveRadio]

@mc68hc000

I uploaded the pictures and you can find the link in the more info of this video.

[mc68hc000]

@AllAmericanFiveRadio Thank you, very useful presentations

[AllAmericanFiveRadio]

Thanks mc68hc000

[thereelmaster]

say your rely good at making videos on how vacume tubes work, can ya make a video on how a transitor works? thanks

[AllAmericanFiveRadio]

@thereelmaster

Funny you should mention that. I am working on draws now, tube and transistor side by side. I have done a few on how transistor works and or functions. I'll send you some videos.

[AllAmericanFiveRadio]

@thereelmaster

I think I sent you three or four videos. YouTube is showing one sent. Let me know if you only got one.

[barn5923]

Just wanted to say I enjoy all your videos Darryl

[AllAmericanFiveRadio]

Thanks barn5923

[barn5923]

Just wanted to say I enjoy all your videos

[TheTransoceanic]

As always Thank You for making the effort, you explained the signal path in simple terms and kept it so interesting. Been restoring radios for 15 yrs. and still learn so much from your videos.

[mondays89]

I have to admit, was about to stop watching the video at the beginning but I am glad I continued watching. Very good info, thanks for posting the vid.

[AllAmericanFiveRadio]

Thanks mondays89

[nottinghamnc]

I have a question about BFO (beat freq osc). I have read that it is used as a variable mixing osc. -> mixing the IF to AF range. Is the BFO represented here in your schematic? thanks.

[AllAmericanFiveRadio]

Thanks nottinghamnc

In Ham Radio, Morse Code is sent with just the carrier, turning it on and off. You can hear it but it is much like thumping the speaker. If you add a BFO oscillator of a frequency very close to the carriers frequency, and then mix the two you will hear and audio tone every time the carrier is on. This radio oscillator does beat with the radio station but it produces an intermediate frequence I.F. of 455KC. Same principle but for a different purpose.

[nottinghamnc]

@AllAmericanFiveRadio Thank you. I have a little more understanding of it but would very much appreciate a video discussing this in more detail. Regards.

[AndyDaviesByTheSea]

Hi Richard, another excellent video, a lot of work there!

The Marconi 878 radio you commented on is going to be sold on eBay for a poorly friend of mine and I hope you don't mind but I've put a reference to your good work in the advert as I think anyone setting out to restore a valve (or transistor) radio would do well to draw on your experience.

Can you upload a video called "index" as there are so many good things to look at in your channel.

Well done!

Kind Regards ...Andy gw0jxm

[AllAmericanFiveRadio]

Thanks AndyDaviesByTheSea

Hey Andy,

Thanks for your kind remarks. Hope you sale goes will on ebay. I'll put the "index" idea in my YouTube Video List.

Regards,

Rick

[dr34mc0d3r]

Excellent description - I love your videos.

[AllAmericanFiveRadio]

Thanks dr34mc0d3r

[joernone]

Rick,

Excellent explanation and great use of graphics. I really enjoyed this vid. Learned a bunch.

Thanks, my friend.

Regards,

John

[AllAmericanFiveRadio]

Thanks joernone

Hey John,

Your video idea is in the YouTube video list.

Regards,

Rick

[FyberOptic]

Would there have been any advantage to using all PNP transistors like that?

[AllAmericanFiveRadio]

Thanks FyberOptic

The only advantage may be that the manufacturer of the radio got a prices cut from the manufacturer of the PNP transistors.

[CameramanLink]

I can see the similarities, but I notice that this radio runs on negative supply voltage. That seems strange, and is backwards from a tube radio. The mixing process is also different because there is no "pentagrid" transistor! Notice that it takes more transistors to do the same thing fewer tubes can do. In my own experience, most ICs can be "replaced" by one or two tubes in a comparable circuit.

It looks like they took an AA5 and tried to transistorize it :)

[AllAmericanFiveRadio]

Thanks CameramanLink

If this radio used NPN transistors the polarity of the battery would be reversed. The frequency mixing is different as for as the medium goes but the physics is the same principle. Yes it takes more transistor than a AA5 tube radio. But transistors are really cheep. Yes they did transistorized it. It is the same AA5 technology modified for the transistors, mainly low impedance transformers, and the small size of all the parts.

[CameramanLink]

@AllAmericanFiveRadio Very interesting! At my first look, the transistors appeared to be hooked up backwards, then I realized the power supply was of reversed polarity. Interesting yet challenging way to think about circuit wiring! Talk about transistors being cheap, they're REALLY cheap now, but I guess they were cheap back then, even though they were newer technology at the time. Thanks for posting.

[AllAmericanFiveRadio]

Thanks CameramanLink

I can remember transistors being somewhat expensive when I was in High School, because I was buying them one at a time. But for manufacturers they were much less expensive.