MIKROWAVE 1 Channel is all about building simple radios like crystal radios and regenerative sets, ham radio projects and converting and restoring military surplus radios. Both solid state and tube (valve) equipment is discussed. On the air with simple radios on the ham bands, shortwave listening, antenna construction and repair tips and techniques are covered. You can build a radio or bring a surplus radio back to life!
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Why 60 kHz? I get that it's well over 3x the highest audio frequency we're likely to see, but most other PWM transmitters I've seen use frequencies like 175 kHz for the sawtooth....my guess was to make it eaiser to filter out any noise from it on the output (you mentioned earlier if you don't filter it out you get spurious sidebands...)
Thanks! I just came across this. I want to build a low-power transmitter for the AM broadcast band to provide "content" for my collection of AM radios, and I think one of these PDM/PWM designs based on the TL494 would be perfect.
To complicated! The one that I built years ago was extremely simple, used a single 555 IC, and was featured in the first few pages of an ARRL handbook, maybe about 1969. It featured volume and tone controls and required a single 9-volt battery. All of the components used would still be available today for purchase. Just wished I had that schematic.
my favourite crystal radio is a shortwave set, back in the 1980s I got loads of Soviet propaganda on it, Thankfully not much of that now.
My first radio was much simple, you just need a radio antenna a germanium diode EFD 108,a speaker(2000 ohm impedance) from a old phone with carousel dial, a ground connection and you can listen AM local radio station no battery needed.
Hi Mike, on the subject of simple projects, I'm building a whole bunch of Paraset portable 12v PSU's. A little birdy says you might need one?
what about using two SSB modulators and a limiter you know you use one SSB as the modulator driving a limiter then back into the second SSB modulator operating as a demodulator should sort any muck and get some clean modulation.
"Enjoy your day, and let nobody steal your joy.". Sage Advise.
If this is a kit, I will buy one.
I built a single transistor code practice oscillator in 1969 while in Vietnam working on a Novice license. I got to 5 wpm, but gave up when sent to another command, thanks for this one Mike. 73's🎙KD9OAM🎧📻
I got an old Eico CPO from an upgraded novice when I was a kid. It was almost identical to this circuit!
Charlie W.
Super cool video!
why?
, Who invented Morse code?
Rudolf Diesel
Charlie Whiskey?
Viewer suggestion: go to all those rallies and buy all the old TRANSISTOR circuit books you can find. ICs come and go. Most transistor circuits, even 60 years old, can still be made to work without much effort.
This was fascinating and so well explained. Thanks Mike. Have you ever used the later Si 4732 and Si47xx series of chips?
"But Mike! Where do we buy the kit of parts?"
Radio Shack? Lafayette? B&A? Waters and Stanton?
Unfortunately, I have a bad habit of looking at all the old transistor radios I find and instead of snatching useful parts from them I think, "I bet I can fix this thing. It's probably just a bad connector or a shorted cap. And even if it's a transistor, I have bins full of them. Sure the tuning cap would be good in a QRP antenna tuner, but this cool old radio is already all here and just needs to be fixed. Besides, I already have a QRP antenna tuner, 2 of them in fact. A little super glue will fix this case just fine and I can stick in a little step-up inverter module, shield it with aluminum foil since this is an AM radio, add a few filter caps and an inductor to quiet it down, and a lithium battery pack to drive it all instead of those 4 old C cells. Probably run for days, especially if I put a small solar panel on top. And I think I have a longer-throw speaker this size somewhere, too. This thing could sound great by the time I'm done with it! And I could listen to it when I'm working out in the shed instead of listening to the 4 channel 400 Watt SONY Dolby system I have in there already."
Could you gives us some close ups of those cool old books you showed briefly in the intro ?
Will do Part 2!
Robert Moog would be proud! So happens that I went though my junk box the other day and found a metal can germanium transistor with a whopping hfe of 42! I've heard that germanium (not geranium) components are heat sensitive to soldering the leads too close. I enjoy ALL of your projects, even when they're way too complicated for me. As it stands, I need to build your noise antenna because I haven't been on the air much since April when we had a power outage and the neighbor's house 500 ft down the road switch mode power supply decided to be an incredible S9 noise maker after we had a power surge when the power came back after we had 30 inches of snow around Easter. Terrible TOROIDS are in my future, but I have found some pretty cheap. Thanks for all you do! You always have excellent content well put together on this channel. 73-W1RMD.
I really don't condone scrapping an old relic of the past like that. Repair that old transistor radio and get the parts somewhere else instead. But that's just me. To each their own I guess. Good video anyway. Thanks and keep up the good work.
Repairing Japanese Transistor radios was my first unpaid job. My father often used to take me along on a Saturday morning to the service department of a group of retail electrical shops where he was the service manager. Rather than me sitting around idle, he put my keen youthful eyes and soldering skills to use, (I must have been about 12) soldering back the thin wires of the long and medium wave coils on in-guarantee tranny radios. Unpaid? Maybe I got paid in solder. 73 Steve M0KOV
Repairing Japanese Transistor radios was my first unpaid job. My father often used to take me along on a Saturday morning to the service department of a group of retail electrical shops where he was the service manager. Rather than me sitting around idle, he put my keen youthful eyes and soldering skills to use, (I must have been about 12) soldering back the thin wires of the long and medium wave coils on in-guarantee radios. Unpaid? Maybe I got paid in solder. 73 Steve M0KOV
The millions of awful old japanese plastic pocket radios are worthless. It's not like he's scrapping an Atwater Kent
I remember having a big box full of crappy AM radios when I was a kid. I would pull out the ferrite antenna and speaker. I once made a speaker "wall" out of transistor radio speakers. It sounded surprisingly good! 73's W3IHM
Right then. That's my girlfriends evening planned out then.
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This is a good video. Keep them coming
Thanks, will do!
This was an absolutely wonderful presentation and answered questions about D-Day communications that I didn't even know I had. My Dad went ashore on D-Day plus three and I'm sure that this equipment kept him and other GIs so much safer in their advance on Normandy.
I did this kind of crap 60 years ago, what’s the point of do this today? Get a life.
Some of the guys want to try something again that did not quite work when they were jonny novices. Others are curious about how grandpa did it. And I already had a life and have left a trail actually, so its for the kids.
Thank you for the history. So FM radio played a big part in WWII.
FM had a cheerleader that engineers around the world trusted - Armstrong.
@@MIKROWAVE1You are absolutely right, Major Edwin Howard Armstrong, without his inventions where would Radio receivers be today, TRF sets, God forbid!
The Jones 1936 Radio Handbook has a RFC-decoupled Headset and B+ line. I'll get you the page-number if you"re interested;
The technique does block RF so it adds to the decoupling possibly improving the RF bypassing (throttle capacitor) thus possibly helping stabilize the feedback.
Thanks I literally haven't fooled around with radio for 60+ years (high school class of 1961). I built a crystal set and a one tube super-regenerative
receiver from kits. Owned a 1930's Hallicrafters S20R shortwave set. This takes me back. Since I can't find the old radios, I'll just make a new crystal set. Thanks .
I had a Viking2 that had an ART13 modulation transformer in it...
You do find them in strange places, and they work at embarrassingly high power levels!
Brilliant again Mike, thank you. I have often been up St Catherine's HIll but only once to do radio. I never reaslied it was such an important site in the context of D-day. Ventnor is the more famous location on the south coast of the Isle of Wight because of the Chain Home station there.
I wonder if anyone knows where the British and US siting were on the beaches? Caen took a while, so it could not have been that far initially,
Excellent presentation Mike! Very well scripted and produced. Great writing and verbal presentation skills are rare amongst engineers, believe me I suffered through many awful ones both as a listener and a reviewer/commenter during their preparation. These DDay videos are A+++! Chris AJ1G Stonington CT
Not saying never, but I was seldom employed as a real pure engineer type like you are talking about. I was more customer facing and applications oriented, so it was sink or swim beyond design - setting to work and training customers on what we designed and supplied. Not that they were not nervous! They even sent me to Dale Carnegie!
The Nazis used FM (foreign modulation) we used AM (American modulation). Why no use of satellites?
Technically Hungary was a satellite.
Well scripted excellent presentation (Can you confirm) I remember reading an article stating that the British cut the German to American submersible cable at the start of the war. I also read that a transatlantic cable was brought ashore in France after the D-Day landing for wireline telegraphy (teletype) with the states
Great Job! Thanks for the great info!
Thanks for watching. I think I have enough information for a third video on what conventional coms systems landed D Day and the first few days after.
Excellent video and very good information. One question... Ft Monmouth, PA? In 1967, I attended a US Army Electronics school in Ft Monmouth, NJ. Thank you for sharing this with us. 73 de K7RMJ.
Yes Ft. Monmouth in NJ. The testing was done there and in the mountains west in PA.
I loved this follow up to part 1. Thanks for taking the time to make these videos.
Living in England, D day has been a large part of the news recently As it is probably the last time that surviving D day military personnel will cross the channel to remember the battle and the fallen. Thanks for this very interesting series which explores and area not much documented generally. Thanks, Mike. 👍
Wow, how interesting! I really enjoyed this history / radio / WW2 video. Thanks for putting this together.
Thanks for watching!
Thank you for posting this video. Well researched and informative. I enjoy the various topics on your channel.
Thanks for watching - and yes this was a research Rabbit Hole al right.
Very nice.
Thanks for another great report Mike. I first saw the 19 set when I joined Cadet Signals in High School in Canada, back in 1950! Great radio! 73, Shlomo 4X4LF
After restoring one , recapping it and aligning it, I finally learned what this set was. I had seen the lend lease jobs mostly built by RCA Northern Electric in Canada with the Cyrillic markings as an oddity, but had no idea how packed with capability they were. That said, they are a tough radio to use on the ham bands, compared to many other low cost sets that were available surplus after the war!
Excellent research, Mike! Thanks for all of your effort.
Glad you enjoyed it!
Lots of research you did there. Thank you.
Did a radio operator have to write backwards in early radio transmission? I recall my dad talking about early transmissions came in backwards and his father could write backwards?
My grandfather was a radio man in D Day... My dads call sign was N3HW... I grew up to Morse code and CQ CQ CQ November 3 hotel whiskey radio contest weekend blasting through every TV and radio in the house and in the neighborhood.... Everyone knew when it was a radio contest weekend.... Great video 73s Do you think the air ships were used for a capacitor drawing atmospheric electricity?
Thanks for the information. Signals don't get mentioned much in documentaries, except as an input for Bletchley Park (Ultra)
Very interesting. The Telefunken gear was surprisingly advanced. Thanks for your hard work, Mike. 73
The Germans were using Spiral-4 cable too for their carrier telco systems. This was captured at times and put into use! The question is, did the US copy it from them or was it the other way around?
Nicely done, Mike! I used to have a boatanchor called R-48/TRC-8 that I was told was part of a phone network. Perhaps a little later than this. Miniature tubes. It had some diagnostics built in - it had its own voltmeter! Only radio I’ve ever seen like that. They used to turn up at hamfests sometimes.
Yes that is the upgrade that was installed with the British WS-10 later on St. Catherine's mostly late and post war.
I think I thought of something about the way the modulation was done that made the system work better than a "simple minded" explanation of it would suggest. Each of the upper channels was being sent as lower side band. SSB-SC The human voice has most of its amplitude below about 1KHz. This would mean that the carrier would be being whipped back and forth in frequency at rates well outside what would end up as audio band for each output. This includes the base band channel which is not a SSB transmission. Thus each channel of audio was functioning as a spread spectrum for the other channels of audio. A strong jamming carrier couldn't mess up the signal for a time long enough to matter to what comes out of the low pass filter than feeds the headphones. You would get distortion from it but a distorted voice up to a point is just fine for understanding what is said.
I have very little information on whether the Wehrmacht systems were FM-FM Subcarrier or FM with SSB Subcarriers or FM with Full AM Subcarriers. I'm hoping for comments and corrections from the continent!
@@MIKROWAVE1 I don't happen to know. If someone comes in with that info, I would be interested in a video that explains it.
Nice, & 73 de kc2wvb