Dubious info.? https://www.facebook.com/reel/680342785062427/?mibextid=9drbnH&s=yWDuG2&fs=e
Archive for the ‘Transmitter’ Category:
2024-11-08 RF Amp Using BD139 Power Transistors
He has a strong Aussie accent, a bit hard to understand. It’s a 28 min. YouTube video. He says BD139s have a fT of 250 MHz, but the datasheet I have does not specify any fT because the D in BD139 means they are a low frequency device, not meant for VHFs or RFs in
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2024-08-31 AM Transmitter, Low Power
This is an AM transmitter that this guy built. He says it’s rich in harmonics – it has no tuning nor low pass filtering and the stages are class C, no forward bias. It should have all the things used to minimize harmonics, like a low pass filter. Class C operation is used to maximize
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2024-08-21 Video: Build An FM Microphone
This 2.5 min video uses a SS8050 transistor which is not very good for a 100 MHz oscillator. https://www.facebook.com/reel/347155875050146?mibextid=9drbnH&s=yWDuG2&fs=e
2023-09-25 TV Modulator Ch 3 Doesn’t Work For Digital TV
I Came across this old analog TV modulator in a box of stuff, so I plugged it into my digital TV and powered it up, with some audio modulation on the input. I set the switch to channel 3, and then pushed 3 on my remote, but I got no carrier whatsoever on the TV.
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2023-08-26 FM Bug, Crystal Locked
From Talking Electronics. I’m not sure if this circuit can be frequency modulated the full amount for the FM broadcast band. It’s difficult to push a crystal off its resonant frequency. I’ll be trying it someday if I can find the right xtal. I would be more inclined to instead use a ceramic resonator. I
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2023-07-16 26H20 Radar Repair At Ft. Monmouth, NJ
In 1966 I completed basic training and went to Ft. Monmouth, NJ for 10 months of Radar repair training. The last half of the course we got to work on the actual Radars in *that* barn-like building in the photo. I was on the graveyard shift. There were birds flying around up in the rafters
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2023-07-09 Groundbreaking Research Transmits Energy From Space To Earth
This is definitely groundbreaking. But I don’t understand why they’re doing it this way. I think the array that’s in space should be as simple as possible – an array made up of thin sheets of metallized mylar that reflect the sunlight to the photovoltaic array on Earth. In their system and mine, there has
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2022-01-03 Periscopes Replaced By Video Cameras
I’m sitting on the grass in the back yard and it’s chilly, but the sunlight feels really good on my back. I can hear some birds up in the trees, I’m waiting to see if they’ll come down and eat some birdseed. I started thinking about a way to watch them up there. What I
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2021-12-06 MP3 Player To FM Radio Link (Mono)
MP3 Player To FM Radio Link (Mono) This circuit allows you to play your MP3 or any stereo audio source into a mono signal for reception on an FM radio. It has no antenna and has a range of a dozen or so meters. It operates off a 6 volt rechargeable Ni-MH battery pack but
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