Archive for the ‘Receiver’ Category:

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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Caroline Joy Barnhart There is not enough tritium in the world to run a single fusion reactor for more than a few months. The energy used for production of tritium (and to a much less extent the supply of deuterium) must also be subtracted from the total output of the fusion reactor. That could reduce

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2022-03-12 Homemade Adjustable Capacitor

Homemade Adjustable Capacitor I read that the 365 pF air variable capacitors are very expensive, $30 or more so I decided to try to build one. It’s not difficult to make an adjustable capacitor out of materials one may have at home. This one does not adjust easily, it’s more of a prototype. I got

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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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2020-05-28 Solid State Shortwave RF Preselector

Comment left 2020 May 29 on YouTube video in the title. This video covers MOSFET, dual gate MOSFET, JFET and BJT tuned preamps (preselectors) for his shortwave crystal radio. “The talk about using 18 volts for the cascode got me thinking about tube designs. When the plates need 100+V, and when the heater to cathode

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2020-05-22 PIM Passive InterModulation Explained

Good article on passive intermodulation, AKA the Rusty Bolt Effect.

2020-03-31 Collecting Novelty Transistor Radios

Also FB group Vintage Transistor Radios Collecting novelty transistor radios has a few drawbacks, the most obvious is that they are much rarer than regular transistor radios. Generally the new novelty transistor radios are much more expensive then a regular radio due to their limited production. The customer who just wants a radio is going

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2020-02-19 Nobility 15 transistor Radio Repair

2020 Feb 18 – Nobility 15 transistors OTL S/N (?J)29549 I replaced the electrolytic capacitors. The spkr buzzed when I touched the volume control. Nothing from the detector (transistor). It’s unusual. I pulled and tested some IF parts including one of the transistors, no problems found – transistor tested good. I called it a night.

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2020-02-17 I Bid On A Boy’s Radio, Lost

From FB group Vintage Transistor Radios Last week I bid on a boy’s radio, $26 which lasted up until near the end. But as usual I was outbid at the last minute. I think the demand exceeds the supply, and the prices go up too high. Looks like I’ll be getting one that no one

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2020-02-14 Zenith Royal 400 S/N Z551549 Replaced Capacitors, Driver Transformer

Zenith Royal 400 s/n Z551549 I soldered broken orange wire to battery holder. Replaced all four electrolytic capacitors. Silent speaker and nothing from earphone jack. I checked the voltage at the collector of the driver transistor, it was zero. One pin of the driver transformer primary measures 5.8 V, the other pin measured 0. Checked,

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