Amateur Radio Stack Exchange
Amateur Radio Stack Exchange

Questions tagged [diy]

Questions dealing with handmade (Do It Yourself) radios and radio accessories.

161 questions
14
votes
5 answers

How can I add amplitude modulation to this transmitter?

I recently built this circuit, and could hear a nice full quieting signal on my short-wave radio with a 7.2 megahertz crystal for the 40 meter band. What is the simplest way I could Amplitude Modulate this signal with a microphone or computer output…
Skyler 440
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Why do we have to hand wind toroids?

Many, if not most, ham radio kits (transceivers, tuners, ununs, baluns) require the builder to hand wind and tap their own toroids. (example) This is a considerable area of stress for newbie builders and a failure point for their builds. I can’t…
RoboKaren
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9
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5 answers

Home-brew 10 meter walkie talkies?

"When I was in high school, we had 8 hams at once. (Probably rare) 4 of us built little 10 meter walkie-talkies and had great fun using them on Field Day, hiking or around town. It was especially fun because this was pre-cellphone and…
Skyler 440
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6
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2 answers

Replacing hand-wound inductors with store-bought versions

I'm wading through some schematics for a direct conversion I-Q SDR receiver, and there is an L-C band-pass filter on the input. Each inductor is specified by an inductance, a toroidal core material, a wire gauge (AWG), and a number of turns. I…
W5VO
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6
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3 answers

What does a first-time operator need to know when looking for a DIY kit?

When I was growing up, I lived about three blocks from a Heathkit, and envied every device on the shelves. Now that I'm older, am teaching myself electronics and have a background in film and television broadcasting, I think I'm coming down with the…
dwwilson66
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6
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2 answers

What should I put in a "Go box", "Go bag", or "go kit" for emergency communications?

If I wanted to build a mostly-portable-but-still-comprehensive kit to use in emergencies, either my own, or simulated ones through ARES or RACES, what should I put in the kit? I'd prefer responses to be generic (see below), though I won't complain…
YetAnotherRandomUser
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5
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2 answers

14dB insertion loss for bandpass filter acceptable?

I'm busy with a direct conversion receiver for the 20m band, using a VXO and a 14.060 MHz crystal. I designed a bandpass filter with the following components, using this design calculator. Someone gave me a nanoVNA to check the shape of the filter…
Hans Fong
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4
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1 answer

Help with readings on schematic

I am in a Kenwood TK805D and a Kenwood TM241A to interface some of the hidden inner circuitry with the outside world so I can use the radios to do more than just talk on (ex. AllStar node, cross band repeater, packet radio, and much more.) I think…
Skyler 440
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2 answers

How to design constant impedance tracks on PCB?

I have designed PCB's in the past, but need to draw a constant 50 ohm impedance track on the project I'm planning. I know the calculations for (for example) a coplanar wave and how to get a straight PCB track around 50 ohms. (I can recommend the…
Dieter Vansteenwegen ON4DD
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Activities for High School ham radio club

I just started an Amateur Radio Club at our High School (KE0FXH) Our school is not a technical school (it is an arts school) and I am trying to find activities to get students interested in ham radio and technology. So far, I ran a foxhunt, we built…
Skyler 440
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Where can I find HAM forum, newsgroup, etc?

Where can I find HAM forum, newsgroup, discussion, chat room, etc., either formal or light hearted, apart from this one?
EEd
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1 answer

Detect multiple broadcast on same channel

I have a number of ear guards with two way radio communication. They can only be set to send and receive on the same channel, and they have the option of dividing themselves according to the ctcss standard. The tricky thing, is that I wish to setup…
Sodori
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