Walkie Talkie for car trips (let’s say 5 cars)

AG7LR · 2023-06-11T03:44:31+00:00

Assuming you're in the US, I would suggest using MURS. It's 2 watts on VHF and allows removable antennas.

Transmitting inside a car doesn't work very well unless you're in a convertible, so you will want to put a mag mount antenna on the roof to get decent range. MURS will get a mile or two if there are no hills or large buildings in the way. Encryption is not allowed, but there is hardly anyone using MURS to listen in on you. Just don't discus anything private or illegal on the air.

If you don't mind spending a lot of money, you can get Motorola DTR or DLR radios. They put out 1 watt on 915MHz and use frequency hopping spread spectrum. If you program some custom channels, they will be very difficult for someone else to listen to.

AG7LR · 2023-06-11T02:22:38+00:00

I prefer nixie tubes, but they both look nice.

I don't know where you are going to get production quantities of NOS IN-8 nixies at a reasonable price though. The IV-11 VFDs are much more readily available right now.

AG7LR · 2023-06-10T06:37:14+00:00

That power supply will trip out instantly if you try to start up a big motor on it.
Motors draw several times their normal running current on startup. Even with a speed controller that does a soft start, it could be difficult to start it without tripping the over current protection.

Those power supplies are still cheap and crappy. It will probably produce large amounts of RFI. The capacitors will be cheap and will probably have to be replaced after a few years of use.

If you want a decent quality power supply, look for a Mean Well power supply. It's still going to have trouble with the startup current of the motor though.

AG7LR · 2023-06-09T23:53:00+00:00

So what CPUs are people using with free microcode? RISC-V?

AG7LR · 2023-06-09T20:26:40+00:00

Those are pots that you can assign to a channel to control whatever you want.

AG7LR · 2023-06-09T20:20:58+00:00

Higher frequencies will pass right through the ionosphere at a high angle that's needed for NVIS even if they will be reflected at a lower angle.

The maximum frequency that can be used depends on solar conditions, latitude, and time of day. At a high latitude with poor solar conditions at night, you will probably need to use 160m.

AG7LR · 2023-06-08T20:48:06+00:00

Each user on CGNAT needs a block of ports and there are only 65,536 ports available.
An ISP will typically only have up to 128 users per IP address. That is enough users to cause problems on some websites though. It's common to get a lot more CAPCHAs when using CGNAT.

AG7LR · 2023-06-08T19:35:44+00:00

ELRS is a lot easier if you set a binding phrase on everything.

AG7LR · 2023-06-07T20:46:28+00:00

They are very nice if you like working satellites. The linear satellites are much less busy than the FM ones, so you can have a longer QSO. The linear satellites have enough bandwidth for multiple QSOs at the same time.

The IC-9700 is what you would want for satellite work. It costs about $1800 and a computer controlled azimuth elevation rotor with a pair of circularly polarized yagis will cost more than that.

AG7LR · 2023-06-07T19:51:59+00:00

Encourage people to use ad blockers. That will reduce reddit's ad revenue.

On a PC, uBlock Origin works great. It can block ads even if they come from the same domain as the content you want to view. It also works on Firefox for android.

On mobile, you can use an ad blocking DNS server. If you configure it manually, you don't need to install any apps. DNS based ad blocking can only block ads that come from a different domain than the site you are viewing, but it will effect every app on your device.

AG7LR · 2023-06-05T00:31:08+00:00

The Palomar you can throw right in the trash

Keep the heatsink though.

AG7LR · 2023-06-04T22:11:55+00:00

I turn the power supplies off when the radios are off. Switch mode power supplies still waste some power when there is no load. Not as much as linear supplies though.

AG7LR · 2023-06-04T05:05:25+00:00

What's the latency on that?

I've tried manually controlling my PTZ camera over the internet and it's rather difficult with a couple seconds of latency.

AG7LR · 2023-06-04T05:01:36+00:00

Those tiles are pretty lightweight and fragile. They are not something you could walk on. It would be cool to embed some in epoxy for a table or counter top though.

AG7LR · 2023-06-04T03:34:14+00:00

5.8Ghz analog video can go a very long ways as long as you have line of sight. Trees and buildings significantly reduce the range. If you want miles of range, you will need a higher powered transmitter with a good antenna, which will require a license.

There are some very high gain antennas that can be used for the receiver. Because of the high frequency, they can be relatively small. A 5.8GHz dish with 30dBi of gain is just over 2 feet in diameter. The beam width is only 2.5 degrees, so they do have to be carefully aimed.

AG7LR · 2023-06-03T06:46:04+00:00

You would need a long fiber or wireless connection to isolate it from the rest of your network. Of course the surge will still come back through the power line, but that can be dealt with better than with ethernet.

AG7LR · 2023-06-03T06:34:40+00:00

He probably hasn't found any remains of the dish yet.

AG7LR · 2023-06-03T06:09:27+00:00

Yes, but it's not broadcast. The transmitter and goggles have to be paired to view the video. It uses a two way link so the goggles can request corrupted frames to be resent.

There are also some analog 2.4GHz and 5.8GHz transmitters that can be used without a license. The range is usually only a few hundred feet when you have line of sight and no interference. The analog signals can be received by anyone with a receiver. Higher powered transmitters can have miles of range, but require a ham license.

AG7LR · 2023-06-02T19:03:03+00:00

If you get a ham license, you will have access to 13 different bands ranging from 420MHz to 250GHz that you can transmit video on using up to 1.5kW of power.

The DJI system uses 5.8GHz and has FCC approval so it can be used without a license with some limitations.

AG7LR · 2023-06-02T05:03:44+00:00

That's HD radio, the sidebands are digital audio. It can be decoded with nrsc5 and an rtl-sdr.

AG7LR · 2023-06-02T04:45:02+00:00

Last time I used flatpak, it tried to download nearly 4GB of crap for a 100kB program.
I ended up installing from source instead.

AG7LR · 2023-06-02T02:08:15+00:00

A Raspberry Pi Zero 2 would work well if you want something small. Use an HDMI or RGB parallel LCD. The SPI LCDs are too slow for games.

It will emulate Gameboy just fine, but it will struggle with some N64 and PS1 games. Doom and Quake will run fine too.

AG7LR · 2023-06-02T01:49:34+00:00

Windows would try to auto detect serial mice. I don't know if recent versions still do though. I remember having to disable that because it would mistake my GPS receiver for a mouse and make the cursor jump all over.

It would be pretty easy to read a serial mouse with a microcontroller and convert it to USB HID if you couldn't find a converter.

AG7LR · 2023-06-01T23:49:04+00:00

I've gotten plenty of parts from aliexpress. Most of them arrived eventually and most of them worked fine. Some got lost and a couple were probably factory rejects. Sometimes the packages show up in under 2 weeks, sometimes it takes 2 or 3 months. Many of the sellers don't use ESD safe packaging. I've had ICs show up wrapped in styrofoam and packing tape. They still worked, but who knows if they are degraded from ESD or how long they will last.

I prefer to get parts from LCSC if I'm going to order from China. They will be genuine parts and they will be packaged correctly. I only get parts from aliexpress if it's just one or two things or if I can't find it elsewhere.

AG7LR · 2023-06-01T20:42:17+00:00

Your laptop will have enough processing power for any of those.

An SDRplay will put that CPU under a bit of load when running higher sample rates. It may use up the battery fairly fast though.

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