20
votes
Accepted
Why do some straight keys have a slider that shorts the contacts continuously?
My understanding is that in at least some telegraph systems, the principle of operation was as in this circuit (where the coils depicted are actually telegraph sounders):
simulate this circuit –...
- 24.4k
14
votes
Can you use a satellite dish for a ham radio antenna?
You can use a satellite TV dish antenna for amateur radio use but how you use it depends on what frequency you want to operate on.
The satellite dish antenna is two basic parts, the parabolic ...
- 342
13
votes
WWV, WWVH, and WWVL may be shut down. Are there any alternatives?
GPS-based frequency standards
@larsks answer rightly pointed at devices that use GPS to generate the 1-second pulsing.
That's the correct way to go.
Curiously, these modules only address the once-...
- 15.5k
13
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WWV, WWVH, and WWVL may be shut down. Are there any alternatives?
In No WWVB? No problem!, KB6NU points at two projects that show you how to build your own low-powered WWVB-replacement to keep your clocks in sync:
μWWVB: A Tiny WWVB Station. This project uses an ...
- 598
8
votes
Why do some straight keys have a slider that shorts the contacts continuously?
Land line telegraph keys are fitted with a circuit closer switch. Radio telegraph keys were not but many radio operators used land line keys because they were so readily available. This includes the ...
- 181
8
votes
Can you use a satellite dish for a ham radio antenna?
Apart from using it as a ham radio satellite antenna (eg. for QO-100) or a microwave terrestrial antenna, you can turn it into a VHF slot antenna. Here is an example: https://w6nbc.com/articles/20xx-...
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6
votes
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Two way ham radio to communicate between two stations
The answer to your question involves both technical and regulatory issues.
Technical Considerations
Radio signals can travel between two locations on earth either by line of sight or by propagation ...
- 18.5k
6
votes
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How long would a radio last in storage?
In modern, medium- to high-end equipment, chances of dry solder joints are slim to none, especially in radio equipment, where your solder process needs to be especially safe against this kind of ...
- 15.5k
6
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Can I communicate 40 miles away with a base setup
With 2 meter FM and common 50 W base or mobile transmitter power and plain vertical quarter wave antenna, range over flat ground to a similar station is roughly twenty-five miles, or forty km (limited ...
- 4,097
5
votes
Suitable acoustic foam rubber for headphones?
Out of left field - If function is the only cause and fashion isn't an issue, use a couple of black cotton socks. On my headphones the plastic outer pieces are removeable. I cut the ends off two socks,...
- 51
5
votes
Accepted
UV-5R 4W BFB297 vs UV-5R 8W BFP3-23 (difference 4W vs 8W)
4W to 8W is a doubling of power, or a 3dB increase. That's 3dB you can add to your link budget. Provided of course that the limiting factor is the other station hearing you, not the other way around.
...
- 51.6k
5
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UV-5R 4W BFB297 vs UV-5R 8W BFP3-23 (difference 4W vs 8W)
The exact answer is given by the Friis equation. If you double the power, your range will increase by 1.413 times whatever it was before doubling the power if you change nothing else. This assumes you ...
- 18.5k
5
votes
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SDR set up that will TX & RX on CB, UHF and VHF
You didn't mention which country you're in, but in the US, it is only legal to transmit on CB with a "type-accepted" radio. In other words, the manufacturer of the radio must apply to the FCC for ...
- 9,162
5
votes
Can you use a satellite dish for a ham radio antenna?
I want to point out an important aspect that is only implicit in the other answers. At the frequencies at which they can be efficiently used, dish antennas are (by design) highly directional. That is, ...
- 151
4
votes
Why do some straight keys have a slider that shorts the contacts continuously?
The switch on the side of the key is or rather was used when tuning up a transmitter. In the old days you had to increase drive and dip the grid of the final amplifier. So this is simply a switch so ...
- 139
4
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SDR set up that will TX & RX on CB, UHF and VHF
Reading about SDR I think I can have one single antenna and use the computer magic to allow me to work with all frequencies that antennae receives, am I mistaken?
Well, I always explain it that way:
...
- 15.5k
4
votes
Accepted
WWV, WWVH, and WWVL may be shut down. Are there any alternatives?
Don't forget about CHU (and here is the official site) which is the Canadian equivalent to WWV. It's at lower power and it's not as well-located geographically (it's located near Ottawa), but it's ...
4
votes
Can you use a satellite dish for a ham radio antenna?
The dish itself is pretty much universal - it will reflect and focus any radio waves that are short enough not to go around (say, 1/4 of the dish radius) and long enough not to be scattered off the ...
- 161
4
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Can I communicate 40 miles away with a base setup
For VHF or UHF, your range is mostly going to be limited by terrain, like Zeiss Ikon writes. On flat terrain the radio horizon can be estimated by a simple formula, but that's not of much use if the ...
- 51.6k
4
votes
What is a "feed-through load" and how does it work?
I think the correct way to understand this is basically as "a dummy load which makes it easy to measure the voltage across itself".
Likely as simple as:
simulate this circuit – ...
- 7,269
4
votes
How should coax be physically wired to a "stud" mag mount?
Generally on a stud mount the center conductor is connected to the threaded stud with a ring terminal, you put the bolt through the terminal, then through the hole in the mount, and screw the stud ...
- 252
3
votes
What is a simple kind of amateur radio transceiver I could try to build, as a beginner?
You say you are "not supposed to build with a kit". Who has set this limitation? This is beginning to sound like a homework assignment.
Are you actually expected to design and build a radio receiver ...
- 4,539
3
votes
Suitable acoustic foam rubber for headphones?
Audiophiles like to replace those plastic and foam earpads with a velour product such as this:
If red doesn't suit you, there are other choices. There are several vendors for this type of product, ...
- 18.5k
3
votes
Accepted
Identify this “large TNC” coax connector
The connector is called an "HN" type connector. It has a 3/4-20 thread and it is usable up to 4 GHz. The Amphenol data on it is available here.
- 18.5k
3
votes
UV-5R 4W BFB297 vs UV-5R 8W BFP3-23 (difference 4W vs 8W)
The correct answer to your question is, I believe, that you should expect an increase of between 20-40% in range, depending on the height of the repeater(s) you are trying to hit as well as your local ...
- 542
3
votes
UV-5R 4W BFB297 vs UV-5R 8W BFP3-23 (difference 4W vs 8W)
Of your quoted testimonials, the one I'd put the least credence in is the 10 miles at 4w and 16 miles at 8W, because I'm not sure what they mean by the "elevation difference" disclaimer; at these ...
- 726
3
votes
How do I listen to the amateur radio satellites?
First Steps in Satellites
As with trying anything new, it’s best to take small steps as you learn. Here’s a simple exercise to help you get started: listening for the AO-91 FM satellite.
Go to AMSAT ...
- 573
3
votes
Accepted
Looking for headset to use with BTech UV-25x2
There are standard connectors for microphones, speakers, and headsets, but unfortunately the pinout diagram (schematic) changes very frequently. There is no guarantee that a headset with a 3.5mm TRRS ...
- 9,162
3
votes
Equipment Pricing
There's really not a upper or lower limit to price -- it entirely depends on what capabilities you want.
At the low end, you can get a receive only SDR for $20; several suggestions can be found at ...
- 5,691
3
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How should coax be physically wired to a "stud" mag mount?
GodJihyo nailed it on this problem. There's definitely a piece missing. (The piece that the feed cable passes through.) The mount base should be shaped like a wedding cake with another 'layer' that'...
- 453
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