32 votes
Accepted

Why does the audio on my FM transceiver cut out every 5.5 seconds?

It's a feature not a bug. When turned on, the weather alert function checks the local NOAA station for its alert tone every 5 seconds for half a second... doing so takes over the receiver. I'd turned ...
webmarc's user avatar
  • 4,105
4 votes

What is the legality of data modes over UHF/VHF in the US?

You may be able to operate the device without consideration of your amateur radio status. CFR 47 Part 15.231 permits the low power use of 433 MHz without a license provided certain transmission ...
Glenn W9IQ's user avatar
  • 18.6k
4 votes

Antenna system components in the rain

A lot of things will work electrically when wet, as long as the water film is thin relative to the size of the thing. For example, a wet dipole, no problem. A tiny coil where water droplets can short ...
Phil Frost - W8II's user avatar
4 votes

Propagation effects of noctilucent clouds

NLCs may propagate radio waves, according to a 21 May 2019 article on Polar Mesospheric Summer Echoes: The underlying physics of these echoes is still uncertain. A leading theory holds that the ...
Brian K1LI's user avatar
  • 7,848
4 votes

Weatherproofing coax connection to balun

In my experience, the small amount of exposed thread on the SO-239 after inserting the PL-259 is the primary challenge in weatherproofing this connection. The first line of defense is to orient the ...
Brian K1LI's user avatar
  • 7,848
3 votes

How to weather protect lightning arrester mounted directly on ground rod?

Don't forget that for the sake of lightning protection, you should bond your ground rod to the ground rod at your electrical service panel, underneath where the electrical mains enter your house. ...
rclocher3's user avatar
  • 9,212
3 votes
Accepted

Open source RS41 decoder

You have to provide the -i option to invert the signal in order to decode it properly. The lowpass filter is not really required as this is a quite strong signal (...
cygeus's user avatar
  • 46
3 votes
Accepted

What is the legality of data modes over UHF/VHF in the US?

Telemetry is explicitly allowed in §97.111. You must use an authorized "digital code", which probably means ASCII. And you must use a publicly documented technique. I don't see any ...
Phil Frost - W8II's user avatar
3 votes

Tuning an antenna with cold weather

The overall antenna length being very close to a perfect 1 wavelength is the linchpin of the issue, I suspect. It is not surprising that it can be easily moved outside of the tuning capability of your ...
Hamsterdave's user avatar
  • 1,844
3 votes

How can I protect equipment against a lightning strike?

What you need to do is follow the requirements of the National Electrical Code (assuming USA). This article covers it well. (ps. Failure to comply with NEC 810 is the #1 reason ham radio operators in ...
user2104506's user avatar
2 votes

How does one know when band conditions are optimal and what factors to consider?

The Band Activity chart at DX Heat is a good way to evaluate propagation from the standpoint of "who is working whom, right now." Combining the color coded activity depiction with your general ...
Brian K1LI's user avatar
  • 7,848
2 votes

Weatherproofing coax connection to balun

Properly applied tape is the appropriate solution: https://ham.stackexchange.com/a/12564/218 The box, and the connection between the connector and the box should already be waterproofed if the balun ...
Phil Frost - W8II's user avatar
2 votes
Accepted

Tuning an antenna with cold weather

You say your dipole's total length is 20 meters, and you are using it on the 20 meter band. When the dipole's length is equal to some multiple of the wavelength (1λ, 2λ, 3λ, ...) the dipole is ...
Phil Frost - W8II's user avatar
2 votes

How to weather protect lightning arrester mounted directly on ground rod?

That can be waterproofed with mastic tape or pads. Polyphaser sells an overpriced kit which is just a mastic pad (probably 3M 2229) and a roll of ordinary vinyl electrical tape. The mastic comes in ...
Phil Frost - W8II's user avatar
1 vote

Propagation effects of noctilucent clouds

Noctilucent clouds are just clouds at a very high altitude. The temperature is low so they are formed by ice crystals. They are visible only when the sun is below the horizon but still shining on the ...
sm5bsz's user avatar
  • 1,009
1 vote

Wireless temperature data logger in the USA on 433MHz

In the US, if you don't want to reinvent the wheel then your easiest solution would probably be APRS, more specifically the Citizen Weather Observer Program, which is a standardized system to send ...
rclocher3's user avatar
  • 9,212
1 vote

Wireless temperature data logger in the USA on 433MHz

Legal discussion To ISM or not to ISM, that is the question So, in Europe, 433 MHz is an ISM band – you could even operate a device there if you weren't a licensed Ham! That also includes the fact ...
Marcus Müller's user avatar
1 vote

How does one know when band conditions are optimal and what factors to consider?

The DXLab Suite includes PropView, a convenient front-end to VOACAP, which makes current and near-term propagation predictions. PropView works in conjunction with the other components of the DXLab ...
Brian K1LI's user avatar
  • 7,848

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