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10 votes

antenna in the rain

The antenna itself won't be significantly affected by the water. However, waterproofing the coax connection is essential. If this is not done, water will creep inside the coax by capillary action and ...
Phil Frost - W8II's user avatar
9 votes

How would you get an "I'm alive" message to family in another state using amateur radio?

The ARRL NTS (National Traffic System) is the method you would use to send messages to anyone anywhere in North America and in concert with other traffic systems to many parts of the world. NTS has ...
K7PEH's user avatar
  • 2,998
8 votes
Accepted

How would you get an "I'm alive" message to family in another state using amateur radio?

When establishing emergency communications in a disaster, the natural choice of band is one that will allow you to communicate out of the disaster zone. Given the scenario you describe, a massive ...
rclocher3's user avatar
  • 9,182
7 votes
Accepted

When and why does the size of a ground plane or radials matter?

Perhaps consider that the objective of the ground plane is to present a low impedance. At the feedpoint, the hope is to have all the current go into the antenna, and none of it on the coax common-mode....
Phil Frost - W8II's user avatar
7 votes

Is Part 90 certification something an amateur radio operator should look for in a radio meant for amateur use?

Part 90 certification is required for radios used in the USA in the land mobile services - often called commercial radio. No such certification is required for the amateur radio service. The closest ...
Glenn W9IQ's user avatar
  • 18.6k
7 votes

antenna in the rain

Water has a drastically different relative permittivity $\varepsilon$ than air (water: ca 88, air: pretty much 1); it is, however, pretty non-conductive, just like air (being distilled and all). In a ...
Marcus Müller's user avatar
6 votes

How would you get an "I'm alive" message to family in another state using amateur radio?

Send an HF-E-Mail addressed to your familymembers using a system like WinLink 2000 (http://www.winlink.org). It uses Radio Message Servers (RMS), which provide a bridge between the Central Message ...
DK3CW's user avatar
  • 61
6 votes

Amateur Radio for a Nomad

The relevant regulation is §97.23: Each license grant must show the grantee's correct name and mailing address. The mailing address must be in an area where the amateur service is regulated by the ...
Phil Frost - W8II's user avatar
6 votes
Accepted

Amateur Radio for a Nomad

The only thing you need to do is make sure you can receive mail at the mailing address on your license, because that is part of the obligation of holding a license. It doesn't have to be your ‘...
Kevin Reid AG6YO's user avatar
  • 24.5k
6 votes
Accepted

What size is the Kenwood TM-D710 panel mounting bracket?

This image of the bottom side of the bracket was taken with a flatbed scanner. The depicted dimensions were taken separately using a caliper, not by measuring on the image. The white inner area is the ...
Kevin Reid AG6YO's user avatar
  • 24.5k
6 votes
Accepted

Better SWR bandwidth

A low SWR bandwidth is a consequence of shortening the antenna for mobile use. SWR bandwidth is related to the antenna system's Q factor, the ratio of energy stored to energy dissipated per cycle. A ...
Phil Frost - W8II's user avatar
6 votes

Need batteries for backpack operation

I used LiFePO4 (read: Lithium Iron Phosphate) for my dad's FT-891. The big advantages of LiFePo4 are: Very power dense, almost as much as Li-Ion, IIRC twice as much Wh/kg than Lead-acid Extremely ...
hjf's user avatar
  • 1,199
6 votes

UHF 70cm unlicensed use

The likelihood that your radios are being operated legally is small in my opinion, at least if you're in the US. The only entirely unlicensed frequency in that section of the spectrum that I'm aware ...
Chris Short's user avatar
5 votes

What wireless communication technologies can travel long distances with a high bandwidth?

All kinds of digital microwave technologies can do this, including WiFi. It takes a good antenna location high from the ground, and good antenna gain / transmit power. Commercial wireless ISPs do it ...
Phil Frost - W8II's user avatar
5 votes

How to log contacts when mobile?

In the USA there is no longer any legal requirement to keep a log. Many HAMs log HF contacts often for use in contests or applying for various awards. There are a few contests and awards for VHF / ...
Jim's user avatar
  • 1,678
5 votes
Accepted

How to figure out my car battery's capacity?

There are many ways to do this. My favorite and I would assume you have these items in your shack. Most inverters have an automatic low-voltage disconnect feature. It makes a beeping sound and stops ...
Gil's user avatar
  • 283
5 votes

Rfi in truck with HF transceiver when running

There are many things you can still do. Here are a few quick suggestions to start with: Proper antenna ground. A mag mount is marginally OK at VHF / UHF, but there isn't enough capacitance at HF. The ...
tomnexus's user avatar
  • 10.9k
4 votes
Accepted

Connecting radio in parallel with inverter in mobile set up

There are two things I like to highlight: 1) You are thinking of putting the radio in the same glove box as the inverter; hence you may need extra ventilation/circulation to ensure neither equipment ...
Edwin van Mierlo's user avatar
4 votes

How do you keep your vehicle clean with a mobile antenna?

They do make weatherproof caps for NMO and SO-239 antenna mounts. I've used those for years. I pull up to the wash, take the antennas down and stow inside, and put the caps on. Post wash, reverse ...
user103218's user avatar
4 votes

Tiger Tail + capacitive coupling... what's the interaction?

I tested your make/model antenna and others in various configurations with and without a tiger-tail on a small 2m HT with results in this article. Here is the money graph... Needless to say the extra ...
JSH's user avatar
  • 590
4 votes
Accepted

Noticeable difference between trunk and roof mount?

Yes there is a difference but it tends to have more to do with the pattern and efficiency of the antenna than anything else. When an antenna is mounted on the trunk, the roof line and the occupants ...
Glenn W9IQ's user avatar
  • 18.6k
4 votes
Accepted

Is there a special term for amateur transceiver speakers or anything that makes them different from any other kind of speaker?

Is there something that makes amateur radio speakers better or different than any other kind of unpowered speaker of equivalent wattage and impedance? Some may have audio filters, headphone jacks, or ...
Kevin Reid AG6YO's user avatar
  • 24.5k
4 votes
Accepted

What are the maximum possible speeds of download over Amateur Radio frequencies?

maximum rate There's no upper boundary really other than SNR. There's no general number. There's what information theorists call channel capacity, which simply relates the amount of bits per second ...
Marcus Müller's user avatar
4 votes

GMRS not transmitting within a half mile

First, the legal issue: in the US, it's not legal to transmit on GMRS frequencies on a radio not type-accepted for GMRS. Having an FCC ID doesn't mean that a radio is type-accepted for GMRS; UV-5Rs ...
rclocher3's user avatar
  • 9,182
4 votes

How does this W6NBC "derivative of the classical slot antenna" work?

The antenna is most like a Planar Inverted F Antenna, or PIFA. Wikipedia has a brief introduction to them. Here is my sketch of a classic example: The PIFA is a wider bandwidth version of the IFA, ...
tomnexus's user avatar
  • 10.9k
4 votes

Boosting Mobile Phone Reception

There are a couple of options. If your phone supports WiFi calling and your provider allows it, I strongly recommend getting WiFi in the shack if you don’t have it already. If you don’t have it, and ...
Maury Markowitz's user avatar
4 votes

UHF 70cm unlicensed use

Without knowing the frequency and country or more information about how they were programmed, there's no way to guess if you are operating legally. In the US, it is possible to lease frequencies at a ...
user10489's user avatar
  • 5,945
3 votes

How would you get an "I'm alive" message to family in another state using amateur radio?

Regarding a response to your simple question of: letting non hams know that I am alive. Have you considered APRS? Not correctly, but commonly known as Automatic Position Reporting System. You probably ...
Roy Lawson's user avatar
3 votes

High SWR on a Jeep with Spare Tire Mount

The metal wheel and the steel-belted tire are big chunks of metal. Those add capacitance between the antenna and ground, so they lower the resonant frequency of the antenna. A shorter whip or a ...
Walter Underwood K6WRU's user avatar

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