Hello and welcome to the 483rd episode of Linux in the Ham Shack. In this short topics episode, the hosts discuss the upcoming JOTA and JOTI event, an additional period of ARRL club grants, the Internet Archive creating a repository for amateur radio content, a kerfuffle at SQLite, making money with Open Source and much, much more. Thanks for listening and have a great week.

73 de The LHS Crew

If you enjoy DXing the broadcast band, then the weekly ‘DX Central MW Frequency Challenge' may be of interest to you. It’s run and organized by Loyd Van Horn, W4LVH, a dedicated DXer and a big promoter of BCB DXing.

Basically, participants are asked to listen on the chosen frequency (or frequencies) for a one week period (Friday to Friday) and report what they have been able to identify. Results of course will be different throughout the continent but if you are near any other listeners, it’s always fun to compare your final results.

The new frequency (or frequencies) are announced Friday evening  on Loyd's regular live-feed Youtube channel as well as on his Twitter feed   @dxcentral 

Loggings are reported via a fill-in form which is updated weekly.

This week's frequencies are 670-702kHz - What do you here there?

Ham College episode 93 is now available for download.

Extra Class Exam Questions – Part 31.
E7B Amplifiers:(part 1 of 2) Class of operation, vacuum tube and solid-state circuits, distortion and intermodulation, spurious and parasitic suppression, microwave amplifiers, switching-type amplifiers.

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YouTube

Recently, I engaged in a discussion about a UHF (Ultra High Frequency) radio. It seems a ham was complaining that someone had advertised an 800 MHz radio, describing it as “UHF”. His issue was that in land mobile radio, UHF is commonly used to refer to radios in the 380 to 500-ish MHz range. I disagreed with him, saying that 800 MHz is in the UHF range I was using the ITU definition of UHF, which is any frequency between 300 MHz to 3 GHz. The disagreement was not a big deal but it did cause some confusion. (Of course, I was right and he was wrong, most definitely.)

This got me thinking about how we toss around these terms quite loosely, even though they have precise definitions. Let’s start with the basics, the ITU definitions of radio spectrum.

You can see that the basic scheme divides up the spectrum into decades (factors of ten), aligned with frequencies that start with 3 (e.g., 3 MHz, 30 MHz, 300 MHz). If we map the amateur bands onto this system, we see that the bands from 80m (3.5 to 4.0 MHz) through 10m (28-29.7 MHz) fall into the HF range, as expected. Note that 10m almost qualifies as a VHF band, coming in just shy of the 30 MHz limit. That band does have some VHF tendencies. The 160m band (1.8 to 2.0 MHz) actually falls into the MF range even though many of us just think of it as HF.

Let’s take a look at how the US amateur bands line up with this scheme.

There are three VHF bands: 6m (50 to 54 MHz), 2m (144 to 148 MHz) and 1.25m (222 to 225 MHz). The UHF range includes the 70 cm (420 to 450 MHz), 33 cm (902 to 928 MHz), 23 cm (1240 to 1300 MHz), and 13 cm (2300 to 2450 MHz) bands.

The two most commonly used bands in the VHF/UHF region are 2m and 70cm. These bands are home for many FM repeaters, FM simplex, SSB simplex, and plenty of other modes. Common dualband transceivers, both mobile and handheld, operate on the 2m and 70cm bands. These radios are so common that we often refer to them as VHF/UHF dualband radios. Accordingly, you will often hear hams refer to the 2m band as simply VHF and the 70cm band as UHF, as if VHF means 2 meters and UHF means 70 cm. I know I’ve been guilty of saying “let’s switch over to VHF” when I really mean “let’s go to the 2m band.” The 2m band is certainly VHF but VHF does not always mean 2 meters. Similarly, we might say “I’ll call you on the UHF repeater” when it would be more precise to say “I’ll call you on 440 MHz.”

Many times being loose with terminology doesn’t matter but there are times when using the right words can make a difference. Think about this the next time you are referring to a particular frequency band.

73 Bob K0NR

The post What Do VHF and UHF Mean? appeared first on The KØNR Radio Site.

Hello and welcome to Episode 482 of Linux in the Ham Shack. In this episode, the hosts take an in-depth look at some common network utilities on the Linux command line to help you configure, monitor and troubleshoot your computers' network connections. We hope you find this episode informative and entertaining. Please send us feedback and we look forward to catching you for the next installment.

73 de The LHS Crew