ham radio

Portable Ham Antenna Gets A Workout

February 1, 2019 by 12 Comments

Ham radio isn’t just one hobby. It is a bunch of hobbies ranging from chatting to building things, bouncing signals off the moon, and lots of things in between. Some of these specialties, such as supporting disaster relief or putting odd locations “on the air”, require portable operation. To encourage disaster readiness, hams participate in Field Days which is a type of contest that encourages simulated emergency conditions. So how do you erect an antenna when you just have a few hours to set up a temporary station? [KB9VBR] shows how he and his friend used a Chameleon Emcomm III portable HF antenna for Winter Field Day. You can see the video review, below.

Unlike some portable antennas, this one is almost 100 feet of wire (73 feet of radiator and a 25 foot counterpoise). The entire affair is meant to be put up and taken down repeatedly.

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This Satellite Finder Can Watch Amateur TV

January 30, 2019 by 24 Comments

Setting up satellite dishes can be a finicky business. To aid in the alignment of these precision antennas, satellite finders are often used which can display audio and video feeds from the satellite while also providing signal strength readouts for accurate adjustment. However, these devices can also be used in interesting ways for more terrestrial purposes (Youtube link).

Using the DMYCO V8 Finder, [Corrosive] demonstrates how to set up the device to pick up terrestrial amateur streams. Satellite reception typically involves the use of a low-noise block downconverter, which downconverts the high frequency satellite signal into a lower intermediate frequency. Operating at the 1.2GHz amateur band, this isn’t necessary, so the device is configured to use an LNB frequency of 10000, and the channel frequency entered as a multiple of ten higher. In this case, [Corrosive] is tuning in an amateur channel on 1254 MHz, which is entered as 11254 MHz to account for the absent LNB.

[Corrosive] points out that, when using an F-connector to BNC adapter with this setup, it’s important to choose one that does not short the center pin to the shield, as this will damage the unit. This is due to it being designed to power LNBs through the F-connector for satellite operation.

By simply reconfiguring a satellite finder with a basic scanner antenna, it’s possible to create a useful amateur television receiver. If you’re wondering how to transmit, [Corrosive] has that covered, too. Video after the break.

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Lime SDR (and Pluto, Too) Sends TV

January 19, 2019 by 21 Comments

If you have experienced software defined radio (SDR) using the ubiquitous RTL SDR dongles, you are missing out on half of it. While those SDRs are inexpensive, they only receive. The next step is to transmit. [Corrosive] shows how he uses DATV Express along with a Lime SDR or a Pluto (the evaluation device from Analog Devices) to transmit video. He shows how to set it all up in the context of ham radio. An earlier video shows how to receive the signal using an SDR and some Windows software. The receiver will work with an RTL SDR or a HackRF board, too. You can see both videos, below.

The DATV Express software has plenty of options and since SDR if frequency agile, you ought to be able to use this on any frequency (within the SDR range) that you are allowed to use. At the end, he mentions that to really put these on the air you will want a filter and amplifier since the output is a bit raw and low powered.

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Morse Code Keyboard 1939 Style!

January 9, 2019 by 25 Comments

If you want to learn Morse code and you don’t have a teacher, you’d probably just head over to a website or download a phone app. Before that, you probably bought a cassette tape or a phonograph record. But how did you learn Morse if you didn’t have any of that and didn’t know anyone who could send you practice? Sure, you could listen to the radio, but in 1939 that might be difficult, especially to find people sending slow enough for you to copy.

Wireless World for August 3rd, 1939, has the answer in an article by [A. R. Knipe] on page 109. While you probably wouldn’t use it today, it is a great example of how ingenious you can be when you don’t have an Arduino and all the other accoutrements we take for granted today.

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All About Ham Satellites

January 7, 2019 by 28 Comments

How hard is it to build a ground station to communicate with people via a satellite? Probably not as hard as you think. [Modern Ham] has a new video that shows just how easy it can be. It turns out that a cheap Chinese radio is all you need on the radio side. You do, however, benefit from having a bit of an antenna.

It isn’t unusual for people interested in technology to also be interested in space. So it isn’t surprising that many ham radio operators have tied space into the hobby. Some do radio astronomy, others bounce signals off the moon or meteors. Still others have launched satellites, though perhaps that’s not totally accurate since as far as we know all ham radio satellites have hitched rides on commercial rockets rather than being launched by hams themselves. Still, designing and operating a ham radio station in space is no small feat, but it has been done many times with each generation of satellite becoming more and more sophisticated.

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Google Assistant, Now Available On Ham Radio

January 5, 2019 by 46 Comments

Depending on who you talk to, Google Assistant is either a tool capable of quickly and clearly answering audio queries in natural langauge, or a noisier and less useful version of Wolfram Alpha. [William Franzin] decided it would be particularly cool to make the service available over ham radio – and that’s exactly what he did.

[William] got the idea for this project after first playing with the Internet Radio Linking Project, a system which uses VoIP technologies to link radio networks over the internet. Already having an IRLP node, it seemed only natural to make it into a gateway to the wider internet through integration with Google Assistant. Early work involved activating the assistant via DTMF tones, but [William] didn’t stop there – through the use of Picovoice, it became possible to use the system with the custom wakeword “Bumblebee”.

[William]’s project could prove particularly useful for when he’s out of cell coverage, but needs a little information like a weather report or a piece of trivia to settle an argument round the campfire. Additionally, it’s even possible to control the IRLP node through voice commands, too.

If you’re just getting started with ham radio, check out this build to get you started for under $100. Video after the break.

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FCC Gets Complaint: Proposed Ham Radio Rules Hurt National Security

November 26, 2018 by 137 Comments

On November 10th, [Theodore Rappaport] sent the FCC an ex parte filing regarding a proposed rule change that would remove the limit on baud rate of high frequency (HF) digital transmissions. According to [Rappaport] there are already encoded messages that can’t be read on the ham radio airwaves and this would make the problem worse.

[Rappaport] is a professor at NYU and the founding director of NYU Wireless. His concern seems to relate mostly to SCS who have some proprietary schemes for compressing PACTOR as part of Winlink — used in some cases to send e-mail from onboard ships.

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