LHS Episode #310: DMR Deep Dive

Welcome to Episode 310 of Linux in the Ham Shack. In this episode, the hosts take an in-depth look at the world of Digital Mobile Radio, otherwise known as DMR. It's a topic that could take volumes or multiple episodes but the idea here is to give you enough information to understand the basics of the technology, acquire appropriate hardware and get on the air using digital FM. We hope that has been accomplished. Thank you for listening.
73 de The LHS Crew
Russ Woodman, K5TUX, co-hosts the Linux in the Ham Shack podcast which is available for download in both MP3 and OGG audio format. Contact him at [email protected].
Weekly Propagation Summary – 2019 Nov 11 16:10 UTC
Here is this week’s space weather and geophysical report, issued 2019 Nov 11 0043 UTC.
Highlights of Solar and Geomagnetic Activity 04 – 10 November 2019
Solar activity was very low. The solar disk was spotless throughout the period. No Earth-directed CMEs were observed.
No proton events were observed at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit reached high levels on 04-06, 08 Nov and moderate levels on 07, 09-10 Nov.
Geomagnetic field activity reached unsettled levels on 06 Nov and quiet levels throughout the remainder of the period, under a nominal solar wind regime.
Forecast of Solar and Geomagnetic Activity 11 November – 07 December 2019
Solar activity is expected to be at very low levels throughout the outlook period.
No proton events are expected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to reach high levels on 12-17, 21-30 Nov and 01-03 Dec, with moderate levels on 11, 18-20 Nov and 04-07 Dec, in response to CH HSS influence.
Geomagnetic field activity is expected to reach G1 (Minor) storm levels on 21-22 Nov, with active levels on 11, 20, 23-24 Nov, due to recurrent CH HSS activity. Quiet to unsettled conditions are anticipated throughout the remainder of the outlook period.
Don’t forget to visit our live space weather and radio propagation web site, at: http://SunSpotWatch.com/
Live Aurora mapping is at http://aurora.sunspotwatch.com/
If you are on Twitter, please follow these two users: 1. https://Twitter.com/NW7US 2. https://Twitter.com/hfradiospacewx
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Be sure to subscribe to our space weather and propagation email group, on Groups.io
https://groups.io/g/propagation-and-space-weather
Spread the word!
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Links of interest:
+ Amazon space weather books: http://g.nw7us.us/fbssw-aSWSC
+ https://Twitter.com/NW7US
+ https://Twitter.com/hfradiospacewx
Space Weather and Ham Radio YouTube Channel News:
I am working on launching a YouTube channel overhaul, that includes series of videos about space weather, radio signal propagation, and more.
Additionally, I am working on improving the educational efforts via the email, Facebook, YouTube, Tumblr, and other activities.
You can help!
Please consider becoming a Patron of these space weather and radio communications services, beginning with the YouTube channel:
https://www.patreon.com/NW7US
The YouTube channel:
https://YouTube.com/NW7US
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Visit, subscribe: NW7US Radio Communications and Propagation YouTube Channel
Publishing a Book: Print and eBook
Over time, I have written several electrical engineering books (see electronic-measurement.com). These books were written in the dead-trees print model, focused on creating a book that you can hold in your hand. I recently published VHF, Summits and More in both print and ebook editions. This was a learning process for me and I’ve come to understand a bit more about the differences between these formats.
I definitely have a soft spot in my heard for a good-quality printed book. It is just plain satisfying to hold a printed book in your hand and flip through the pages. Moving quickly between pages and chapters is easy; very tactile with immediate feedback. I often look at our bookshelf at home filled with various engineering, ham radio, hiking and travel books. It just feels good knowing I can reach out to any one of them and access useful information.
Monochrome Kindle
Last year, we went on a long cruise and I wanted to have plenty of reading material while still traveling light. I did not want to drag along a big pile of books, so I purchased a monochrome (“paperwhite”) Kindle with the promise of long battery life and the ability to read it in bright sunlight. It delivered on both items. And it holds a ton of books (most of them I didn’t have time to read).
It didn’t take long to realize that the monochrome e-readers are optimized for plain text. They do pretty well with text-heavy books such as novels but aren’t very good for technical books that have photos or graphics. I mean, the display is only monochrome (and many of the readers are small.)
While creating my new book, I wasn’t really happy with how my book looked on the monochrome Kindles. It seems that there are some legacy formatting behaviors that cause them to present the text in some interesting ways. Also, the photos and other graphics really didn’t look that great. I was not encouraged and almost tossed the idea of publishing an ebook version.
Kindle Fire
Then I decided to purchase a Kindle with a color display, the Kindle Fire HD 8 tablet. This device has an 8-inch display and 16 GB of storage, costing $79. I downloaded the mobi file of my book to the Kindle and was immediately impressed with the presentation of the material. The photos and graphics show up in color and look great. Another added feature compared to print, is that the embedded hyperlinks allow easy to access to web-based information.
One thing I had to adjust to was losing some control over how the Kindle displays the book. With a print book, you have absolute control…put each comma, period, character right where you want them and they stay there. On the Kindle, the reader gets to make a lot of decisions: font type, font size, color, line spacing. While the author gets to choose the words and graphics, the final presentation is in the hands of the reader.
Read Kindle on non-Kindle Devices
Amazon has done a fantasic job of supporting the reading of Kindle books on a variety of hardware platforms. You can get a free Kindle reader for both Windows and Mac. Mobile devices are supported, too, with their own readers (iOS and Android). The mobi (Kindle) file format is dominating the ebook market so I don’t have any plans to add other ebook versions.
The post Publishing a Book: Print and eBook appeared first on The KØNR Radio Site.
Bob Witte, KØNR, is a regular contributor to AmateurRadio.com and writes from Colorado, USA. Contact him at [email protected].
Software error messages…..gotta love them!!!
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| A drive though town |
While on FT8 Saturday morning on 30m which is my normal watering hole these days with a cup of Java as I greet the morning I noticed a message appear on my PC screen. It was a message from my Win4icom software suite. Usually these messages are not a good sign and rarely contain info you really want to see while having fun on the radio. This message was not good news...and my FT8 stopped working, my rig was stuck in transmit and CAT communication was lost.
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| Just love seeing these messages |
| Make shift connection |
Mike Weir, VE9KK, is a regular contributor to AmateurRadio.com and writes from New Brunswick, Canada. Contact him at [email protected].
ICQ Podcast Episode 311 – Pocket Electronic Workshop
In this episode, Martin M1MRB is joined by Leslie Butterfield G0CIB, Edmund Spicer M0MNG, Dan Romanchik KB6NU and Ruth Willet KM4LAO to discuss the latest Amateur / Ham Radio news. Colin M6BOY rounds up the news in brief and this episode’s feature is Pocket Electronic Workshop.
ICQ AMATEUR/HAM RADIO PODCAST DONORS
We would like to thank Joey Ferguson (W4JF) and our monthly and annual subscription donors for keeping the podcast advert free. To donate, please visit - http://www.icqpodcast.com/donate
- AM Amateur Radio Europe announce the AM QSO Party 2020 - HackSpace magazine Antenna Article - West Point Cadets use Amateur Radio to Contact ISS - Build a Long-Distance Data Network using Ham Radio - FCC Asked to Clarify Amateur Rules Governing Encrypted or Encoded Messages - New Arkansas Beacon on Air - Saudi Arabia and Seychelles join IARU - Irish Digital Radio Stations to Close
Colin Butler, M6BOY, is the host of the ICQ Podcast, a weekly radio show about Amateur Radio. Contact him at [email protected].
Oh, They Should’ve … Here’s Why and Why Not on the QSX
How often have you seen into the thinking process of the development engineering team for an amateur radio manufacturer? Or an industrial test and measurements manufacturer of devices used frequently by amateur operators? In the latter case, the HP Journal was (and still is for vintage equipment) a key source for their line of equipment and often had an in-depth article from the engineers who designed one of their popular test devices. Less so but often with the Tek Journal, too. I always see if there’s a “design article” for any HP or Tek vintage equipment before I make a purchase. While MFJ Enterprises frequently gives factory tours, even for a single visitor, Martin Jue rarely gives public disclosures of the thought process of a device. At least, not until it’s well into production and sales.

But Hans Summers G0UPL, recent winner of the Homebrew Heroes Award for 2019, has done just that! In the October issue of QRP Quarterly (Vol 60, Number 4: 24-38), Hans weaves his thinking and design choices for the SSB QSX multiband, multimode 10-watt QRP transceiver. He’s been publicly discussing the concept since 2017 but rarely do we get this level of detail and insight for a major transceiver release. Oh wait. It’s not a product of one of the major manufacturers so what makes it a major product?
Review the QRP-Labs website on the QSX for the interim specifications and feature set. And pay attention to the projected price. Now, let’s revisit the reticence at calling it a major product release. Block diagrams, schematics, mock-up designs, and the pricing-performance choices going into Hans’ decision matrix for each element of the forthcoming rig are there. Even the case and the choice of no hardware volume control! And the choice of a soft switch for power on and off. The inclusion of several test equipment circuits built directly into the transceiver package ramps up what other manufacturers have included. And did I mention that the target price is $150 USD?
Ashar Farhan made a real splash in the QRP homebrew space when he released the Bitx40 ($59USD) and uBitx ($130USD). There is a small army of builders, modders, and third-party add-ons and case makers surrounding Farhan’s products. But reading the target specifications for “just a little bit more” at $150USD on the QSX QRP transceiver (including a nice case), it will set a new bar for the value proposition in the QRP market place!
And who knew how much the inclusion of a “simple” potentiometer for power on/off and volume control could impact the overall design and cost for a multiband transceiver? If you read this article, you’ll be somewhat shocked and amazed at how the designer’s careful analysis of his product target goals factored into the decision to just not include one. But that’s only one of the interesting twists and turns in this intriguing article on the design of the QSX transceiver.
Read the article and see if you agree with my assessment. QRP Quarterly is edited by Mike Malone KD5KXF. It is the publication of the QRP Amateur Radio Club International with an annual subscription price at $25 USD for domestic subscribers and $28 USD for international subscribers. The QRP-ARCI sponsors the Four Days in May Symposium held in conjunction with Hamvention in Xenia, OH. Hans G0UPL is also a member of the QRP Hall of Fame.

Source: HomebrewHeroes.org
The market shall see what the final version, performance, and exact price will be. Reviewers will leave no stone unturned in putting the QSX through it’s paces when it’s available for retail purchase. But very rarely will buyers know as much about a transceiver’s design and why it was so as with the QSX. The snarky reviews that we almost always see of why didn’t “they” do this or that in a rig will almost all have been answered well in advance of the official release of the QSX. While “they” usually represent an engineering design team, QRP-Labs is staffed by one, Hans G0UPL, Hero 2019.
Frank Howell, K4FMH, is a regular contributor to AmateurRadio.com and writes from Mississippi, USA. Contact him at [email protected].
30m FT8 is treating me well.
Mike Weir, VE9KK, is a regular contributor to AmateurRadio.com and writes from New Brunswick, Canada. Contact him at [email protected].
















