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I have been a ham since 1981.  I got my technican ticket at the FCC field office in Boston, MA with my father, Clarence Williams, W1ROM - an avid 80 meter DX chaser in his time.

I did a career in the United States Air Force (21+ years) and most of it was spent in the Electronic Warfare field.  Now, instead of jamming emitters,  I help build them.  A Wi-Fi engineer of sort for the last 10 years - working for a large cellular carrier.


For the past 10 years, we have been living in Euless, Texas.  Most of that time was spent on HF operating a myriad of digital modes with a lean towards JT65A and JT9.  These weak signal modes will always amaze me in what they can do with just a couple of watts of RF power applied to an odd bit of wire in the back yard.   HF activities have been put aside in the past two years as other things required my attention.

Current interest is DMR and it global reach on the planet.  On a whim, I picked up a Tera 7400 DMR HT from Ham Radio Outlet in Plano, TX.  I spent the next few days learning about things like talk groups and code plugs.  I do not have a D-Star or Fusion background, I jumped feet first.  Next thing was a project to build up a DMR HotSpot.  I was intrique by what a Raspberry Pi 3 could do - a simplex repeater which connected to the Internet and the world.  I could not leave well enough along with the HotSpot.  I chucked its "stub" antenna and made a Slim Jim antenna with the goal of improving coverage in to the park next to me.  Best distance - .85 miles so far and the operators work reported that my audio was fine.  Amazing what a 10mW HotSpot will do given a respectable antenna is attached.

Now, I am trying to working out text messaging via DMR.  The results vary and I find it interesting to figure would what the root cause of the problem is.  The fact that DMR is not perfect make it all the more interesting and inspires me to experiment.


Project Echo - The DMR HotSpot


The Echo project is my initial journey in to the wide world of Digital Mobile Radio (DMR).   I had become bored with radio over the past year.  However, in November 2016,  I purchased a DMR HT - the Tera 7400 from Ham Radio Outlet in Plano, Texas. 

Without any background in any of the other digital voice technologies, I jumped in - feet first, in the wide world of DMR.  Next came a DMR HotSpot as I was intrigued with the concept of having a UHF simplex repeater which would provide not only good coverage around the home QTH, but also coverage in to a city park located across the street from our house.  Thus began The Echo Project.


Echo 1 - 1st DMR HotSpot


The DMR HotSpot I threw together consisted of:

         1 Each - Raspberry Pi 3


1 Each - DV MEGA VHF/UHF Radio Board

1 Each - Homebrewed Slim Jim 70cM Antenna (made out of 450 ohm window line)


1 Each Cisco USB Wi-Fi Interface Adapter

1 Each 20 Amp/Hour Sealed Lead Acid Battery (SLAB)

1 Each Powerwerx Power Meter and Analyzer

Operating System: Raspbian/Linux 8

HotSpot: MMDVMHost by Jonathan Naylor, G4KLX - https://github.com/g4klx/MMDVMHost

   Version: 20161021 

RX Frequency: 446075000Hz
TX Frequency: 446075000Hz

Transmitter Power: 5 mW

Antenna: 70 cM  Slim Jim (450 Ohm Window Line)


7748668 Last modified: 2016-12-09 19:35:08, 6489 bytes

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QRZ Logbook Summary for - KA1GMN
Latest Contacts for KA1GMN at QRZ.com
dedateband mode grid Country op
OE3BUB 2013-12-17 40m JT65 JN88fg Austria Bernhard Buchta
W9MDB 2013-12-13 40m JT65 EM49HV United States Michael D Black
N9OJC 2013-12-06 40m JT65 EN60tr United States JOHN E TIMMONS
N9DUG 2013-12-06 40m JT65 EL87 United States DOUGLAS H HERROLD
N8ESP 2013-12-01 20m THOR EN80ld United States JOHN C GARCIA
AK4BB 2013-12-01 20m JT9 EM83cl United States GEORGE D WALDROP
KD8GNC 2013-11-30 20m HELL EN80lc United States Tery
KI6WJP 2013-11-29 20m JT9 CN81uh United States Martin J Nile
W9SMR 2013-11-28 17m PSK31 EL87sf United States STANLEY M ROBINSON
K4PYR 2013-11-28 30m JT65 FM17rd United States ERIC R WOOSTER
KR4IP 2013-11-20 15m JT65 EM83bm United States RICHARD K STUDDARD
N6SBN 2013-11-17 20m PSK63F CM96ax United States CRAIG A HARLAMOFF
KT4DLB 2013-11-17 20m PSK31 EM61sh United States Danny L Brown
K8JTD 2013-11-17 40M JT65 EM79wo United States JEFFREY T DEVOE
K3FS 2013-11-17 40m JT65 EN90xj United States Franklin S Speicher, IV

Book Totals: 476 qso's   458 confirmed Get a free logbook at QRZ.COM

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