Sep 17, 2019

ZUM Repeater

K9KMS's new ZUM Radio duplex repeater board on a Raspberry Pi # B+

I am currently working on a project involving a ZUM Radio duplex MMDVM and a Raspberry Pi 3 B+ combined with my trusty old Yaesu FT-7900 and FT-7800 radios, and a couple of mini Din cables. Together, a trial version of small digital all-mode repeater capable of full duplex D*Star, DMR, NXDN, P25, POCSAG, or YSF should be the result. If this works out as expected, I will likely be seeking out an old GE Master II, or any other robust analog repeater, to handle whatever mode is selected.

More to come, I'm quite sure...

Sep 6, 2019

You're Grounded

Since my "ham budget" is, well... there is no ham budget. So spending big bucks on thick copper busbar, copper mats, copper this, and copper that can get pretty pricey, not to mention a non-negotiable with the wife. This is true especially if it's all prefabricated PnP stuff.

Being like most of you other hams, I like to design and build my stuff myself. In furtherance of this manly, hamly expression of creativity, I designed and built two ground and lightning suppressor boxes, and two interior ground busbars. One set for myself and one set for my friend Stu, KD9MNK. Here is what I came up with.

Busbar in the box with two ATT3G50U's installed

The busbar is constructed with a 1.5 x 1.5 x 0.125" aluminum angle and #10 x 3/4 stainless machine bolts. I drilled 1/4" holes spaced 1.75" apart, allowing for three Alpha-Delta ATT3G50U surge and lightning suppressors to be mounted on the bar, and a heavy ground wire block (top right) for the ground wire. While assembling the busbar, I applied Noalox to all metal surfaces to insure electrical connectivity and prevent corrosion. The exterior bar is housed in a 8 x 8 x 4" PVC junction box with a waterproof cover. The interior and exterior busbars are identical in construction, except for the length - the interior busbar is four inches longer.

The box I made for Stu is fed from the bottom with a 2" PVC conduit running from his home to the back yard where the box is mounted at the base of his antenna. A second 2" opening on the box floor provides the coax exit. this is plugged with a 1/4" thick rubber disk with holes for the coax to pass through. A third exit in the box - also plugged with a rubber disk - is for the cable grounding the busbar and the ATT3G50U's. Water tight. Bug tight. Nice.

The KD9MNK busbar box for the base of the tower

The interior busbar is mounted in the house, just inside the coax conduit feed point. Another set of Alpha-Delta ATT3G50U's reside here, as well as the grounding point for the radios. I designed a 1.25" conduit that passes from the basement, into the wall cavity of the room above, where the KD9MNK station is located. The 20" long conduit terminates into the bottom of a sealed plastic duplex electrical box. A standard blank wall plate holds two SO-239 connections and a grounding stud. Nice and neat. A ground line runs from the wall plate stud to the busbar and out an exit point from the coax conduit, just outside the house. Grounding rods take it from there.

Yup, this should work fine.

The K9KMS busbar box ready for installation at the base of the tower

The KD9MNK interior connectors and grounding stud

Aug 21, 2019


"CQRLOG is an advanced ham radio logger based on MySQL database. Provides radio control based on hamlib libraries (currently support of 140+ radio types and models), DX cluster connection, online callbook, a grayliner, internal QSL manager database support and a most accurate country resolution algorithm based on country tables created by OK1RR. CQRLOG is intended for daily general logging of HF, CW & SSB contacts and strongly focused to easy operation and maintenance."

A couple years ago, I wrote about several Windows-based and web-based logging software systems for amateur radio enthusiasts. The web-based software provides users the option of using any OS, as all that is needed is a web browser, but on the downside, you also need an internet connection.

Long ago, while looking to get off the Windows bandwagon, I experimented with Linux, Redhat, and a few other OS's, but recently, I was introduced to Raspbian, a Debian-based / Linux-based OS designed for the Raspberry Pi computer. My opinion of Raspbian so far is very positive. The fact that the OS is free, and thousands of programs are available for free, helps my wallet recover from the ever-expanding money pit Windows based computers can be.

Currently, I have ten computers consisting of the following. Maybe this is more info than you really want to know, but this should give a bit of understanding regarding my OS and computer experience.

  • Windows laptop used exclusively for amateur radio WIRES-X
  • Former Windows tower now running Linux Mint
  • Former Windows tower now running Raspbian PC
  • Two Chromebox computers that run as good as new (4 years old)
  • Two Chromebook laptops as our primary laptops
  • Raspberry Pi Zero W running Pi-Star and a ZUMspot MMDVM hat
  • Raspberry Pi 3 B+ Raspbian with RPi official screen for experiments
  • Raspberry Pi 4 (2G) Raspbian now my primary desktop computer

The main window of CQRLOG for entering QSO's

Now let me jump forward to what I really want to talk about - the new Raspberry Pi 4 and CQRLOG. The CQRLOG software package is touted as the best Linux-based amateur radio log program on the planet, and I may just have to agree. The Raspberry Pi 4, on the other hand, may just change the way we currently look at desktop computers. This is good.

I am a big fan of Ham Radio Deluxe, a fantastic Windows-based program, but now it is quite expensive, initially $100, then $50 per year for maintenance. And if you still mail out QSL cards, the annual cost of the hobby can really eat into the household budget. More recently, I was using the Log4OM software, another fantastic Windows-based program that has most of the bells and whistles of HRD, but the best part is Log4OM is free, but please make a donation to their work if you like it.

Then there's CQRLOG, an open source software system that, when used with a few other Linux-based open source software packages, rivals anything out there, and it's free! CQRLOG integrates with LoTW,, eQSL, and Clublog. It also provides live logbook support through HamQTH or QRZ. HamLib takes care of TRX controls so current radio configurations auto-populate in the QSO window.

The full log / QSO / QSL management window in CQRLOG

You can find all available software packages in the Raspbian/Debian repositories. In Raspbian OS, simply go to the Preferences menu and click on Add / Remove Software. Search Amateur Radio and select all the desired software packages. Easy as pi.

The DX Cluster window in CQRLOG
The Grayline map in CQRLOG

More later...

Filum Receptorem 101

Back in the day, we were all taught that the most significant component leading to successful QSO's is the antenna. A really good, well tuned antenna can help you generate more QSO's with even the most mediocre radio, than any other upgrade you can make in your system. For this reason, we first need to analyse our antennas in every aspect, and second, be sure we are providing the best possible environment for the antenna to work properly. With this in mind, antenna design, polarity, placement, and feed should all be considered.

At my home QTH, I currently have two antennas set up. For 144/440 MHz, a Comet GP-6 sits atop a 55 foot tower, and for HF work, a GAP Titan DX is mounted 2 meters above the ground, both in a less-than-ideal environments. We live in a tall forest with sandy soil and beach sand containing magnetite, and my home and barn have metal roofs. The GAP is positioned half way between the buildings, about 30 feet from either. As you might agree, not the best of situations as far as antennas go, but that's the best we can do here, given all factors.

As the antennas are in their current position and environment - on a sunny August 21 with heavy foliage - I captured the following readings with my Comet CAA-500 Mark II antenna analyzer. I am pretty happy with what I found. This should help me take better advantage of the frequencies that might provide the best situation for success.


Comet GP-6


GAP Titan DX


Even so, I am having a great time making QSO's all around the world and making good distance in the local area. So far, I have nothing to complain about, though I have no experience or knowledge of what it is like having what one might consider ideal conditions. I'm in this for the enjoyment of the hobby, and "just havin' fun" is what I am doing!

Aug 15, 2019

Favorite Pi(e)

When Nancy and I go out to a new restaurant, we always ask if they have my personal favorite, Key Lime pie. But since last week, I may have to change my thinking and cautiously consider Raspberry...

First, it was the Raspberry Pi zero for my ZUMspot. I was so amazed with it's simplicity and usefulness, I had to get a Raspberry Pi 3 B+. It was like a whole new Raspberry world opened before me. And all I could think about before was Key Lime pie. Ha! And now comes the Raspberry Pi 4, the newest Pi on the pi rack, my favorite Pi so far.

The new and amazing Raspberry Pi 4 (2GB) running Raspbian is my shack's main desktop computer.  CQRLOG software is now my go-to radio log, the FreeDV software is set up for digital HF, and Gpredict for satellite tracking. The Raspbian/Debian repositories have a Ham Radio package that includes a host of programs for amateur radio Linux users. Did I mention all of this open source software is free? Yup. Free.

Space TV

Of all the out-of-the-box things I can think of, this was not one of them - sending pictures via amateur radio from space to earth, especially when they originate from the International Space Station orbiting the earth at 19,000 mph!

Here are the results of my very first attempt with SSTV on August 3, 2019.

And the confirmation from ARISS.

How cool is that!

Are you experimenting with amateur radio? If not, why not.

Jun 26, 2019


For a while now, its been a little tough to get regular DX the old-fashioned way. Aside from that, FT8 works fairly well on 20m, but that's not for everyone, and it pretty robotic and impersonal. There isn't enough people on HF DV like the FreeDV 1600 and 700D modes, so it's less than a thrill right now.

That being said, there is hope. There has been a tremendous increase of activity on the MMDVM front. With new gadgets hitting the market as fast as baby rabbits, even the Tech hams can now talk around the world, and on an HT to boot! Yeah, it's not like the traditional and personally rewarding "contacts" like we are used to, flexing our RF muscles in cunning and calculated ways, but the end result is the same. Hams talking to hams around the world, and how cool is that!

So my FT-991A isn't used quite as much right now for DX, but the FTM-400XDR and FT-70D are barking up a storm from my ZUMspot and a few connected Yaesu WIRES-X repeaters in the area. My favorites right now are America Link and MNWis. Ride the wave, baby! But if the internet goes down, make sure you are squared away in your own shack. Independence is highly rewarding!

Nov 10, 2018

Golf Sportwagen Mobile Setup

It has been a couple years since the EPA v. Volkswagen mess, and now Volkswagen diesel TDI buy-back cars are hitting the market. I have been eagerly anticipating getting another TDI since selling my 2003 Jetta Wagen TDI to my son. With this recent opportunity, I was able to pick up a 2015 Golf Sportwagen SEL TDI with all the goodies and the DSG transmission, almost exactly what I was looking for. I would rather have a manual like the '03 TDI, but I do like the DSG, and it sure is nice to enjoy the 45+ mpg again, especially after driving the Jeep at an average 17.5 mpg!

Moving my mobile rig into the Volkswagen presents a number of issues. Unlike the Jeep which has a multitude of places to mount equipment, the Golf Sportwagen is much more refined and makes efficient use of all available space for VW gadgets and options. Finding even a little real-estate for the FTM-400XDR without blocking the use of VW gadgets, or sitting out of reach up on the dash, is quite a task. After a few trial setups, I have settled on giving up the use of the storage box in front of the shift console, as I think it is the least intrusive, and certainly the safest place for the radio head.

The radio head is attached with some Scotch permanent clear mounting tape (UPC 51131 76272), a thick, conforming, double sided sticky tape that, in spite of it's name, is not permanent in this application. It's like sticky-booger kind of stuff that cleanly rolls off if need be. A small 1/4" x 1" x 8 5/8 piece of oak rests against the sides of the compartment door opening with sticky tape. The radio head is sticky taped on the back to the oak bar and the bottom of the compartment opening. It is a perfect fit for height. The extra room on the right allowed me to add my FT-7900 radio into the mix with no issues.

Fortunately, the Golf Sportwagen has a great place to mount up to a few radio bodies. On the driver's side of the rear cargo area, there is a trap door in the sidewall, located behind the rear wheel well. Remove this trap door and you have a solid, removable mounting platform for radio bodies and accessories. It makes for an out of the way mounting location that is easily accessed for servicing the gear in your mobile "utility room". The bodies remain in the climate controlled area of the car, and are hidden when the rolling cargo cover is pulled to the rear.

Currently I have power supplied by the fused, ignition controlled, power outlet on the passenger side of the rear cargo area. In the near future, I plan on installing a RIGrunner 4005H on the top of the panel above the radio body as an expandable, fused power supply for the FTM-400 and any other rigs I may install. Maybe my MARS modified FT-7900, or a drop-in charger for the FT-70D, or FT-60, or MD-390 portable radios. Even power for the FT-991A or other HF rig on a field day. All of the wiring is temporary until I run everything hidden and protected in the car's wiring harness raceway. The main power supply will be running straight off the battery and back to the RIGrunner 4005H.

The Comet NMO antennas are mounted on two stainless brackets I made and attached to the roof rails. Everything is electrically grounded, so after running the Comet CAA-500 Mark II on the setup, both antennas are about as good as it gets.

Sep 30, 2018

ZUMspot Nextion

Ah, the awesome ZUMspot, a digital voice door open to the world! How fantastic it is to talk all around the world with no static and no noise, like everyone is in the same room! Very cool! Between all the modes of digital voice, I have to say my favorite is YSF C4FM for its exceptional voice quality. My second favorite is DMR, but this requires getting used to the frequent "R2D2" picket fence sound.

The thing about the ZUMspot - and many other hotspots - is there is no display. It has the Pi-Star on-board html software, but to see the station information requires using a second device. But since this technology is fairly new, it is evolving very quickly. This is a good thing.

Riding along with this forward momentum, I'm now exploring computer programming for Raspberry Pi, and designing programs for the Nextion display. As it goes, I now have an awesome 3.2 inch Nextion touch display programmed and connected via USB to my ZUMspot. OMGoodness! It is, yes, AWESOME!

Next? Maybe program links to QRZ on the call sign...

Aug 6, 2018

FT-991A with GPS

I'm not sure why, but the Yaesu FT-991A does not come with a built-in GPS unit. So if you want that data included in digital QSO's, you will need to connect your own external GPS antenna. Now comes the Garmin GPS18x PC, a fully compatible NMEA GPS, WAAS enabled antenna that connects to the FT-991A's GPS/CAT DB9 serial port. Power is supplied by a 12 volt plug into my Yaesu FP-1030A power supply.
Setup is pretty simple with radio menu 028 set to GPS1, the default setting. Plug it in. Turn it on. Wait, slow down. Did you get that?

Now when you key up on a C4FM repeater - as well as with a few other functions - your location/distance is also transmitted/received for the other stations. And if it makes your day, you get the cool little green GPS satellite icon showing up on the FT-991A touchscreen. Nice!