The AM Forum

What was supposed to be achieved by this project?

The annual MRCA Gilbert event in cooperation with Red Ball Military Vehicle Collectors event was this past weekend. Friday September 27th and Saturday the 28th.

The event included setting up exhibits of military radio equipment in the Howell building, a frequency measurement contest and field exercises.

Friday’s exercise centers on field radios, Man pack portables and systems as large as my M151/GRC-106 set up and operating around the Beltsville Lake State park.
Frequencies would include 3.57 MHz for CW, 3.885MHz AM, 5.357MHz USB, 51.0MHz FM as a coordinating frequency, 144.25MHz AM and 146.52MHz FM.

Saturday local operation from the M151 hosting the MMRCG Net on 7.296 USB at the Howell building along with “Show and Tell” of the radios on display in the Howell building.


What was actually achieved?

I arrived Thursday afternoon. Set up the crew tent that I would be staying in while at the event, unloaded the truck at the Howell building and unloaded the M151A1 mutt.
Multipole MRCA members arrive on Thursday and set up, the vendors are for the most part all set up on Thursday despite the rain earlier that day.

On Friday morning I checked out the vendors and all the stuff that was for sale at the event. Red Ball is not only a military vehicle show but also a military equipment sale and swap fest. A number of military radios were for sale that included VRC-12 family of radios in the $200 to $450 range, tons of accessories and things like intercom and field telephone equipment and several items like what appeared to be a NOS PRC-47 set with transit case, accessories and generator for $1,100.00, a GRC-9 transceiver with power supply, cable and vehicle mount for $450.00 and PRC-25/77 sets in the $100 to $250 price range. There was also the usual collection of WW2 ARC-5 and related communications equipment in various states and prices along with a huge gray Navy RBB or RBC receiver that was under a table with its power supply.

Around eleven Walt (KB3SBC) and I loaded up the mutt and did the fifteen mile trip between Gilbert to Beltsville and set up the mutt in advance of the days nets.
This year Walt operated the GRC-106 on the mutt on 14.325 and activated Beltsville State Park as a “Parks on the Air” station from noon to around one local and completed around thirty SSB contacts including four European stations for a very successful NOPA session.

Around 1430 local 60 meters (5.357 USB) activity picked up with Walt operating the mutt the GRC-106 while I took the AN/PRC-108 and headed out for a remote location for pedestrian mobile.  I drove four miles up the road to the head of the Beltsville lake and drove down a road that I thought would lead to the water but ended up somewhere in the state park that was heavily wooded.  Decided to take a trail that I thought would lead to the water but only looped around in the woods and came back to the road.
Had the PRC-108 on my back with the whip antenna and a drag behind counterpoise and was able to work multipole stations on 60 meters without issue. Did notice a difference between when I was in the wood as opposed to when in an open aria as to how well people would receive and have to assume that the trees make a big difference.

We used 51.0 FM to coordinate most of the stations located on or around Beltsville Lake and in addition also had a 144.225 and 146.52 The RT-246 (VRC-43) decided to fail after it got hot so lost all 51.0 operation in the mutt at that time.
When I returned from my walk with the mosquitos and before closing down operations at the mutt we QSY over to 3885 AM and operated several stations on that mode. Did not do any CW.

On Saturday using the GRC-106 and the large wire antenna that was set up at the Howell building for the MRCA base station the mutt served as the Net control station for the MMRCG Net on 7.296 USB. Copied most stations and according to reports was not an issue with the remote stations copying me. Did not use the generator for powering the mutt but used a DC power supply via the slave connector to power everything. Did have some local interference at the Howell building that required relays at some points.

The Show and Tell operation went without issue with explanations of several of the displays but somehow assumed that I was skipped over and left before I had the opportunity to talk about the MAK transceiver that I brought. But that was my mistake.


What aspects of the project work?

The M151/GRC-106 set up worked great. Accomplished Parks on the Air activation, worked all HF Nets without issue including Saturdays hosting MMRCG Net using the MRCA wire antenna.
Also used URC-110 for VHF AM and FM communications from the mutt and both my backpack operations with the PRC-108 and the MAK transceiver that I brought for Show and Tell worked without issue.


What didn't work and why?

The VRC-43 (RT-246) had failed again in an issue that I thought I had resolved before. Think it’s time to investigate getting a RT-524 for the mutt and killing off the RT-246
Saw a RT-524 that was “Demilled” for $200 and thought about making an offer and using the RT-246 to put it back together but by the time I got back to where it was it was gone.
I had a PRC-68 as a backup for the VRC-43 but did not realize that its batteries had died so it was useless.
And last but not least had around an S-8 local noise at the Howell building from the florescent lights from HF to VHF that resulted in difficult copy of weak signals.
This resulted in asking for relays a couple times during the MMRCG Net.


What would you change if given a second chance?

Replacement of the RT-246, or at least a repair that works all the time. Replace the disposable batteries in radios like the PRC-68 before the event.
Think about relocating the mutt for operation of the MMRCG Net prior to operation. The problems would be if locating away from everything would need to use the MEP-025 generator or perhaps locate somewhere close to one of the many electrical poles located throughout the fairgrounds? This will result in a clean received signals.
Still need assistance from a good CW operator. Walt is great for doing the voice operations but would like to be able to support CW operations from Beltsville Lake.
Noise suppression for the MEP-025, the generator has a fifty foot cable that connects it to the slave connector on the mutt. But the generator itself is so noisy (acoustic not electrical) that it is annoying. Cannot imagine that you were intended to use them in a war zone with all the noise they produce. Maybe find a more modern acoustically shelled version or something. The manual for the MEP-025 series generators spends about half of it telling how to build an in ground covered shelter so think that’s how you were supposed to solve the problem?

Submitted by Ray F/KA3EKH