KJ4AJP's GE MVS Radio Projects


Around 2008 there was an eBay seller offering used GE MVS radios without microphones for $25 each. Being '90s vintage they were 25Mhz wide, and the 2013 FCC Part 90 narrowbanding legislation eliminated their use in the Land Mobile Radio Service, but they're fully usable for Amateur Radio. I bought six of the 40W VHF and six of the 25W UHF units,and it's was probably the best $300 I've spent on the hobby so far. The MVS radios still show up on eBay, but often for more money and without the EPROM that contains the programming. Buyer beware.

You can find helpful hints, the programming software and screenshots of it in use at N0RQ's website . You can buy the programming (RIB) cable from one of the places mentioned, but if you want to take a stab at building it yourself here's the schematic, along with the connector pinouts and their Molex part numbers. This document also contains the pinout and Molex numbers for the GE MLS II series radios, which can use the same MAX232 based programmer interface. Note the MLS II require their own specific software, so the MVS software cannot be used. The GE MLS I series radios require a "suitcase programmer", so the MAX232 programming cable cannot be used with those.

Although N0RQ states the MVS software will run under XP and Win7, I haven't had much luck with that. I run it under DOS like it was originally written for. Orignally I used bootable 3.5 floppys and the dos622basic.exe tool to put DOS 6.22 on them. When I obtained a PC with a bios capable of booting from USB, I found Bootable USB Drive Creator Tool, which installs Windows ME DOS using the included "MS-DOS" files. With either I include a folder named "MVS" with the MVS files (and "MLS" for the MLS files) with the DOS files installed by the tools. Once you boot into DOS, you simply CD MVS to get into the MVS directory, and at the MVS prompt, type MVS to execute the program.

In all cases I believe you will need a computer with a hardware COM1 or COM2 port. If anyone has had luck with a RS232 to USB convertor to program these radios, please let me know.

My very first MVS project was KJ4AJP-10 and a Diamond D-130J on a 20' mast outside the University of Tennessee at Martin's EOC. When I was offered tower space for it, I set up KJ4AJP-1 on the discone. I added IGate and fill-in digi capabilities to KJ4AJP-1, and soon after a duplexer became available and KJ4AJP-1 became KJ4AJP-5, a full W2,TNn-N digipeater and bi-directional IGate duplexed with KJ4AJP-10 on the tower. The current KJ4AJP-1 now uses the D-130J.

Here's pictures and info on the seven of my twelve MVS radios that are currently in service, along with a link to the pinout for the TNC connections. Clicking on a picture will go to a larger view and you'll have to use your "back" button to return to this page. Clicking on a documentation link will open up a gif and you'll need to click back to return as well.



 
KJ4AJP-5 (radio on the left side of the shelf) is an APRS Digipeater and IGate connected to a Dell Optiplex GX620 through a TinyTrak4 TNC. UI-View32 software is used. It's located in the tower shack on the campus of the University of Tennessee at Martin and is connected through a 4-cavity duplexer to a DB224E antenna at 230'.

Documentation is the TinyTrak4 "radio" side DB9 and the MVS Mic connector. The TT4 is powered by the MVS. I also include a two-resistor divider as a "line level convertor" inside the DB9 so the 4 ohm 3 watt output of the MVS is reduced a bit. All TT4s are flashed with KISS_TNC firmware rather than the Alpha firmware since the tracker functions are unused.

Since the stock MVS microphone has a preamplifier in it, all of my kit TT4s have R6 replaced with a jumper wire, and the factory-built TT4 has a 2-pin header soldered into JP10 so R6 can be bypassed. This increases the TT4 audio output to the MVS mic input.

 
KJ4AJP-10 (on the right side of the shelf) is a Winlink RMS Packet gateway on 145.630MHz connected to another Dell Optiplex GX620 computer through a KPC3+ TNC and shares the other side of the duplexer.

Documentation is the DB9 on the KPC3+ to the Molex on the MVS.

Both KJ4AJP-5 and KJ4AJP-10 are powered by a Astron 50M.

 
The two Small Form Factor Optiplex GX620 PCs came from Overstock.com. When new, they shipped from Dell with the XP OS, but after being refurbed by Joy Systems they arrived with Win7 Home Premium (and I didn't have to search for any compatible drivers!). Both have 3.2GHz P4 processors, 2GB RAM and 80GB HDDs, and although they may be considered lacking by today's standards, they have more than enough horsepower for an APRS applicaton from the Win2K era and a radio email gateway application with minimum hardware requirements of a 500 MHz or greater Pentium/Celeron processor.


 
 
KJ4AJP-1 is the APRS base radio at the University of Tennessee at Martin's EOC. It's connected to a Dell Optiplex FX160 Thin Client with UI-View32 and Precision Mapping V9 through a TinyTrak4 TNC. The SPDT toggle switch to the right of the digi mutes the radio's internal speaker and puts a 4 ohm load on the audio amplifier.

Documentation is the same as for the KJ4AJP-5 digipeater/IGate.


 
 
KJ4AJP-4 is a "field expediant" APRS digi designed for Special Events and Emcomm. The 2-channel radio is programmed with the standard 144.390Mhz RX/TX on one channel and "Alt Digi" 144.990Mhz RX/144.390 TX on the second. Like KJ4AJP-1, a mute switch is on the right side. The aluminum rack contains a TNC-X with X-Digi daughterboard plus a Jetstream JTPS28 power supply (rear view).

Documentation includes the 5-pin circular DIN rig control connection used by the TNC-X to the MVS mic's Molex. The DIN connector normally leaves pin 5 unused, I've used it to supply V+ to the TNC-X's "BAT" terminal via the MVS. The SPDT "mute" switch wiring is also included on this document.

The aluminum used in construction of the portable MVS units was purchased from OnlineMetals.com rather than a local home store since even with shipping the cost came to around half (be sure to check out the "Metal Repair Spray" they offer). #8-32 stainless steel hardware came from The Nutty Company, as well as the 1/4"-20 stainless steel rod and acorn nuts used on the handles. The 1/2" CPVC handle grip was left over from plumbing my shop.


 
KJ4AJP/R utilizes two UHF MVS radios as a "field expediant" Special Event/Emcomm voice repeater on the SERA iteneriant pair of 440.800. The 16 channel radios are programmed with 16 different CTCSs tones. At the top is a case containing a NHRC Micro controller and a mute switch identical in function to the external ones. Below the controller is a JIESAI mobile duplexer. The repeater is designed to be powered from the JTPS28 in KJ4AJP-4's rack, and a Comet diplexer (rear view) splits a Diamond X50NA antenna between the duplexer and KJ4AJP-4's radio.

Documentation includes the NHRC Micro pinout to both MVS radios, and the DB9 to the PC COM port for programming the controller.

KJ4AJP-12 is designed as a "field expediant" portable digital station for APRS, Winlink and NBEMS, paired with a Sony Vaio PCG-FRV28 laptop I was given. The rig has gone through many changes, originally the MVS was on a CB "hump mount" with a TNX-X (now used on KJ4AJP-4), Workman SX-144/430 meter and a Rigblaster Nomic strapped to the top of the MVS with velcro. This took up two USB ports on the Vaio, which only had three to begin with. The next change was building the aluminum rack and swapping the TNC-X for a TinyTrak4 TNC, cased in an enclosure with the Nomic board, where a switch was used to select between the TNC or soundcard interface so only one RS232-USB convertor was needed. When I "upgraded" the Vaio to Windows 7, I gave up trying to find audio drivers for the on-board sound and bought the current Tigertronics SignaLink USB interface, since it has a fully Win7 compliant USB sound card built in.

Similar to KJ4AJP-4, on the right is a toggle switch for a speaker mute for the radio. The 16 channels are programmed with National APRS, 4 area Winlink RMS Packet frequencies and eleven other area coordinated VHF simplex digital frequencies. The Vaio runs UI-View32 with PMap9, PacLink and NBEMS/FLDIGI clients. The power supply in the lower portion of the rack is a Jetstream JTMINI15, and a box in the rear has two 15A PowerPole connectors to tap off from for additional devices. A Firestik 2M-CKB antenna is normally used. (rear view)

Documentation includes the MVS Molex to RJ-45 to the SignaLink, the SignaLink's internal jumpering and the MVS speaker's mute switch.

One PCMCIA port of the Vaio is used for an AKE GMYLE 2-Port USB 2.0 PCMCIA Cardbus hub for the mouse and WIFI nubs. That leaves the two left side motherboard USB ports of the Vaio for the SignaLink and a USGlobalSat BU-353-W puck GPS, the rear USB port open, and eliminates the need for an external USB hub (for now!).


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