I picked up a GE Orion VHF radio from facebook. It came with a full keypad control head, microphone, radio unit and cables. The only things left is programming and a speaker.
The radio has a remote control head that is connected to the main radio with a DB37 to DB25 custom cable. The remote head has a DB connector to attach accessories to, like a speaker. It has an output power of 110Watts and a default frequency range of 150 to 174 MHz.
The cables with the radio are all very large, meant to be installed in a car and keep working for years with no maintenance. They are also fairly long. To make it easier to deal with, I purchased another power cable off eBay to adapt to Powerpoles to easily connect the radio. The radio also has a TNC connector for the antenna. I got an adapter to bring that to a UHF connector as that is what I have on my other radios.
The radio has 8 AWG wires for it's power. Standard Anderson Power Poles only go down to 10 gauge. This means that I have to use another connector on the power cable. I ended up getting 75 Amp powerpoles, and a short jumper from PP75 to PP45.
Note: I could have probably just used a 45 amp powerpole with the 8awg cable. I decided to go with the 75 amp connectors just to be on the safe side. I also could not find any numbers on how much current the radio draws on transmit.
Programming the radio is just done over serial. Three connections are made to the data cable and some pins are shorted. I used a DB37 Diagnosis Breakout Board to easily make the connections. The document LBI-38901S has the schematic for this cable on page 76. You can find the whole document with a quick search, I have included just that page here. When the programming cable is connected and the radio is turned on, the front panel should say "PC PROG".
I used MA-COM Conventional ProGrammer (R18A) to program the radio. The software is able to be installed on Windows 10. I used a USB to Serial adaptor to connect to the radio. I found the software on hamfiles.co.uk.
I could not read the existing programming from the radio, as it was programmed with a later version of the software. There is a groups.io group for the GE Orion Radio which can be found here. They have an excellent file library including a programming file I was able to use. The software uses a .per (personality) file for all the settings. There is additionally a SC4 file for the frequency shift. I wanted to shift the frequency down by 6 MHz, giving a new range of 144 to 158 MHz. The frequency shift happens when the software writes to the radio so all frequencies entered into the software is before the shift. So to enter 144 MHz, a frequency of 150 MHz is entered into the software. Both the .per and .sc4 file I found from the groups.io group.
To use a SC4 file, under "Tools", then "Options and Directory Settings" the "Enable SC4 Files" needs to be checked. Then in the personality under "Options", then "General Options" a SC4 file can be selected at the bottom.
The software uses frequency sets, each of which can have 64 channels. The radio supports P25, both conventional and trunking, but a different software license key is needed. There are also systems. A frequency sets is assigned to a system. Some settings apply globally to systems like power level. Multiple systems with the same frequency sets are used to be able to change the power level on the radio. From the software the keys on the control head can be set.
Programming Cable built with a DB37 Breakout Board
Programming Setup with Radio, Power supply, and Dummy Load
Once the radio is programmed with the frequency shift, most likely the radio will give an error. This is because the VCO (Voltage Controlled Oscillator) is not setup for the lower frequencies. This is not too hard to fix, it just requires adjusting two potentiometers on the board. I programmed the radio with channels from 144 to 148 MHz in 250 kHz steps. This is important to make sure that all frequencies in the wanted band will work correctly for RX and TX.
Once this file is uploaded, the radio will give the error "NO LOCK ERR=0401" and will continually restart. This is all the radio is not able to lock onto the frequency. Turn the radio upside down, and unscrew the four torx bolts holding the panel on. This is the smaller of the two panels, on the far side of the connectors.
The radio with the panel removed. The connectors are at the top.
The two VCO potentiometers and test point labeled.
Next slowly adjust the RX VCO potentiometer until the error stops. At the same time, use a multimeter to read the voltage at TP201. This is easily accessed through the hole under the two VCOs. From KG4CYX's website this should be between 3.5 to 7.5 V. Mine was not between these and I could not adjust it to be. I am not sure why this is. Go through all the channels and make sure the radio can lock on all of them.
Next repeat this process, but do it while transmitting. It is best to be using a dummy load so you are not transmitting a blank signal.
Once this is done, any channel programmed in the frequency range should both receive and transmit successfully. I tested this with a HT, using the BSY LED to confirm it was receiving as I do not have a speaker yet.
Picking back up in August 2021, I wanted to see how feasible it would be to add the radio to my car. I got the radio setup on my desk, connected to a dummy load and went to test TX. My baofeng went into rx mode, but I couldn't hear any audio. Using an SDR I could see the carrier, but no modulation!! My best guess was the microphone was busted so I bought a "new" one from ebay. While I waited for it to arrive, I decided to check if I could transmit DTMF tones to make sure the radio could TX correctly. After some digging online and in the software, I figured out that I needed to program a button to be the "PHN" key. When this is activated and PTT is pressed, the radio transmits DTMF tones when pressing any of the number keys. For each system it will be used in, DTMF needs to be enabled. It worked!! Now all that's needed is a working microphone and speaker!
A week later the new microphone showed up. I plugged it in and it worked!! I opened the broken on to see if it might be an easy fix, but I didn't see anything noticeably wrong. I also got the speaker working! It turns out I had the pins connected as I was looking at the wrong diagram.
I also took some current measurements to see how much power the radio was actually drawing.