Motorola “Biophone” as seen in Emergency TV Show

I have wanted a Motorola radio since before I became a licensed Ham – I’d been fascinated with the radios I saw in the television shows ofmy childhood Adam-12, Emergency, and S.W.A.T., especially the

Classic Motorola Head Unit

EMT radio “Go-box” (as we would call it today) called the “Biophone” featured in Emergency and the full-on tight shot of the Motorola head unit on the dash of the police cruiser in Adam-12.

The other day I was flipping through the For Sale listings on QRZ.com and came across a radio that appealed to me on several levels. It was in great shape, it came with all new accessories (microphone, mounting bracket and power cord), it had a “split” that included half of the 2 meter band, supported “wide” and “narrow” FM modulation (more current radios only support “narrow” FM and sound weak on ham bands) and the price seemed right ($100 shipped). I quickly Google’d the radio and found that it was 32 channels, 45 watts, covered 146-148 MHz and it appeared that CPS radio programming software and cable were readily available. I pulled the trigger and sent the seller the requested payment, $100 via PayPal. (I choose to use Family and Friends option on PayPal so the seller got the full $100, I paid the PayPal fee myself and lost any buyer protection for the transaction – it’s a choice I made, no regrets.)

When the radio arrived – it looked great, better than it did in the photo in the listing, and I was very happy… Then I realized I had a problem – the antenna connector looked like a UHF connector in the photos in the listing, but smaller, oh no! I quickly determined it was what is referred to as a “Mini UHF” connector – a very common connector on Motorola radios. A quick Google and I turned up the needed adapter, Mini UHF male to SO-239, at a local retailer for $5 – excellent! While in the store I picked up a few other items – a Tram NMO magnet mount that came with 17’ of coax with a Mini UHF connector (about $25) and a power adapter to convert the “Bullet” power connector on the back of the radio to the ubiquitous Anderson Power Pole connectors ($8). For those of you keeping score, I’ve invested $100 on the radio, $5 for the antenna connector adapter, and a purely optional power adapter ($8) – I easily could have crimped a pair of Anderson Power Pole connectors on the supplied power cord – so I’m almost $120 into this radio.

Motorola CM300 Radio main unit

With everything I needed collected together I powered on the radio, and confirmed the radio a) powered-up, and b) operated on the channels a previous owner had programmed the radio with (VHF weather channels and 146.520 simplex). Then I set about the task of securing a programming cable and the required Motorola CPS software. The cable was easy, a quick search on eBay turned up a USB to RJ45 cable that claimed it worked with the CM300 radio – perfect! Several sites talked about the need for a DOS (not windows) computer and a “real” serial port. I decided to risk the few dollars the cable cost and put my trust in the positive comments from previous buyers for this specific cable and this specific radio model. I then went to a website called HTTP://hamfiles.co.uk/ and downloaded the Motorola RP05 software after registering on the site. After installing the software, I powered up the radio, attached the radio to the computer with the eBay cable, and everything just worked – it quickly downloaded the current programming on the radio.

Relying on my experience programming consumer (and so-called “prosumer”) DMR radios I was able to quickly program in a couple local repeater pairs. The channels were easily written to the radio, and the programmed channels all worked as expected – success! I quickly added a half-dozen more local repeaters, set the scan list for the radio, and programmed the few programmable buttons on the front of the radio for functions like “Scan On/Off” and “Hi/Lo power”. Exploring the software a bit more, I found there was a capability to print out a “cheat sheet” on the programmed channels and programmable button settings – what a neat feature! I wish the various Chinese DMR radios and Japanese FM and digital radios had similar capabilities.

So, that’s all fine and good, but what did I get? First off, I found a great deal on a well-built radio with all new accessories and in like-new condition, I was able to find programming software, and I got lucky with my USB programming cable. But at the end of the day, I invested about $120 and put in a fair bit of work to make the radio work on part of the 2 meter band (remember, the radio’s “split” only went down to 146 MHz) with 32 channels and 45 watts RF output. For a few dollars more I could have gone to my favorite local Ham retailer and gotten a radio purpose-built to work the 2 meter band with higher output and way, way more channels… But I have no regrets – I got a great radio, learned a bit about the Land Mobile radio service radios, and now I finally have a pristine 2 meter radio – I couldn’t be happier with my purchase.

My advice, if you decide to try your hand at repurposing a Land Mobile Radio for Amateur Radio service, go for it, but realize it is a different world, you can’t make any assumptions about power/antenna connectors, included accessories, or suitability for use in the Amateur Radio Service – FM radios need to support “wide” FM modulation, Land Mobile radio services typically use “narrow” modulation, and using “narrow” modulation on “wide” amateur repeaters will result in a weak-sounding signal – and make absolutely certain you can get programming software for the radio you are considering buying. If I had to purchase programming software for this “bargain” radio it would have cost me $300 for a three year license. At three times the price of the radio, I would have had a hard time justifying the purchase, even though the software supports numerous Motorola radios, I only have the one radio. While it is illegal to copy the Motorola software, it is perfectly fine to take your radio to a friend that does have the Motorola software and ask them to program your radio.

I’m very happy with my new (to me) radio, you’ll start to hear me using it on the air in coming 2 meter nets around the area after the holidays. See you on the air!