Retro Review: Philips FM92 Mobile FM Transceiver
Introduction:
The FM92 transceiver is one of the FM900 series commercial 2 way transceivers which was designed by Philips in the early 1980s for commercial 2 way radio applications. As businesses, emergency services and Government departments have converted to trunking systems, a large number of ex commercial transceivers, including FM 900 series radios, have flooded the secondhand market and fallen into the hands of amateurs, where they now see service on the VHF/UHF bands. My own FM92 was purchased for a few reasons. Partly so I could have a 2m radio for general FM work, and one that was easy to modify for packet or other modes, and partly for sentimental reasons, as they remind me of my time as a volunteer firefighter.
First Impressions.
My first contact with the FM92 was when they were in service with the Country Fire Authority (CFA) in the mid 1980s. As I was a volunteer and radio operator from 1985 to 1991, I had a lot of contact with the FM92. In CFA service the FM92s were dependable and simple to operate. Just select the channel, set the squelch and talk. I have seen or heard literally hundreds on the air, and there were few failures. Certainly a radio one could (and did) entrust their lives to. Those very same FM92s were decommissioned in the early 1990s, when the CFA moved to new frequencies, and many are now in the possession of amateurs, having been converted to the 2m band (the CFA used to use frequencies around 163 MHz). There are also a number of low band (E) and UHF units, which have found themselves on the 6m, 70cm and UHF CB (yes, FM92s are legal on CB, provided the power is limited to 5 watts) bands. The FM92 has distinctive tonal qualities, excellent for communications, but not to the taste of a lot of amateurs, as well as a distinctive "clunk" when the PTT is released, if the standard microphone is still fitted.
The controls of the FM92 are very straightforward. On the right hand side, just above the mic connector is a column of 3 blue buttons, which control Selcall sending, scanning and the power switch. To the left of those are 3 LEDs, a red one to indicate when the radio is transmitting, a yellow one for received signal, and a green one for power. Next is the channel display and up/down buttons. The display indicates the channel number (0-99), and it and the LEDs dim under low light conditions.
To the left of the display are the volume and mute controls, which are standard rotary pots, and finally, there is a small speaker for received audio on the left hand side of the panel. Speaking of the panel, the FM92 came in local (the panel being on the front of the main transceiver unit) and remote, where the front panel can be mounted separately to the rest of the rig.
As for the construction, these things are built like tanks. The case is solid diecast, with the top and bottom panels being held by a dozen(!) screws. Inside, the PCBs swing out for easy access. Construction is neat and well laid out. Definitely a design that lends itself to easy modification.
On air:
The FM92 uses an EPROM to store all its channel information and a lot of its other functions. The EPROM data can be generated quite readily, as the programming software is available in many places on the Internet for download. All one needs is an EPROM burner to program their radio. The FM92 has 100 channels, which store both Tx and Rx frequency, as well as power level (1, 5 or 25W), CTCSS tone, Selcall and other settings. This keeps the operation simple for its intended purpose, but is somewhat less flexible for amateurs.
As a basic 2m FM rig, the FM92 is easy to use (surprise!), and with careful programming of the EPROM, covers much of the 2m band. The receiver is not as sensitive as dedicated amateur rigs, but on the other hand, it is very tolerant of out of band rubbish, such as the paging transmitters on 148 MHz. It is obviously commercial spec here, where a small amount of sensitivity is traded off for much improved interference rejection. In practice, the lack of sensitivity is hardly noticeable, except on very weak signals where you might pull in the other station better if you hook up your HT (that's if the pagers don't then wipe you out!). The FM92 is still capable of receiving good signals from the SO-35 satellite on a non optimal antenna. Received audio is a bit tinny on the internal speaker, but re-routing the audio through a larger speaker gives excellent audio, and the mute control has just the right amount of hysterisis, enough to minimise "chopping" on weak mobile signals, without needing millivolt signals to open the gate.
The transmitter is quite well behaved, as one would expect from a quality commercial 2 way radio, and transmitted audio using the standard mic is a little tinny, with that well known "clunk" when the button is released. Several amateurs have modified their FM92s to give improved audio, which results in audio as good as any purpose built amateur rig (but I prefer the nostalgia of the original audio! :) ).
Conclusion:
The FM92 is an excellent rig for amateur use. The prices now are so low that it's an inexpensive way for a new amateur to get started on air, especially on 2m, where the prices for a converted unit can fall to around $50. They also make excellent packet rigs, or perhaps as a second FM box on the band of interest.
They are also good for environments where treatment may be a little rough, and an expensive purpose built rig is not appropriate, such as 4WDs, Field Days and public events, or where a rugged transmitter is required, such as a repeater.
Overall rating:
5 out of 5.
Excellent value for money!
Copyright and Disclaimer:
This review is copyright Tony Langdon, 2000, All rights reserved Persons or organisations wishing to distribute part, all, or a derivative of this review are welcome to email me on the link below. Unauthorised distribution is prohibited.
This review is provided for the benefit of radio amateurs, and was independently written by me without the assistance of or under the direction of any other party, continuing my tradition of reviewing most new radio equipment I purchase.