There were a few Syntors that came to Australia for Vic Rail(presumably T43 models), but the current status of those units is unknown. Other than those few units there were no Syntors imported into Australia. ACMA regulations limit commercial mobile FM radios to 25 Watts, so there was no point in importing a Syntor, thus Australian amateurs have missed out on an excellent commercial radio. Syntors are probably the most powerful mobile radio ever made. If you are a Foundation Licence holder, don't worry you can still use a Syntor, just back the power off to 10 Watts.
A Syntor is quite different from the local Aussie Syntrx, they have some common design ideas, but nothing is really interchangeable between them.
The unit pictured below is a Syntor X, imported for test and evaluation. This discussion deals mainly with the Syntor X model, and not the earlier or later models.
The Syntor X is particularly easy to reprogram and realign. The channel and various other data is in a 2816 EEPROM which just programs in a conventional eprom programmer.
The VHF units easily tune down to 2Meters with a touch up on the VCO and a tweak of the Rx strip. A 2716 UV erasable eprom works fine as well.
The UHF versions all seem to be 450-470Mhz models, the manual clearly indicates that other UHF ranges are available, but they don't seem at all common. However the news is good, the 450-470Mhz models will pull down to 70cm, or up to UHF CB, but they won't do both at the same time because the Tx switching bandwidth is a bit under 30Mhz. The Rx strip isn't wide enough either for 70cm and 477Mhz at the same time.
All Syntor X radios are 64 channel capable with no hardware mods to the main body of the radio. Many of the control heads do not allow the full quota of channels, this is quite easily fixed with the addition of toggle switch(es).
From John, KB0ONB "So what exactly is the advantage to a 20 lb cast aluminum transceiver with limited versatility? Try the 150 to 175 Watts or so of output, beautiful audio, and a rig you can hit with a water hose while backing over it with a truck, and still keep talking on it. Motorola keeps it reliable, potent and simple. And this simplicity is just exactly what is called for in real emergency communications applications. There is a definite place in the ham world for a powerful, reliable, no frills transceiver that anyone can use in a crisis without reading a 90 page jinglish owner's manual.
If your power supply is stiff enough and set to 14 Volts or so, be aware that the High power set adjustment might give you as much as 200 Watts. All the radios I've adjusted have hit 150 Watts at a minimum, and that was with only 12 Volts or so applied. The higher automotive type voltages to 14V can make a substantial difference when this power limiting is opened up. Choose your dummy load accordingly. I've seen one of these radios set at about 2/3 power melt a mobile antenna coil, and the top of the whip fell over. Don't let it happen to you."
The picture clearly indicates the size difference between a Syntrx and a Syntor, it doesn't show the weight difference, and the unbeleivable robustness and build quality of the Syntor.
From my testing these units here in Australia, at the Naidia Test and Experimantal Range, I'd make the following observations.
Although the VHF T73 and T83 prefix radios are rated at a nominal 110W, the reality is that they will deliver in excess of 150W on 2 meters if wound up, the massive chassis provides adequate heat sinking. There are no trimmers in the PA, which is obviously quite wide band and requires no adjustment for 2 meters. The UHF T74 model will deliver up to 150 Watts on the 70cm band (and yes I can trigger my local repeater thank you!) but it's not realistic to run it at that power level, apart from anything else the current draw is 37 Amps.
The antenna needs to have very good SWR because the Syntors are proteced by a directional coupler and in the event of the reflected power exceeding about 3 or 4 watts, power control will fold back the PA, and power can easily drop to 40 or 50 watts. To put this in perspective you cannot run a 5/8 mobile whip with a Syntor and still get full steam. A 1/4 wave works well, as does an RFI Mopole, and my mopole hasn't melted yet. A further issue in mobiles is that the high RF levels, especially in the event of a marginal antenna system, can play havoc with vehicle electrics and electronic engine management systems.
A big issue with running a 100 Watt plus Syntor is the considerable power consumption, for example a 25Amp Codan power supply will almost run a Syntor but under protest, you can hear the laminations rattling! Because the transmitter is on full power whenever PTT is pressed, the total average power consumption is 3 or 4 times more than with a 100Watt HF radio like a Codan or IC706. Rx standby current is less than 1 amp, so better than a IC706.
Mounting the radio in a car requires very heavy wiring, an ongoing problem in the test vehicle was the VCO failing to lock on Tx, not because there is a fault with the VCO but because of shoddy connections (my own fault). The voltage at the radio was dropping below the critical level for stable VCO opertation.
Of course if you like long overs when parked in the car you may need a jumpstart! There is an ignition Tx disable optional setting, to discourage operators from transmitting without the motor running.
The Rx side of the Syntor X is very well developed too, in order to balance the Tx power it needs to be.
Many units seem to be fitted with an Rx pre-amp betweeen the transmit switching relay and the receive strip. Pager rejection is first class and the receive bandwidth is excellent, I have a 150odd Mhz commercial frequency, in my radio and can't really discern any drop off of sensitivy, although I peaked the unit at 147Mhz. (At that frequency the Syntor X was benchtested transmitting at 150 Watts!)
The VCO is as wide as you could want, it may need all the pads connected in order to work well at 145Mhz (or 430Mhz for the T74) but the manual indicates 20Mhz switching bandwidth, and that is probably conservative. So overall the radio is "wide" and running 2meters and VHF Marine and CFS all in the same radio is not a problem.
There are no "smarts" in a SYNTOR or SYNTOR X control head and they are similar, but not identical. The SYNTOR X9000 is a different head altogether, it is addressed with data lines.
The Syntor X contol head simply provides a junction box for the Mic and Speaker, Vol and Squech pots, and a BCD switch to select the channels. A Syntor or Syntor X would easily run in headless operation if required. Not all control heads have the full quota of channels, easily remedied with the additon of a switch or two. Not all control heads have a scan button, which in the real world means it may not be possible to switch off scan mode, so don't program in scan channels and all is OK.
Below is a push button 32 channel SyntorX control head, the Pri button is for Scan enable.
An optional interface allows the Syntrx control head to run on a SyntorX, this would be highly desirable because of the ergonomic convenience of the Syntrx control head, however these radios seem a little hard to find.
The above picture is of a "clamshell" SyntorX control head. The unit is a 16 channel head with the small toggle switch on the left toggling between the A and B banks of 16 channels ( 16 + 16 = 32) giving this control head 32 channels, many of the B bank channels are repeater reverse for the matching channel in the A bank . Effectivly making the A - B switch repeater reverse.
The toggle switch on the right is Scan enable. Each channel can have its own separate scan group and 2 priority channels assigned to it. It makes scanning particularly flexable. The small green button is Power-On. This control head is quite compact and would fit into quite tight spaces.
The above picture shows a 32 channel push button Syntor X control head. The clamshell and push button heads are comlpetely interchangable. The Pri button is actually what we in Australia would call a scan button. On the rear of the control head is an additional toggle switch to bring in another bank of 32 channels giving 64 in total.
Below, SyntorX with the top lid removed, the black box on the left with the orange stripe contains the EEPROM, it just unplugs, for easy access.
The business end of a SyntorX has a pair of M1104 finals to provide the 110W plus. Current limiting, reflected power protection and thermal protection circuits all help to keep things safe.
Preamplifier Mod for 2 meter operation: The HLD4213A1 VHF Hi-band Rx preamplifier really lifts the receive performance level, almost too much gain. Unfortunatly the pre-filter stage is a bit marginal for 2Meter operation, although it's right on the edge and varies between units. Remove C126 and repace it with a trimmer cap, I used a 6pf to 50pf trimmer, but probably about 20pf would be right. Adjusting the trimmer cap then makes a huge difference to the performance of the receiver.
For Sale: 110Watt++ VHF Syntor X (T73) 64 channel programmed and aligned to your requirements $AUD500, inc GST, programmimg software and Full Service Manual included on CD.
All Rights Reserved syntor@bigpond.com.au
Richard