THE
DIFFERENCE BETWEEN THE MIDLAND SYNTECH
AND A.W.A. RT-85
COMMON
AREAS:
The Midland Syntech 1 radios ("ST1") and the A.W.A. RT-85 share the
same Hitachi synthesiser/exciter and receiver PCB assemblies, and both radios use the
Z-273 EPROM
module.
THE
MAIN DIFFERENCES:
Transceiver case/chassis/heatsink.
- The RT-85
uses a one-piece die-cast case incorporating the PA compartment and
heatsink.
- The Midland
has a detachable die-cast PA chassis/heatsink; the remainder of the
assembly is sheet metal.
PA assembly.
- The Midland
PA is capable of typically 40 Watts output (higher power versions also).
- The RT-85 PA
maxes out at 25 Watts.
Microprocessor
code and Z-273 data storage.
- Several
functionality differences (e.g. one vs. two scan groups) are
incorporated into the mask-programmed microprocessors, resulting in key
differences in the data content in the Z-273 EPROM module. As a
result, the Midland 70-1000 programmer which was produced to support
the Syntech 1 series will NOT program the module for the RT-85 unless
fitted with after-market firmware. The SkyLine 70-1000X is
designed to natively support both.
Configuration.
- The ST1 was
offered in under-dash (local) or trunk-mount (remote) configurations.
- The RT-85
was offered only as a remote-mount, although after a time an option kit
was offered which close-coupled the remote head to the chassis using a
sheet metal extender incorporating a small speaker. This option
was not widely deployed; examples in the wild are fairly rare and are
usually embodied in a "porta-pack" assembly.
MINOR
DIFFERENCES:
There are
numerous "features" differences, most of which don't warrant much
comment, such as:
Microphone.
- The ST1 - in
common with other Midland families - uses an amplifier within the
plug-in microphone.
- The RT-85
uses an unamplified mic hard-wired to the control head which
incorporated a mic amplifier.
Scan groups and
patterns.
- RT-85 one mode, one group, 64 max in
list, hardware requirements by default.
- Midland two
groups of 32 max, multiple modes, requires option kit(s) to have any
scan capability.
Low power.
- Terminal on
rear of RT-85 control head selected alternate (low) power setting when
grounded.
Display.
- RT-85
display auto-blanks after 20 seconds; this unpopular feature is not
programmable and can only be defeated with a hardware add-on.
Antenna connector.
- ST1 - "UHF"
series.
- RT-85 - BNC.
MY
PERSONAL OPINION OF THE RELATIVE
MERITS OF THE TWO RADIOS:
The typical RT-85 PA is struggling to deliver at the 25 Watt output
level, and
the APC (power level control) is flat out. By comparison, the
ST1's APC is backed off a fair bit at this level and - apart from
stressing the output device less - provides far better protection
against adverse SWR.
Midland scanning modes are flexible, but confusing to many users, and
the standard radio is delivered without the front panel controls to
support scanning.
Display auto-blanking on the RT-85 is b$##@y annoying. While it
is painful to fit a mod into the head to defeat it, that is the lesser
pain. Whatever possessed A.W.A.'s engineers to specify this as a
non-programmable "feature" remains one of life's great mysteries.
The RT-85 is
80-channel capable, despite the RT-85 service manual and sales
brochures stating 64 channels. Again, why A.W.A. persisted with
this myth remains a mystery.
The
frequency response of the RT-85 mic amp did not roll off fast
enough at the low frequency end. As a result, some RT-85 users
experienced talk-off on CTCSS-equipped repeaters which
we could not replicate when they used the ST1. (G'day Ron!)
The Auxiliary connector on the RT-85 lends itself to a host of
"systems" add-ons and applications.