RT85A FAQ & Files
by Mark, VK3BYY
This page is a collection of information on the AWA RT85A.
Most of this information applies specifically to the A-model UHF
that were used by the Royal District Nursing Service, Melbourne,
and found their way into the amateur 70cm service around January
RT85A personality data (configuration bits)
the RT85, RT85A, & RT85C to 70cm
NERG78K8.zip - NERG
70cm 2764 EPROM ver 7.8 for RT85A
operate correctly ONLY in the RT85A UHF (403-420MHz) sets that have
to the 70cm amateur band (Transmit 433-440MHz, Receive 438-440MHz).
The 2716 EPROM may
work with the original RT85 Z-273 module, however the personality data
is not correct for the standard 85 model and may cause unexpected
operations. The 2764 EPROM will not work in the RT85C model.
NERG78K2.zip - NERG
70cm 2716 EPROM ver 7.8 for RT85A
70cm ver 7.8 Frequency list and notes (PDF)
70cm ver 7.8 Frequency list (Excel xls)
70cm 2764 EPROM ver 7.0 & bug patch file (NERG70k8.zip)
70cm EPROM frequency list
Reverse Engineered files:
Disassembled 2764 RDNS
Disassembled AWA RT-85A/A
Beware - although the
can program the channel data for the RT-85A, it does not set up the
personality data or scan channels correctly. Some hand editing of
the EPROM data is generally required.
The auxillary port on the RT-85A doesn't always work as expected for
applications such as packet radio or IRLP:
One reason could be that a non-standard pin
numbering scheme is used - consult the manual carefully!
The other reason is that some pins may have been rewired for special
applications. The PTT line was used for an emergency button in
the RDNS radios.
Still to come:
Circuits for the HD63056/2764 controller board
A little history behind the RT85 linage
Other useful favourite links:
Email me at this address after removing obvious stuff
to confuse the
spammers: [email protected]
Last updated: 10/10/2007