The DR-135TE, DR-235T and DR-435TE SINGLE-BAND radios are popular with the IRLP folks
as they are inexpensive. Unfortunately the internal CTCSS decoder has very poor performance.
I mean it is really bad - it's slow to open and can take from 1/2 second to as long as four
seconds (!) to close.
Glen Roe WA6MHA uses one as a point-to-point link from an IRLP node to the local repeater.
He ended up disabling the internal decoder and adding a TS 64 Decoder. He documented the
procedure here (a local copy), or you can go to
http://www.irlpcables.com/AlincoTS64.html
for the original writeup (offsite link).
Many Alinco radios use a round 8 pin mic jack with 7 pins around the
outside and one in the middle.
Click here for a photo.
There are tiny numbers molded into the
plastic on the plug and jack. Several Alinco and Kenwood radios use this pinout:
| 1 | Mic audio |
| 2 | PTT |
| 3 | Down button |
| 4 | Up button |
| 5 | +5VDC out (for DTMF encoder, keypad backlight, or both) |
| 6 | Audio output (paralleled with the speaker jack) |
| 7 | Mic audio ground (the shield of pin 1) |
| 8 | Ground for PTT, up and down buttons, speaker audio and 5vDC |
|
|
Many radios that use the 8-pin modular mic jack ("RJ-45" style) use this pinout:
With the locking tab down, and looking into the connector or at the back of the
plug the pins are numbered from left to right.
| 1 | +8v DC out (max is 10mA) |
| 2 | CLO (data out for PC programming) |
| 3 | AFO |
| 4 | PTT (input port for transmitter control. DTMF sent on this pin will
control the radio.) |
| 5 | Mic audio GND |
| 6 | Mic audio |
| 7 | GND for PTT |
| 8 | CLI (data in for PC programming) |
|
Many Alinco radios have a DE-9 connector on the back of the radio. When the
EJ-41U optional TNC board (for the DR-06, DR-135, DR-235, or DR-435 SINGLE
BAND radios) is not installed the ribbon cable from the connector is
plugged into the control board and audio, COR and PTT signals appear on the
pins as per the left side pinout below for connection to an external TNC.
See the DR-135/235/435 Instruction
Manual page 36 for signal level and impedance details.
When the EJ-41U board is installed the ribbon cable is moved to that board
and the pinout changes to the right hand list below. This lets you use a
straight-through DE-9 cable to connect a PC to the radio. The EJ-41U
instruction manual is
here, a schematic is contained in the
DR-235T Mark III Service Manual or the
DR-135/235/435 Service Manual
and a photo is here. Note that
the EJ-41U is designed to fill the basic packet communication functions, such
as keyboard operations and APRS. For more elaborate operations requiring
KISS mode, digipeater mailbox functions or node operations, do not use
the EJ-41U; instead use an external TNC like a KPC, an AEA, etc.
The DR-635T/E radio uses the EJ-50U optional TNC board. The instruction manual
can be found here. I presume the pinouts for
the DE-9 connector are the same as they are on the EJ-41U TNC board.
|
| Without optional TNC board |
| 1 | COR signal, open collector, active low. Use a 10K resisitor from this
pin to pin 8 as a pull-up resistor. |
| 2 | Receiver audio output. The audio on this pin is not de-emphasized. Used
for 9600 baud packet data. |
| 3 | Transmitter audio input. The audio on this pin is not pre-emphasized.
Used for 9600 baud packet data. |
| 4 | Receiver audio output. The audio on this pin is de-emphasized. Used for
1200 baud packet. |
| 5 | Ground. |
| 6 | No connection. |
| 7 | PTT input, active low. |
| 8 | +5vDC out, max current is 50 mA. See comments below. |
| 9 | Transmitter audio input. The audio on this pin is pre-emphasized.
Used for 1200 baud packet. |
|
|
With optional
TNC board |
| 1 | Not Connected. |
| 2 | Serial data in from computer. |
| 3 | Serial data out to computer. |
| 4 | Jumpered to pin 6. |
| 5 | Ground. |
| 6 | Jumpered to pin 4. |
| 7 | Jumpered to pin 8. |
| 8 | Jumpered to pin 7. |
| 9 | Not connected. |
|
Heavily Biased Personal Opinion:
I do not recommend Alinco mobiles for use as a point-to-point link radio or as a
repeater transmit radio. Buy a used YaeComWood or even a Motorola GM300 - but
watch the duty cycle. Why? For one, the CTCSS decoder in the Alinco is slow to
decode and does not release properly. Adding an outside decoder (like a
Communications Specialists TS-64) fixes that but why should the customer have to
buy another piece of hardware to patch Alinco's bad design?
Alinco should fix their design - or copy the one in the cheapest Yaesu, Kenwood
or Icom - any of those does a better job. It's not a difficult design, even my
old Motrac did it better, and it was built in 1962, 50 years ago.
Secondly, the Alincos seem to work when new, but you have to leave them in carrier
squelch. Plus, over time I have had nothing but trouble. I was helping a gentleman
that was putting up a 2m repeater on a extreme budget. It took an original and
three replacement radios over 17 months at one location before we got something that
lasted - and no, we were not abusing the duty cycle, nor was the operational
temperature out of spec (how do you abuse the duty cycle on a UHF control receiver?)
As a carrier squelch mobile, or as a packet radio, they are great... especially as a
"first radio" for a new ham.
Other Unsolicited User Comments:
John W1GPO purchased a DR-235T Mark III radios before coming across the above
comments. After reading them, he was somewhat dismayed about the apparently poor
CTCSS performance, so he was anxious to run some tests of his own on the unit when
it came in. He was quite happy to determiner that the CTCSS decoder operated just
fine, exhibiting none of the qualities listed above. He did extensive testing of
the radio's Modulation Acceptance Bandwidth and found it to be just as good (or
bad) as some Kenwood and Yaesu radios he owns. Time will tell how the radio performs
as a link transmitter. It would seem that Alinco fixed a bunch of deficiencies in
the Mark III radio models. Don't blindly believe everything you hear and read.
You can read his short technical review here.
Lonney KL3NO reports: I have been using a DR-135T MK III for an IRLP simplex
node. I got this new in late 2015. I've not had any issues with the CTCSS decoder,
including when used on the WIN system - these guys will quickly block nodes if they
show any signs of bad behavior. It's running at the 50W setting into a Diamond X50
with LMR-400 coax. A 24V computer fan is mounted flat over the heatsink, running at
half speed on 12V continuously. The radio is located in a space that rarely exceeds
75F ambient, much of the year it's 40-60F. The radio is mounted facing down, with
the heat sink pointing up; this may help the PA cool as heat likes to travel up!
Perhaps thermal stability is a factor in making these things last longer than five
minutes in high duty cycle environments. After 3 years, it's working as it did on
day one. Granted it spends most of its time idle, with the occasional periods of
long duty cycle activity for several hours or more, such as nets. If using one of
these for a heavily used link, then you'd most certainly want to dial it back to
20W or even 5W, and have continuous PA cooling, or PTT activated cooling at a
minimum.
Wiley KF6IIU reports that, at least on a DR-235 Mk III without a TNC installed,
pin 8 (+5V) is only active when the radio is in digital mode. When a TNC is installed,
this signal is used to turn the TNC on and off. Don't rely on this signal to power
an external RigBlaster or other adapter. In addition, going into digital mode shuts
off the speaker audio. It is probably safe to assume the other Mk III radios behave
the same way.
Contact Information:
The author can be contacted at: his-callsign // at // repeater-builder // dot // com.
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