Alinco DR-590 modifications

Created 22nd August, 2017

This is modification of the Alinco DR-590 dual band FM mobile transceiver
Alinco DR-590 2/70 mobile mods:

I finally sorted my problems with my Alinco DR590, fixed the UHF PA, the radios that were imported
into Australia are T model for the USA 440-450MHz market and the 70cm PA is guaranteed to cook itself,
hence you could never get more than 30w at 433-434 Mhz, now that I put the correct E model components
into UHF PA it can do 42w at 13.8v, (the actual RF block is rated at 45w at 15.2v) but I wound
it back to 30w and she runs cool now on high pwr, the way it should be. The basic change is a couple
of caps and an inductor, L4 goes from 1.25T on 3mm diam, to 1.25T on 4.0mm diam. It makes a big
difference for such a small change. Running it on incorrect band cooked the PA and dried out the solder
joints of main inductors, forcing me to cleanup all original soldering and resolder all components in
the UHF Driver/PA section. I did this back in 2009 and the radio worked reliabley ever since.

Then I fixed the freq stability, it kept wandering off freq, it drifted about 4kHz from cold to warmed up,
I give it a quick squirt of freezer spray, the TX freq would wander 10 kHz, found the soldering in
the oscillator cct on the VHF main board was looking dry, so retouched the solder joints for all the
components associated with the Xtal and it is now stable again.

Only one issue is the mic for the Alinco is crap, so I working on a better mic with DTMF, in fact,
I updated my old micrphone for a new Alinco DR-435 microphone, with backlit keys, (from Ebay)
with much better DTMF operation, The reason for this is the original Alinco DR590 microphone was so
sensitive it picked up the echo inside the plastic casing, which overides the actual speech audio,
plus the DTMF operation is garbled, as the DTMF tones are partially clobbered by the induced sound
of pressing the DTMF buttons, so the DTMF tones were not clean. 
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NOTE: only licensed Amateur Radio operators can operate this equipment on assigned Amateur frequencies/bands.

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