Moving Forward - Post ISS
Posted: 29 October 2008 07:23 PM   [ Ignore ]
Total Posts:  1078
Joined  2008-08-28

About a month ago, my Kenwood TS-440SAT HF transceiver started exhibiting the symptoms of an unlock condition in one of the radio’s phase-locked loop (PLL) circuits.  This is a known problem with this particular radio.  There are two PLL circuits that are affected.  Both circuits are critical to the proper operation of the radio.  To keep a small number of components in these circuits from vibrating mechanically, they were both “potted” in a rubber-based material that surrounds the components.  Over the years, this material breaks down and allows the parts to vibrate.  This vibration causes the circuits to malfunction.

I purchased this transceiver in 1985 while I was stationed in Munich.  At the time, this was nearly Kenwood’s top-of-the-line radio.  And it was a vast improvement over the radio it replaced in my “shack.”  All solid state whereas my older radio had vacuum tubes in the transmitter’s power amplifier.  Also, this new radio had a general coverage receiver capable of continuous tuning from .5 to 30 MHz.  The radio it replaced was tuneable only in the amatuer radio bands.

So, this has been my main HF radio for these past 23+ years. 

I’d told myself a few years ago that when the good old Kenwood went south for whatever reason, I’d replace it with an Icom radio.  Icom, Kenwood and Yaesu are the main manufacturers of amateur radio equipment.  The Japanese took over the amateur radio market back in the late ‘70s when the American manufacturers like Hammurlund, Hallicrafters, Collins, etc. couldn’t compete.

The Icom model I purchased last week is the IC-746 Pro.  And it’s not the top-of-the-line radio in the Icom lineup, but it’s a quantum leap forward compared to my vintage Kenwood radio.  Modern amateur radio equipment is all microprocessor controlled and this radio has way too many features to list, but among the more interesting is the capability to copy/decode radio teletype (RTTY) on the radio’s large LCD display with no interface or external gizmos required.  The digital signal processing circuitry forgoes the need to purchase pricey crystal or mechanical filters to vary the bandwidth of the received signals.  The radio also receives continuously from below .1 MHz to 174 MHz and has three antenna inputs, selectable from the front panel.  They call it an HF/6/2 rig because it operates on all of the amateur HF bands as well as the 6 and 2 meter bands.

This evening I modified (with invaluable assistance from a friend) the radio so it would transmit outside the amateur radio bands so I could check into the AFMARS nets.  Works like a charm.  I expected nothing less.

I’ll send the old Kenwood off for repair and keep it as my backup rig.


Glenn Miller - AA5PK
USAFSS/Rimbachvet Aug ‘72 - Jun ‘75