High Frequency Radios


This page is somewhat of a catch-all for photos of assorted radios in my collection which didn't fit anywhere else and were difficult to categorize. Some of these also appear on my friend Klaus-Peter's greenradios.de web pages, where you can also see other examples along the same lines.  These are presented in no particular order. Most are post-WWII although some were made in wartime as the descriptions will note.


This is an HF SSB radio actually made by CAI (Communications Associates, Inc.) in New York for Motorola about 1968-72.  Fully solid state, it is capable of being used as a battery operated portable, a mobile or a temporary base station.  It has two crystal controlled channels and, somewhat surprisingly, no receiver incremental tuning (RIT.)  Examples can be found with either CAI or Motorola labels.  It appears that Motorola eventually absorbed the CAI line in the early 1970's and all products after that date show only Motorola labeling.  It is interesting that Motorola had a habit of disavowing knowledge of the existence of these sets, which were probably designed for some application in Southeast Asia, based on the olive drab anodized color scheme.  This one was used by the U.S. Bureau of Land Management (BLM,) and the other examples which have turned up have been from that source as well.

The SA200 could have an optional antenna tuner, which clipped across the front of the set, apparently in lieu of the battery charger / AC power supply which this example has.  Originally, there would have been a battery box which clipped across the rear panel of the radio.  It was missing on this example. It can be seen that the microphone is the same as that used on the Motorola PT200/300/400 series of pack set VHF FM radios.

Early models had different power connectors and featured a microphone gain control and a different metering switch arrangement.  When using the battery power pack only, output power was reduced to just a couple of watts.  This radio is more useful than others as it incorporates both USB and LSB, while many competitive radios from other makers offered just USB.  In the "what were they thinking?" category, this radio uses an oven assembly to maintain crystal temperature.  In portable operation, a good portion of your battery power is being wasted heating the oven!  Motorola was already using TCXO crystal oscillator assemblies in their VHF two-way radios, so why not in these?

CAI CA-26A (Motorola SA 100)

This is another CAI product which can be found branded either CAI or Motorola, yet usually featuring a Motorola branded microphone.  

A 100 Watt class SSB/AM transceiver covering the usual HF spectrum of approximately 2-14 MHz, this example was originally used by the Army Corps of Engineers.  It appears of earlier design than the radio above, as it is a hybrid, containing both transistors and tubes.  The power supply is a separate item and is invariably missing when these are found.  The power supply is a 12 Volt DC transistorized inverter.

An interesting feature of this set is the European slot-style "magic eye" tube to indicate modulation level on transmit.  Motorola advertised these in approximately 1968 as a high power mobile radio.  It is unknown whether any customer was found other than the U.S. Government.  Probably out of production by 1972.

There are various modifications on these, involving added switches on the front panel.  This one has a "squelch" switch; others have a "tone" switch.  There were accessory phone patch and selective calling adapters.


Kachina, an Arizona company, was the first manufacturer to produce a computer controlled "black box" amateur radio transceiver, and they also made a number of paramilitary radios as well as a few utility type HF SSB sets.  This is one of them, the KC 100, which I am told is basically a crystal controlled version of the Alda 103 amateur transceiver.  It dates from the late 1970's or early 1980's.  All the ones I have seen have been USB only, with a plug button in the mode switch hole.  Kachina went out of the radio business in the late 1990's, leaving orphans such as this behind. They also made a model KC 102, which is similar in size but of different appearance, which is probably similar in design,

Kachina also offered a companion AC power supply.  This item is best described as "scary."  It turns out to be a 17.5 Volt (when unloaded) unregulated power source.  The only thing in it is a large transformer, two stud diodes, two huge electrolytic capacitors, and a large filter choke.  No regulation, nothing else, not even a bleeder resistor!  It seems to work fine in conjunction with this transceiver, but I would expect there to be tears before bedtime should you try to power anything else with it.  I printed a label on mine which says "Warning - - unregulated 17.5 Volts!" and stuck it where some label had been at one time but fallen off.  That one probably said the same thing.  

All of these that I have seen have been surplus from the Civil Air Patrol, where they seem to be no longer type-accepted for use.


Dentron, the linear amplifier and antenna tuner manufacturer of the 1980's, tried their hand at at least one radio, the Scout.  This is an HF SSB 5 channel transceiver which I am told uses the basic circuit board from a Mizuho HF SSB radio (not that it's of much help to know that.)  It is shown with its companion AC power supply.  My gripes about this radio are that it has no clarifier control (RIT) and is USB only.  On the other hand, it sounds great on the air with my junkbox 500 Ohm dynamic CB microphone.  This one was probably another surplus item from the Civil Air Patrol, as it has their 4 MHz western regional calling frequency in it.  This is also shown over on my "Mystery Radios" page, where some additional comments are made.  This probably dates from the early 1980's. Common opinion is that this was produced at the end of Dentron's existence and a great many, complete and incomplete,  were just stored at the end of the company and filtered out onto the marketplace in mysterious ways, and that no manual was ever printed.  Therefore it is pointless asking me for one!  

RCE TR-4B  (Canada)

This is the Radio Communications Equipment Co. TR-4B, a Canadian portable AM transmitter-receiver made in Montreal, Canada.  The capsules inside the handset are dated 1957.  It uses all miniature 1 Volt battery tubes and has room inside for several 45 Volt B batteries and apparently two # 6 cylindrical dry cells.  There are still crystals in it for a 5.1 MHz frequency.  I have never seen another of these; this was obtained through the kindness of friend Rick, W6NIR, a fellow forestry radio collector.


HUMBLE P-12 (Model B)

This is a Canadian portable forestry radio from the early 1950's made by Humble.  Also used by assorted utility users such as logging and trapping.  I have a separate web page for this radio, look here:



This set has no maker's name on it that I have been able to find.  That leaves out Morrow and Radio Specialty which always engraved their name on equipment somewhere.  If you recognize this radio, please tell me!  The marking of the parts suggests this was made in the USA in the mid or late 1950's. It has an interesting self contained telescopic antenna rod that doubles as a handle when replaced, and a loading coil that stows inside the handset area.  This is crystal controlled on a single 5 MHz channel.  If the receiver were tunable it would be an ideal candidate for 75 Meter use!  This was very possibly not a forestry radio at all, it may have been made for some entirely unrelated government agency .  It is still tuned on 5422.5 kHz.



This is a high frequency AM receiver-transmitter made during the war primarily for military police and military fire engine use.  All octal tubes.  Eventually it was given a standard military type number, late in wartime or early thereafter, of AN/VRC-4.  Fisher Research was a Palo Alto company that later would make personal marine radios and metal detectors.  They are still in business as far as I know, but have moved out of Palo Alto.  Most were black but the military example below is gray.  The receiver is interesting in that in addition to crystal controlled channels there is one screwdriver-tunable channel as well.




Ver. 3/29/2023                                                                                                                                                             Geoffrey C. Fors, 2023  All rights reserved