(c) 1999,2008 Peter McCollum
The Delco 5300 Series HF Transceiver
The Delco 5300 is a portable solid-state HF transceiver
developed in the early 60's. It resembles a small lunchbox, with a hinged lid.
It transmits on four crystal-controlled channels, with a power output of 5W CW
and 1.5W AM, and can be operated from a high-speed keyer such as the GRA-71.
The receiver also has four (separate) crystal-controlled channels, and includes
a BFO. Most models include a switch to select two bandwidths: 6 KC and 0.5 KC
(the latter using a Collins mechanical filter). Power is supplied by a battery
that provides 4V (receiver), 24V (transmitter), and 12V (for modulator, only
required for AM). This set is unusual for a clandestine radio in that it
supports AM voice transmissions on the HF band. The set’s antenna matching circuitry is far less
flexible than most earlier sets, so the user would be required to pay more
attention to proper antenna configurations.
Some interesting 'clandestine' features include:
- A
plunger-type switch that turns off the power if the lid is closed. If
you're in a hurry, just close the lid - you don't have to remember to turn
off the receiver or transmitter.
- A
"whisper switch" which increases the microphone sensitivity.
There are two earphone jacks, and one mic jack - all are the
submini "transistor radio" type of plug. The H-264 earphone for the
PRR-9 is nearly identical to the PRC-64 earphone, and works well as an
alternative. The earphone can also be used as a substitute microphone.
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Delco 5300 Transceiver Specifications |
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Transceiver Delco 5300 |
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Weight |
7.5 lbs with battery |
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Dimensions |
10" X 5" X 4.5" |
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Frequency Bands |
3-8 MC, four crystal channels (separate crystals for xmit and recv) |
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Power Output |
5 watts CW, 1.5 watts AM |
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Misc. Specs |
Receiver sensitivity: 5 uV AM, 2 uV CW. AF output: 5 mW into 600 ohms. Antenna: 50 ohm wire, ¼-wave or ½-wave wire. IF freq: 455 KC. |
Differences between models in the Delco 5300 series:
- Delco
5300: tunes 3-8 MC, has no BW switch on receiver. This is the model that
was originally adopted for CIA use. Unlike later models, the CW key is a
true key, and is fully adjustable.
- Delco
5300A: tunes 3-8 MC, has BW switch on receiver.
- PRC-64:
the Army adoption of the Delco 5300. Tunes 2.2-6 MC, has BW switch on
receiver, battery-test circuitry is simplified (tests only the 24V),
transmitter uses a larger type CR-89 crystal (so that receiver and
transmitter crystals cannot be accidentally interchanged???). The CW key
on the PRC-64 is implemented with a panel-mounted microswitch, thus
perhaps making it easier to keep the front panel watertight.
- PRC-64A:
same as PRC-64, except that there is an added 'daughter board' on the
transmitter module that improves high-speed keying performance. The
PRC-64A manual says that all PRC-64's were modified by the addition
of the daughter board, thus making them PRC-64A's. However, the author has
an unmodified PRC-64 that was formerly a "parts unit" at the
Tobyhana repair depot. The ID plate on PRC-64A's indicates a contract date
of 1968.
A PRC-64 transceiver. The white label inside the lid
is not original, and the wire-bale knob is missing from the storage compartment
lid. Author's collection.
According
to Conboy and Andrade’ (see reference [27]), the Delco 5300 was a replacement
for the RS-1 with some Special Forces troops in Vietnam, and SOG ordered two
sets in April 1966 (although the sets apparently had not arrived by the end of
the year). The main advantages of the 5300 set would be its small size and
battery power, meaning that it could be operated by an individual without a
hand-crank generator. It appears that the 5300 may have seen duty somewhat
similar to the “Village radios” (see separate section), which would involve use
by relatively untrained operators. This type of usage provides an explanation
for the AM-voice capability of the set, which is otherwise nearly non-existent
on cold-war clandestine sets, due to the lack of security and the greatly
reduced effective range.
Delco 5300A receiver schematic (209 KB)
Delco 5300A transmitter schematic (248 KB)
Delco 5300A modulator schematic (223 KB)
