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Kenwood TR-8300 Notes Compiled by Mike Morris WA6ILQ

The TR-8300 was a darn nice no-frills crystal controlled UHF 1 watt/10 watt radio. I had a TR-8300, a mag mount and a small power supply (5 amps) parked on the local club repeater channel and placed on top of the refrigerator for a few years (until I picked up a Yaesu 720R synthesized replacement). The 8300 had a huge internal speaker, and such niceties as a factory zero-center discriminator meter jack on the back to assist in netting the receiver crystals on channel. The channel knob has 23 positions... a lot of crystals! It came stock with 446.0, 446.5, and 449.1 (transmit) and 444.1 (receive). The last set was useless to me as the repeater band in southern california uses 440-445 MHz as the repeater inputs. The CALL CH pushbutton, the HIGH/LOW (TX power) button and the MON button on the front panel were all DPDT push-on-push-off buttons and could be rewired as needed for special functions. The CALL button does NOT force-select channel 1 as you would expect, instead it is factory wired to control a tone encoder. The volume control has a push-on / push-off power switch. The two jacks on the back are unlabeled from the factory, the discriminator jack is nearer the model tag. The speaker jack is near the outside edge.

Two TR-8300 brochures:     One     Two

The crystals are HC/25U case and 3rd overtone. The formula for receive is (channel-frequency-10.7 MHz)/12. This is a common scanner crystal. The transmit formula is (channel-frequency)/18.   I prefer International Crystal.

The microphone connector is a 4 pin, with pin 1 is mic audio, pin 2 is PTT to ground, and both pin 3 and 4 are ground. The antenna connector is a SO-239. The official power supply is a Kenwood PS-5 rated at 3 amps. I used a 5 amp Lambda from aerospace surplus.

This document is the Com-Spec writeup on adding an SS-32 encoder. While it specifies an SS-32 any external encoder will work - a TS32, a Vega 188, etc. I used a TS-32 in mine as that model offered PL decode (I repurposed the MONI pushbutton switch on mine to select carrier receive when out or PL receive when depressed).

Note that the unit as shipped was tuned to transmit from 445.0 MHz to 450 MHz and receive from 442.0 MHz to 447.0 MHz. Southern california and many other areas are upside down from that, and the radio needed to be retuned. You needed to tweak both the receiver and the exciter, both are about 5 MHz wide, and the tweaks should be made in the center of the 5 MHz range desired.

The last page of the PDF manual below is a Trio-Kenwood Service bulletin no. 16, dated Sept-02-1977:
RX ALIGNMENT:
Adjust the oscillator coil L14 1/2 to 1/4 turn counterclockwise until the LED in the channel indicator window turns on. This indicates that the oscillator is now working. Connect a signal generator to the TR-8300 and adjust L15, L16, TC-6 and TC-7 for maximum "S" meter indication. (These should be very small adjustments.) Adjust TC-5 in the helical resonator for maximum "S" meter indication. This is the only adjustment made to the helical resonator.
TX ALIGNMENT:
Connect a wattmeter and dummy load to the TR-8300. Adjust the oscillator coil L3 for maximum RF output.

Manuals:

TR-8300 User Manual   1.9 MB PDF donated by WA6ILQ.

Contact Information:

The author can be contacted at: his-callsign // at // repeater-builder // dot // com.

Information provided from various sources as listed in the text.
Hand-coded HTML © Copyright date of last edit by Mike Morris WA6ILQ.

This page created on 16-Nov-2004 by Mike WA6ILQ.

This web page, this web site, the information presented in and on its pages and in these modifications and conversions is © Copyrighted 1995 and (date of last update) by Kevin Custer W3KKC and multiple originating authors. All Rights Reserved, including that of paper and web publication elsewhere.