My First Kenwood Hybrid Transceiver A Kenwood TS-520SE Complete with AT-230 Antenna Tuner, SP-230 Speaker and DG-5 Digital Frequency Counter.
My Second Kenwood TS-520SE Hybrid Transceiver.
Dated 1978 - Almost 40 Years old, and Lovingly restored by Keith (G0TSH)
About three years ago, I sold my first TS-520SE - thinking I would move up. Bought in 2010 for £150, plus another £110 for the quite rare DG-5 Frequency Counter imported from an American Amateur . Later sold on in 2010 for £300, to buy an Icom 746 Pro....... Bad Move - It was really disappointing - the performance of the 746 Pro, and after a few months sold that too, in a hunt for better equipment.
In March 2014 - three years later, a friend was complaining that he had too many Kenwood Hybrids, and jokingly asked if he wanted to sell a very recent TS-520SE restoration he had done. After a little persuasion, he agreed to sell me the transceiver and a DG-5 Frequency Counter to go with it. It is absolutely 'As new' cosmetically and working specification, and bought it at a little more than half the 'New' price it was sold at in 1978.
The transceivers described here include, in the order they were produced, the TS-520, TS-520SE, TS-530S, TS-530SE and TS-530SP,. They were developed and manufactured from 1978 to 1983 by the Japanese company Kenwood (formerly Trio) known as the Kenwood 'hybrids." They are mostly solid state, but at the time they were first produced, high power transistors were not economically viable for amateur products. To achieve the desired 100 Watts continuous output, Kenwood's engineers turned to valves (tubes)with a 12BY7A Driver and two 6146B final amplifiers. This hybrid combination of solid state technology (reliable, low power consumption) and vacuum tube technology (high efficiency, linearity) proved to be extremely successful and popular with radio amateurs over almost 25 years of production. Each new model incorporated additional features and performance improvements while retaining the best of the previous model, and they are still used by serious amateurs around the globe.
The TS-520 Manufactured from 1978 - 1980 was succeeded by the TS-520S in 1980, and then by the TS-520SE in production from 1981 to 1983. The interface for Kenwood's external DG-5 digital frequency display is included and does not require installation of a kit. The 160 meter band and a separate channel for receiving WWV at 15 MHz were added to the 80, 40, 20, 15 and 10 meter coverage of the TS-520. Much of the point to point wiring of the TS-520 was replaced with printed circuit boards and improved solid state devices. Also added were a phone patch and a compression speech processor. The compression processing increases SSB average power without significantly degrading audio quality and intelligibility.
Like the TS-520, the TS-520S can be operated from 120 or 240 Volt power mains or from 13.8 Volts DC, so it is also suitable for mobile, portable, or emergency use. The TS-520SE added some features and retired some. It discarded the transverter connection and 13.8V DC operation. It added a switch to select either of two crystal filters if installed, and a number of circuit refinements were made possible by improved solid state technology. Its SSB crystal filter is adequate for casual CW operation, but an optional 500 Hz wide crystal filter can be installed for the dedicated CW operator.
These models remain very popular with amateurs because of their elegant design and reliability. They are simple to operate, and frequently used functions are readily accessible from the front panel. As with all the hybrids, band change tuning takes less than 10 seconds. The audio quality both receive and transmit is excellent when properly aligned.
The TS-520 is the grandfather of the Kenwood hybrid line, and it was the most advanced transceiver of its day. 40 years later it still holds its own since it has the features most demanded by serious amateurs: 100 watts output for CW with a bit more for SSB; a very stable VFO or selectable fixed frequency crystals; an analog frequency dial accurate to 1 kHz in conjunction with a 25 kHz crystal calibrator; receiver incremental tuning useful in receiving a station slightly off frequency; an effective impulse-noise blanker; and VOX with semi-break-in CW.
While the SSB crystal filter is satisfactory for CW operation, an optional 500 Hz wide crystal filter can be installed for excellent CW selectivity. Provision is made for installing a kit to drive Kenwood's external DG-5 digital frequency display. The combination of solid state and vacuum tube technologies provides an architecture best described as simple but elegant, and it produces the fine audio quality for which the Kenwood hybrids are noted. It is easy to operate, and tuning the power output stage when changing bands can be accomplished in half a minute or less. Frequently used functions are readily accessible from the front panel. It can be powered by 120 or 240 Volt AC mains as well as 13.8 Volts DC, which makes it ideal for mobile, portable and emergency use.
If you have a nice TS-520, hang onto it. It doesn't have many bells and whistles, but it has everything you need for solid SSB and CW QSOs including DX. It will serve you well.
SPECIFICATIONS OF ALL MODELS
Type: Amateur HF transceiver Frequency range: 10-160 m Mode: SSB/CW RF Power output: Max 100 W Receiver: Single Conversion Sensitivity: 0.25 uV S+N/N 10 dB or more Selectivity SSB: 2.4 KHz (-6 dB), 4.4 KHz (-60 dB) CW: 0.5 KHz (-6 dB), 1.5 KHz (-60 dB) with optional CW filter Image rejection: Better than 50 dB Voltage: 13.8 VDC or mains (520SE Mains only) Current drain: RX: 5 A (heaters on), 0.6 A (heaters off) TX: Max 15 A Impedance: 50-75 ohms, SO-239 Dimensions (W*H*D): 333*153*335 mm Weight: 16 Kg Manufactured: 1978 - 1984 (Discontinued) - The TS-520 Range. Other: 3 tubes
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