In the case of other radios you must be fairly aware of the years during which the radio was made.

Kenwood Ts-590 B1B Serial Number Is

Lets say you have a TS-850 or TS-870 and the serial number is in the 8 million range, that is 800134.

The first number minus 1 seems to equal the last digit of the year in which the radio was made.

Now the dillemma.

The TS-940 has a serial range of 10 million (1989) during which some very significant changes were made to the design of the radio, such as soldering in the eprom to eliminate erratic problems.

You naturally want to get that latest serials that exist for a certain radio to get the most recent updates to its design.

Does anybody have a clue as to when this radio might have been made Am I to assume 1991 Is this method of determining age accurate for Kenwood Larry AD0G.

However, I have received email replies that pretty much back up the rule of thumb that I mentioned.

So maybe it is a fairly accurate way to tell a Kenwood radios age.

This is less than what ICOM suggests and, narrowly though, within Kenwoods recommendation.

Kenwood Ts-590 B1B How To Hook Up

In Yahoo Groups forums Ive seen so many posts asking about how to hook up TS-590(G) or TS-990 to an amplifier via the REMOTE connector to key it properly and how to configure in the menu setting for it.

I too was confused initially and have found Kenwoods explanation in Instruction Manuals ( TS-590, TS-590G, TS-990 ) and In-Depth Manuals ( TS-590, TS-990 ) rather vague and inadequate.

There is a mechanical relay inside the radio behind the REMOTE connector.

Its made by Panasonic (or NAIS, Aromat) and the datasheet is here.

This is astronomical enough so we need not worry about its lifetime, but who knows about premature failure due to extremely harsh use, like making more than 3,000Qs in CQ WW contests Or in DXpeditions.

They are really just a relay contact and isolated completely from other circuits, so the polarity between the two doesnt matter (interchangeable).

See schematics at the end of this article for details.).

Alternatively you can use solid state switches inside the keying circuit.

They are comprised of several components but the main part is 2SB1188 bipolar transistor for Active High and 2SK1824-A (or SSM3K15AMFV ) MOSFET for Active Low configurations.

Yaesu, ICOM). But unfortunately, Kenwood has designed this to have only 10mA as the recommended maximum.

Active High configuration With this configuration, pin7(RL) is pulled up to DC 12V while TX.

To use this configuration, you probably need an inversion buffer between the exciter (radio) and the amplifier.

There are many commercial solutions but here is my attempt using a digital transistor (a transistor with built-in bias resistors).

Tnx to JA7UDE, Oba-san for suggestions.).

Since this is a single part project, you can even house this inside the casing of a DIN plug.

It has 50V, 30mA (100mA max) output rating so can be used with most solid state amplifiers but may not be used with older tube amplifiers with higher keying voltage.

You can choose a similar device that has large enough output (open collector) rating to match your amplifiers keying specification and ensure to limit the base current well below 10mA.

Heres another attempt using a photo-relay that has much larger tolerance.

In this case cramming all parts (including a resistor and a diode) into a DIN casing may be more difficult.

This particular device (Toshiba TLP222G) has 350V, 120mA output tolerance so this will safely key virtually ANY (including older tube) amplifiers.

Added benefit is that now the radio and the amplifier are galvanically isolated over this line, so hopefully less vulnerable to RFI.

Though you may still have unisolated ALC line.) Active Low configuration With this configuration, pin7(RL) is pulled down to the (near) ground while TX.

So for this setting to work, the pin7 needs to be pulled up externally while RX (usually by a buffer or an amplifier).

Personally Ive never been able to utilise this configuration.

Kenwood recommends maximum resting voltage of 15V at RX and keying current less than 10mA while TX that seem too low for direct keying.

Here are some of the keying specifications from amplifier manufacturers.

Kenwood Ts-590 Serial Number B1B