TS2000 LNA/other sequencing/buffers

[VK3XDK]

I have had a few inquires lately on how i interface LNA's/Transverters/ PA's ect to my TS2000
so here is the circuit i use (i have it made up in a separate "buffer box") To suit the TS2000 accessories socket.
The box should be powered from the same supply as the transceiver.

The ts2000's are only able to "sink" 10-15ma?? (at a maximum of 20V) SO relays with transistor buffers are normally needed. (as per circuit)

There is a delay setting in the TS2000 menu, I normally set it to max.
BUT
Be aware that the TS2000 has separate menu settings for VFO A and VFO B, so you will need to engage the menu setting for both.

If you use large case PNP transistors, they can be glued to the side of the relay for easy mounting/ construction

[VK4ZEJ]

I personally would like to thank Graham for his assistance in getting my LNA's & sequencer working. Graham built & tested the LNA's, however through the drawing above I was able to build the sequencer/buffers myself as well as wire correctly the accessory socket. Very pleasing as I have not damaged either the TS-2000 or Graham's LNA's.

Eddie

[VK4RF]

Just what i need here for my TS2000X. Looks like i will have to make some enquiries and swap an email or two with Graham

[VK1JA]

Perfect timing!

Thanks for sharing Graham.

[VK3XDK]

Just some further notes,

Technically the PNP transistors should be on the supply side of the relays but they will work in either position. (PNP's are typically "High side switches")

I use TO-126 case PNP transistors, they are convenient for gluing on the relays (i glue them in a position where their leads can be connected straight to the relay pins.)

I have manual switches between the relays and output, this allows me to bypass the switching/LNAs

I use RCA sockets for all of the outputs allows me to swap amps/transverters ect easily. The rca sockets are grounded to the case. (be careful to mark the RCAs so that there is no confusion, remember that some will have 12v during RX)

I mount everything in a die cast box, case of box being gnd.

Obviously this circuit can be adapted to other transceivers.

[VK6ZFG]

Hi Some coments on the circuit.

1. It would be better if the PNP transistor waslocated on the positive side of the relay. This would allow the transistor to fully switch on (saturate). This will result in the lowest transistor volts drop and dissipation and maximise the voltage to the relay.

2. A resistor should be included between the base and emitter to ensure that any residual voltage on the control line does not keep the transistor partly switched on and relay partially energized (and pulled in). The value of this resistor should be less than that used in the control line. The value of the control line resistor could be increased with the transistor relocated to the positive line (will depend on the transistor used and current wanting to be switched).

[VK2OMD]

Hi Some coments on the circuit.

1. It would be better if the PNP transistor waslocated on the positive side of the relay. This would allow the transistor to fully switch on (saturate). This will result in the lowest transistor volts drop and dissipation and maximise the voltage to the relay.

...

A disadvantage of your (VK6ZFG's) solution is that the relay is no longer connected to +12 or whatever... as it typically is inside an amplifier etc. Contact closure to ground is a common topology for these type of things.

Owen

[VK3XDK]

The PNP's work either side of the relay, i have done it for years (lets not confuse the people that need these ideas!)


Although they can be very sensitive, a pull-up resistor may help? And probably capacitive decoupling (just in case)
but lets keep things simple?

Dont think there will be a power dissipation problem if TO126 transistors are used (i have used tiny smd transistors and they dont even mind)

With transceiver interfacing another possible issue is open cct voltage on the base, but if supplies are kept below the transceivers maximum there will never be a problem (for the ts2000 it is 20V)

The circuit supplied works very well-i very much doubt anyone will have any problems whatsoever.

[VK4TI]

Hi Some coments on the circuit.

1. It would be better if the PNP transistor waslocated on the positive side of the relay. This would allow the transistor to fully switch on (saturate). This will result in the lowest transistor volts drop and dissipation and maximise the voltage to the relay.

2. A resistor should be included between the base and emitter to ensure that any residual voltage on the control line does not keep the transistor partly switched on and relay partially energized (and pulled in). The value of this resistor should be less than that used in the control line. The value of the control line resistor could be increased with the transistor relocated to the positive line (will depend on the transistor used and current wanting to be switched).

This works fine with our Arduino amplifier sequencer + control ( in development) dead simple and costs just a couple of$ for several channels

[VK3XDK]

Nice circuitbut no good here!
That needs high voltage to turn on! (high = on)
We need low=on