Need Lil Help

[W8NIC]

Geetings,
I have a Heathkit SB-220 that i would like to pair with my Yaesu FT-920. My question is, what cables and/or relay will I need to get them to work together? Tuner I'll be using is a Palstar 1500CV.

thanks.

larry
w8nic

[KA5N]

The SB 220's relay uses 120 volts DC and the control line should be keyed to ground.
The easiest way to accomplish this (since most modern transceivers will not switch this
voltage and current) is to get a HarbacH  SK-220 soft key kit which will be mounted internal
to the SB 220.  Look at the manual of your transceiver for the connections and cabling needs
to connect the transceiver and amp together.  Use of the soft key reduces the voltage and
current needs of the switching signal to 0.7 vdc and 1.5 ma.

Allen KA5N

[K4DPK]

K4POZ sells an amplifier keying interface that is the simplest of all to use.  Plug in one wire from the radio, plug in one wire from the amplifier, and you're done.

It doesn't require external power.

It doesn't care what the keying line polarity , current or voltage is.

You can find it at www.k4poz.com
'
Phil C. Sr.
k4dpk

[W1QJ]

Rons unit I think has a battery in it, but it lasts a long time because all it does is bias the transistor switch.

[K4DPK]

Yes, the 9v battery is bias on the switching mosfet.  Lasts virtually same as shelf life.

Phil C. Sr.
k4dpk

[K6AER]

Why not buy a SPDT relay from radios shack and connect the relay coil from the + 12 out on the radio to the relay and the cold end of the coil to the radio key line. Then connect the N/O relay contacts to the amplifier. No battery, key any voltage and the relay only cost under $2.00.

[K8AXW]

I Googled "amplifier keying interface" and found several.  I adapted two and they both work fine.  One is all solid state and uses a high voltage transistor that works with the SB-200.  I then went to a transistor driven relay and wired it to use with either of my two amplifiers. 

Finding a relay that will handle the current but also has a coil that has a low current demand isn't as simple as one might think.  Then you have to remember the coil kickback spike which needs to be dealt with. 

This is why I went to the transistor driven relay.  My transceiver relay now has to handle just a few mils of current and is protected by the relay kickback spike.  I power it from my 13.8VDC power supply that is used for several other station accessories.

Final note: It cost was considerably less than $37.50 that POZ charges for his little box.

[KA5N]

The Harbach soft key costs   $ 27.00. runs off the power inside the SB 220 (6VAC)
and so has no battery to run down.  Plus it was designed to work with the SB 220.
Of course there are a number of other interfaces available that have not been mentioned
in this thread which will work well with the SB 220. 
As always you pays your money and you makes your choice.

Good Luck
Allen KA5N

[W8NIC]

i found a website run by w8mis and he sell buffers for amps. just like the arb-704 for the icoms but his will work on my yaesu.
thanks for all the inputs.

73.

larry w8nic

[W8JX]

i found a website run by w8mis and he sell buffers for amps. just like the arb-704 for the icoms but his will work on my yaesu.
thanks for all the inputs.

73.

larry w8nic

If I was going to use that amp I would do soft key mod and be done with it. It will add to resale value too if you part with it.