[Icom] ICOM rigs with other amplifier brands

[Larry Benko]

Larry,

Many of the new amps such as Alpha 87 and 99 and the Acom
1000 and 2000 are fine to use without any buffer circuitry
as they have buffer circuitry and only have open circuit
voltages of 5 to 15V and short circuit currents of <10mA.
Both the Acom and Alpha web sites provide specs.  I have
driven an Alpha 87 and an Acom 1000 for more than 15,000
qsos from a 756 PRO with no buffer circuitry.  However if
you are not certain that the amp only requires a low voltage
and current to key it then be certain to get a buffer relay.
Also some buffer circuits will only drive amps that have
a positive voltage (many old Heathkits had an AC voltage).
Also some of the buffer relays may not operate fast enough
(the 756 operates the send jack 9 to 10 ms. before the RF)
to guarantee that the amp does not hot switch which would
burn up the amp output relay and generate huge amounts of
RF splatter.  Tell us what amp you are planning on using
and someone her probably has experience with it.

73,
Larry, W0QE

W3UIO wrote:
> ICOM publishes circuits which, when inserted in the
> amplifier keying line, will prevent destruction of the
> XCVR send relay from current coming back from the amp
> as the relay field collapses in the amp.
> 
> There is an Ameritron circuit which compensates for
> various keying voltages and polarities which costs
> $50. By comparison, the ICOM circuit costs only a
> couple of dollars.
> 
> Does anyone know whether ICOM has corrected this
> problem in the 756 Pro or Pro II so that this extra
> item is not needed?
> 
> =====
> Larry, W3UIO
> 
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