Your OM7 has two delays adjustments (pre and post transmitted signal).
Unless it is a prehistoric amplifier, the OM7 will take care of the timing
The more important parameter is the keying voltage.
Your OM7 keys with an open collector transistor circuit, not a relay.
This is dangerous with many old amps (dangerous = will blow the OM7's
With the TT amps, definitely no problem. You don't need the 318.
With the term "old Henry Amp", you haven't given us enough information to
answer the question.
We need to know which old Henry Amp and have an EXACT description of its T/R
relay keying specs.
As Ken wrote, most amps in the past 20 years have simply keyed 12v to ground
and their current demands were so little that they could be keyed by an open
Earlier amplifiers often had 110v AC or even higher voltage, sometimes
negative, sometimes positive.
Without knowing exactly what the amp is doing, we can't answer how the OM7
ALSO IMPORTANT: Usually people who own these old amps and take them to
multi-multi events have already modified their amplifier to enable it to be
keyed by an open collector circuit (transistor keying, rather than relay
There are many such kits available on the after-market.
ONLY THE OWNER OF THE AMP CAN KNOW IF THIS MOD HAS BEEN DONE OR NOT!
ONCE YOU KNOW THAT, the answer to your question is found on page 27 and 28
of the OM7 owner's manual.
It says the OM 7 uses open collector keying (no relay) and specifies the
maximum voltage and current it can key.
Here is the warning:
IMPORTANT NOTE: The AMP KEY line
should not have applied to them more than
+100V (output inactive) nor should it draw
more than 250 mA (output active). Many
older linear amplifiers like those
manufactured by Collins, Drake, and
Heathkit have a higher voltage on the
keyline. Such amplifiers require a relay or
transistor switch between the OMNI-VII AMP
KEY jack and the amplifier PTT input. A
sample plug-and-play device that can be
used between OMNI-VII and your amplifier
is the Ameritron ARB-704 interface box. If
you are unsure if your amplifier is suitable
for use as-is with the OMNI-VII, please
consult the operator's manual for your
amplifier or contact the Ten-Tec service
department at (865) 428-0364 or
THAT WAS WRITTEN BEFORE THE MODEL 318 WAS AVAILABLE.
You can substitute "Model 318" for "Ameritron ARB-704).
From: email@example.com [mailto:firstname.lastname@example.org]
On Behalf Of Richards
Sent: Monday, March 12, 2012 11:21 PM
To: Discussion of Ten-Tec Equipment
Subject: [TenTec] TT Amp Keying Interface
OK...two questions re: TT Amp Interface Box --
let's say I have an Omni VII and want to take that down to my friend's
"contest station" and use it with some older Alpha or other brand amp.
Would I want to get one of the Model 318 Amp Keying Interface boxes...
or just set the rig up for a transmit delay in the MENU settings.
I think there is an old Henry amp down there, also -- and
some Ten-Tec Titan amps, which I suspect work like my
Centurion, and the interface is not needed for those TT
Let's say I have a Kenwood TS-590s... same question as above.
Thanks for any insight, and groovy enlightenment, you can provide herein.
================== James -K8JHR ==================
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