Wallace Watson wrote:
All,
I used Dale, N0XAS's, Univeral Keying Adapter for my Amp keying scheme.
This little board uses an optically isolated,MOSFET solid-state relay part
# G2-1A03 as the interface to the amplifier with the following specs;
1) Keys solid state, grid block or cathode keyed amplifiers or transmitters
up to 400V AC or DC
2) Optical isolation between rig and key input
3) Self contained and low voltage power requirement
4) Compact size ideal for integration into other equipment
For our proposed use, the only other component required, besides the
optically isolated MOSFET chip, is a current limiting resistor in the range
of 270 - 500 ohms for use with the 5V DC power source available from the
SDR radio's X-2 connector pin 14. The optically isolated MOSFET chips
input is driven directly from X-2 pin 7.
If we wished, we could include on the Poor Man's Universal controller board
(PMUCB) a group of these same optically isolated MOSFET chips for
protecting X-2 control lines, pins 1-6. If the isolators are not required
we could have pads or headers to bypass the optically isolated MOSFET chips
and terminate at a 6 or 10 pin Berg connector as suggested by Eric2.
It would be my desire to utilize 1/8" phone jacks mounted on the PMUCB for
a foot switch or hand switch for keying the SDR via X-2 pin10 PTT input.
I would like to thank Eric2 for making this proposal on the email
reflector. We had discussed this subject prior to the Belize DXpedition
trip on Teamspeak, and unfortunately he suffered an SDR radio component
failure as a result of trying to connect a relay in an amplifier directly
into the radio on x2-7 without any buffering.
I believe now is the time for this supplemental SDR radio interface
kit. We are all pleased with the Delta-44 breakout box replacement that
Tony designed and had circuit boards manufactured for. And for which Eric2
purchased all of the components and dry assembled the entire kit to make
available to all of us SDR-1000 radio owners. I don't know if it was ever
verbalized by the SDR Radio owners community but I wish to thank Eric2 and
Tony for a job extremely well done!
Thanks, Wally - M0ZAZ.
At 05:55 AM 11/20/2005 -0500, you wrote:
I have this problem in real-time. I am, right now, trying to work out
the details of keying a Harris Miltary Surplus Amplfier.
It is a very interesting device, having apparently been used all over
the government (military, especially) over the last 20 or 30 years.
Not least of the problems is figuring out how to safely hook up a rig
like the SDR 1000 to it.
I'm going to have to do what I'm least good at -- a little homebrewing
-- at the moment it would be most dangerous to our favorite transmitter.
And, of course, I'd like to get it done before CQ WW this next weekend,
so I don't have forever, at least not if I want the amp for the contest.
The more obvious schemes, using readily available parts, would involve
using twelve volts to trigger 110v AC relays. At least, the T/R HF
switch I currently have is triggered off of 110, but obviously, I don't
want to switch that directly.
The most readily available scheme would be a 12v triggered AC relay
which would then be hooked to the T/R antenna switch, itself switched
off of 110v. But, ultimately, if I want to trigger this from the SDR
itself, I'm going to need optical isolation or open collectors or
something so I can translate the available voltages off the back of the
SDR to the 12v that my current scheme, at least, will need. Maybe there
are 5v triggered relays out there, but this is what I have for now.
I'm going to get a hand from Terry, W0VB, who really understands this
stuff 100 fold better than I do. But, at least at the present, this is
what I'm expecting to do. A supplemental SDR interface board that made
it easy to do these sorts of things, especially if it protected the rig
against most errors and stupidity, would be a real boon to me, right
now, today.
Larry WO0Z
