[TenTec] Any issues with Corsair II --> SB-200 amp?

Sat Dec 18 03:14:10 EST 2004

Mike thanks for the tip on the "adjustable dropout".  This is the same thing
that I called "QSK-Delay" (which it is now called in the ORION).  

In my previous post I said to add this extra delay assuming you would need
to build or buy something - well I had forgotten that the Corsair provisions
this itself.  (It's been about 15 years since I've used a Corsair).  

I fully agree with Mike.  I built my own interface box to provide the
TX-Delay and the QSK-Delay about 25 years ago (long before I had a Corsair)
and after I began using it, I did not burn relays anymore either.

So now I'll revise my advice on running the Corsair II with the SB-200:

AGAIN, IT IS PERFECTLY ACCEPTABLE TO KEY THE SB-200 DIRECTLY WITH THE
CORSAIR, USING THE CORSAIR'S BUILT-IN EXTERNAL T/R KEYING RELAY!

(Please heed my warning about QSK-Delay in my previous posts AND USE THE
CORSAIR'S RELAY DROPOUT DELAY TO DO THIS.)

(Thanks Mike).

73
Rick

-----Original Message-----
From: tentec-bounces at contesting.com [mailto:tentec-bounces at contesting.com]
On Behalf Of Mike Hyder -N4NT-
Sent: Friday, December 17, 2004 7:03 PM
To: tentec at contesting.com
Subject: Re: [TenTec] Any issues with Corsair II --> SB-200 amp?

Harbach made a "soft key" circuit for my SB-220 (yes I know we're discussing

the SB-200) that reduced the voltage / current needing to be switched to 
almost nothing.

I've used that SB-220 for about 25 years on CW with a Ten-Tec rig for the 
last 20.  I set the amp relay in the rig for the longest drop out.  When I 
key the rig, the amplifier keys and to me it works better than a full QSK 
amplifier.  The antenna relay in the amplifier passes enough signal to the 
receiver that I can hear the other station between my sending, but it does 
attenuate the received signal somewhat.  This makes for a lower background 
noise while transmitting and is just great.  In addition there is no clatter

of a relay following the actual sending.

About "hot switching" of the amplifier's relay contacts...  In 25 years of 
use, I have seen no deterioration in the relay contacts.

73, Mike N4NT

----- Original Message ----- 
From: "NJ0IP" <Rick at DJ0IP.de>
To: <tentec at contesting.com>
Sent: Friday, December 17, 2004 8:19 PM
Subject: RE: [TenTec] Any issues with Corsair II --> SB-200 amp?

The SB-200 does indeed have tuned inputs (only for 80/40/20/15/10 meter
bands) and will work just fine with the Corsair II (from an RF standpoint)
on these 5 bands.  The SB-200's T/R relay keys with -130v @0.051A., so that
prohibits keying it with an open collector circuit.  I can't remember if the
Corsair II also had a relay for keying external amps.  I think it does.  If
it does, then enable it and it will key the -120v just fine.

I'm sure someone here can tell us if the Corsair II has a keying relay for
the amp.  It will also be described in the user's manual if its in the rig.

If the Corsair does not have a relay for keying the external Amp, you can
obtain a "Soft Key" kit from Rich Measures  (http://www.somis.org/) - I
think it only costs a couple of dollars.  You have to make a slight
modification to the SB-200's relay to enable it to key with +130v instead of
- 130v, but that's very simple to do.  After installing this simple kit, you
can key the amp with open collector circuitry.

If you run a lot of CW, one problem you will probably run into over time is
arcing and possible burning of relay contacts on the SB-200's T/R relay.
This will happen regardless of whether you are keying with the softkey or
with the Corsair's relay (assuming it has one).

The combination switches to TR to transmit fast enough because the Corsair
adds enough delay to allow for this.  The problem is, you really need to add
some delay before the Amp's T/R relay switches back to RX.  Otherwise you
will often incur the state where the relay has begun switching back to RX
when the TX signal comes again.  It is unable to change directions fast
enough to settle in the TX position before RF is applied, and it arcs.  Not
bad the first 20 or 50 times it happens, but eventually it burns the relay
contacts enough that you incur errors.  This is typically a failure of the
relay to switch the antenna back to the transceiver in RX mode.  Easy to
recognize because you don't hear anything (or else it is very weak). In this
case, you have to clean the relay contacts with a burnishing tool.  This is
easy to do, but requires pulling the cabinet off of the amp.  How often this
is required will depend on your amount of use of the amp.  I found I was
cleaning mine every 2 or 3 months.  I finally built my own device to allow
me to adjust the relay delay and was able to eliminate this problem.  By the
way, my device also keys the -130v so you don't need the softkey.

Rich also sells a kit for replacing the open-frame relay with a vacuum
relay, but that costs a bit more. Once you have installed this mod, you can
run full QSK with the SB-200 and the Corsair II.

I also have to ask what you mean by "interface".

There are probably all kinds of boxes available on the market which I am
unaware of.

Gud luk and have fun with it.

73

Rick

-----Original Message-----
From: tentec-bounces at contesting.com [mailto:tentec-bounces at contesting.com]
On Behalf Of Paul - W8KC
Sent: Thursday, December 16, 2004 4:47 PM
To: tentec at contesting.com
Subject: RE: [TenTec] Any issues with Corsair II --> SB-200 amp?

What do you mean by interface?  Do you mean an antenna tuner?  Because

that's what I *think* you need to use those two together.

I don't believe the SB-200 has a tuned input which will be trouble for a rig

without a tunable output :-)

But I could be wrong, I'm a QRP kinda guy.

73! =paul= W8KC

Collector of Ten*Tecs and other fine plastics.

Visit the Virtual Ten*Tec Museum at http://mywebpages.comcast.net/w8kc

Listen to 7.040 MHz from anywhere with Media Player v9

http://www.w8kc.com/stream.asx

-----Original Message-----

From: tentec-bounces at contesting.com [mailto:tentec-bounces at contesting.com]

On Behalf Of john.brewer at us.schneider-electric.com

Sent: Thursday, December 16, 2004 12:55 PM

To: tentec at contesting.com

Subject: [TenTec] Any issues with Corsair II --> SB-200 amp?

I want to give this a try over Christmas. I do have an interface to place in

line between

amp and rig. Most operation will be CW.

I've got the manuals for both, just wondering if there were any specific

gotchas

I should be aware of.

Thank you and Merry Christmas!

John K5MO

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