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Re: [TenTec] Eagle & Heath SB-200 Amp

To: prosolar@sssnet.com, tentec@contesting.com
Subject: Re: [TenTec] Eagle & Heath SB-200 Amp
From: Ron Notarius W3WN via TenTec <tentec@contesting.com>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Tue, 25 Feb 2020 19:18:33 +0000 (UTC)
List-post: <mailto:tentec@contesting.com>
Thanks for the correction Mike... like I said, it's been a while...

But the key point remains that the Eagle keying circuit was not designed for 
that level of voltage.

73


-----Original Message-----
From: Mike Bryce <prosolar@sssnet.com>
To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Cc: Ron Notarius W3WN <wn3vaw@verizon.net>; richardmccay 
<richardmccay@icloud.com>
Sent: Tue, Feb 25, 2020 2:15 pm
Subject: Re: [TenTec] Eagle & Heath SB-200 Amp

gang,
the SB-200’s key line sits about MINUS 130 ish volts DC.
Mike, WB8VGE
SunLight Energy Systems
The Heathkit Shop
http://www.theheathkitshop.com/
J e e p
o|||||||o 

A man with one clock knows what time it is. A man with two clocks is never sure.

On Feb 25, 2020, at 2:12 PM, Ron Notarius W3WN via TenTec 
<tentec@contesting.com> wrote:
Rich,

I'm just getting a chance to view my email now, so I apologize if some of what 
I have to say seems redundant.

The simple answer is, NO, this is NOT OK.  

A couple of quick answers off the top of my head...

1.  Amplifier:
Keep in mind that the SB-200, which is a great amp (I used to own one), was 
designed back in the days when every commercial transceiver had tube outputs, 
at appropriate voltages.  If memory serves, the keying line was either 90 or 
100 V -- which the Eagle will NOT be able to handle (without modification), 
which means you likely WOULD cause damage to the rig.

When I owned that amp, I had a Kenwood TS-140S.  I rigged up an external relay 
-- the rig tripped the relay, the relay tripped the amp -- as a buffer.  At the 
VERY least, you'll need to do the same.  There are also some commercial 
interface solutions for the same purpose.  I'm SURE MFJ has one (don't they 
always seem to have one of everything?) but check around.  There are a few 
small companies that make excellent interfaces at very reasonable prices.

2.  Antenna tuner... and SWR meter if it's external

Make sure that the tuner can handle 600 W or more output power.  The smaller 
tuners (rated 100 - 200 W) will arc or burn up with the output power of the 
amp.  Same for an external SWR bridge.  And... if your coax to the antenna is 
RG-58 or RG-8X, you may run some risks there too, in terms of power rating.  
I'm not sure about RG-58; I have run 600 W through RG-8X for short runs, but it 
gets warm (I believe 600 W or so is the maximum rating), and it is NOT 
recommended.  RG-8 / RG-213 or equivalent should be used.  You want your power 
to go to the antenna, NOT to heat the coax!

3.  Antenna

What antenna?  Same thing as above... is it rated for 600 W?  Most commercial 
verticals are, but if it's a wire antenna... better check.  

Also, you didn't mention this, but... you do have a dummy load for tuning the 
amp?  If not, you will need one.  

I hope this doesn't come across as negative.  That's a great amp, and it's a 
big step up in terms of power output.  I had a lot of fun with mine, back in 
the day.  Just make sure you don't accidentally blow up the rig, or portion 
thereof... or cause yourself other headaches down the road.  

And don't let this discourage you.  You might have to do a few upgrades in the 
shack, but it will be worth it!  

(Now if I can just get a 220 V line into the shack...)

73, ron w3wn

-----Original Message-----
From: Richard Wagner via TenTec <tentec@contesting.com>
To: tentec <tentec@contesting.com>
Cc: Richard Wagner <richardmccay@icloud.com>
Sent: Tue, Feb 25, 2020 9:14 am
Subject: [TenTec] Eagle & Heath SB-200 Amp

I’ve never dealt with an Amplifier before. A friend gave me a Heath SB-200. It 
appears I have to make a connection between the AMP KEY terminal of the ACC-1 
accessory connector and the AMP KEY Socket of the amp. A plug for the socket 
and short jumper wire were included with my Eagle. This appears to be all that 
is needed. I’ll connect from the Eagle to the Amp then through my Antenna Tuner 
to the Antenna. Does this seem OK?

Rich Wagner
K4MZE
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