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Author Topic: SB-200 and Kenwood 570SG  (Read 857 times)
WD4OHD
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Posts: 8




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« on: August 03, 2004, 08:49:10 PM »

I have a Heath SB-200 that I would like to run from a Kenwood 570SG. Can someone who is using this combination of components give me a quick rundown on what I'll need to connect the two properly? (cables, proper interconnections, etc.) Many thanks.
Bob WD4OHD
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K6AER
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Posts: 3500




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« Reply #1 on: August 10, 2004, 06:04:32 PM »

The keying circuit in the SB-200 is a 125 volt bias with a series T/R relay that when grounded put the amplifier from standby to transmit. The Kenwood TS-570D has a comparable keying circuit in their design to be backward compatible with their old TL-922 linear that uses the same keying method. Having said that, it is always safer to add a small 12 volt relay to the keying circuit as a buffer. The main connections are RF in from the transceiver, Key line and ALC. You might have to add a series 5K pot to reduce the ALC out5put from the SB-200. The SB-200 ALC output was a bit aggressive for today’s solid state transceivers.
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WD4OHD
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Posts: 8




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« Reply #2 on: August 13, 2004, 10:27:35 PM »

Thanks for the interconnect info. I have decided to make some mods on this amp and operate it through a keying interface, probably the one Ameritron makes. Been looking at the SB200 manual for interconnect info and just wanted to double-check my conclusions with someone experienced in what I'm trying to do. Many thanks. Bob WD4OHD
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W9GB
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Posts: 2616




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« Reply #3 on: August 25, 2004, 11:22:40 AM »

Bob -

A couple of suggestions for your SB-200.  Now is the time to clean and "refresh" your SB-200 (e.g. tubes, needed changes (didoe protection of multi-meter, etc.)

I highly recommend that you look at Bob Norgaard's highly regarded SB-200 Rebuild Notes (with photos of updates and protection additions).
http://home.gci.net/~rnorgard/ampnotes.html

He covers about very possible update or change that should be considered.  He did have a "kit of parts" avaialble for SB-200 owners - at one time.

The steps that I would definitely recommend are:
Diode Protection for R12 (meter)
New Value for C10 (.0025 uF, 10 kV) - better 80 meter operation
Extra Meter Lamp Bypassing (2 - .02 uF disk capacitors)
Filament voltage measurement to 572-B tubes (to prevent early failure of tubes)
http://home.gci.net/~rnorgard/images/SB200-11.jpg
HV Filter Capacitors changout

Harbach Electronics (catching up on summer orders)
http://www.harbachelectronics.com/

Rick Measures' web site
http://www.somis.org/

w9gb
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