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Re: [Amps] SG-500 ALC Interface to Kenwood TS-480HX

To: "Jim Thomson" <jim.thom@telus.net>, <amps@contesting.com>
Subject: Re: [Amps] SG-500 ALC Interface to Kenwood TS-480HX
From: "Jim W7RY" <w7ry@centurytel.net>
Reply-to: Jim W7RY <w7ry@centurytel.net>
Date: Thu, 28 Jan 2016 17:32:53 -0800
List-post: <amps@contesting.com">mailto:amps@contesting.com>
Why not just adjust the power output control on the front of the radio? Or does the radio have ALC overshoot.. I don’t the the TS-480 has this problem...

This isn't rocket surgery!

73
Jim W7RY


-----Original Message----- From: Jim Thomson
Sent: Wednesday, January 27, 2016 5:39 PM
To: amps@contesting.com
Subject: [Amps] SG-500 ALC Interface to Kenwood TS-480HX

Date: Mon, 25 Jan 2016 18:19:13 -0500
From: Ron Youvan <ka4inm@gmail.com>
To: amps <amps@contesting.com>
Subject: Re: [Amps] SG-500 ALC Interface to Kenwood TS-480HX

   Larry Dighera wrote:

Given the SG-500's ALC control signal is +1 to +5 VDC, and the Kenwood
TS-480HX's ALC signal expects -7VDC, how have others interfaced these two
pieces of equipment?

  I don't know, but a 9 Volt battery might do it.

--
  Ron  KA4INM - Youvan's corollary:
                Every action results in unwanted side effects.


## A 9 vdc battery fed across the far ends of a 50k pot. Then take the output, between wiper and positive end of pot. Then you can vary the output of the mess from 0-9 vdc, and its all negative Vdc..then feed that negative 0-9 vdc into your TS- 480 HX ALC jack.
Then NO alc connection from xcvr to amp.

## Then you can set the PO of the TS-480HX.....if it has an adjustable PO to what ever the amp requires. Then dial up the pot till po of the amp just drops a tiny bit. At that point, you can scream all you want..and never over drive the AMP. You can also turn the PO on the xcvr to max, and tweak the pot for desired drive into the amp. Same deal, scream all u want, and u cant overdrive the amp.

## this 2nd scenario works better, since there is no time lag in developing ALC voltage in the xcvr. You have already developed it via the 9 vdc battery and pot. The only drawback to using the 9 vdc battery + pot is..... if you whisper into mic you will have reduced po from the xcvr. In normal operation it works superb.

## an alternate method that may well work is to use a SS DC to DC converter. Then you could feed the +1 to +5 vdc from the amp.... into the input of the DC to DC converter, the output side will be either 0-5 vdc positive..OR 0-5 vdc negative. The dc to dc converter isolates the input to the output side. In your case, the output side will have its positive
bonded to chassis of xcvr, with negative going to alc jack of xcvr.


Jim   VE7RF
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