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

[Jim Thomson]

##  Some of the kenwood  xcvrs have no provision for a PO control.
Some of these amps  require very little drive power.  But a 3-6 db pad on 
the
input side of the amps tr relay would help a lot.   So the pad is not in the 
RX path.
Dunno if the SGC  SS amp has overload circuitry in there, so if its 
overdriven, it kicks
itself offline?

##  On my  yaesu FT-1000 MK-V, 200 watt version, there is 3 x power options 
in the menu.
10w, 75w, 200w.  In the alignment manual, there are 3 x pots  to tweak for 
those  3 x po levels.
And each pot can be tweaked from 0-200w.   So if the amp required say 100w 
to drive it,
the 75w setting can be used..and tweaked for 100w.   Problem solved.

##  Another possible option is he could, if possible, adjust the internal po 
control on his kenwood,
and turn it way down.   Ur right though, this is not rocket science, and all 
sorts of options could be used.

Jim   VE7RF





-----Original Message----- 
From: Jim W7RY
Sent: Thursday, January 28, 2016 5:32 PM
To: Jim Thomson ; amps at contesting.com
Subject: Re: [Amps] SG-500 ALC Interface to Kenwood TS-480HX

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 at 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 at gmail.com>
To: amps <amps at 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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