[ICOM] IC-746PRO with Ameritron Amps

[Larry Winslow]

I'm not exactly sure what you're seeking but if you're looking for a means 
of switching the amp fast for modes such as Pactor, you might want to look 
into the QSK-5 by MFJ (or is it Ameritron).

Back when I was active on Amtor & Pactor, I was keying my SB-220 via the 
QSK-5 with my IC-765. I worked great for those modes plus full break-in CW. 
It isn't cheap but it works - although you might want to add the suggested 
fan for high power operation, I used a surplus computer fan.

73 - Larry WØNFU
larry_w at comcast.net


At 08:27 PM 1/23/2005, you wrote:

>I have the same "Sometimes" delay with my 746Pro. did the same with my
>Kenwood TL922A amp and now with my AL811H amp. It was a lot worse with the
>TL922A than with the AL811H. The relay in the AL811H is a lot faster than
>the TL922A amp was. Maybe someone can come up with a solution.
>
>73
>Van
>WD6FGB
>
>----- Original Message -----
>From: "Alan Zack" <k7acz at cox.net>
>To: "IC746 Group" <IC746 at yahoogroups.com>; "IC746/7400 Group"
><ic746_7400 at yahoogroups.com>; "Icom List" <icom at mailman.qth.net>
>Cc: <mfjcustserv at mfjenterprises.com>; <ameritron_equipment at yahoogroups.com>;
><n4dek at triad.rr.com>; <fsense at copper.net>; <ameritron at ameritron.com>
>Sent: Sunday, January 23, 2005 7:16 PM
>Subject: [ICOM] IC-746PRO with Ameritron Amps
>
>
>Several of us with Ameritron Amps have been experiencing keyup
>problems when using IC-746PRO's.
>I tried searching the archives on the 3 IC-746 related lists but could
>   not find any info on this problem.
>
>Here is the situation:
>IC-746 and Ameritron Amp combo works fine on AM, FM, CW, and RTTY.
>On SSB there is SOMETIMES, not always, a slight delay to see power out
>when keying.  For example, my call is K7ACZ.  I can push the PTT on my
>mic, say K7ACZ but only the ACZ gets transmitted.  The amp relay
>clicks in fine with the PTT being pressed but does not show power out
>until after a slight delay.
>Looking at the IC-746's meter when this happens I observe the Po not
>showing power out on my first word or so, the SWR is at minimum and
>the ALC goes full scale, past the normal range.  After a short delay
>everything is normal.
>Operating conditions:
>1.  Does this regardless if the ALC line is connected between the 746
>and amp or not.
>2.  Does it at all power levels of the 746.  Have tried from 10 watts
>to 100 watts, no difference.
>3.  Does it on all bands.
>4.  Does it regardless if the 746PRO auto tune is on or off.
>5.  Hitting the 746PRO TUNER button (to force the 746 to tune to the
>amp's input circuits) does not help.
>6.  Tried doing a steady AHHHHHHHHHHHHHHHHHHHHHH into a dummy load,
>hitting the PTT on and off, and watching sometimes full power as soon
>as the PTT is pressed and other times a slight delay.  Each time there
>is a delay the 746PRO meter shows no Po and max ALC for a second.
>7.  As expected, VOX cannot be used as each time VOX drops out and
>then kicks back on you may or may not be putting power out.
>
>Have tried different coaxes, went direct into a dummy load, different
>antennas, no change.
>
>Keying circuit is a direct connection from 746PRO's SEND jack to Amp's
>RELAY jack, no buffers or extra keying circuits.  Ameritron says their
>amps will not damage the 746PRO's keying circuits by using a back
>pulse canceling diode in the AL-80B I have.
>
>Has anyone else experienced this?  On the Ameritron Amp reflector it
>seems only a few of us see this, and only with the 746PRO.
>
>I have just purchased this amp Friday from AES and am ready to return
>it if I can't figure out this keyup problem.  I am a contester and
>want to use my VOX, which I can't do with this amp.
>
>TIA & 73
>--
>__________________________________________________________________________
>
>Alan Zack
>Amateur Radio Station K7ACZ
>Las Vegas, Nevada, USA
>Quality Engineer, The Boeing Company, Retired
>Aviation Chief Warrant Officer, U.S. Coast Guard, Retired
>U.S. Coast Guard, Always Ready, Always There
>Every hour, Every day, Around the Clock and Around the World
>SEMPER PARATUS
>http://www.gocoastguard.com
>http://www.uscg.mil/d14/units/asbp/uscgasbp/
>DEPARTMENT OF HOMELAND SECURITY
>
>----
>Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
>Win a new Icom IC-756 PRO III and help QSL/QTH.net
>Details at: http://mailman.qth.net/
>
>----
>Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
>Win a new Icom IC-756 PRO III and help QSL/QTH.net
>Details at: http://mailman.qth.net/