[ICOM] AMP INTERFACE TO 756 PRO II (CONTINUED)

[Dan Coleman W8KMX]

Thanks Adam.  Good info.
73,
Dan


----- Original Message ----- 
From: "Adam Farson" <farson at shaw.ca>
To: "'ICOM Reflector'" <icom at mailman.qth.net>
Sent: Friday, June 17, 2005 2:33 PM
Subject: RE: [ICOM] AMP INTERFACE TO 756 PRO II (CONTINUED)


> Hi Dan,
>
> According to the OMR-109 relay data sheet, the operate and release times 
> are
> 1.0 and 0.5 mS respectively. Using a reed relay as an auxiliary relay, one
> would double the time between transmitter keying and closure of the
> amplifier's PTT line to approx. 2 mS. By using a solid-state keying 
> buffer,
> one could largely eliminate the additional keying delay.
>
> The exciter probably applies RF a few mS after extending a ground on the
> SEND line. One could shorten this interval by using the ACC(2) Pin 3 SEND
> line to turn on a solid-state buffer, which would in turn ground the amp's
> PTT line.
>
> http://www.qsl.net/icom/auxrelay.html
>
> In any event, the output reflectometer in the exciter will sense the brief
> open RF interval and turn down the drive to protect its PA. One should not
> count on this exclusively, though - hence it is best to shorten  as much 
> as
> possible the interval between transmitter keying and amplifier PTT 
> closure.
>
> Cheers for now, 73,
> Adam VA7OJ/AB4OJ
>
>
> -----Original Message-----
> From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] 
> On
> Behalf Of Dan Coleman W8KMX
> Sent: 17 June 2005 11:19
> To: icom at mailman.qth.net
> Subject: [ICOM] AMP INTERFACE TO 756 PRO II (CONTINUED)
>
> I big thanks to all that answered my broadcast message.  I posted my 
> inquiry
> and then left town for a few days so sorry that I did not answer promptly.
>
> As to interfacing the Ameritron ALS-600 to the ICOM 756 Pro II the 
> consensus
> is:
>    1) Although it will "likely" be OK, it would be best to use an outboard
> relay that can be driven easily by the Pro II ("cheap insurance").
>    2) Although some have had good results without ever hooking up the ALC,
> again it is best to use it.
>
> One thing that was not mentioned by anyone is the time delay required to
> pull in the slave or ALS-600 relay for that matter, thereby causing the 
> Pro
> II to transmit into an open load for a short time period.  I have seen 
> some
> comments in the past as to the need for a delay to make sure the Pro II is
> fully connected to the AMP before your first word (using VOX) produces RF
> output.  One person (in a previous conversation) said he did not use VOX 
> for
> that reason and, he made sure the PTT was depressed an instant before he
> spoke etc.
>
> Any comments on this?
>
> 73,
> Dan
>
> p.s. Yes I would like to talk with K5CWO and since you have unlimited
> calling, you can call me at (864) 638-3001 (I don't have unlimited 
> calling).
>
> DGC
>
>
> Scanned by WinProxy
> http://www.Ositis.com/
> ----
> Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/