[VHFcontesting] IC-910H and Mirage Amp keying

[Rogers, Ron]

The "Send" signal from the output of the ACC jack (Pin 3) on the rear of the IC-910H (or any of the Icoms) is actually the internal PTT bus logic signal. It goes "low" anytime the radio is in transmit mode. If pulled "low" externally, it will put the radio into Transmit mode.

It is not recommended that the signal be used to key an external amplifier directly for a couple of reasons I won't go into detail on here. 

However, you CAN use that signal to drive a small 12 volt relay (Omron, Radio Shack, etc.) between pin 3 ("Send") and pin 7 (13.5 volts. Make sure the relay used requires no more than 20 ma of current to drive.  Be sure to also properly install a "snubbing" diode, such as a 1N4007, across the relay coil to prevent inductive kickback from the relay coil back into the IC-910H logic circuits. 

The relay's contacts can then drive your Mirage amp's relay line to ground. 

For years I have used multiple amplifier keying interfaces such as this with all of my Icom radios used in contesting.     


Ron 
WW8RR


-----Original Message-----
From: vhfcontesting-bounces at contesting.com [mailto:vhfcontesting-bounces at contesting.com] On Behalf Of Jon Casamajor
Sent: Monday, June 15, 2009 4:31 PM
To: vhfcontesting at contesting.com
Subject: [VHFcontesting] IC-910H and Mirage Amp keying

Had a great time this past weekend in the June contest! I put a new Mirage brick on for a little more 2m power. I about went nuts listening to the relay chatter so I want to hard key it but I'm not sure which pins to solder up a cable to.  The pin out for the accessory 8 pin show pin 2 as GRND and pin 3 as SEND. Do I go from 3 to the center pin and 2 to the shield of the RCA?  The IC-910 manual says zip about keying an external amp and the Mirage amp only says you need to pull the RELAY line low. (GRND)

I bought the B 2518 G Mirage amp from AES btw. The first two were DOA so I called Mirage who sent me a new one, 2nd day air and a return label to send the second one back directly to Mirage.  If you ever need a contact at MFJ who cares and will take care of you, ask for Bob Ellis who is the service lead. He has helped me out twice recently. He has been there forever.

Thanks in advance for any help with the keying.

 

Regards,

Jon-K6EL

k6el at comcast.net

 

_______________________________________________
VHFcontesting mailing list
VHFcontesting at contesting.com
http://lists.contesting.com/mailman/listinfo/vhfcontesting