Custom Products for the Digital Radio Amateur Enthusiast

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Background:
Inability of the DRA-Series radio adpaters to key the ICOM IC-706MKIIG.

A few people who own a DRA-70 advised that their set-up worked fine with VARA FM, but their issue with the IC-706MKIIG is that other applications like FLDIGI under VOX operation didn't actually key the radio. One person claimed that when they shorted the keying line on the DRA-70 to ground the radio would successfully go into transmit no matter the mode (HF or VHF). Thinking this was an issue with the solid-state keying of the DRA Series (in all instances a 2N2222 or with VOX a MPSA-13 NPN transistor) I built a board that converted the keying line(s) of the DRA-70 to a reed relay. The apparatus you see connected to the DRA-70 is just that. While kludgy, my hope was to see if this modification affected the operation in a positive way.

I've additionally seen some references that might suggest HF keying on the IC-706 needs to be done on the accessory connector. This would require the wiring to be split so the PTT lead can connect to the proper pin on the accessory jack.

Installation:
This device is intended to be installed directly plugged into a DRA-70. A small wire is routed between the two cases to provide 5V power for the relay. The wire is routed beside the Mini-DIN-6 connector - NOT on top of it. Pull the original jumper (short) off of JU2 (the Yellow header). Install the blue jumper with the red wire in the "A" position. You can hang the original shorting bar off of the "B" pin and into mid air for storage.

Recommended powering requirements:
The adapter board is supplied with 5 VDC from inside the DRA-70's case.
After disconnecting the PTT adapter, remember to reinstall the jumper/short in the "A" position on JU2 (yellow header) or the DRA will not produce any TX audio.

The following videos might be helpful:
While the radio in these videos is not a IC-706, and the application used in the first video is SoundModem, and the radio adapter is a DRA-36, the situation still applies to the IC-706.

NS7C Video 1 - Audio Level Issue IC-7000

NS7C Video 2 - VARA HF Keying

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Product of Masters Communications, all rights reserved.
Specifications may change without notice.
Images property of Kevin Custer - W3KKC
Videos property of Scott Currie NS7C - used, hosted and included with permission.
Board layout by Kevin Custer - W3KKC.
HTML April 5, 2021, W3KKC All Rights Reserved!