[VHFcontesting] Any one use an FT-991A with a mast mounted pre amp?

[nosigma at aol.com]

Pat 

Thank you for the great description.  A simple variant of what you have done should suit my needs nicely.

73
John
KM4KMU



Sent from AOL Mobile Mail

On Sunday, November 19, 2017 Pat Patterson <ppattrsn at swbell.net> wrote:

Hi John,

I have a FT991A in my Rover.  I don't have preamps (except those built into "brick" power amps).  I use a headset with Yaesu mic connector adapter.  PTT on the front panel jack is broken out by the adapter...1/8" jack for Mic and 1/4" for PTT .  I use a foot switch to key a PTT relay that, through band select relays, keys band specific T/R switches and AMPs.  I have a small fixed delay from that relay to the PTT lead on the front panel of the FT991A. I have VOX and CW Break-in disabled.  I'm adding bands and preamps so there will be some form of sequencer in the future.


Best I can tell, the TX INH lead on the FT991A Linear/Tuner DIN jack will prevent any RF from being made by as long as it is held high (over 5V).  So, If you can provide >5V to TX INH until your Preamp is safely conditioned for transmitt that should eliminate the possibility of screwing up with VOX or Break-In on CW....overriding the front panel PTT lead.   Here a nice article by David, VK3HZ, that layouts out a sequencer for use with a Yaesu FT-817 and transverters/Amps.  http://www.vk3hz.net/sequencer/FT817_Sequencer.pdf .  I think all Yaesu rigs that have TX Inhibit leads work the same way.


Enjoyed visiting with you at the Pack Rats conference.  Good luck in the January Test.


73,

Pat, W5VY



From: John Young via VHFcontesting <vhfcontesting at contesting.com>
To: vhfcontesting at contesting.com 
Sent: Saturday, November 18, 2017 4:47 PM
Subject: [VHFcontesting] Any one use an FT-991A with a mast mounted pre amp?


I would like to add a 2M mast mounted pre amp to my station.  The FT-991A has a rear jack for tuner and RF power amplifier control.  The manual describes each pins purpose (ex: TX INH, TX GND, GND) but it gives no information on the function of each pin or more importantly timing information.  I would like to think that I can use these pins with a set of relays to prevent transmission until the pre amp is taken out of the RF transmit line.



I can not find anything on line after several google search sessions describing these pins, their affect on the transmitter  or showing how anyone else has used a mast mounted pre amp with the FT-991A (or the FT-991 for that matter).



Any advice on how to proceed would be appreciated.



73

John Young

KM4KMU

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