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Re: [VHFcontesting] Setting up TE RF amp for use with a sequencer.

To: jim.k0mhc@earthlink.net, kc2tn@comcast.net
Subject: Re: [VHFcontesting] Setting up TE RF amp for use with a sequencer.
From: John Young via VHFcontesting <vhfcontesting@contesting.com>
Reply-to: nosigma@aol.com
Date: Mon, 16 Dec 2019 12:04:14 +0000 (UTC)
List-post: <mailto:vhfcontesting@contesting.com>
James
Thank you for pointing out protection of the internal pre amp.  I had not 
thought of that.  For my set up I have not found the internal pre amp to be 
helpful so perhaps I should disable it so I cant accidentally turn it on.  
There are instructions for doing this in the TE manual.  Of course I could just 
tape the switch in the down position.

73
John
KM4KMU 
On Sunday, December 15, 2019 James Froemke <jim.k0mhc@earthlink.net> wrote:
Don’t blow up the internal pre-amp accidentally.  The RF sense protects against 
losing the hardwired PTT. 

> On Dec 15, 2019, at 8:49 PM, KC2TN <kc2tn@comcast.net> wrote:
> 
> I’d be interested in what they tell you regarding the pin 5-6 jumper. 
> 
> I’m looking to disable this as well. 
> 
> Joe - KC2TN 
> 
>> On Dec 15, 2019, at 6:30 PM, John Young via VHFcontesting 
>> <vhfcontesting@contesting.com> wrote:
>> 
>> 
>> Taking pin 2 to ground turns on the PA with 5 and 6 still internally 
>> connected.  
>> 
>> However with 5 and 6 internally connected the rf sensing is still enabled 
>> which defeats part of the purpose of the sequencer.  The amplifier can turn 
>> on if RF gets to it even if the PTT ground to rf amp lead from the sequencer 
>> is not grounded.  
>> 
>> I have had my 991A on 6m buzz my 1.25m amp, same thing happened with the 
>> W4IY Elecraft on 6m in september.  If I had been using a hard keyed pre amp 
>> on 1.25m it would have been fried.
>> 
>> I opened up the amp and there is no obvious sign of the pin 5-6 internal 
>> shorting wire.  Maybe you have to cut a trace now?
>> 
>> 
>> Calling TE Tomorrow.
>> 
>> 73
>> John
>> KM4KMU 
>> On Sunday, December 15, 2019 John Young via VHFcontesting <nosigma@aol.com> 
>> wrote:
>> 
>> The TE manual gives some simple instruction for hard keying the amplifier 
>> but out an abundance of caution I want to verify my understanding of them 
>> before I start cutting wires and adding relays.
>> 
>> The DEMI sequencer gives a sequenced PTT ground to enable the amplifier.  
>> The TE  instructions are to cut the internal  shorting wire between pins 5 & 
>> 6 and then connect the PTT ground to pin 2.
>> 
>> To enable the RF amplifier the TE instructions are:  1) Connect pin 5 & 6 
>> then 2) connect pin 2 to PTT ground.
>> 
>> My interpretation of these instruction are:
>> I need to use the PTT ground to close a relay that connects pins 5 & 6 and 
>> then use an output from this relay to close another relay that connects the 
>> PTT ground to pin 2 on the amplifier.
>> 
>> Is this correct?
>> Is there a better way?
>> 
>> 73
>> John
>> KM4KMU 
>> 
>> 
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