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[TenTec] RE : Re: Keying Amp with my new Omni VI+

To: tentec@contesting.com
Subject: [TenTec] RE : Re: Keying Amp with my new Omni VI+
From: "knesbitt@nucleus.com" <knesbitt@nucleus.com>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Mon, 6 Jun 2005 19:05:13 -0600
List-post: <mailto:tentec@contesting.com>
thanks for the idea. I do believe the hf2500dx has the qsk feature, 
&nbsp;however I will have to confirm this when I get back home. In any event it 
would appear that the linear relay on the&nbsp;OMNI is more than up to the task 
of switching this load in non-QSK mode which I'd be quite happy with in any 

Best regards!

Kirby,&nbsp; VE6IV

>------- Original Message -------
>From : Ken Brown[mailto:ken.d.brown@verizon.net]
>Sent : 6/4/2005 9:17:37 PM
>To : knesbitt@nucleus.com; tentec@contesting.com
>Cc : 
>Subject : RE : Re: [TenTec] Keying Amp with my new Omni VI+
>You may not even need to use the relay in the Omni VI to key the 
>amplifier. The TX OUT line on the Omni VI which is used with Ten Tec 
>amplifiers is connected to the open collector of Q11 (on the Control 
>Board) a MPS-6514. When connected to a Titan 425 amplifier there is 28 
>VDC from the 425 connected here. That transistor pulls this line low 
>with 10 k ohms to the +28 VDC supply. That works out to 2.8 mA if Q11 
>pulled it all the way to ground. This does not prove that the MPS-6514 
>can handle 80 mA, but it can certainly handle 28 VDC so 12 VDC should 
>not be a problem. I suggest looking up the specs on a MPS- 6514 ( check 
>out the fairchild spec sheet I found) to see if it can handle 80 mA. If 
>it can, then you need not activate the relay in the Omni VI, and you can 
>just use the open collector TX OUT line of the Omni to key the HF-2500.
>I found a spec sheet which says the maximum collector to emitter voltage 
>is is 25 Volts, which is kind of strange since the Titan 425 puts 28 
>volts on it. It also says the the maximum continuous collector current 
>is 200 mA. That indicates to me that you could safely switch 12 VDC at 
>80 mA directly with the open collector TX OUT of the Omni VI and not use 
>either an intermediate relay or even the Omni VI internal relay.
>If the QRO HF-2500DX is not QSK capable, and you need a "hang time" on 
>the keying, you will probably want to opt for relay control.
>Here is what I found on the MPS-6514:
>Have fun,
>> whether I will require an
>>intermediate keying relay between my "new" Omni VI+ and a QRO HF-2500DX amp.
>>Amp manual states that the t/r relay should be capable of switching 12v@
>>80 ma. The OMNI op's manual indicates its to be used to switch low
>>voltage DC only but does not provide a current rating.
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