[TenTec] Omni VI & SignaLink USB

[Bob McGraw - K4TAX]

Tigertronics i.e. SignaLink has transformers on the input and output signals 
for isolation.  My friend is and has been using the Omni VI and his hand 
mike with excellent audio.  He has had the SignaLink USB for some time and 
attempted to get it working earlier. He ordered the cable to connect to the 
radio at the same time he ordered the SignaLink.  He describes to  me that 
this cable terminates into the RJ-45 on one end and to RCA connectors on the 
other. And he describes that it is twisted pairs.   That sure doesn't sound 
correct to me.

I have used both the Omni VI and Paragon radios feeding audio into and out 
of the rear connectors and have kept the mike plugged in at the front very 
successfully.  In my case I was just running shielded cables between the 
computer soundcard and the radio. No interface, transformers or attenuators 
were used.  It worked quite well. VOX was used to handle the PTT function.

The use of optional mixers and such is not a viable solution in this case. I 
do understand what you have and how you handle the signals.

I'm sure if I were at his QTH I could solve the issue in a matter of 
minutes. However, he is a 5 hour drive each way.

Thanks for your thoughts on the issue.

73
Bob, K4TAX




----- Original Message ----- 
From: "Richard Gerardi" <qdot22 at gmail.com>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Thursday, July 10, 2014 8:29 AM
Subject: Re: [TenTec] Omni VI & SignaLink USB


> Hi bob,
>
> With my Omni VI, I bypass the front mic jack altogether and do everything
> from the back. I use a little Bucscomm Rascal for digital interface. I 
> have
> a balanced mic through a mixer. I noticed that my mic audio looked a 
> little
> "rougher" on the monitor scope when they were both connected in the back 
> at
> the same time. For the mixer output, I built an line level isolation with
> pad audio box using a 600:600 audio transformer and a pot. I think my
> Bucsomm has an isolation xfmr in it as well. With both connected into the
> Audio In RCA jack using a Y adapter in the back I get no interaction
> between the two at all now. Interested to see what Tigertronics uses for
> it's isolation.
>
> Rich
> AA6VX
> 18 more days until I get my Omni VII and counting down....
>
>
> On Thu, Jul 10, 2014 at 5:45 AM, Bob McGraw - K4TAX <RMcGraw at blomand.net>
> wrote:
>
>> I'm trying to assist a friend setting up his Omni VI with a SignaLink 
>> USB.
>>  He does have the cable supplied from SignaLink and it seems to be
>> connected to the radio correctly.  It receives and decodes PSK-31 very
>> satisfactorily and it keys the transmitter correctly.
>>
>> The difficulty is having both the SignaLink connected to the Audio IN on
>> the rear and the microphone connected to the front at the same time.  The
>> SignaLink appears to key the radio correctly but does not produce output.
>>  When he then later and on a different frequency tries to transmit SSB 
>> only
>> white noise is heard.  If he unplugs the cable to/from the SignaLink the
>> noise is not heard. This occurs when the SignaLink is off or on.
>>
>> It appears from the schematic the mike input on the front and the rear
>> Audio In are each isolated by a 10K series resistor to a summing point at
>> the mike amp input.  Using a low impedance {500 ohm} dynamic mike and the
>> SignaLink output being some 600 ohms, I calculate the isolation between 
>> the
>> two inputs would be some 35 dB or so. Certainly this would seem to be 
>> very
>> adequate isolation such that having the two connected, although the
>> SignaLink is off, it would not interfere with the use of the mike.  And
>> with the SignaLink on it would produce audio and it would not be 
>> interfered
>> with the connected mike.
>>
>> Anyone have any specific experience or thoughts on this configuration?
>>
>> 73
>> Bob, K4TAX
>> _______________________________________________
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>> TenTec at contesting.com
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>>
>
>
>
> -- 
> Richard Gerardi
> North Santa Barbara County ARES
> Satellite Amateur Radio Club, W6AB
> aa6vx at arrl.net
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