[TenTec] RFI and Behringer MX-602a

[tlogan7 at cox.net]

Bob -
I think I mislead you. My external speaker is connected to the HEADphones
jack - thus it does not need an amplifier and gives excellent volume and
ability to control via the mixer. The Omni's external speaker jack is fed to
a channel input. It works very well except that transmitting cw is
unacceptably distorted. I have not tried Tx with SSB. Hope that sounds more
logical!
73/Tim
----- Original Message -----
From: "Robert & Linda McGraw K4TAX" <RMcGraw at blomand.net>
To: <tentec at contesting.com>
Sent: Sunday, March 02, 2003 8:56 PM
Subject: Re: [TenTec] RFI and Behringer MX-602a


> Tim:
>
> If I read this correct, you are taking a speaker level signal into a
> microphone level input.  Chances are that you are driving the input into
> distortion, pre any gain control or level control stage on the mixer.
> Secondly, the phone output level of a mixer is only slightly above line
> level and is designed to drive a much higher Z than a speaker.  Also, it
is
> most likely rated at a few milliwatts of power where a speaker needs an
amp
> of 2 or 3 watts (2000 to 3000 milliwatts) to be clean.
>
> I doubt that you have an RFI problem.
>
> I suggest that you place some 20 to 40 dB loss attenuation between the
> speaker out of the radio to the input of the mixer.  A simple 5 to 10 K
pot
> will do the trick and allow you to make adjustments to suit yourself.
> However, to drive a speaker from the phone output of the mixer, you'll
need
> to put a audio amp capable of some 5 or more watts between the mixer and
the
> speaker.  This most likely will address your concerns.
>
> 73
> Bob, K4TAX
>
>
>
> ----- Original Message -----
> From: <tlogan7 at cox.net>
> To: "tentec reflector" <tentec at contesting.com>
> Sent: Sunday, March 02, 2003 12:29 PM
> Subject: [TenTec] RFI and Behringer MX-602a
>
>
> > Hi folks -
> >   Been fooling around abit with the above mixer. Seems pretty great for
> > receive but sure distorts/ruins cw sending. I'm assuming the terrible
> sound
> > of my cw sig is from RFI - in which case I probably won't spend much
time
> > trying to fix it.  Any adjustments to gain and other settings does not
> cure
> > it.
> >   I run the speaker into the phone input and am using channel 1 from the
> > mixer to the rigs speaker out - no amp or anything. Any suggestions
other
> > than normal RFI cures or is there something about setting the mixer that
I
> > may be missing? If it's RFI the mixer goes - not worth the effort to me
> > since I'm not real heavy into the audio manipulation part  - in case
> anybody
> > wants to buy a mixer.
> > Thanks folks.
> > 73/Tim NZ7C
> >
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>
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