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Re: AM Audio Processors
To: CRTech <crtech@crtech.org>
Subject: Re: AM Audio Processors
From: JIm Turvaville <jimturbo61@yahoo.com>
Date: Wed, 11 Jul 2018 22:38:41 +0000 (UTC)
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Reply-to: JIm Turvaville <jimturbo61@yahoo.com>

Putting the processor before the STL is often problematic as you describe.  The modulation and the demodulation of the audio via the STL will affect the symmetry much like you are seeing.  

You'd be better off putting some kind of limiter only in front of the STL-10 so it would not be over-driven and then put the 9200 as close to the TX as possible. I'm not sure there is any benefit to reducing the bandwidth when it comes to symmetrical modulation, and some of us still have radios which can pass up to 10khz really nicely and enjoy properly processed AM audio on the radio!
Jim "Turbo" Turvaville 
SBE Certified Radio Engineer 
Turbo Technical Services 
 PH: 719-459-1859 

From: RADIO DOCTOR <lylehenry@fastmail.fm>
To: CRTech <crtech@crtech.org>
Sent: Wednesday, July 11, 2018 5:30 PM
Subject: Re: [CRTech] AM Audio Processors

Two questions for the group:

I have an Orban 9200 at the studio ahead of a Marti STL-10 mono system.
The xmtr hits positive peaks of 140% regularly while negative is tight
at 100% all the time.  Could the STL be messing with the asymetry as I
don't think the 9200 would create that kind of difference.
Interestingly, it's not particularly loud over the air.

I'm also wondering if it would make sense to cut the audio bandwidth in
half from the 9200, say 4.5kHZ instead of 9-ish to stop wasting
modulation on frequencies that almost no receivers except the modulation
monitor can pass?

Remember, I'm an FM guy :)

On Wed, 11 Jul 2018, JIm Turvaville wrote:

> I installed my first VOLT on an AM just last month - was amazed at the
> great sound and really clean.  Positive and Negative were right on
> spec and easy to set up.  Jim "Turbo" Turvaville SBE Certified Radio
> Engineer Turbo Technical Services PH: 719-459-1859 www.jimturbo.com

FMeXtra digital SCA systems - encoders and receivers
SCA/FM/FMeXtra radios: fixed & tunable-wood cases-nice sound
Sidekick SCA generators - 67/92kHz-checked and calibrated
  Lyle Henry, CPBE  THE RADIO DOCTOR  K9DKW  Los Angeles, CA
SCA Consultant:  Brazil, China, India, Mexico, Taiwan, SE Asia
        323-660-4690 Home/Office    213-880-4690 Mobile

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References: AM Audio Processors
(Tom Van Gorkom <tomvangorkom@gmail.com>, 11 Jul 2018 19:16:24 -0000)
Re: AM Audio Processors
(Mark Carol Bohnett <mbohnett43@bevcomm.net>, 11 Jul 2018 21:53:21 -0000)
Re: AM Audio Processors
(JIm Turvaville <jimturbo61@yahoo.com>, 11 Jul 2018 21:56:54 -0000)
Re: AM Audio Processors
(RADIO DOCTOR <lylehenry@fastmail.fm>, 11 Jul 2018 22:30:07 -0000)
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