[TenTec] Orion II AM Mic Adjustment

[Ken N9VV]

You might be interested in this new AM adjustment device from 
Tyler KW0AM (neat call):  http://www.cleanrf.com/
de ken n9vv

Bob McGraw - K4TAX wrote:
> To correctly set these radios for AM one should have some type of waveform 
> monitor such as the old Heath SB-610 or HO-10.
> 
> One thing that I noticed with my Omni VII and the 708A mike.  The Positive 
> modulation peaks were not 100% when the negative peaks were hitting 100%. 
> The solution, reverse the Red and White wires in the XLR-4 connector that 
> plugs into the back of the mike.  Once this was done, the positive 
> modulation is equal to the negative modulation.  Without a waveform monitor 
> being a Heath SB-610, I'd never seen the issue.  And yes, it takes more mike 
> gain for AM than for SSB.
> 
> Even with the Heath Apache and the RCA BC transmitter I have found that mike 
> phase does make a difference in modulation symmetry.  A monitor scope will 
> tell the true story.
> 
> 
> 73
> Bob, K4TAX
> 
> 
> ----- Original Message ----- 
> From: <ac9s at mchsi.com>
> To: <tentec at contesting.com>
> Sent: Tuesday, October 02, 2007 2:52 PM
> Subject: [TenTec] Orion II AM Mic Adjustment
> 
> 
>> I have begun to play with AM on the O2 and it appears the microphone 
>> settings
>> are significantly different than with SSB.  I am running a Heil Goldline
>> through an NCS multiswitcher.  With the current gain setting on the NCS 
>> box I
>> have the red led on the O2 flickering with the O2 software mic setting at 
>> 18.
>> Today I checked in with an AM group on 3875khz and was informed that my 
>> audio
>> was light.  Sure enough, there was no flicker on the led.  I turned the 
>> mic
>> gain almost up to 100 - I could see increased gid current on my amplifier, 
>> but
>> never a sign of the led lighting.  The group informed me the audio level 
>> had
>> increased, but that it was still a little on the light side.
>>
>> Does the LED work on AM?  Should the mic gain be radically different 
>> between
>> SSB and AM?  I didn't see anything specific in the manual.
>>
>> Thanks for any input on the proper way to set the mic gain on AM.
>>
>> Keith
>> AC9S
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>>
> 
> 
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