[Elecraft] K3--Too much ALC creates energy on opposite sideband?

[donovanf at starpower.net]

Hi Fred, 


The ALC level you recommended is the recommended level for digital modes such as FT8 where no ALC is the standard practice. 
Elecraft's recommended for the K3 or K3S ALC level when operating in voice modes is 5-7 bars. 


The exact quote from page 30 of the latest K3S manual 
https://ftp.elecraft.com/K3S/Manuals%20Downloads/K3S%20Owner's%20man%20A1.pdf 


Optionally select TX TEST mode (pg. 13) or set power to zero. This will not affect your CMP/ALC bar graph readings. 


Set CMP to 0 


Hold METER to select CMP/ALC metering 


While speaking into the microphone in a normal voice, adjust MIC for a peak ALC meter indication of about 5-7 bars (see below). 


Adjust CMP for the desired speech compression level while speaking.The CMP scale shows approximate compression level. 


73 
Frank 
W3LPL 

----- Original Message -----

From: "Fred Jensen" <k6dgw at foothill.net> 
To: elecraft at mailman.qth.net 
Sent: Wednesday, August 28, 2019 5:19:58 PM 
Subject: Re: [Elecraft] K3--Too much ALC creates energy on opposite sideband? 

Nate: 

You should run your MIC gain such that you see 4 bars of ALC with the 
5th just flickering occasionally on voice peaks. Make this adjustment 
with compression at zero. Then, adjust the compression as desired. I 
generally set it so that voice peaks show 10 dB compression. The first 
4 bars on the ALC display are in fact just a VU meter. ALC action 
begins at the 5th bar. Elecraft transceivers set the power out with a 
closed feedback loop [PWR setting], not the MIC gain. 

Driving the ALC too hard will create IMD which, among other things, will 
show up as energy on the opposite sideband. It all happens in the RF 
chain after the DSP has generated the SSB. 

73, 
Fred ["Skip"] K6DGW 
Sparks NV DM09dn 
Washoe County 

On 8/28/2019 9:40 AM, Nate Bargmann wrote: 
> I received a note this morning advising that I should check my ALC as he 
> is seeing some energy on USB when I check into a 75m voice net on LSB. 
> I am using an MC-50 microphone and am running the mic gain at 35 and the 
> compression at 11. My thinking was that generating opposite sideband 
> energy would be quite difficult with the K3's DSP. Am I wrong? 
> 
> I'll try working with him some morning and back down the mic gain a bit 
> and see what that does for him. 
> 
> 73, Nate, N0NB 
> 

______________________________________________________________ 
Elecraft mailing list 
Home: http://mailman.qth.net/mailman/listinfo/elecraft 
Help: http://mailman.qth.net/mmfaq.htm 
Post: mailto:Elecraft at mailman.qth.net 

This list hosted by: http://www.qsl.net 
Please help support this email list: http://www.qsl.net/donate.html 
Message delivered to donovanf at starpower.net