[600MRG] WSPR-15

[jrusgrove at comcast.net]

Claude

Transmitting two separate signals like that would require a close look at the IMD performance of the 
exciter and amplifier stages ... otherwise you will have unwanted products in the band. Reducing 
each tone by 6 dB would, for practical purposes, maintain the same PEP power as a single tone. If 
you're running at close to maximum output, your 3rd order IMD products will likely be down only ~ 30 
dB with higher order products down a bit further. Reducing power below -6 dB for each tone will 
improve the IMD. This of course assumes that you're running a linear amplifier and not Class D or E 
which aren't linear. Have done this here with a high power linear amplifier run at low power levels 
... works fine when the above limitations are accounted for.

Jay W1VD  WD2XNS  WE2XGR/2  WG2XRS/2


----- Original Message ----- 
From: "Claude Baker" <ac0zl at yahoo.com>
To: <600mrg at w7ekb.com>
Sent: Monday, December 30, 2013 12:35 AM
Subject: [600MRG] WSPR-15


> As you've probably noticed, I leave a receiver parked on 630M decoding WSPR-2. After missing a few 
> hours of XSV tonight, I've decided to continue running WSPR-2 and WSPR-15 simultaneously as the 
> norm. If anyone else decides to run WSPR-15, I'll be listening!
>
> On the topic of running WSPR-2 and WSPR-15 simultaneously, has anyone considered transmitting both 
> signals simultaneously? Modern Windows and sound cards don't seem to have any problem putting out 
> (combining) multiple sound streams. WSPR is just a digital sound stream in the computer, it seems 
> simple in principle to transmit both signals unless you're using an Ultra 3.
>
> I think I'll try it on a higher band tomorrow and see what happens.
>
> Claude, AC0ZL
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