[R-390] R-390A On 160 Meters

[2002tii]

David wrote:

>All Receivers are fed thru a DA-4 Multicoupler.

Bill wrote:

>>At the time, all three were sharing the same antenna
>>via a Stridsberg MCA104 receiver multicoupler.

Don't discount the effect the multicouplers may be having on the 
results.  The output-to-output isolation is only on the order of 20 
dB for these units, and the noise figures aren't great (claimed 8 dB 
for the DA-4, claimed 2.5 dB for the MCA104, although the ones I've 
measured have been significantly worse -- around 10-12 dB for 
each).  If one of the receivers is putting junk out its input (common 
with some of the digital receivers), all bets are off.  Distortion in 
the multicoupler amp can spread the junk all over the bands, so even 
out-of-band spurious emissions can hurt the performance of other receivers.

I'm not saying I think this explains any of the reported results, 
just that it can't be ruled out.

Best regards,

Don