[CQ-Contest] Multi-Transmitter Operation (Was about IC-7610)

[Jim Brown]

LOTS of truth here.  There are two applications notes on my website, two 
about stubs for harmonic suppression (one is text, the other a Power 
Point), another about bonding, that are also required reading.  The one 
about bonding was the jumping off point for Ward's book, and the one 
about stubs offers important insights that George missed.

http://k9yc.com/LocatingStubs.pdf
http://k9yc.com/StubPlacement.pdf
http://k9yc.com/GroundingAndAudio.pdf

Another issue that W3LPL reminded us of is Passive Intermod which can be 
both inside and outside our stations. One common place it occurs is at 
the junction of the boom and mast via the rotator, and is solved by 
bonding around the rotator.  It also happens in electronics of all 
sorts, most notably switch-mode power supplies. If the harmonics/spurs 
you hear are "growley" sounding, it's probably passive intermod.

73, Jim K9YC

On 3/21/2018 7:15 PM, Tim Duffy wrote:
> As AC0C points out - making multiple stations work is not easy. Bonding is
> important (much more than most station owners realize) and using high
> performance filters and quality interconnect cables (with good quality
> properly installed connectors) is mandatory. Connectors MUST be tight. The
> recent N0AX book on grounding and bonding is a good read on this subject.
>
> What was a state of the art station design 20 years ago will not cut it with
> the high performance SDR RX platforms of today. The epic W2VJN book is a
> MUST read for anyone wanting to make SO2R or multiple stations at a single
> QTH work properly.
>
> Bottom line - there is no free lunch.