[Top] [All Lists]

[CQ-Contest] Win M/S? You need 3 rigs. Maybe 4.

To: cq-contest@contesting.com
Subject: [CQ-Contest] Win M/S? You need 3 rigs. Maybe 4.
From: Scott Robbins <w4pa@yahoo.com>
Date: Wed, 5 Aug 2009 09:19:50 -0700 (PDT)
List-post: <cq-contest@contesting.com">mailto:cq-contest@contesting.com>
On Aug 3, 2009, at 12:19 PM, Milt, N5IA wrote:
> The rules for M/S say "one transmitter", and do NOT say anything  
> about time
> slicing (someone elses terminology) no more than they do for SO.

It really comes down to your interpretation of "transmitter".  Is a transmitter 
a physical box sitting on the table?  Is a "transmitter" really a transmitted 

The accepted definition for the CQ contests has always been that a 
"transmitter" = a transmitted signal.  Suffice it to say that if you're running 
one rig as M/S entry in CQ WPX or CQ WW, fail.  Two rigs is also fail.  You 
need a minimum of three, and we ran up to four for a M/S entry back in the 
K4JNY salad days (we won USA M/S for WPX SSB in '04 and '06). 

We employed a series of lockout devices so only one transmitted signal was in 
use at any one time.  On the main run band, we used two HF rigs interlocked via 
a common linear amplifier with a homebrew relay device I designed and built.  

Rig #1 > Run freq rig > linear #1 > transceiver main antennas

Rig #2 > Run freq rig on same band > linear #1 > main antennas TX, separate RX 

When rig 1 was transmitting, merely hitting the PTT button on the mic of rig #2 
simultaneously shut off the #1 transmitter and "stole" the main antennas and 
linear #1 to transmit with rig #2.  Release PTT, rig #1 is now re-enabled, rig 
#2 listens on their RX antennas.  The converse was not true; if rig #2 was in 
use, rig #1 could not "steal" the amp and antennas, it was locked out until #2 
stopped transmitting. 

Rig #3 > Mult radio > linear #2 > main antennas not in use by run

Rig #4 > Mult radio #2 > linear #3 > interlocked with rig #3 with simple PTT 
lockouts to prevent transmitting on both at the same time. 

Since you have 10 minutes on a band to work mults, often more than 10 minutes 
would go by, you'd have mult tuners on two different bands other than run and 
whomever found a mult listening or on packet would work them, and then the 
other station would have to wait until the 10 minute period expired before they 
could work someone on another band.  Having the lockouts was almost not needed, 
but you want to be SURE.  They were good mostly for reminding yourself you were 
doing everything right. 

There are other tricks that you can use with M/S (and M/2 and M/M) that 
surprise me others don't use, the most prominent being the use of two ops on 
the main #1 radio.  We use to have KD4HIK listening on a second set of 
headphones on the #1 rig doing nothing but copying inbound callsigns with the 
run op and it was consistently surprising who would copy what as callers came 
in.  Definitely helped both speed and accuracy. 

Also try putting your best operator on the mult station or second radio as much 
as possible.  Running guys in a contest at 70 or 90 an hour really is no 
amazing feat, do you need your best op doing this?  The best ops are good 
because they really know how/when/who to S&P all over the place.  Think about 
it.  Why are the best SO2R guys really, really good?  It's not because they are 
demons on the run radio ...

So to take a shot at winning M/S:  3 or 4 rigs covered for 48 straight with 5 
or 6 ops.  Top of the line radios with low transmitted composite phase noise 
and big antennas are de rigeur.  I'd be happy to make a suggestion :-)

Back to work. 

Scott W4PA


CQ-Contest mailing list

<Prev in Thread] Current Thread [Next in Thread>
  • [CQ-Contest] Win M/S? You need 3 rigs. Maybe 4., Scott Robbins <=