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

[Scott Robbins]

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 signal?  

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 antennas. 

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. 

73
Scott W4PA