Topband: Contest

W2RU - Bud Hippisley W2RU at frontiernet.net
Tue Feb 2 08:39:54 PST 2010


On Feb 1, 2010, at 10:56 PM, Gary Smith, KA1J, wrote:

> There were several multipliers I needed to go after 
> and I had to transmit off their transmit frequency 
> to be heard. Sometimes 50-75 Hz was all that was 
> necessary but I could have replied on their transmit 
> freq. all night and they would have never heard me.

Most modern transceivers actually do transmit CW on a carrier frequency precisely locked to the pitch of the local sidetone chosen by the operator.  Unfortunately, many of those same transceivers don't allow their owners to set the pitch low enough for their personal preference, so some operators (blush, blush) end up off frequency when replying to another station's CQ  because they're unwittingly tuning for the most pleasing received pitch, which may, as Gary notes, be 50 Hz or more away from perfect zero-beat.  Example:  My Kenwood's lowest selectable pitch is 400 Hz, but I prefer to listen around 300 Hz.  If I tune a station in so that the resulting beat note I hear from him is 300 Hz, my transmit frequency will be 100 Hz off from his.  The "simple" cure, of course, is to match the pitch of his signal to your local sidetone pitch, but in the heat of battle you may forget.  

To make sure I don't lose any replies to my CQs because of others with a similar situation or who have accidentally left their RIT or XIT on, if I'm on Upper CW ("normal" CW on my Kenwood, Reverse CW on a K3, for instance) I turn on my RIT and set it at -100 Hertz or thereabouts.  If, following a CQ, no one calls me within this "offset" passband, I sweep the RIT up and down.  Every now and then I catch someone calling me as much as 500 Hz off in one direction or the other.  (My assumption is that this is frequently a person who doesn't realize his RIT or XIT is "On".)

With modern rigs like the K3 having such excellent dynamic range, my preference when CQing is to combine 100 Hz of RIT offset with a filter passband of 500 Hz or so, and to obtain the final selectivity between my ears.  Then I can copy stations calling me who are on either side of my transmit frequency by as much as 200 Hz or more without having to tune around.  The benefits of this approach are:
  a.  I seldom require a repeat from losing the first part of someone's callsign, since almost everyone who calls me is already within the passband of the receiver.
  b.  This allows me to keep both hands on the keyboard or use one hand to select the best RX antenna.   

It may take some practice to keep your "internal filter" from jumping from one signal to another when many stations are calling you.  Of course, my internal filter works best when I'm not exhausted.

Bud, W2RU 


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