[Trlog] How to use 2 vfos?

Kenneth E. Harker kenharker at kenharker.com
Wed Oct 13 08:53:19 EDT 2004


On Tue, Oct 12, 2004 at 09:20:45PM -0700, Bob Tellefsen wrote:
> I'm curious how one might use a radio with two vfos, when there is
> really only one vfo and one tuning knob, switched between A and B.

The primary reason is for working in-band split-frequency contacts.
In contesting, this is far more common on phone (40M and 75M, and
maybe occasionally on 20M.)  It is an incredibly common feature of 
DXing, however, on CW, phone, and even RTTY.

Some radios (Yaesu FT-1000MP for example) can let you listen to both 
VFOs at once.  This can be useful for in-band search and pounce while
keeping a run frequency (such as you might want to do in a single-band
contest operation.)  When you find a new station on the B VFO 
(your S&P VFO) you simply A/B over, work it, and A/B to get back your
run frequency on VFO A.  This technique can be done on a rig that
does not have dual receive (i.e. K2, TS-850, etc.) but it really 
wears out your A/B button finger after a while, and is a lot more 
cumbersome.

Another use for two VFOs might be to quickly QSY to another frequency.
Perhaps in a multi-op operation you are searching and pouncing, but
also keep a clear frequency at the top of the band in one VFO so
that other band-stations can pass a new mult station to your band.  
Another situation might be where two operators are at a multi-op, and 
while one is running stations, the other is punching frequencies of 
"new ones" (found on a second receiver or packet cluster) into the 
other VFO for the operator to work when opportunity arises.

You can also use the second VFO to keep track of rivals or the pileup
on some multiplier you need.  If you are S&Ping and come across a 
station of interest like this (and maybe the pileup is too big to 
get into yet) store it in B VFO and every so often you can quickly
check on that frequency by a quick A/B switch to see if the pileup is 
now bustable or to see what serial number your rival is up to, 
if they've moved to another band, etc.

There are all sorts of contest uses for two VFOs.


> I use a K2, which can do A/B switching, but still only operates one
> circuit at a time.
> 
> Thanks for any ideas that might come up.
> 73, Bob N6WG
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-- 
Kenneth E. Harker WM5R
kenharker at kenharker.com
http://www.kenharker.com/



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