[CQ-Contest] Results - SO2R Audio Switching Survey

Hal Kennedy halken at comcast.net
Tue Dec 30 20:30:46 EST 2003

My apologies for getting this second posting out very late.  I had promised
it weeks ago, before the Holidays and contests slowed me down.  This is a
very long post - if you are not interested in SO2R layout issues, hit
'delete' and Happy Holidays!

In November I asked a few questions on the reflector about handedness and
left/right layout in SO2R stations.  I got 44 replies and put the results
out here - which generated lots more discussion via private email.  Those
who responded to the left hand/right hand questions were sent the following
question as follow-up:

"With regard to audio switching, do you:

1. Always have the left radio in the left ear, right radio in the right ear,
2. Left in left ear, right in right ear when both are RX, and both ears on
the S&P radio when the run radio is calling CQ, or:
3. Other?
4. Comments appreciated"


There were 33 responses.  32 were from the 44 stations asked the question,
one came in unsolicited!  As in my prior post I won't identify individuals'
responses, as I did not ask their permission to do so.  Two responses were
of the "I just do whatever is required" variety - I was able to coax useful
info out of one of these (via a second email) and I had to set the other
aside, leaving a data set of 32.  Among the 32 are many frequent top-ten
finishers and long-time contesters/SO2R operators.

Caveat Emptor:  The sample size is fairly small given the large number of
potential answers - the statistics should be viewed with caution.  Also, the
question was not asked very elegantly, so there were a lot of 'other' (#3
and #4) replies which are all over the map.  Also, since the question was
not explicit except for switching, it could not be known when an individual
did not mention a given practice whether they don't do it, or simply failed
to mention it.

1.  30 of the 32 replies (94%) indicated at least some operation with LR=LE
(left radio in left ear) and RR=RE, with audio either fully separated or
with minor mixing (small amount of L into R and R into L).  Two responses
indicated both radios in both ears all the time together with 'riding the AF
2.  Of the 30 stations using LR=LE and RR=RE, 12 (40%) indicated they do not
switch both ears to the Rx radio when the other is Tx, 16 (53%) indicated
they do switch both ears to the Rx radio when the other is Tx at least some
of the time, and two (7%) did not indicate.
3.  Of the 30 stations using LR=LE & RR=RE, 7 (23%) specifically mentioned
mixing a little of one channel into the other, the rest did not mention
4.  11 of the 30 stations (37%) mentioned at least occasionally shifting
both ears to one radio for one or more of three reasons.  Eight mentioned
doing it to pull weak ones out of the noise.  Five mentioned doing it when
run rates were so high they considered the S&P radio a distraction.   Two
mentioned dropping back to SO1R when fatigued or to 'take a break.'


1.  With regard to switching both ears to the Rx radio when the other is Tx,
the population is about evenly split between those who do and those who
don't.  There were only two responses indicating non-switching because their
gear didn't support it.  The rest of the 'non-switchers' indicated or
implied they had tried it and didn't like it.

A typical comment from a non-switcher: "I tried...having the CQ radio in
both ears and then the S&P radio in both ears but personally I find that
very disconcerting.  The whole world is jumping in and out of my head and it
drives me nuts."

A typical switcher's comment: "..automatically switches the second radio
when the run radio is transmitting.  That's a NECESSARY feature IMHO for
me!" [caps and punctuation are from the original writer]

>From the data and the written commentary, it does not seem possible to
generalize that one method is better than the other - this is an item of
personal preference.  As conjecture, it may be possible to 'learn' to deal
with switching given enough practice.  Both of the commercially available
SO2R boxes provide the feature, but allow you to turn it off.

Making this really difficult to draw conclusions about is the fact that to
switch or not to switch is interrelated to the next four subjects:

2.  Switching vs. pots.  There are advocates of each, but I only received
one strong pro-potentiometer reply.    A pro-switch comment:  "Some folks
like a pan pot left and right control, but I find the switchbox focuses my
attention nicely."   The one pro-pot comment:  "I have BOTH radios in BOTH
ears all the time.  I use a variable potentiometer to control the amount of
audio from the right radio and audio from the left radio, which can vary
from 100% right radio to 100% left radio."  [Note: This station is virtually
always top ten and often wins contests outright]

3.  With regard to mixing audio, I suspect many more stations do so than
indicated they do - as this was not asked about.  If you own an FT-1000MP
(maybe other rigs as well?) you can hear the effect of mixing by
experimenting with menu 4-8, which allows the two receiver audio streams to
be completely split, completely mixed or slightly mixed.  Proponents of
mixing like the fact that mixing-in a small amount of opposite-channel audio
makes the sound appear to be coming from somewhere inside your head.

Two typical pro-mixing comments: "I put a pot across the left and right
headphone channels in order to mix a little audio from each side into the
other.  This tends to enhance the stereo effect by narrowing the spatial
separation a bit.  Without that, the fields were separated too far and I
found it more difficult to copy both radios at the same time," and,  "Total
isolation is too hard to deal with."

On the other hand, stations that indicated they moved both ears to one radio
to dig out the weak ones implied they didn't want mixing during such times.
As one put it: "If I am really digging a weak one out of the mud..it is
easier to "get inside the radio" with both ears involved on one radio."

4.  Transmit radio CW sidetone.  Most ops want it, particularly for
occasional hand sending - some want it all the time: "...It helps my
rhythm..."  Two ops specifically did not want it: "...the sidetone coming
back from the Tx radio will be confusing.  Its easier to kill the
sidetone...," and, "...no sidetones for CQing for distraction!"  This seems
to be another area of personal preference.  There is a very clever
alternative mentioned at the end of this post ("One-off" #2).

5.  QSK.  [Two responses]  When operating QSK, the operators want to hear
'in-between' the sending, so these stations do not switch both ears to the
Rx radio when the other is Tx.

Other Considerations:

1.  Software vs. Hardware.  Most responses indicated their SO2R functions
were implemented in hardware.  They were either using homebrew SO2R gear,
the TTD DXD or the WX0B SO2R master.  However, there were three mentions of
WRITELOG's "headphone latch + split" commands.  Discussion of the many
things WRITELOG can do in support of SO2R is beyond the scope of this post,
but one thing it can do is software control headphone switching, including
switching both ears to the Rx radio when the other radio is Tx, AND inhibit
that switch-over if you are sending manually (as opposed to via the F keys
or keyboard) so that you can hear the sidetone.

2.  CW vs. phone.  This was mentioned several times without yielding any
clear information [at least to me].

3.  Stateside vs. DX.  One ZL mentioned he sometimes spends significant time
running pile-ups of weak US signals...both ears to the run radio was a
requirement.  Where you are and exactly what you are trying to do does

Some interesting comments received:

1.  "Ear matches radio location, left and right. God help me if I ever stack
the radios vertically."  [The Op who favors vertical stacking has no problem
with it, however]
2.  "I find that keeping the audio levels as constant as possible helps my
brain function.." [This station does not switch audio when transmitting]

Some interesting one-offs received:

1.  "Speakers, no switching"  [One respondent]
2.  "A "code reader" remains the best utilization I've made in the
shack--some way to determine the radio I no longer hear (the running rig) is
"doing the right thing" as it's transmitting while I am listening to
something else. [Note:  Only response where audio monitoring of the transmit
radio was replaced by visual monitoring - this is damn clever!]
3.  [From a CW Op:] "The radio on the left is set to "zero beat" at about
400 HZ (lower note) and the one on the right is set for about 700 HZ (higher
note). I find it helpful to "stereo-ize" them in my head.  [I have to try
this - I never would have thought of it]


What started out as my trying to figure out if folks thought it worthwhile
to switch both ears to the Rx radio when the other radio was Tx, turned out
to be not so simple!!

I could not have said it better than this perennial top finisher:  "What
works best for a given contest op is a very individual thing.  Everyone's
brain works a bit differently and everyone's ability to hear the freq.
spectrum and distinguish audio from noise varies as well.  You need to try
everything and see what works best for you and makes you the most

Since I can't possible provide the 'correct answer,' I hope this at least
yields up some food for thought.

I have received a lot of encouragement to put this and the prior post into
an NCJ article - that's in the works.

Thank you to all the respondents for sharing your info - we appreciate it.

(N4GG at arrl.net)

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