Wayne,
Thanks. You are doing what I've advocated for a long time, don't get
fancy just put up some wire and it will work. I hope new hams take note
of what you are doing. :-)
73,
Barry
K3NDM
------ Original Message ------
From: "Fred Jensen" <k6...@foothill.net>
To: elecraft@mailman.qth.net
Sent: 9/21/2018 1:17:09 PM
Subject: Re: [Elecraft] Conditions, shmonditions: DXing anyway
This probably is related to the commercial CW operators trick of laying
the phones down on the desk to copy a weak ship station through noise.
It really does work. Unfortunately, today's over-the-ear headphones
tend to stick together rather than laying flat on the desk as the old
"cans" did, but it still works. Tailoring the K3 RX equalizer for your
ears and headphones/speaker is well worth some time and effort too,
even on CW with narrow bandwidths. You just have to go slowly and
evaluate each setting before changing anything.
In SE Asia in the mid 60's, we used 11.5 KVA 400 Hz turbine generators.
The primary reason was weight. A 10 KVA 60 Hz diesel MB-5 was
trailer-mounted and weighed about 3,500 lbs [1,600 kg]. Two troops
could carry the turbine units, and of course, the 400 Hz power supplies
were correspondingly lighter too. A side benefit was that the high
frequency whine of the turbines, running at around 9,000 RPM, was very
easy to muffle with a few sandbags [generators were small]. The low
frequency rumble from the 60 Hz generators was essentially impossible
to suppress.
High frequencies seem to come forward, straight off a speaker and with
compromised hearing, I lose intelligibility if I move off to the side.
If I am having a hard time understanding you, speaking louder won't
help much, speaking directly at me usually will.
73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County
On 9/21/2018 1:03 AM, Jim Brown wrote:
On 9/21/2018 12:22 AM, David Cutter via Elecraft wrote:
On a related tack, I am often surprised at how high the radio volume
has
become in the club shack. On turning it down, it is quite a relief on
the
ears and yet perception of the signal we are listening to improves.
Two possible reasons. First, if a radio has a relatively low power
audio output stage, higher sound levels are more likely to drive it
into distortion. Loudspeakers, especially cheaper ones, also distort
more at higher power levels. Second, reverberation and echoes are
"noise" as far as speech intelligibility is concerned; while that IS a
linear ratio, human hearing is not, so reducing the level may bring
those echoes/reverb down to a level where it is less perceived.
It is also significant that a separate loudspeaker on a shelf being
more in line with our ears provides significant improvement in our
ability to "hear" the station.
Exactly right, and that is ENTIRELY the result of 1) loudspeaker
directivity -- lows are more omni-directional from nearly all
loudspeakers, while the highs becomes increasing directional. [This is
due to wavelength of the sounds as compared to the size of the
loudspeaker diaphragm.] When we and the loudspeaker are facing each
other, we're getting both highs and lows. When the speaker is turned
away from you, we hear the lows but not the highs, AND those highs
spray to whatever surface they face, and bounce around to create
echoes.
2) The higher speech frequencies are most responsible for speech
intelligibility, lows provide almost none.
Louder is not better.
Louder is only one part it.
73, Jim K9YC
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