FW: [CQ-Contest] SOME THOUGHTS ON USING THE K3 ON SSB

[w0mu]

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Larry Schimelpfenig
Sent: Saturday, April 11, 2009 12:04 PM
To: [hidden email]
Subject: [CQ-Contest] SOME THOUGHTS ON USING THE K3 ON SSB

What I'm about to relate here may very well be posted at other spots on the
Inet, but I haven't had much luck in finding it, so this will hopefully be
helpful to contesters using the Elecraft K3 on phone.

I address two points. First is setting the crystal filter center frequency
offset which greatly affects transmit audio quality. Second is use of the
rear panel mike and audio in jacks in conjunction with sound card voice
keying.

We don't operate a lot of ssb from NR4M, but it's on the rise (don't blame
Steve - a gun was held to his head). Somehow or other we decided to make an
M/M effort in the ARRL SSB DX test. We spent hours trying to get good audio
out of the K3. We were using a Heil headset with the HC-4 element.

To make a long story short, while going through the menus I found  FLx FRQ
in the configuration menu. After reading about this menu item I played with
it a little to see if it made a difference. Did it ever!

The 5 pole crystal filters have a label on them specifying what the offset
should be. Most are labled "-0.91".  At some point we had done a master
reset of the radio which set the offset at "0.0".  When we set the offset to
-0.89 as the filter in one of the K3s was labled, we received great audio
reports.

One of the contesting stations in MD was having transmit audio problems with
the K3s there and they weren't sure that the 20M stack was working correctly
as well. This morning four or five stations including the one with audio
problems did some horse racing and got comparative audio reports from
European stations.

I told the station with problems about the filter offset. Interestingly
enough they were using the eight pole ssb filters that should not have
required offset according to the manual. On a whim, they tried the offset
adjustment and found that made a difference. When we were done both of their
K3s went from sounding terrible to being quite acceptable.

Has anyone else using the eight pole ssb filter had to adjust the offset to
get it to sound decent on transmit?

In addition to a couple pair of Heil headsets with HC-4 elements, we have a
couple of very comfortable headsets with hi fidelity mikes. We found that by
adjusting the transmit audio equalizer, we could get pretty decent sounding
audio from the hifi mike.

The problem was that when we recorded the voice keyer messages on the
computer and played them back through the radio there was one problem when
using mike input and another when using line input. It appears that there is
no transformer isolation on the mike input which resulted in hum and other
extraneous noises. When running the audio into line in, it doesn't get
pushed through the transmit audio equalizer. Ken K4ZW said he ended up using
an extrernal isolation transformer and ran the sound card input into the
rear mike jack.

It would be nice if Elecraft could run the line in through the transmit
audio equalizer when in the ssb mode!

If there is detailed information regarding either of these subjects on the
web, I'd appreciate knowing where! Otherwise, I hope it might be useful.

73 de Lar K7SV




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[Barry N1EU]

W0MU Mike Fatchett wrote

-----Original Message-----
From: [e-mail]
[mailto:[e-mail]] On Behalf Of Larry Schimelpfenig
Sent: Saturday, April 11, 2009 12:04 PM
To: [e-mail]
Subject: [CQ-Contest] SOME THOUGHTS ON USING THE K3 ON SSB


When running the audio into line in, it doesn't get pushed through the transmit audio equalizer.

It would be nice if Elecraft could run the line in through the transmit audio equalizer when in the ssb mode!

73 de Lar K7SV

Line in audio DOES go through the K3 transmit audio equalizer.

73,
Barry N1EU

[Geoffrey Downs-2]

After extensive experiments with tx audio settings in pursuit of "perfect
audio" for my purposes - dxing on 80m - I came to the conclusion that for my
voice with the HC-4, an offset of -0.07 with the 2.8 kHz filter was about
right.

However I would not say that I "had" to do this to make the audio "decent".
It was very decent, excellent even, without offset and with appropriate
settings of mic gain, compression and equaliser but to my ears, rightly or
wrongly, it sounded slightly better *for my purposes* with the offset.

In the same way I tried both the 2.7 kHz and the 2.8 kHz filters after
building my K3 in January 2008 and to my ears the tx audio from the 2.8 kHz
sounded slightly better for what I wanted than from the 2.7 kHz.

Others may have a different view. Opinions about tx audio are very
subjective and also have to be taken in usage context. I am looking for
audio that I think will be heard on the other side of the planet on 80m when
my signal is at or below the noise level, but that might not be right for
another band or for another purpose. My method of experimenting is to make
recordings on my PC from another receiver, but of course the characteristics
of the other rx will not necessarily match those of the rig of the station I
am trying to work, and the recording process can make subtle changes too. So
it's a rather inexact science providing hours of harmless fun that almost
keeps me out of mischief ;-)

73 to all

Geoff
G3UCK


----- Original Message -----
From: "W0MU Mike Fatchett" <[hidden email]>
>
> Has anyone else using the eight pole ssb filter had to adjust the offset
> to
> get it to sound decent on transmit?
>

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[Bill W4ZV]

Geoffrey Downs-2 wrote

After extensive experiments with tx audio settings in pursuit of "perfect
audio" for my purposes - dxing on 80m - I came to the conclusion that for my
voice with the HC-4, an offset of -0.07 with the 2.8 kHz filter was about
right.

It's not unusual for the 8-pole filters to have small offsets, which would be particularly noticeable if on the bass side of the passband.  I've heard of up to 80 Hz (0.08) in some CW filters.  Anything large than that, indicates something else may be going on (like accidentally resetting the 5-pole offset to zero as K7SV noted in the original post).

73,  Bill