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Transmit audio frequency shift on USB?

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Torrey Mitchell

Transmit audio frequency shift on USB?

I'm having a ball with my newly assembled K3! I was on the air (USB,
14.170) this weekend trying to fine tune my audio equalization. Two
gentlemen told me I sounded great. However my audio was smoothest 30-50 Hz
above my operating frequency. They are both audiophiles. My RIT was OFF.
One based his opinion on critical listening. He said the audio was very
good at our mutual frequency but had a slight rasp to it. This went away
about 30 Hz higher. The second gentleman was using a FLEX 5000. He
indicated that my signal "measured" 50 Hz higher than our stated operating
frequency. He recorded my signal at both frequencies. It was clear that I
sounded best 50 Hz high.

I am using the TX ESSB option set at 3.0.

Do these observations make sense? If so, do I need to make an adjustment?
It was just the 2nd hour on the air with the new rig, so I'm not 100% sure
that my fine tuning was turned on to 3 digits past the decimal. But could
there be some other explanation?

Thanks and 73,

Torrey N9PY

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John Lemay

Re: Transmit audio frequency shift on USB?

Nothing to worry about: unless your contact knows your voice face to face
(ie not over the radio), I don't think they can be sure what is right or
wrong. Anyway, 50Hz "off" at 14MHz is peanuts.

John G4ZTR

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Torrey Mitchell
Sent: 25 July 2011 11:35
To: [hidden email]
Subject: [Elecraft] Transmit audio frequency shift on USB?

I'm having a ball with my newly assembled K3! I was on the air (USB,
14.170) this weekend trying to fine tune my audio equalization. Two
gentlemen told me I sounded great. However my audio was smoothest 30-50 Hz
above my operating frequency. They are both audiophiles. My RIT was OFF.
One based his opinion on critical listening. He said the audio was very
good at our mutual frequency but had a slight rasp to it. This went away
about 30 Hz higher. The second gentleman was using a FLEX 5000. He
indicated that my signal "measured" 50 Hz higher than our stated operating
frequency. He recorded my signal at both frequencies. It was clear that I
sounded best 50 Hz high.

I am using the TX ESSB option set at 3.0.

Do these observations make sense? If so, do I need to make an adjustment?
It was just the 2nd hour on the air with the new rig, so I'm not 100% sure
that my fine tuning was turned on to 3 digits past the decimal. But could
there be some other explanation?

Thanks and 73,

Torrey N9PY

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Bruce Beford-2

Re: Transmit audio frequency shift on USB?

In reply to this post by Torrey Mitchell

Hi, Torrey.

Congratulations on your new K3.

As for your questions regarding ESSB and trying to fine tune your
equalization-

For ESSB use, you need the 6 KHz filter installed. Trying to produce 3 KHz
ESSB audio with just the 2.7 or 2.8 KHz filter won't work (well).

As for your friends' comments that you sounded off frequency by 30-50 Hz,
have you calibrated the reference oscillator against WWV, or by some other
method? You may well be off by this amount unless you have done so... or,
they may be off 20 Hz, you may be off 30 Hz, etc.

Enjoy getting to know your new radio!

73,

Bruce, N1RX

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Don Wilhelm-4

Re: Transmit audio frequency shift on USB?

In reply to this post by Torrey Mitchell

Torrey,

Turn the manual to the Calibration section and do (or re-do) the
Reference Oscillator calibration.
Use Method 2 and be certain you are zero-beating with the carrier and
not one of the transmitted tones.

After that, run your on-the-air test with another ham who is familiar
with your voice face to face. Someone that you only know over the air
will only be able to tell you what they *think* you should sound like,
and that may be different than reality.

73,
Don W3FPR

On 7/25/2011 6:34 AM, Torrey Mitchell wrote:

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KD8NNU

Re: Transmit audio frequency shift on USB?

In reply to this post by Torrey Mitchell

Have you done the ossilitor (sp) calibration via a zero beat to WWV?

Not only will this have your tx & rx wrong but your filters will not be
centered properly for the math to work for the DSP.

Depending on temperature there can also be some drift so make sure
everything is up to temp and stable.

~73
Don
KD8NNU

On Mon, Jul 25, 2011 at 6:34 AM, Torrey Mitchell wrote:

> I'm having a ball with my newly assembled K3! I was on the air (USB,
> 14.170) this weekend trying to fine tune my audio equalization. Two
> gentlemen told me I sounded great. However my audio was smoothest
> 30-50 Hz
> above my operating frequency. They are both audiophiles. My RIT was
> OFF.
> One based his opinion on critical listening. He said the audio was
> very
> good at our mutual frequency but had a slight rasp to it. This went
> away
> about 30 Hz higher. The second gentleman was using a FLEX 5000. He
> indicated that my signal "measured" 50 Hz higher than our stated
> operating
> frequency. He recorded my signal at both frequencies. It was clear
> that I
> sounded best 50 Hz high.
>
>
> I am using the TX ESSB option set at 3.0.
>
>
> Do these observations make sense? If so, do I need to make an
> adjustment?
> It was just the 2nd hour on the air with the new rig, so I'm not 100%
> sure
> that my fine tuning was turned on to 3 digits past the decimal. But
> could
> there be some other explanation?
>
>
> Thanks and 73,
>
> Torrey N9PY
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html