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[KX3] Need Advice - Xmt & Rcv frequencies differ but RIT turned off

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AB3SX

[KX3] Need Advice - Xmt & Rcv frequencies differ but RIT turned off

I am guessing I have mis-set some menu-settable parameter and I am looking for advice as to which one I might have mis-set so I can solve the following problem:

I am finding that I must set my KX3 receive a few hundred hertz higher than the actual frequency on which a station says he is transmitting so that I achieve natural sounding voice on receive. When I do that, the other station says my voice pitch is too low. ( So he corrects, then I correct, and we chase one another up the band. )
The same behavior occurs on CW operation.

The error seems to increase with operating frequency as shown in the following table:

In LSB receive WWV 05.0 megahertz carrier zero beats at approximately 05.000 133
In LSB receive CHU 7.335 megahertz carrier zero beats at approximately 07.335 190
In LSB receive WWV 10.0 megahertz carrier zero beats at approximately 10.000 250
In LSB receive WWV 15.0 megahertz carrier zero beats at approximately 15.000 384

Thanks for any suggestions; for now I am back to studying the operator's manual :)

Jerry AB3SX

tcollen

Re: [KX3] Need Advice - Xmt & Rcv frequencies differ but RIT turned off

Hi Jerry,

My TS-590 exhibits almost a similar situation, without the SO-3 high-stability oscillator installed. The specs say the 590's frequency stability is within +- 5ppm, and I've found the higher in frequency I go, the further up I need to tune to zero-beat a station. On 20m, I've found I have to consistently tune up a bit to center.

Doing the math, it looks like your KX3 is at least consistently off by 25 or 26 ppm:

133 / 5.0 = 26.6 ppm
190 / 7.335 = 25.9 ppm
250 / 10.0 = 25 ppm
384 / 15.0 = 25.6 ppm

25-26 ppm definitely adds up, and it seems to me the unit is mis-calibrated, but I don't know what the KX3's tolerance for frequency stability is. I'm a new KX3 owner myself so I haven't had enough experience with it to figure out if my unit is off by a small bit or not.

Does the behavior change when the unit has been off for a while, vs when it warms up?

Cheers,

- Tony, N0RUA

Don Wilhelm-4

Re: [KX3] Need Advice - Xmt & Rcv frequencies differ but RIT turned off

Frequency stability is normally expressed in terms of ppm over a
specific temperature range.
For the KX3 it is +/- 1 ppm over 0 to 50 degC.

I believe the statements below confuse tuning frequency calibration
inaccuracy with stability - one has nothing to do with the other.
Problems with the KX3 being consistently off frequency can normally be
resolved by doing the Reference Frequency Calibration (see the
Caalibration section of the manual).

73,
Don W3FPR

On 8/12/2014 3:14 PM, tcollen wrote:

> Hi Jerry,
>
> My TS-590 exhibits almost a similar situation, without the SO-3
> high-stability oscillator installed. The specs say the 590's frequency
> stability is within +- 5ppm, and I've found the higher in frequency I go,
> the further up I need to tune to zero-beat a station. On 20m, I've found I
> have to consistently tune up a bit to center.
>
> Doing the math, it looks like your KX3 is at least consistently off by 25 or
> 26 ppm:
>
> 133 / 5.0 = 26.6 ppm
> 190 / 7.335 = 25.9 ppm
> 250 / 10.0 = 25 ppm
> 384 / 15.0 = 25.6 ppm
>
> 25-26 ppm definitely adds up, and it seems to me the unit is mis-calibrated,
> but I don't know what the KX3's tolerance for frequency stability is. I'm a
> new KX3 owner myself so I haven't had enough experience with it to figure
> out if my unit is off by a small bit or not.
>
> Does the behavior change when the unit has been off for a while, vs when it
> warms up?
>
>

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dmb@lightstream.net

Re: [KX3] Need Advice - Xmt & Rcv frequencies differ but RIT turned off

In reply to this post by AB3SX

Jerry,

Not sure I understand; are you saying that your KX3 transmit frequency is
actually DIFFERENT than its receive frequency (with RIT and XIT off)? I
didn't think that was even possible. I understand that your KX3 may not
display the correct frequency when tuned in correctly to an ssb signal,
but that's just a matter of running the frequency calibration on the KX3.

As for crawling up and down the band as a result, if you tune in the SSB
signal so that it sounds proper, the other station should be receiving you
at the proper 'pitch' as well. No need for anybody to change the VFO dial
if you're tuned in. Yes, your frequency display may not agree with the
other stations frequency display, but tuned-in is tuned-in (unless the KX3
TX and RX can truly be on different frequencies).

Hope I didn't muddy the waters any further with this; just trying to
understand what's happening.

73, Dale
WA8SRA

> I am guessing I have mis-set some menu-settable parameter and I am looking
> for advice as to which one I might have mis-set so I can solve the
> following
> problem:
>
> I am finding that I must set my KX3 receive a few hundred hertz higher
> than
> the actual frequency on which a station says he is transmitting so that I
> achieve natural sounding voice on receive. When I do that, the other
> station
> says my voice pitch is too low. ( So he corrects, then I correct, and we
> chase one another up the band. )
> The same behavior occurs on CW operation.
>
> The error seems to increase with operating frequency as shown in the
> following table:
>
> In LSB receive WWV 05.0 megahertz carrier zero beats at approximately
> 05.000
> 133
> In LSB receive CHU 7.335 megahertz carrier zero beats at approximately
> 07.335 190
> In LSB receive WWV 10.0 megahertz carrier zero beats at approximately
> 10.000
> 250
> In LSB receive WWV 15.0 megahertz carrier zero beats at approximately
> 15.000
> 384
>
> Thanks for any suggestions; for now I am back to studying the operator's
> manual :)
>
> Jerry AB3SX
>

tcollen

Re: [KX3] Need Advice - Xmt & Rcv frequencies differ but RIT turned off

In reply to this post by Don Wilhelm-4

Don,

Thanks for setting clearing this up for me. Very helpful.

Regards,

Tony

On Wed, Aug 13, 2014 at 8:04 AM, Don Wilhelm <[hidden email]> wrote:

> Frequency stability is normally expressed in terms of ppm over a specific
> temperature range.
> For the KX3 it is +/- 1 ppm over 0 to 50 degC.
>
> I believe the statements below confuse tuning frequency calibration
> inaccuracy with stability - one has nothing to do with the other.
> Problems with the KX3 being consistently off frequency can normally be
> resolved by doing the Reference Frequency Calibration (see the Caalibration
> section of the manual).
>
> 73,
> Don W3FPR
>
>
> On 8/12/2014 3:14 PM, tcollen wrote:
>
>> Hi Jerry,
>>
>> My TS-590 exhibits almost a similar situation, without the SO-3
>> high-stability oscillator installed. The specs say the 590's frequency
>> stability is within +- 5ppm, and I've found the higher in frequency I go,
>> the further up I need to tune to zero-beat a station. On 20m, I've found I
>> have to consistently tune up a bit to center.
>>
>> Doing the math, it looks like your KX3 is at least consistently off by 25
>> or
>> 26 ppm:
>>
>> 133 / 5.0 = 26.6 ppm
>> 190 / 7.335 = 25.9 ppm
>> 250 / 10.0 = 25 ppm
>> 384 / 15.0 = 25.6 ppm
>>
>> 25-26 ppm definitely adds up, and it seems to me the unit is
>> mis-calibrated,
>> but I don't know what the KX3's tolerance for frequency stability is.
>> I'm a
>> new KX3 owner myself so I haven't had enough experience with it to figure
>> out if my unit is off by a small bit or not.
>>
>> Does the behavior change when the unit has been off for a while, vs when
>> it
>> warms up?
>>
>>
>>
> ______________________________________________________________
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>
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