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External 10 Mhz reference level

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Dave Sublette-2

External 10 Mhz reference level

I have a K3s, delivered in January this year. I am using an external GPS
disciplined 10 Mhz reference to the External Ref input on the back. I
cannot find anywhere in the manual what the required level for this input
is. I have -1.1 dBm and it seems to work. However, once in a while, the
K3s frequency shifts down 10 hz, then back to the original frequency, then
up 10 hz, then back to original frequency, all in a matter of two t four
seconds. This happens maybe once a week and lasts for a minute or two. I
have never heard it do more than one sequence of down-back-up-back at
time.

It is very noticeable on receive and a local ham told me he noticed it on
my transmitted signal also.

Could it be that my input level is too low?

It is possible that the GPS reference is jumping, but I haven't been able
to observe that yet. I am watching.

73,

Dave, K4TO
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Grant Youngman-2

Re: External 10 Mhz reference level

It’s in the K3XREF manual. +4 to +16 dBm. Your reference doesn’t have enough output.

Grant NQ5T

> On Nov 21, 2019, at 3:33 PM, Dave Sublette <[hidden email]> wrote:
>
> I have a K3s, delivered in January this year. I am using an external GPS
> disciplined 10 Mhz reference to the External Ref input on the back. I
> cannot find anywhere in the manual what the required level for this input
> is. I have -1.1 dBm and it seems to work. However, once in a while, the
> K3s frequency shifts down 10 hz, then back to the original frequency, then
> up 10 hz, then back to original frequency, all in a matter of two t four
> seconds. This happens maybe once a week and lasts for a minute or two. I
> have never heard it do more than one sequence of down-back-up-back at
> time.
>

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Dave Sublette-2

Re: External 10 Mhz reference level

Ok, thanks. I can fix it! I have another amplifier/splitter I can put on
it. I didn't remember that there was an addition manual for the K3REF

:-(

73,

Dave

On Thu, Nov 21, 2019 at 3:40 PM Grant Youngman <[hidden email]> wrote:

> It’s in the K3XREF manual. +4 to +16 dBm. Your reference doesn’t have
> enough output.
>
> Grant NQ5T
>
> > On Nov 21, 2019, at 3:33 PM, Dave Sublette <[hidden email]> wrote:
> >
> > I have a K3s, delivered in January this year. I am using an external GPS
> > disciplined 10 Mhz reference to the External Ref input on the back. I
> > cannot find anywhere in the manual what the required level for this input
> > is. I have -1.1 dBm and it seems to work. However, once in a while, the
> > K3s frequency shifts down 10 hz, then back to the original frequency,
> then
> > up 10 hz, then back to original frequency, all in a matter of two t four
> > seconds. This happens maybe once a week and lasts for a minute or
> two. I
> > have never heard it do more than one sequence of down-back-up-back at
> > time.
> >
>
>

Edward R Cole

Re: External 10 Mhz reference level

In reply to this post by Dave Sublette-2

+4 to +16 dBm (2.5mw to 40mw). It's stated on last page of kit
instructions (I don't have a copy of the current manual as I was a
beta tester).
but look here: http://www.kl7uw.com/K3EXREF.htm

I use a 10-MHz amplifier with four 10 dBm outputs made by DEMI:
https://www.downeastmicrowave.com/searchresults.asp?Search=10-4&Submit=

I built the kit into my own enclosure. My OCXO is Russian surplus
obtained from e-bay for about $45. I outputs +7 dBm but has strong
2nd harmonic which the DEMI amp filters out. I lock two transverters
in addition to my K3.

+10 dBm would be a good target level for driving the EXREF. Be sure
to check CONFIG: REF CAL for blinking asterisk between REF and
CAL. That indicates that the radio is under EXREF control.

=========================================

From: Grant Youngman <[hidden email]>
To: [hidden email]
Cc: Elecraft Refl <[hidden email]>
Subject: Re: [Elecraft] External 10 Mhz reference level
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=utf-8

It?s in the K3XREF manual. +4 to +16 dBm. Your reference doesn?t
have enough output.

Grant NQ5T

> On Nov 21, 2019, at 3:33 PM, Dave Sublette <[hidden email]> wrote:
>
> I have a K3s, delivered in January this year. I am using an external GPS
> disciplined 10 Mhz reference to the External Ref input on the back. I
> cannot find anywhere in the manual what the required level for this input
> is. I have -1.1 dBm and it seems to work. However, once in a while, the
> K3s frequency shifts down 10 hz, then back to the original frequency, then
> up 10 hz, then back to original frequency, all in a matter of two t four
> seconds. This happens maybe once a week and lasts for a minute or two. I
> have never heard it do more than one sequence of down-back-up-back at
> time.
>

73, Ed - KL7UW
http://www.kl7uw.com
Dubus-NA Business mail:
[hidden email]

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Dave Sublette-2

Re: External 10 Mhz reference level

Ed, et.al.,

I did get my instructions out for the EXTREF. I had forgotten that there
were extra sheets for that. I use an HP Z3801 through an 8 way splitter
and run the 10 MHz from the garage to the shack, a fifty foot run, on .14
in diameter 75 ohm cable. I also put a 1:1 isolation transformer in that
line before it left the garage.

By the time it got to the shack, there was only -1.0 dBm left. So I took
my DEMI 4 output box and tried that. It wouldn't put out more than +2 dBm
to the K3s. So, I hacked the circuit board, taking one of the four
circuits and using it as a driver for the other three. I now get 12.5 dBm
drive to the K3s. All the asterisks are lit. All appears to be working as
advertised.

Thanks for all the advice. It helps to know I am not alone in making these
sorts of decisions.

73,

Dave, K4TO
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