Installed K3EXREF

[Edward R Cole]

It took me about 1-1/2 hours to install the new EXREF for referencing
the TCXO to external 10-MHz.  I have not installed the new firmware
or tested it yet...more news, later.


73, Ed - KL7UW, WD2XSH/45
======================================
BP40IQ   500 KHz - 10-GHz   www.kl7uw.com
EME: 144-1.4kw, 432-100w, 1296-testing*, 3400-winter?
DUBUS Magazine USA Rep [hidden email]
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[David Pratt]

That seems quite a long time to install it, Ted. What's involved?  I
have looked for the manual on-line but it does seem to up there yet.

Any more details would be appreciated;  I'd like to order one.

73 de David G4DMP

In a recent message, Edward R. Cole <[hidden email]> writes
>
>It took me about 1-1/2 hours to install the new EXREF for referencing
>the TCXO to external 10-MHz.  I have not installed the new firmware
>or tested it yet...more news, later.
--
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[AC7AC]

CONTENTS DELETED

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[Roger de Valle]

Is the K3EXEREF production or still in test? I see no mention of it on
the Elecraft WEB site, I have 10Mhz, just nowhere to plug it.

Roger VK3ADA.

On 20/03/2011 10:13, Ron D'Eau Claire wrote:
> Installing the K3EXREF involves installing a connector/cable assembly in the
> REF. hole in the K3's rear panel and running the cable under the RF board to
> the front panel shield, then up behind the front panel shield. The other end
> plugs into the TMP connector on the KREF3 reference oscillator board that
> sticks through the hole in the shield.

--
Roger de Valle
Genette Pty Ltd
03 5330 3081
0407 320 121

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[Eric Swartz - WA6HHQ]

Field  Test.
73, Eric  WA6HHQ

_..._


On 3/19/2011 4:19 PM, Roger de Valle wrote:

> Is the K3EXEREF production or still in test? I see no mention of it on
> the Elecraft WEB site, I have 10Mhz, just nowhere to plug it.
>
> Roger VK3ADA.
>
> On 20/03/2011 10:13, Ron D'Eau Claire wrote:
>> Installing the K3EXREF involves installing a connector/cable assembly in the
>> REF. hole in the K3's rear panel and running the cable under the RF board to
>> the front panel shield, then up behind the front panel shield. The other end
>> plugs into the TMP connector on the KREF3 reference oscillator board that
>> sticks through the hole in the shield.

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[P.B. Christensen]

I installed it on Friday in about 30 minutes, but I'm comfortable with my
way around the K3.  I would think that most users could install it in about
an hour or less.  Installation is actually very simple with very few parts
involved.  K3EXREF came with an SMA connector and SMA to BNC between-series
adapter.

Performance is exactly as promised by Elecraft.  Although K3EXREF will not
phase lock the K3 to the external frequency source, I'm finding that it
stays within 1 Hz on 20m when locked to CHU at 14.670 MHz.   I'm also
finding that testing for zero-beat to WWV at 10 MHz is not a good idea in my
shack, and perhaps yours too.  There are many 10 MHz signals being emitted
by nearby appliances, LAN routers, security system, Ethernet boards, etc.
That common, even frequency is everywhere in a household these days.

In much of North America, CHU is an excellent source for testing since it
keeps cesium accuracy like WWV but the odd frequency of CHU is a real
benefit since the chance for beating against extraneous signals is much
smaller than at 10 MHz.  Testing at a higher frequency rather than say the
MW broadcast band also provides for a reasonably good account of how the
K3EXREF performs.   After installation, I would also suggest not trying to
test zero beat K3EXREF against commercial MW or SW BC stations since their
carriers are allowed to deviate much more than the cesium-based time and
frequency standards of CHU and WWV.  Commercial AM broadcast station
frequencies are typically only accurate to about +/- 20 Hz although most are
better than that.

The K3's 49 MHz oscillator is only adjusted at intervals between 4 and 8
seconds by K3EXREF in order to minimize jitter.  The K3 retains its original
phase noise performance since the external reference is not used internal to
the K3's frequency generating scheme.  Think of it this way -- K3EXREF is
like lightly touching the 49 MHz oscillator with a feather every few seconds
if necessary to keep it within 1 Hz or so.  Also, the K3 frequency stays
accurate even at the moment of powering up the K3.  Kinda' fun to watch the
49 MHz oscillator display change during warm-up as it's being corrected and
compared against the external reference.

External references:  There are three primary types, and all can be
purchased for less than USD $150 on the used market.  Cesium standards (a
fourth type) are also available but are generally much more expensive,
complicated, and won't offer any benefit to K3 users since K3EXREF limits
resolution and accuracy to about 1 Hz.

The first type is the GPS Disciplined Oscillator (GPS-DO).   This type of
standard locks itself onto the visible GPS satellites orbiting the sky.
Requires a GPS antenna and is self-calibrating to the GPS satellites.  The
GPS-DO's time and frequency averages from the visible satellites, each
satellite having it's own on-board cesium-based oscillator.  Long-term
accuracy is usually good to at least 1 x 10^-11.  Extreme accuracy and only
a magnitude or two behind cesium.  Look for Hewlett-Packard Z3801A, Z3816A,
Trimble Thunderbolt, Brandywine, Symmetricon, and Datum models.  Short list,
but many others available.

Rubidium is the next type.  No GPS tracking needed.  Accuracy commensurate
with GPS-DO.  No antenna required.  Long-term performance is highly
dependent on the quality of the optical beam from the rubidium pump lamp.
Look for EF Efratom, Datum,

Third, is a high quality oven-controlled crystal oscillator (OCXO).
Requires periodic calibration.  Accuracy good to at least +/- 0.05 ppm and
offer the best phase noise performance among the three types of oscillators,
but as noted earlier, the excellent phase noise attributes of the OCXO will
not be carried over to the K3.

A shack reference oscillator is good for use with other equipment too (e.g.,
frequency counter).   Although a bit lossy, I currectly use a Mini-Circuits
passive three-way splitter, but one can purchase a distribution amp to feed
many pieces of equipment from a single oscillator.  Unlike the splitter, a
DA offers unity gain and very high port isolation.

Finally, be mindful that most GPS-DO and rubidium units use internal
switch-mode DC-DC converters.  Switching noise was bad enough on two of my
units that I decided to gut the converters and used an outboard
triple-output linear supply.  The Trimble Thunderbolts that have been
retired from the cellular industry require an external triple-output supply.
If choosing this model, get a linear type and avoid the headaches.

Paul, W9AC

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[Jack Smith-6]

On 3/19/2011 9:34 PM, Paul Christensen wrote:

<Major snip of excellent information>

At least some AM stations operating with digital subcarriers are GPS
locked and can be extremely accurate. WMAL 630 KHz here in the
Washington DC area is one example. It's as close to 630 KHz as I can
measure (about 10 milli-Hz) and E-mail correspondence with the station's
chief engineer confirmed the transmitter frequency is GPS locked.

I've measured other local AM stations as far as 16 Hz off - within the
FCC's tolerance, but not of much use as a frequency standard.
> Commercial AM broadcast station
> frequencies are typically only accurate to about +/- 20 Hz although most are
> better than that.
>
>
Jack K8ZOA

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[David Pratt]

Many thanks to Ed KL7UW, Ron AC7AC and Paul W9CA for your helpful
comments on the K3EXREF.

I look forward to this product being available in due course and I have
my 10 MHz standard poised in readiness.

73 de David G4DMP
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[KD8NNU]

So if I understand correctly this soon to be option is basically
constantly adjusting the frequency of the K3 to be correct.

Or in other words a constant adjustment to the reference oscillator.

This could be a real nice to have, as I have been re-adjusting (zero
beating to WWV) to try and tune my K3 to be spot on.  The reason I have
been doing this is that I was thinking I was off frequency but I think
that many radio's out there are off.

Thanks, now I need even more money.

Don
KD8NNU


On Sat, Mar 19, 2011 at 7:13 PM, Ron D'Eau Claire wrote:

> Installing the K3EXREF involves installing a connector/cable assembly
> in the
> REF. hole in the K3's rear panel and running the cable under the RF
> board to
> the front panel shield, then up behind the front panel shield. The
> other end
> plugs into the TMP connector on the KREF3 reference oscillator board
> that
> sticks through the hole in the shield.
> A small pony board plugs into the connector on the component side of
> the
> KREF3 board, held in place by a screw that passes through it and the
> KREF3
> board and into the PEM nut in the shield.
> The biggest part of the project is taking the left side off of the K3
> to
> install the cable. If you have the K144XV installed, it needs to be
> removed.
> If you have the KRX3 subreceiver, it can be left in place. You do
> *NOT* need
> to remove the KRX3 module with all its cables.
> Ed's time of 1.5 hrs sounds about right for someone working carefully
> and
> methodically, doing the job for the first time. There's no soldering,
> of
> course, but still a fair bit of mechanical disassembly/reassembly.
> After doing it several times, I can probably do it in 30 minutes or a
> bit
> less without rushing.
> Ron AC7AC
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of David Pratt
> Sent: Saturday, March 19, 2011 3:49 PM
> To: Edward R. Cole
> Cc: [hidden email]
> Subject: Re: [Elecraft] Installed K3EXREF
>
> That seems quite a long time to install it, Ted. What's involved?  I
> have looked for the manual on-line but it does seem to up there yet.
>
> Any more details would be appreciated;  I'd like to order one.
>
> 73 de David G4DMP
>
> In a recent message, Edward R. Cole <[hidden email]> writes
>>
>> It took me about 1-1/2 hours to install the new EXREF for referencing
>> the TCXO to external 10-MHz.  I have not installed the new firmware
>> or tested it yet...more news, later.
> --
>  + - - - - - - - - - - - - - - - - +
>  | David M Pratt, Kippax, Leeds.   |
>  | Website: http://www.g4dmp.co.uk |
>  + - - - - - - - - - - - - - - - - +
>
>
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[Rick Stealey]

Excellent posting by W9AC, a great reference, to be saved.
Now I wonder if it would be possible for someone to enlighten me as to
the need for such extreme accuracy?  Is it because my K3 reads out to 1 Hz
but I can't really believe the absolute accuracy of that number unless I
get a K3EXREF?  But if that is the case, my question would still remain,
wouldn't it?
Not that I need something else to put on my list ahead of my P3 and
sub receiver.
Rick  K2XT
     
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[David Pratt]

The K3 is indeed sufficiently accurate for amateur use, but if you
already have a 10 MHz Rubidium, Caesium or GPS standard, Rick, then why
not couple it up your K3?  It's just another refinement and helps to put
yours existing frequency standard to good use.

73 de David G4DMP

In a recent message, Rick Stealey <[hidden email]> writes
>
>Excellent posting by W9AC, a great reference, to be saved.
>Now I wonder if it would be possible for someone to enlighten me as to
>the need for such extreme accuracy?
--
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 | Website: http://www.g4dmp.co.uk |
 + - - - - - - - - - - - - - - - - +



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[Mike Maloney]

the need? 
Just because its there and something the import rigs dont have?
Mike AC5P





________________________________
From: Rick Stealey <[hidden email]>
To: [hidden email]
Sent: Sun, March 20, 2011 9:45:59 AM
Subject: Re: [Elecraft] Installed K3EXREF



Excellent posting by W9AC, a great reference, to be saved.
Now I wonder if it would be possible for someone to enlighten me as to
the need for such extreme accuracy?  Is it because my K3 reads out to 1 Hz
but I can't really believe the absolute accuracy of that number unless I
get a K3EXREF?  But if that is the case, my question would still remain,
wouldn't it?
Not that I need something else to put on my list ahead of my P3 and
sub receiver.
Rick  K2XT
                       
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[Jim AB3CV]

What's a GPSDO setup go for including an antenna?

73

jim ab3cv
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[Guy, K2AV]

The question of 1 Hz accuracy can get multiplied a lot in VHF work.

If one is talking about HF, it is hard to see the need.  Personally, I
*LIKE* the idea of being spot on.  It's not a technological justification,
but one I might spend a moderate sum to nail.  If I was doing VHF or UHF
work, I would want it to get the combination of equipment very close.

If you are listening to HF SSB and expecting signals to be spot on kilohertz
boundaries, there are still many signals out there on equipment over a
quarter century old.  I helped an older gentleman with a 160 meter antenna
problem, and he included a station photo with an email. I was surprised to
see that he is STILL using a World War II ARC-5 transmitter as his main
transmitter on 160.  He uses an old National NC183 as his receiver at MF.
 AND, he has some recent contest first place in section finishes on 160 to
prove that it works.

This is perhaps the extreme, but many hams have and use very serviceable
older analog rigs without the frequency accuracy, and you will not find them
at kilohertz boundaries with 1 Hz accuracy.  I would only advise to have a
REASON for the accuracy before you start spending the money, even if that
reason is just that you WANT to be dead on a kilohertz boundary when you
transmit.  Nobody is going to throw you off the air because you are 10 Hz
off.

As the old gentleman proves quite adequately, it ain't the STUFF, it's what
you DO, that is all the fun.

That said, IS there a GPS governed 10 Mhz source to be had out there for
something less than a third world national debt?

73, Guy.

On Sun, Mar 20, 2011 at 10:02 AM, <[hidden email]> wrote:

> So if I understand correctly this soon to be option is basically
> constantly adjusting the frequency of the K3 to be correct.
>
> Or in other words a constant adjustment to the reference oscillator.
>
> This could be a real nice to have, as I have been re-adjusting (zero
> beating to WWV) to try and tune my K3 to be spot on.  The reason I have
> been doing this is that I was thinking I was off frequency but I think
> that many radio's out there are off.
>
> Thanks, now I need even more money.
>
> Don
> KD8NNU
>

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[N5GE]

My reason for wanting one of them is to maintain a stable frequency on VHF and
UHF.

73,
Tom
N5GE

On Sun, 20 Mar 2011 14:45:59 +0000, Rick Stealey <[hidden email]> wrote:

>
>
>Excellent posting by W9AC, a great reference, to be saved.
>Now I wonder if it would be possible for someone to enlighten me as to
>the need for such extreme accuracy?  Is it because my K3 reads out to 1 Hz
>but I can't really believe the absolute accuracy of that number unless I
>get a K3EXREF?  But if that is the case, my question would still remain,
>wouldn't it?
>Not that I need something else to put on my list ahead of my P3 and
>sub receiver.
>Rick  K2XT
>    
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[Jim AB3CV]

I'm guessing this is really useful for EME at UHF.

jim ab3cv
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[Bruce Beford-2]

Jim asked:
> What's a GPSDO setup go for including an antenna?
> 73
> jim ab3cv

You can put together a GPSDO system with 10 MHz output for less than $200.
Here's just one example:
Ebay item # 290322053618 By buying the items separately, you can sometimes
do even better on price.

The Trimble thunderbolts are very popular because a lot have been pulled
from mobile phone tower sites during upgrades. I use one here to phase-lock
my HPSDR system and it works well.

Bruce, N1RX



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[Nate Bargmann]

While this sounds interesting, has any progress been made for those of
us who have the TCXO to be able to program its printed offsets in the
firmware and have it act on them?  The fields are currently there in the
K3 utility but as yet unused, as I understand it.  I would be pleased to
have this functionality enabled.

73, de Nate >>

--

"The optimist proclaims that we live in the best of all
possible worlds.  The pessimist fears this is true."

Ham radio, Linux, bikes, and more: http://www.n0nb.us
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[AC7AC]

CONTENTS DELETED

The author has deleted this message.

[KK7P]

See < URL:http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm >

73,

Lyle KK7P

I have no financial interest in James' products.  I know from decades of
working with him that his stuff is meticulously engineered and
optimised.  LJ

> That said, IS there a GPS governed 10 Mhz source to be had out there for
> something less than a third world national debt?

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