While all of the methods using WWV are excellent, many of us already have the
GPS downloaded 10 MHz signal for the shop and ham shack. I mentioned some time
about using a Video distribution amplifier to pipe the 10 MHz signal around. I
have it at the operating console for any checks I need.
Mel, K6KBE
From: Ron D'Eau Claire <r...@cobi.biz>
To: 'Brendon Whateley' <bren...@whateley.com>
Cc: 'Elecraft Reflector Reflector' <elecraft@mailman.qth.net>
Sent: Sunday, December 18, 2016 11:49 AM
Subject: Re: [Elecraft] Sync AM and checking VFO accuracy using WWV
The methods described by Wayne in the K3 or K3S Owner's manuals are
excellent.
I used Method 2 (comparing to WWV's carrier frequency) and easily achieve
less than 1 Hz accuracy. If one needs something in the tenth's of a Hz or
better then more exotic techniques are required (and likely the K3EXREF and
an external frequency reference).
NOTE: When using Method 2 with WWV, wait until the tones stop and only the
ticks are transmitted, then check to be sure you are still "zero beat". Some
ops get confused between the tones and carrier and end up several hundred Hz
off because they zero-beated the tone instead.
For SSB/CW/RTTY modes accuracy to within some tens of Hz is fine. AM is even
less sensitive.
73 Ron AC7AC
-----Original Message-----
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of
Brendon Whateley
Sent: Sunday, December 18, 2016 10:56 AM
Cc: Elecraft Reflector Reflector
Subject: Re: [Elecraft] Sync AM and checking VFO accuracy using WWV
Depending on why you want the accuracy, I think you could improve things by
building a phase comparator to "listen" to the radio output frequency
against a local reference. That would allow you to get much closer than
using your ears as a phase detector. That should get you accuracy of a few %
of 1Hz at your frequency you are measuring.
If you are really serious about accuracy, you can build a frequency
reference based on the WWV transmissions that will get you to within 1 part
per billion at 1MHz without too much trouble.
There was a QEX article recently, which you can find on the web at
http://www.arrl.org/files/file/QEX_Next_Issue/2015/Nov-Dec_2015/Magliacane.p
df
.
I'm sure that spending money on a GPS reference would be quicker, but less
fun than building a project.
If you go down that road, you'll be well on your way to winning frequency
measuring contests!
- Brendon
KK6AYI
On Sun, Dec 18, 2016 at 5:07 AM, Don Wilhelm <donw...@embarqmail.com> wrote:
> Brian,
>
> The higher the WWV frequency, the possible percentage of error goes down.
> One or two Hz is a smaller fraction of 20MHz than at 5MHz.
>
> In the K3, you are calibrating the reference (out of the synthesizer)
> rather than calibrating the actual VFO frequency. The actual VFO
> frequency is derived from and phase locked to that reference.
>
> 73,
> Don W3FPR
>
>
> On 12/18/2016 12:17 AM, Brian Denley wrote:
>
>> Fred, Don:
>> I ask because I am curious. On any older receiver, calibration at 20
>> MHz would not guarantee cal below that ( or at any other frequency ).
>> One could be 5 hz high at 30 MHz but 10 hz low at 7 MHz. Why is the
>> K3 different?
>>
>> Brian Denley
>> KB1VBF
>> Sent from my iPad
>>
>> On Dec 17, 2016, at 3:43 PM, Fred Jensen <k6...@foothill.net> wrote:
>>>
>>> I guess it depends on how accurate you want your K3 frequency
>>> display to be. I think AM-S will warp the frequency a tiny bit to
>>> sync the carrier so that may not be the best mode. I'd also go as high
as you can on WWV.
>>>
>>> Wayne suggested a method that is somewhere on the E-site which I
>>> used--
>>>
>>> Use the highest WWV frequency that you can hear well. USB or LSB,
>>> WIDTH to 500-800 Hz, SHIFT so can hear the carrier beat note [it
>>> will be very low]. CONFIG-->REF CAL, wait for a tone-less minute
>>> and adjust REF CAL for exact zero beat. You'll be counting the
>>> pulsations in the background noise as you come up on zero beat.
>>>
>>> I got mine to about 10 seconds per pulsation on 20 MHz back when
>>> there were sunspots. That's an accuracy of 0.1 Hz and everything
>>> below 20 MHz will be at least that good.
>>>
>>> 73,
>>>
>>> Fred K6DGW
>>> - Sparks NV DM09dn
>>>
>>> - Northern California Contest Club
>>> - CU in the Cal QSO Party 7-8 Oct 2017
>>> - www.cqp.org
>>>
>>> On 12/16/2016 5:12 PM, Michael via Elecraft wrote:
>>>> If I set my K3's VFO to WWV at 5.000000 MHz with AM-S on....and I
>>>> adjust "REF CAL" to a number where my VFO's frequency readout is
>>>> exact or near this number +/- maybe a Hertz or two. Is this an
>>>> accurate way to calibrate my K3?
>>>>
>>>> It seems to be very accurate as far as I can tell.
>>>>
>>>> Has anyone used this method?
>>>>
>>>> Michael
>>>> N2ZDB
>>>>
>>>
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>>
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