[Lowfer] ARGO

Douglas D. Williams kb4oer at gmail.com
Mon Dec 31 16:39:04 EST 2012 

Thanks, Jay. Just took a screenshot. Receiver tuned to 137.781 so I'm one
tenth of one Hz off.

https://dl.dropbox.com/u/33457409/133781Hz.jpg

Still looking for MP in there though.....

That faint trace right below XNS must be MP.

Sorry, kinda combining two separate threads here. I don't multitask well.
:-)

73, Doug KB4OER




On Mon, Dec 31, 2012 at 4:32 PM, <jrusgrove at comcast.net> wrote:

> GPS referenced to137781.000
>
> Jay W1VD  WD2XNS  WE2XGR/2
>
>
> ----- Original Message ----- From: "Douglas D. Williams" <kb4oer at gmail.com
> >
> To: "Discussion of the Lowfer (US, European, &amp,UK) and MedFer bands" <
> lowfer at mailman.qth.net>
> Sent: Monday, December 31, 2012 4:28 PM
> Subject: Re: [Lowfer] ARGO
>
>
>
>  Anyone have the exact transmit frequency for XNS at the moment?
>>
>>
>>
>>
>> On Mon, Dec 31, 2012 at 4:20 PM, Douglas D. Williams <kb4oer at gmail.com
>> >wrote:
>>
>>  Nope, gonna have to eat some crow. That's not MP I'm seeing, so I may be
>>> off more than I think. :-)
>>>
>>> Still looking for MP.
>>>
>>> 73, Doug KB4OER
>>>
>>>
>>>
>>>
>>> On Mon, Dec 31, 2012 at 4:13 PM, Douglas D. Williams <kb4oer at gmail.com
>>> >wrote:
>>>
>>>  John,
>>>>
>>>> I'm sure you are absolutely correct. The method I described is just a
>>>> quick and dirty method, not needing a frequency counter, known
>>>> calibrated
>>>> audio tone source, or any other equipment whatsoever. It has worked well
>>>> enough for me for several years now that I know when (after I allow my
>>>> receiver to warm up) I tune to a certain frequency from 10-500 kHz to
>>>> receive a QRSS or WSPR signal I'm never more than half a Hz off.
>>>> Looking at
>>>> MP scrolling across now.... it looks like, now that my receiver has
>>>> warmed
>>>> up (and assuming MP is right on frequency), that I am one tenth of one
>>>> Hz
>>>> off in my calibration. I can't remember when I last did an Argo
>>>> calibration
>>>> on this receiver+upconverter....**probably early October, when the
>>>> listening
>>>> season started.
>>>>
>>>> I rarely tune above 500 kHz, so I don't give much thought to frequency
>>>> calibration errors at HF or above.
>>>>
>>>> 73, Doug KB4OER
>>>>
>>>>
>>>>
>>>> On Mon, Dec 31, 2012 at 3:50 PM, John Andrews <w1tag at charter.net>
>>>> wrote:
>>>>
>>>>  Doug,
>>>>>
>>>>> Just to split a couple of hairs:
>>>>>
>>>>> You need a known audio frequency to calibrate the sound card sampling
>>>>> rate. An audio tone from a receiver that depends on a converter L.O.,
>>>>> and
>>>>> one or more conversion oscillators (and maybe the BFO) doesn't qualify.
>>>>>
>>>>> The combination of the converter and receiver likely has a frequency
>>>>> offset that varies with receiver tuning. Calibration of that offset at
>>>>> 60
>>>>> kHz may be in error at other frequencies.
>>>>>
>>>>> The above applies to fussy situations like WOLF and slow PSK modes,
>>>>> where sampling rate must be nailed to keep framing consistent, and
>>>>> receiver
>>>>> offsets nulled out.  For QRSS use, you'll likely see cal errors between
>>>>> bands, and they MAY be small enough to ignore.
>>>>>
>>>>> John, W1TAG
>>>>>
>>>>>
>>>>>
>>>>> On Dec 31, 2012, at 2:43 PM, "Douglas D. Williams" <kb4oer at gmail.com>
>>>>> wrote:
>>>>>
>>>>> > Hi Mike. My method for calibrating ARGO is very simple, and does not
>>>>> > require any extra equipment. As someone else pointed out, first you
>>>>> have to
>>>>> > know the BFO sidetone of your receiver. Most modern receivers allow
>>>>> you to
>>>>> > vary this sidetone through some sort of menu. I happen to like to
>>>>> hear
>>>>> a
>>>>> > 700Hz tone when listening to CW, so that's what I keep mine at. I
>>>>> tune
>>>>> to
>>>>> > 60 kHz WWBV with the receiver set to CW mode (reverse CW for Icom
>>>>> > receivers), and allow the receiver to warm up for an hour. If you are
>>>>> using
>>>>> > an upconverter, then simply tune to the converter's LO frequency + 60
>>>>> kHz,
>>>>> > so in my case that would be 3.060 MHz. At this point I would set Argo
>>>>> to
>>>>> > some relatively fast QRSS speed such as QRSS10, and center 700Hz on
>>>>> the
>>>>> > right side scale. You may have to reduce the receiver's audio gain
>>>>> and
>>>>> > lower Argo's sensitivity slider quite a bit because WWVB is very
>>>>> strong in
>>>>> > the lower 48. If your total system calibration is within 20Hz or so
>>>>> of
>>>>> > being correct, you should see a bold, thick line start scrolling
>>>>> across the
>>>>> > screen, with thinner lines (sidebands, I guess) above and below it.
>>>>> What
>>>>> > you want to do is go into Argo's setup menu and choose Calibration.
>>>>> If
>>>>> you
>>>>> > see the bold line at, say 705Hz then you would enter 700 (if that's
>>>>> the
>>>>> > sidetone you are using) in the Measured frequency box and 705 in the
>>>>> > Displayed frequency box. That should get you within one Hz of being
>>>>> dead
>>>>> > on. You can dial it in even more at the slower QRSS speeds by using
>>>>> decimal
>>>>> > places in the numbers you put in the Displayed frequency box.
>>>>> >
>>>>> > What you are doing is calibrating the total receive system (receiver,
>>>>> > upconverter, computer sound card) to be correct on the Argo screen.
>>>>> Of
>>>>> > course, the job is easier if the oscillators in your receiver and
>>>>> > upconverter are close to the frequency they should be. If you are
>>>>> using an
>>>>> > upconverter with one of those little 4 MHz crystals about the size
>>>>> of a
>>>>> > child's fingernail, good luck. ;-)
>>>>> >
>>>>> > At this point, many people go a step further because they like to
>>>>> have
>>>>> > Argo's frequency scale (the one on the right) display the actual
>>>>> frequency
>>>>> > (in Hz) that they have the receiver tuned to. This can be
>>>>> accomplished
>>>>> by
>>>>> > using the Offset box in the Calibration window and typing in the
>>>>> frequency
>>>>> > you have the receiver tuned to, minus your BFO frequency, if I
>>>>> remember
>>>>> > correctly. I'm usually too lazy to do this, so my screen captures
>>>>> tend
>>>>> to
>>>>> > just have the BFO sidetone frequency.
>>>>> >
>>>>> > Well, that was a lot of typing to describe something that generally
>>>>> only
>>>>> > takes about five minutes to do, once the receiver is warmed up. ;-)
>>>>> >
>>>>> > 73, Doug KB4OER
>>>>> >
>>>>> > On Mon, Dec 31, 2012 at 1:58 PM, Mike Sanders <k0az at centurytel.net>
>>>>> wrote:
>>>>> >
>>>>> >> Stan, Charlie and Mark, Thanks very much for all your input.
>>>>> >> I am going to continue to follow through with this until I get it.
>>>>> >> Your help may make the difference.
>>>>> >> I am also using a converter and it is introducing minus 302 hz
>>>>> >> of aggravation from the LO. My first lowfer target is WMS only
>>>>> >> about 170 miles South of me.
>>>>> >> I have not looked through all your email info yet but will as well
>>>>> >> as checking out John's write up on ARGO set up.
>>>>> >> Thanks again and you will know when I get a good capture.  73
>>>>> >>
>>>>> >> Happy New Year
>>>>> >> Mike Sanders
>>>>> >>      K0AZ
>>>>> >>
>>>>> >>
>>>>> >>
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