[Lowfer] ARGO

jrusgrove at comcast.net jrusgrove at comcast.net
Mon Dec 31 16:54:26 EST 2012 

Doug ... thanks for the capture

Mitch ... new smaller loop (with smaller area) may rob enough power from the bigger original loop to 
end up reducing ERP ... dunno. Would have to run numbers. No ... I have not started drinking.

Jay


----- 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 4:39 PM
Subject: Re: [Lowfer] ARGO


> 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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>>>>>
>>>>>
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