[Lowfer] ARGO
jrusgrove at comcast.net
jrusgrove at comcast.net
Mon Dec 31 16:32:47 EST 2012
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, &,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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>>>
>>>
>>
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