Ray Wells vk2tv at exemail.com.au
Sun Jul 3 07:46:47 EST 2011


Anyone with access to WWV(H) and a CRO has an accurate means of easily 
calibrating a receiver to <<10Hz.

Checking the waterfall display calibration is just as easy, feed a known 
audio tone into the sound card input and check against the waterfall 
audio tone calibration.

If you consider a discussion on frequency accuracy as an example of 
packet police, it's probably just as well your gear is turned off.

What's the problem Kevin, is the discussion too technical for you?

Ray vk2tv

On 02/07/11 15:40, Kevin wrote:
> Hi all,
> All this hot air about relative frequencies I just wonder just how many
> of you have the means of calibrating your receiver?? I seem to remember
> that was a mandatory requirement of the regs or has that been relaxed as
> well.
> How do you all calibrate those wonderful waterfall displays that many
> keep referring to? or is it a case of the blind leading the blind. After
> all you are relying on the software writer to have his maths correct.
> On the SCS DSP trackers I have one here and they certainly are worth the
> investment but with the packet police out and about it remains like all
> my APRS gear switched off and with discussions like this it will likely
> remain that way for a long time to come
> Enjoy what you have
> Kevin VK4SP
> On 07/02/2011 03:10 PM, Norm, VK3XCI wrote:
>> Unless of course if it's an *international* net. Then the primary
>> *international* net station is the *only* one on frequency, and subnet
>> should be within +or- 1x10^-n of the primary ( where n represents the
>> number we all agree on, say -6)
>> :)
>> 73 de Norm, VK3XCI
>> Mildura, Australia
>> The Wintersun City
>> QF15bt.
>> On 2/07/2011 11:50 AM, Ron Perry wrote:
>>> On Sat, 2011-07-02 at 08:35 +1000, Ray Wells wrote:
>>>> Mike,
>>>> A query re the figures shown at http://aprs.fi/?c=raw&call=vk6uz-4
>>>> VK3MY-4 is shown with a figure of +78 which suggests he is higher in
>>>> frequency than a station shown as +50, for example.
>>>> How can this be so when VK3MY-4 is clearly displayed in a waterfall
>>>> display as being lower in frequency than almost every other station and
>>>> other contributors to this forum have made the same observation?
>>>> I know the figures are relative but that relativity suggests that,
>>>> given
>>>> the number of stations shown as +50, those stations are on the correct
>>>> frequency and VK6UZ-4 is not.
>>>> I think we need to decide on a reference (net) station that is on
>>>> frequency and from that known reference, every station would be able to
>>>> use a waterfall display to net to the reference station. Those simple
>>>> steps would eliminate most of the frequency error related problems. In
>>>> fact, if one station was the standard, every other station could, by
>>>> using a waterfall display, become a pseudo sub-standard - a bit like
>>>> calibrating meters.
>>> The Net station is the *only* one on frequency. All the others are off
>>> frequency. It is a Net frequency. Nothing else matters.
>>> Ron
>>> vk3ecv
>>> _______________________________________________
>>> OZAPRS mailing list
>>> OZAPRS at aprs.net.au
>>> http://lists.aprs.net.au/mailman/listinfo/ozaprs
>> _______________________________________________
>> OZAPRS mailing list
>> OZAPRS at aprs.net.au
>> http://lists.aprs.net.au/mailman/listinfo/ozaprs

More information about the OZAPRS mailing list