Kevin kevcav at bigpond.com
Sat Jul 2 15:40:23 EST 2011

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 

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
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Kevin Cavanagh

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