[OZAPRS] VK3 APRS News - Follow up

Richard Hoskin vk3jfk at amsat.org
Tue Sep 12 22:10:16 EST 2006


Here is some more details for using the On-Air deviation meter.


To assist packet operators in Melbourne and surrounds to setup their
stations with the correct 3.5 kHz deviation, an automated packet deviation
tester has been set up. This device reports the deviation and signal
strength of all stations it hears.

To use the device, connect to VK3XDE-11 on 145.200 MHz. Issuing the Mheard
command makes the device report the signal strength and deviation of all
stations whose packets it is able to decode (whether they have connected
the device or not). Issue the MHeard command a couple of times to give the
device several packets to sample.

The device may report erroneous readings under the following conditions:

* A badly distorted audio signal

* Badly off frequency

* A noisy signal

* Hum on the transmitter

Also, the signal strength range of the device is currently -108 to -87
(approximately .1 to 10 uV in 50 ohms) Signals below -108 dbm will not be
decoded and signals above -87 dbm will be reported as -87 dbm. You will
actually need a signal of about -100 dBm (approx 2.2 uV in 50 ohms) to be
decoded reliably.

You need to be able to be heard by VK3XDE-11 (in Mt. Waverley) directly to
use the device. If you connect via a digipeater, XDE-11 will report the
deviation of the digipeater.

The device uses a function available in the NETROM Digipeater firmware
some additional hardware added to the TinyII for measurements of the
discriminator etc.






> -----Original Message-----

> From: ozaprs-bounces at aprs.net.au [mailto:ozaprs-bounces at aprs.net.au] On

> Behalf Of Gavin Rogers

> Sent: Tuesday, 12 September 2006 9:54 PM

> To: VK / ZL APRS Users

> Subject: Re: [OZAPRS] VK3 APRS News


> At 07:43 PM 12/09/2006, you wrote:


> >VK3XDE is running an on air Deviation meter.

> >

> >

> >

> >If you wish to test your station's deviation tune to 145.200Mhz and

> connect

> >to VK3XDE-11.

> >

> >Request a list of the commands using the Help command and follow the

> >prompts.


> Wow!


> How does it work? :-)




> 73

> Gavin




> ---

>        Gavin Rogers                     |  Amateur radio station VK6HGR

>      http://www.livingwaters.com/good   |     http://vk6hgr.ampr.org/

>      ICQ: 17230395       MSN/Skype/Email: grogers at vk6hgr.echidna.id.au


> _______________________________________________

> Ozaprs mailing list

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