[OZAPRS] RE: Ozaprs Digest, Vol 5, Issue 20

[Ian Mills]

Darryl,

I'm having a hard time comprehending your statement 
" .. since you are transmitting at 8 times the speed, and so this is the equivalent of only transmitting 1/8th the power"

Is there any theory I could google to understand it better, I'm not sure where to start my search?

Thanks
Ian vk2him

------------------------------

Message: 3
Date: Fri, 23 May 2008 09:26:29 +1000
From: "Darryl Smith" <Darryl at radio-active.net.au>
Subject: RE: [OZAPRS] 70cm APRS
To: "'Australian APRS Users'" <ozaprs at aprs.net.au>
Message-ID: <049f01c8bc63$42ff4930$c8fddb90$@net.au>
Content-Type: text/plain;	charset="US-ASCII"

I think a 9600 bps UHF APRS frequency is not a great idea.

The reason is that each APRS transmission at 1200 bps takes about 1 second.
Most of this is the TxDelay. The TxDelay on UHF is commonly the same, so you might go from 1000 mSec to 600 mSec. This is not much of an improvement.

But since you are transmitting at 8 times the speed, and so this is the equivalent of only transmitting 1/8th the power. Your 9600 bps 24 Watt radio becomes a 8 Watt 1200 bps radio.

Darryl

-----Original Message-----
From: ozaprs-bounces at aprs.net.au [mailto:ozaprs-bounces at aprs.net.au] On Behalf Of Peter Schrader
Sent: Thursday, 22 May 2008 10:59 PM
To: VK / ZL APRS Users
Subject: [OZAPRS] 70cm APRS

Hello all,
What does everybody think about having a dedicated frequency for 9k6 APRS on UHF?

Next question, could we all agree on a nationwide frequency?

Regards,
Peter Schrader,
VK4TGV/9V1PS
Redcliffe and Districts Radio Club
Singapore Amateur Radio Transmitting Society WIA Assessor 4-055

APRS - VK4TGV-12, VK4TGV-7, VK4TGV-2 and 9V1PS ALE HFN Pilot Station - http://hflink.com

AWA Limited

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