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[aprssig] cellphone as control link?

Andrew Rich vk4tec at tech-software.net
Thu Oct 20 20:18:13 UTC 2005


why not ?

You are licenced to TX on a band

You can listen anywhere

-----------------------------------------
Andrew Rich - VK4TEC
Satellite Ground Station for PCSAT2
vk4tec at tech-software.net
www.tech-software.net
Brisbane AUSTRALIA

-----Original Message-----
From: aprssig-bounces at lists.tapr.org
[mailto:aprssig-bounces at lists.tapr.org]On Behalf Of Jim Lux
Sent: Friday, 21 October 2005 5:07 AM
To: aprssig at lists.tapr.org
Subject: [aprssig] cellphone as control link?


Jeff KT2K commented:
This raises a great discussion on putting trackers on
vehicles of non-licensed persons.

Is it legal to have a non- licensed person turn a amateur radio
on and off and can a cel phone call function as a control link?
---

Interesting point here..
I think everyone will agree that the control operator can control a remote
transmitter by means of a wireline connection (historically, a leased line).

Further, you can use a control link on an appropriate frequency (220
MHz).  The link doesn't have to be continuous, does it? (i.e. I can use a
PTT on my control signals)

You can also control by a "virtual wireline connection" (maybe not a leased
line, but a "nailed up" ISDN phone call across the United States, for
instance).

What about more ephemeral controls though:?

Autoanswer and wireline phone call?
VoIP?
Cell phone to autoanswer phone and TT decoder?
Internet remote access (telnet?)

Two incoming phone lines at the remote site, each of which rings a
different bell and lights a different colored light, with a trained pigeon
who observes the light and pecks at one switch or another to turn the
transmitter on or off.

Cellphone call to teenage daughter and have her turn on or off transmitter
(assuming you can get through with call waiting) [one might argue the
pigeon approach is more reliable than the teenager]

Mailing a letter to the remote station, and when the site maintenance guy
comes through once a month, he reads the letter and flips the switch
accordingly.

Clearly, at some point, the control mechanism has become either unreliable
enough, or has sufficient latency that you're not really "controlling"
anymore.

How reliable does the link need to be? If my internet access at home is
disabled because of  DoS attack, do I need a backup control plan? What if
my telephone is disconnected or fails?

Is there some implied requirement for a "failsafe" or "deadman" (If the
remote doesn't receive some sort of communication within 2 hours, it shuts
down the transmitter.)

Jim, W6RMK



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