[UK-CONTEST] RE: Telnet

[Andy Cook, G4PIQ]

I've certainly had much better experiences with O2 and managed to get on
OK with Writelog & GPRS at least in the test environment for GB5HQ - I
used Bluetooth to do the connection to the phone - not sure if that
solved issues with Writelog grabbing serial ports.

However - the big issue with GPRS is if you're in an area which is
reasonably well covered by more than one cell site (actually more than
one sector to be correct - most cell sites have 3 sectors - usually 120
degrees apart) then GPRS can flop between cells as one signals gets
dominant over another due to usual multipath fading effects at 900/1800.
This causes your throughput to fall through the floor since handover
between cells is not (almost) instant like it is for voice. Not a lot
that I'm aware that you can do about that except try moving the phone
about to stop it happening.

Andy, G4PIQ

-----Original Message-----
From: uk-contest-bounces at contesting.com
[mailto:uk-contest-bounces at contesting.com] On Behalf Of Andy Summers
Sent: 15 December 2003 10:22
To: uk-contest-X-contesting.com-POP-1 at mail-x-change.com
Subject: [UK-CONTEST] RE: Telnet


Steve,

I see you've already had some useful replies, but I thought I'd chip-in
with some experiences from the GB5HQ 15m SSB station.

We used GPRS to access the internet for WriteLog log sharing and to
receive telnet cluster spots. The telnet connection was somewhat more
successful than the log sharing. What I want to bring to your attention
is the loss of connection problems we encountered. The GPRS connection
was regularly dropped, either by Orange, or by the ISP Orange uses. It
happened about once an hour, but it wasn't exactly an hour. This can't
have been due to lack of traffic! We also had a good signal.

Getting the link back was pretty painful. Both the phone's accessory
handling software and the PC resident software that provides the serial
interface appeared to crash. Mostly you could get it all back by
terminating the telnet session, powering the phone off then on, then
re-inserting the butt-plug. Sometimes a complete PC re-boot was required
to get everything talking again. Note that Writelog grabs all available
serial ports for itself, so it has to be started after the telnet
session.

I don't know if this is just peculiar to Orange. Anyone any better
experiences with other companies?

73,
Andy, G4KNO.

> -----Original Message-----
> From: uk-contest-bounces at contesting.com 
> [mailto:uk-contest-bounces at contesting.com]On Behalf Of

> ----------------------------------------------------------------------
>
> Date: Sat, 13 Dec 2003 07:43:26 +0000 (GMT)
> From: Steve Bunting <stephen.bunting at kcl.ac.uk>
> To: uk-contest at contesting.com
> Subject: [UK-CONTEST] Telnet
> Message-ID: <Pine.GSO.4.21.0312130741460.14106-100000 at redwood>
> Content-Type: TEXT/PLAIN; charset=US-ASCII
> MIME-Version: 1.0
> Precedence: list
> Message: 1
>
> Hi again everyone,
>
> I have a brief question for you all from a computing innocent.....
>
> I am looking into telnet cluster access to using a GPRS mobile phone. 
> The idea is to get reliable cluster access from a remote contest 
> location, RF links have proved to be nothing but trouble. I am trying 
> to assess the cost of keeping the link live for a 24hour contest. As 
> you probably know the phone companies charge per MB transferred rather

> than unit time, with Orange it is 2.55UKP plus VAT per MB.
>
> Now my questions: how many bytes constitute one cluster spot? A more 
> difficult question is how many spots are there per contest weekend? I 
> am guessing at a mean of 3 spots per minute, i.e. 180 per hour and 
> therefore 3420 per 24 hours. Lets round that up to a ballpark 5000. Is

> that reasonable for a FD?
>
> I don't want to commit to a route that will cost a fortune to keep 
> alive, but I am guessing that a single spot is pretty small. If I am 
> feeling very tight, I can probably reduce traffic (and hence costs) by

> setting filters at the cluster.
>
> Can anyone advise or add experiences to this?
>
> Thanks as always.
>
> 73
> Steve
> M0BPQ


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