Message-ID: <000d01c84ce2$f74df3a0$0e00000a@AGB>
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
To: <rsgb_lf_group@blacksheep.org>
References: <477AA0AB.1000300@w1tag.com> <002d01c84cbe$d255e180$0e00000a@AGB> <477AB9A0.5010007@w1tag.com>
Date: Wed, 2 Jan 2008 01:58:17 -0000
MIME-Version: 1.0
Subject: Re: LF: Re: Keyboard modes for 600 meters
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Fine John,



Yes, every little helps  !



That true, you can communicate over quite a range using 'fec' the navtext on 
518 prints well , but as far as I know the published service range is 50 
miles for a navtext station , that would fall in with 'our' observations of 
reliable, fade free,  communication range.



The problem sets in outside that range , I have seen good print from my psk 
signals outside the uk and good results from the Olivia system using 250/16 
, showing the transmission medium is 'stable' ie not 'phase disorientating' 
but notably displaying deep selective fading at carrier shifts over 100 hz , 
leading to recommending shifts of  85 hz and lower. The redundancy in the 
250/16 filling the gap's but still a low date rate, with no indication of 
actual % reception.



Unless you are experiencing qsb  depth and cycle period 'time' considerably 
less than 'we' have experienced, your still up against the final test , 
during qsb 'outage times' no signal = no copy,



The time intervals  have reduced attempted 'data qso's' to  near farce, with 
resolution periods of only  some 10/20 seconds in a 90 second period. An 
increase in power might slightly increase the 'print window' duration ,  but 
is still not proof against the deep fade's



Oddly , I would suspect that 'hf packett' would actually work quite well , 
where it not for the high bandwidth, conversely the short data burst would 
actually ensure the bulk of the traffic was transferred in 'one qsb window' 
, notably the pk232 tnc  will allow  the baudrate for 'hf packet'  to  be 
reduced to  50 , 50 is a bit slow , but 75 or 110 may allow the introduction 
of the 'missing' arq function , notably it uses a simple two tone fsk 
transmission mode as dose rtty and fec and as such my be amplified by 
non-linea means.



G ..









----- Original Message ----- 
From: "John Andrews" <w1tag@w1tag.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Tuesday, January 01, 2008 10:07 PM
Subject: Re: LF: Re: Keyboard modes for 600 meters


> Graham,
>
>> Non of the send and forget modes are of any use on 500 as you have no 
>> idea if the other end has even seen your signal ,let alone resolved it, 
>> that's unless the station is in ground range and then any mode works ,
>
> Perhaps with the higher ERP's over here we are getting better results, as 
> excellent winter-time copy with FEC has been fairly easy over long 
> distances.
>
> If suitable ARQ software materializes, we'll be happy to put it through 
> its paces. My T/R setup would certainly need some redesigning, first! 
> Clunk!
>
> John Andrews, W1TAG
>
>
>
>
>
> -- 
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