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[Linrad] Re: Linrad network connections

Hi Doug,

Thanks for letting me know of your continued interest in a 
version of MAP65 optimized for 23 cm.  I haven't forgotten 
about it ... but it hasn't reached the top of my "to do" 
list, yet.  Too much going on around here, I guess ...

Have a good vacation!

	-- Joe, K1JT

Doug G4DZU wrote:
> Hi Joe,
> Unfortunately the convention conflicts with our annual vacation, so I can't
> be there.
> Since we last spoke I've got a SDR-IQ and SDR-1000 which makes JT65 via the
> moon a lot easier.
> But still waiting, and hoping, for MAP65 being able to function with JT65C
> for 1296Mhz work.
> 73s
> Doug
> -----Original Message-----
> From: linrad@xxxxxxxxxxxxxxxx [mailto:linrad@xxxxxxxxxxxxxxxx]On Behalf
> Of Joe Taylor
> Sent: 24 July 2008 22:02
> To: linrad@xxxxxxxxxxxxxxxx
> Subject: [Linrad] Linrad network connections
> Today I've been playing with the Linrad+MAP65 combination, in
> preparation for making some demonstrations at the EME Conference in
> Florence.
> I noticed something that may be interesting to others on this list.
> You'll recall that Linrad serves as a "front end" to MAP65.  Digital
> data in the Linrad "timf2" format, taken after the first inverse FFT,
> are sent over an ethernet connection to MAP65.  The default Linrad code
> does this transfer in the form of multicast UDP packets.  Multicast
> means that there is one source of packets -- Linrad -- and in principle
> there may be many receivers.  Many months ago I changed my working copy
> of Linrad (version 02.34) so that instead of multicast it uses
> "unicast".  That is, data are sent explicitly to a single IP address,
> that of the machine running MAP65.  This resulted in more reliable data
> transfer -- and also, even more importantly, it prevented swamping my
> local network with Linrad traffic so that my wife could not use the
> network to check her email, etc.
> Today I discovered another big advantage of sending unicast rather than
> multicast packets.   On my network, at least, multicast transfers make
> *much* more RFI.  Every packet transfer is clearly audible on an HF
> receiver tuned to the 30 m band.  I don't hear anything at all when I
> switch to making transfers to a single IP address.
> 	-- 73, Joe, K1JT
> > 

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