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[Linrad] Re: MAP65 for SDR-IQ
- Subject: [Linrad] Re: MAP65 for SDR-IQ
- From: Joe Taylor <Princeton.EDU; joe@xxxxxxxxxxxxxxxx>
- Date: Mon, 16 Feb 2009 10:27:05 -0500
Many thanks for your reply to my post about MAP65-IQ! I
expect that within about one more week I will be ready to
package the program with some basic instructions so that
others may test it and provide feedback. I'll let you know
when it is ready!
-- 73, Joe, K1JT
Edward Cole wrote:
> I am deffinitely interested. My eme system is H/V switchable in Rx
> and Tx independently, so I can tap off 2m in the shack to my DEMI
> 144/28 + SDR-IQ whihc is connected to the computer via USB-2.0. I
> have an earlier version of MAP-65 and winrad and JT-65 all on a Dell
> Vostro duo-core2 2.33 Gb computer (win-XP-Pro).
> 73, Ed
> QRV with 2m-8877-600w
> At 11:08 AM 2/13/2009, you wrote:
>> Hello Moonbouncers,
>> Many people have asked about a version of MAP65 that could
>> be used with the SDR-IQ receiver. I'm happy to report that
>> an operational version of "MAP65-IQ" now exists. It should
>> be ready soon for testing by others.
>> You'll recall that MAP65 works together with Linrad in a
>> dual polarization or "stereo receive" system. It takes
>> advantage of many of Linrad's excellent features -- the
>> waterfall displays, noise blanker, dual-channel coherent
>> processing, etc. -- as its receiving "front end". Partially
>> processed data are sent from Linrad to MAP65, which searches
>> for all JT65B signals in a 90 kHz bandwidth, measures the
>> polarization angle of each one, and decodes them all. The
>> Linrad sample rate must be set to 96000 Hz.
>> MAP65-IQ differs from the standard MAP65 in respects:
>> 1. MAP65-IQ is intended for use with single-polarization
>> systems. (Thus, no polarization matching can be done.)
>> 2. MAP65-IQ uses a slightly different sample rate, 95238.1
>> Hz, in order to be compatible with the SDR-IQ hardware.
>> MAP65-IQ appears to work very well. In one test using the
>> H-polarization (horizontal) data from 11 minutes of the 2006
>> ARRL EME Contest, MAP65-IQ decodes 82 messages from 24
>> different stations spread over the range 144.100 - 144.160
>> MHz. For comparison, the standard MAP65 decodes 127
>> messages from 36 stations in the same 11 minutes of data,
>> using both H and V polarizations. For a rough sensitivity
>> calibration, I was using a pair of 2MXP20 yagis when these
>> data were recorded.
>> These results are just what one would expect: the somewhat
>> smaller number of messages decoded by MAP65-IQ is a result
>> of its having no access to data in the "other" polarization.
>> In order to make tests of MAP65-IQ you'll need a receiving
>> setup with Linrad and an SDR-IQ, and you must be familiar
>> with the use of JT65 in WSJT. If you meet these
>> requirements and would like to participate in early tests of
>> MAP65-IQ, please send me an email with some details.
>> -- 73, Joe, K1JT
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