Re: Using the FlexRadio IQ channel with WSJT-X and MAP65 #Q65 #map65 #FlexRadio #Windows10


Amos Sobel 4X4MF
 

Bill

1. WSJT-X accepts the IQ stream it does create almost similar FT8 results as the base band.

3.1 I am using an H/V Yagi with symmetrical horizontal and vertical 10 by 10 elements on the same boom.
3.2 Flex 6600 has 2 antenna inputs with a 16 bit A/D converters on each antenna input creating a base band and an IQ data stream. Both ADC operate from the same clock.
3.3 Merging the 2 data streams into an interleaved single stream appears to me as a simple software job that can be done by WSJT-X or Flex.

Amos 4X4MF

-----Original Message-----
From: main@WSJTX.groups.io <main@WSJTX.groups.io> On Behalf Of Bill Somerville
Sent: Thursday, October 14, 2021 1:20 PM
To: main@WSJTX.groups.io
Subject: Re: [WSJTX] Using the FlexRadio IQ channel with WSJT-X and MAP65 #Q65 #map65 #FlexRadio #Windows10

On 14/10/2021 08:47, Amos Sobel 4X4MF wrote:
I have recently discovered that WSJT-X v.2.5.0 does accept the DAX IQ
RX audio channels of my Flex 6600 instead of the DAX Audio Rx I did
use for years.
1. Does WSJT-X take advantage of the additional information in the IQ
stream in FT8?
2. Same question for Q65.
3. I have an H/V antenna connected to dual 2m transverter connected to
2 instances of WSJT-X running Q65. Is there a way to combine those 2
channels same way as MAP65 does?

Amos 4X4MF
Hi Amos,

1) no WSJT-X does not currently understand I/Q data, you will get some decodes by selection one of the I or Q channels but that is sub-optimal and you should use a base band audio stream of up to 5 kHz bandwidth as input.

2) Q65 is no different, the front end audio processing in WSJT-X is the same for all modes.

3) I have explained this before to you, for polarization diversity mode
MAP65 requires a pair of synchronized I/Q data streams. That can only happen if the two data sources are received from co-located aerials (receiving the same wave-front), use a pair of ADCs sharing a common clock, and the two data streams are interleaved so that MAP65 can process each sample together with its partner from the other ADC (other polarization). As far as I know none of this is possible using a Flex Radio multi-slice SDR since the I/Q data sources are independent (think Humpty Dumpty https://en.wikipedia.org/wiki/Humpty_Dumpty, once broken some things cannot be easily reassembled!)

73
Bill
G4WJS.

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