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Friday, 29 July 2016

It doesnt get more Bonkers!!!!


You may recall that some time ago, myself and Vince, G0ORC, set up a Wires-X repeater.

This has been an endless cause of headaches as it has continually suffered lock-ups in FM TX mode since we connected it to the Wires-X network and the big bad Internet. It's odd that the TX lock is in FM mode because the repeater is configured in Digital only.

Having tried many re-flash of the firmware in the repeater, different network connections, updating firmware in the HRI-200, operating with a chicken down my trousers whilst facing north and also changing the version of Wires-X software on the PC, even sending the repeater back to Yaesu - we have finally given up.

We can't find what causes the TX lock-up nor can we stop it.

So we now have the most Bonkers solution I can think of - this is a £300 solution to a problem that shouldn't exist.

So instead of connecting the repeater to the Wires-X network using a HRI-200 and PC as it is designed to do, we are connecting via RF to a nother radio using a dummy load! We have a separate node configured to TX on the repeater input and RX on the repeater output, the repeater is now configured as a stand alone digital only repeater. The only connectivity between the two is via RF through a dummy load on the "node" radio; which is a FTM-100D configured as a Wires-X node.

Quite ridiculous, egh?

Here's our beautiful Bonnie Dog - she's now 8 months and 29 days old and quite fab.

Local conditions.

Sunday, 17 July 2016

SDR with the Red Pitaya


I came accross this board on the RS Components website, it's called a Red Pitaya:

Now this board is very much designed with RF and SDR (Software Defined Radio) in mind, it's got some very high speed ADCs (Analogue to Digital Converters) and DACs (Digital to Analogue Converters) on board - it also has a SoC (System On a Chip) with an ARM processor and a FPGA (field programmable gate array) pluis a whole other bunch of useful stuff also on-board.

Now, there's a very clever chap Pavel Demin who has written some fab and groovey software for the board to try a whole bunch of stuff from a simple SDR receiver all the way to a VNA (Vector Network Analyser). There has also been some interesting introductory articles to the board published in the Data Modes column in Practical Wireless.

I've been playing with the WSPR decoding software as a starter-for-10.

You have to go and get the software from the website here. You can download an image of the Red Pitaya boot device (memory card) and create the memory card for the device to boot from - I used Win32DiskImager for Windows - you could also use DD for Linux.

Once you have that device created you can boot the board from the card, then you need to access the board from your network - I used Advanced IP Scanner to find the board and then used Putty to create a SSH connection. From there it was a simple task of editiing the file, adding my callsign and grid square and then rebooting.

I have the board configured (by editing the write-c2-files.cfg file) to decode 8 bands similtaneously (yes that's correct).

Here's a map of my decodes with the Windom connected to the input connector of the Red Pitaya (via a small attenuator pad for impedence matching).

I've also tried the SDR Receiver software with HDSDR configured to conenct to the RedPitaya SDR accross the network - it worked superbly.

I now intend to try to get the TX side of the SDR functioning - using WSPR first. To facilitate this we will need a bit more hardware. I found a great buffer amplifier design by SV1AFN here. I ordered the PCB only from him and here's the finished article (I am one SMA connector short of a party):

I'll also need a TX RX switch which I will create using a latching SMA relay I have here and a kit from W6PQL.

To move on to the VNA experiments I will need some other bits and bobs including this:

So, much more to follow!

Here' our Choppsy cat (AKA Git Basterd Cat from Hell):

Good, egh? Local conditions.