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WPX RTTY

February 14, 2016, 7:02 am
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Well,

Very, very little time spent, but some excellent propagation about, including great openings on 10M. Just shows you what stable solar conditions can support on the high HF bands.


Local conditions.
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23cm from a HillTop - Most definately!

February 17, 2016, 12:40 am
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Look what I've got

March 24, 2016, 9:33 am
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Well,

Came home with one of these today:


It's a new IC-7300 from Icom.

First impressions are excellent.





I'll post more once I have RTFM and used it a bit.

Local conditions.
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IC-7300 - the first Casualty?

May 6, 2016, 12:34 am
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Well,

You will remember last time that I came home with a new IC-7300. I've played with it quite a bit and it seemed to be an excellent radio with very good close in signal rejection on receive.

Yesterday I was using the radio on WSJT and noticed that even though the power output was set at 40% and the audio drive levels set such that the output power was 25W, when the radio entered TX the PO meter shot up to 100%, then almost immediately back to 0% and then crept up over 3-4 seconds to the 25% it should be at. This was looking like the worst ALC overshoot I had ever seen - I wondered if this was something to do with the new firmware upgrade.

Anyhow, a few minutes later the radio started to "re-boot" on entering TX. I checked all the obvious things like PSU voltage and SWR et cetera, then I simplified the setup.

I have a very simple PC based audio tone generator so I set that up to generate a 1200Hz tone on the USB audio device from the IC-7300, then when I put the radio into PTT using either a CAT command or the mic PTT the radio "re-boots".

Here's a video showing this:


So, the radio has gone back to Icom....

Here's Bonnie Dog and Miss Luna Cat who appear to be the very best of friends:


Local conditions.
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Frequency Reference

May 15, 2016, 10:27 am
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Well,

Been thinking for a while that my shack frequency reference is a bit old hat and could be a bit more useful. What I would really like is a GPS disciplined VFO so I can set the frequency for my needs rather than only having 10MHz, 5MHz and 1MHz outputs as I do from the old project here:

http://g0mgx.blogspot.co.uk/2013/11/frequency-reference-how-accurate.html

So I have started to look at the possibility of using a newer device like the Si351A from Silicon Labs.

The first part of the project will be a new GPS receiver to give us the 1pps signal we need for the frequency control. I found a really neat kit at QRP Labs

I've built the kit today and it looks like this:


Mine has been built to utilise an external active GPS antenna.


The output from the 1pps looks like this on the 'scope:


So all seems well with the first phase.

More to follow!

Here's our Pepper Cat who has been almost completely in the way most of today:


Local conditions. Good egh?
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More Frequency Reference

May 17, 2016, 7:24 am
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So,

Following my musings last time over the QRP Labs GPS module, I've now also built two further kits from QRP Labs. The S5351A Module and the VFO.

When you combine all these together in the way I have you can create a GPS disciplined frequency reference with two outputs.

One of the outputs can be fixed in the firmware and I plan to put mine on 10MHz, I've made a low pass filter for this output to clean out the harmonics. The other output can be user set to any frequency up to about 290MHz or so.



Here's the LPF for the 10MHz output:


And here's the 10MHz output before the LPF:



and after:




All good, egh?
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Frequency Reference Completion

May 20, 2016, 11:37 am
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Well,

The project from last time is even in a box now:



Good egh?

You will see that we adhere to strict rules whereby the dogs are not allowed on the furnature:



Local conditions.

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4M - Alive and well?

May 30, 2016, 10:13 am
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Well,

Some interesting propagation on 4M today. A beacon very loud from JN86:


Here's the 4M map from the great DXMaps.com:






Definately experiencing some "local conditions"

Good, egh?
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RTL on HF? no way!

June 3, 2016, 10:21 am
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Well,

I read with interest an article in Practical Wireless from June 2016 describing a neat looking receive converter to be placed up front of an RTL dongle type receiver.

These RTL devices are easy to find for a few GBP:



Here's the schematic of the converter:

 

And its built on a PCB from OHS Park which cost a staggering $5 USD for 3 including postage to the UK. They were delivered in a very timely manner too! 


You will see that I have actually built two - but basically we have a 50MHz oscillator and a mixer, so in the example below my SDR would be tuned to 70MHz and I would be listening to my signal generator on 20MHz. The output contains what you would expect from a mixer in that we have the input frequency, the on board oscillator frequency, their sum, their difference and all the other harmonics from this mixing process:


More to follow once I have it up and running with the RTL dongle, but so far so good!

Local conditions.
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I've made another one!

June 19, 2016, 10:32 am
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Well,

You may recall the recent Frequency Reference that I made, I've just finished building another one for someone else! This one is almost identical except I have included a 1MHz low pass filter as this one will be configured to have a 1MHz fixed output.






Here's the 1MHz output:




Good, egh?
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New Amplifiermabob

June 25, 2016, 9:24 am
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Well,

I've been thinking for a while about upgrading the amplifiers I have here for 4/6M and also 2M. Here's the result of my investment:






The 950 deliveres 1KW on 6M (500W on 4M) and the 1000 is 1KW on 2M. Both solid state amplifiers from Beko in Germany.

Given the termoil on the currency markets as a result of Brexit - I might have just timed this right.

Local conditions.
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SDR with the Red Pitaya

July 17, 2016, 12:37 am
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Well,

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 decode-wspr.sh 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.
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It doesnt get more Bonkers!!!!

July 28, 2016, 11:59 pm
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Well,

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.
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Following the Birds!

August 21, 2016, 9:46 am
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Well,

For quite some time I have wanted to try my hand at Amateur Satellites. Now, I plan to utilise my IC-9100 for this task - it is a full duplex radio meaning I can TX on one band whilst RX on the other.

I decided I would build myself a "proper" satellite tracking antennamabob, and here it is up in the air:


There's 3 elements on 144Mhz and 7 elements on 70cm. The antenna has both azimuth and elevation rotation capabilities using one of these:


It's a Yaesu G-5500 rotator; unfortunately they don't supply the necessary hardware to separate the azimuth and elevation rotators - so I had to fabricate something suitable. I've mounted the azimuth rotator way down the pole and utilising these brackets from Barenco and a Yaesu thrust bearing we have a suitable working arrangement with minimum weight at the top.

The plan is to develop a means of automatically controlling the antennas such that they will auto track satellites using PC based software. I've bought one of these kits from AMSAT, here in early construction:


And here ready to wire up and start to play:


So, lots to follow on this topic!

Here are a few of the feline family members:


Good, egh? Local conditions.
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Some More Bird Time!

August 22, 2016, 8:28 am
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Well,

Following the progress last time, today I have finished the LVB Tracker kit.

The kit is complete and the programming of the PIC done; I had some issues with this part of the project. I couldn't get the PicProg executable as supplied as part of the fileset to function - it would appear to program OK, but the verification failed. There were way too many variables involved so I dug out the PIC programmer I purchased way back when and programmed the PIC that way. Once I had figured out all the configuration bit settings I was up and running....


The image above was taken during the calibration process. Basically the rotator control box outputs two voltages which are representative of the position of the AZ (0-360) and EL (0-180). You tell the software when the rotator is at 0 in both AZ and EL and then again when in 360 and 180. It can then calculate the appropriate voltage for anything in between.

I've chosen to use SatPC32 software for tracking the birds, controlling the rotator and also handling CAT control of the radio to automatically turn the antennas (both AZ and EL) when a selected satellite is in reach, and also control the frequency setting on the radio - including the adjustment for Doppler shift as the bird is moving towards or away from my station.


Here's a quick video of my first ever reception from an Amateur satellite. This is before getting the CAT control functional - just the antennas are moving automatically to track the bird as it passes:


And here is a quick video showing the auto tuning for Doppler (no sound):


So now it's time to do some research and some listening before I decide which satellite and how to make my first QSO. Fun egh?

Here's Miss Luna Cat asleep behind one of my monitors:


Local conditions.

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QED on the Birds!

August 26, 2016, 11:33 am
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Well,

Following my last post here, I've managed to complete my first Satellite QSO.

I'm using SatPC32 to control the antennas and also the Radio:


My first QSO was with RN6MA in LN06uo - Thanks Victor!

We were using the XW-2A satellite; uplink on 435 MHz and downlink on 145 MHz.


So much to learn!

Here's a video of the antennas in action:


And here a quick video of the IC-9100 receiving the telemetary beacon from XW-2A showing the auto doppler tuning.


Here's Florrie the Ham cat enjoying some sunshine:

Local conditions.
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Doppler, Frequency Inversion, What's all that then?

August 29, 2016, 11:32 am
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Well,

As I fiddle, I learn. That's the basic idea anyhow.

So, I've been making a few QSOs through these amateur satellite thingamagigs.

There are a series of Japanese birds called the XW-2 series. Their frequency allocation is as follows:

Now, the number on the far left top of that image is wrong and should read 435.000.

I just had a QSO through XW-2C, the linear transponder (the bit that receives speech on the uplink and re-transmits it on the downlink) are actualy at the following frequency ranges:

Uplink:       435,150 -> 435,170
Downlink:  145,815 -> 145,795

Now, the observant amongst you will note that the Downlink frequency I have listed goes from high to low and the Uplink from low to high. Thats because it's a linear transponder with Spectrum Inversion. So as I tune in the 20KHz passband of the satellite I have to tune +ve in the Uplink and -ve in the downlink (or the other way round).

So when the Uplink is at 435,150, the Downlink is at 145, 815 and when Up is at 435,170 Down is at 145,795. Thats all before you add in the complexity that the Uplink is in LSB and the Downlink in USB. And then theres the further complexity of Doppler.

Now, I like to think of things very simply. If you can imagine a Sine Wave shape, with the right hand end fixed and the left hand end moving left, it is quite easy to see that the frequency is being stretched and is therefore decreasing. Similarly, if the left hand end of our imaginary sine wave was being moved to the right, the wave is being squashed and the frequency is increasing.



Therefore as the fixed point (my antenna) and the satellite (moving) get closer together the frequency that I need to tune to receive the Downlink and transmit to find the Uplink are both increasing, similarly when the bird is travelling away from me, the frequency is decreasing. The effect of this change is dependent on the actual frequency itself, so the higher the frequency the more pronounced the shift needed.

Luckily the Sat32PC software calculates the Doppler for me, but I hope the rather simplified explanation above helps explain whats actually going on.


Fun egh?

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DG8 Pre-Amp - More gain, really?

September 3, 2016, 11:10 am
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Well,

I ordered a DG8 pre-amp for 2M from here last week and it duly arrived. I only ordered the "short" kit as I thought I would probably have a lot of the more common bits needed anyhow.

Here's the completed project:


Here's a close up of some of the surface mount gubbins on the other side of the PCB:


And here's my bench after I had built it - a complete disaster area:





I aligned the pre-amp in accordance with the instructions using a SSB RX but thought the results were quite noisy; I then used the tracking generator and the Spectrum Analyser to align, here's the unit in bypass:




The markers are at 144, 145 and 146 Mhz, here's the aligned version:




I backed the gain off as per the instructions and used my ears to adjust L1, still seems noisy to me.

May have to fiddle some more.the IC-9100 used for my new satellite station can power the pre-amp straight down the coax.

I'm planning to run the amp under the radio bench initially; there's not a very long run of coax to the antenna so I am not sure there is that much to be gained by mast mounting it. Let's see.

Here's Miss Luna Cat, I'm rather hoping she doesn't decide to play "shelf swat" with my Nixie Clock!




Local conditions.
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TXing WSPR with the Red Pitaya

September 23, 2016, 11:10 am
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Well,

You may recall some time ago that I had a fiddle with a Red Pitaya? This was back here in this post.

So further to the WSPR RX I was doing back then, I made a request via Mike Richards G4WNC (He writes the Data column in Practical Wireless) to add a PTT switch to the software. The TX signal was on the output connector and the RX input on the Input connector - I only have one antenna and I wanted to switch between the two.

Well, lo and indeed behold, the code for the Multiband WSPR transciever has been updated here.

I've downloaded the new software which includes an extra module called gpio-output which switches the DIO0_P pin (its pin 3 on the E1 connector) to 3.3V when the device is in TX.

Now, I noted a few things when I downloaded the new files and executed the make command:

  1. The Makefile downloaded ended up with a .1 extension and needed to be renamed.
  2. The new .sh files had the wrong permissions and needed to be chmod ed to be executable
other than that updating the software and re-building was easy. 
To accommodate this I have made a very simple PTT switch (please excuse my TinyCad capability):

which connects to the Red Pitaya Pin 3 and GND on the E1 connector and then feeds a PTT line (grounded during TX) to my TX/RX relay.

The only Relay I had was a latching type so I have made a board from W6PQL to drive the relay from a grounded line:

This board looked like this when I had it under test:



And this is what the latching signal looked like before I added some diodes on the relay coils:


Now, you may remember that I also purchased a board from SV1ASM to add some extra drive to the Red Pitaya output, here it is under test:


Now, this is supposed to give me about 14dB of gain, but my tests suggest it's a bit short. The Tracking Generator is at -20dB in the test below:





It may just be that I am not driving it hard enough in the test above, as I am getting more like 7dB gain. It seems to be good to about 100MHz though - I will look more at this later.

Before I hooked all this stuff up together, I did some tests on the Red Pitaya output lines. This 'scope screen grab is showing the TX output plus the IO line at 3v3 during TX:


And here we have the 'scope connections to the output connector and the E1 lines:


So, hooking all this lot together, we have a mess like this:





I need to make a low pass filter for the output; mine is currently configured to TX on 30M. Once I have the LP filter I will stick this on the air and see how far I can hear and be heard.

This project is now a good starting point for lots of other TX/RX type ideas on the board.... next though I think I am going to have a go at the Vector Network Analyser.

Here's Florrie the Ham cat being almost completely in the way throughout:



 Good egh?
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RTTY Everywhere!

September 24, 2016, 12:57 pm
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Well,

It's the CQ WW RTTY test this weekend, because of travel tomorrow and other commitments - only a very quick play this year.

Here's the 15M log as a map:



With SFI:86, A:9, K:2, R:49 - the 15M band hasnt been in bad shape today at all.

Local conditions.





I'm off to the Kingdom of Saudi Arabia tomorrow - I think Maggie cat wants to come too!

Good, egh?
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