Frequency Reference Completion

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.

Man with two watches...

....never know correct time.

Because of this syndrome the correct thing for me to do now that I have established the GPS disciplined OCXO from here:

http://g0mgx.blogspot.co.uk/2013/11/gps-disciplined-really.html

Is to simply use this as the master frequency reference and calibrate everything else against it.

If I went ahead with my plan to use the GPS 1pps signal for a frequency counter, imagine the dilemma if they didn't agree! The GPS Disciplined OCXO uses some complex averaging to ensure that an out of sync 1pps pulse due to an aeroplane passing overhead or the washing machine (the second item isn't a likely cause; I am just checking you are paying attention) are not acted upon. Using the 1pps signal to gate a frequency counter wouldn't be able to do this.

So, to cut a long story short I have taken the frequency counter I first started here:

http://g0mgx.blogspot.co.uk/2011/07/pic-n-choose-how-to-count.html

And have calibrated it against the GPS OCXO:

So, all in all I am very pleased with the results of this project. I have learned a great deal and have a very accurate frequency reference and a counter to go with it. From conception to finish the counter project has only taken 2 years and 4 months!

Another great homebrewed addition to my RF workbench.

Good, egh?

Back to real homebrewing!

You may recall my discovery back here:

http://g0mgx.blogspot.co.uk/2012/04/well-this-looks-just-great.html

So, Ive managed to make some progress. I've modified the software from W3PM from here:

http://www.knology.net/~gmarcus/

and have managed to get the GPS module working and also the DDS drive routines....

The code is written in C for the Arduino; and it's now interfaced to a four-line LCD, the AD9851 DDS module and the GPS receiver. The GPS module isn't in the picture as it's hanging out the window so it has visibility to the sky.

I've started to box the project, and have also built an RF amp to get me a staggering 100mW out...

Progress has been quite good today, I need to think about how I can get the RF levels the same on each band because as the frequency increases, so the amplitude out of the DDS and hence out of the RF amplifier decreases. I'm really not sure how to tackle that one, so I may have to ask for some help here.

Yesterday myself and Vince G0ORC went over to the "Dambusters Rally":

http://www.qsl.net/gb4tcm/dambusters.html

The rally was really good, albeit a bit small, but there was loads of really good radio junk to rummage about in. I picked up all sorts of stuff including this meter which I am rather proud of:

I've cleaned it up, mounted it on some wood, and stuck it in the corner of the shack with some amps flowing through it...

The next step will be to put some lighting inside...

Looks god though, agree?

Extreme Soldering (DDS-60) Complete!

It seems that the extreme soldering is complete for another project! The DDS-60 I got from AmQRP is built.

I've found that photographing the soldering and then inspecting it blown up is about the best way I have found for checking the integrity of SMT soldering. Here is the complete board (top and bottom):

But when you actually look at the soldering blown up, it's quite a mess! I don't think there are actually any problems or shorts though:

Tomorrow or over the weekend I'll be testing this....

Fun, egh?

GPS Time Sync? How's That Work Then?

I've made a bit of progress with the latest project that I mentioned here:

http://g0mgx.blogspot.co.uk/2012/04/well-this-looks-just-great.html

It's this project here for WSPering using the Arduino development board and the Analogue Devices DDS 9851 chip I've been experimenting with:

http://g0mgx.blogspot.co.uk/2012/02/its-even-in-box-now.html

So, I've got the Anduino board:

And have just soldered together the GPS module to get the timing information:

So I have no idea how to interface to this GPS module, but I have an extended Easter weekend to try and find out. There seem to be loads of reference pieces of code on the Internet for almost anything you could think of, so I'm sure I'll think of something.

Here's the Geddy cat, he really isn't helping much today:

Not such a great shot, but here's where the bed is (out of reach of the pesky Chopsy cat):

Fun, egh?