Sunday, 25 September 2016

A break

I'm taking a short break from kitting Anglian 3 transverters. Two weeks of intensive kitting, component preparation, paperwork and shipping has taken its toll. I need a break from it. 
Started to investigate integrating the DRiACS dish controller into my existing system, beginning with an eddy current damped gravity pendalum elevation indicator. 
I was extremely disappointed with the Machine-DRO digital pendalum inclinometer. Although the reading updates very quickly ( too quickly?) it is very unstable. It seems to be similar to the well-know 'Lidl' digital inclinometer. That is also totally unsuited to moon tracking as it takes ages to settle down to a reading. The Machine-DRO is exactly the same. It is suitable for indicating elevation if hou have time (>30-45seconds) but totally unsuited to tracking, where the 'noise' masks the immediate moon (or sun) position.
So, i'm back to trying to implement the MAB25 absolute encoder solution, but with the possibility of using eddy current damping to reduce reading instability, especially during windy conditions when the dish mount will inevitably shake.
On a very positive note, the add-on GPS clock works well, even inside my garage shack. GPS lock is solid. The DRIACS indicates the actual moon ( or other celectrial object in the almanack) without worrying about clock drift.
Sam



Saturday, 17 September 2016

Crawley

All now ready to attend the Crawley Microwave Round Table tomorrow (18th September).
I'm taking a few VLNA preamp kits and PGA144 preamp kits. I'll also take some of the WA5VJB antennas and other boards.
Accompanied by Alan, G3NYK, who will take some of his boxes for sale as well as some of the HUPRF kits.
Should be a fun day.
There are some interesting talks scheduled for the afternoon. For once I'm not speaking at one of these events.


Wednesday, 14 September 2016

Disappointed

I am disappointed that apart from the usual entry in the published RSGB Convention programme, I have seen only a two-word mention in Radcom of what I think is my talk at the Convention.

This year I am scheduled to speak (The secret life of the transverter) at 16:00 on Saturday. Looking at the programme published in Radcom I see I am scheduled against some pretty good alternative talks.

Only by self-advertising am I likely to attract a few to my session, otherwise I might get overlooked!


😎

Friday, 9 September 2016

Paperwork

I've been busy preparing the documentation for the Anglian transverter. Takes as long as developing the circuitry!
Separate technical description and assembly manual for the kit
Kits only. No assembled SMD boards for now.
Should be available soon. Just waiting for some back ordered components.

Thursday, 1 September 2016

Venice and beyond

We've been back from EME2016 in Venice for one week, having stayed on a few days to have a better look at the city. For sure it was heaving with tourists and cruise ship visitors (the Cunard Queen Victoria was the only liner I recognised).
I have to congratulate the Conference organisers for a job well done. Having been one of the Cambridge 2012 organisers I know just how much work goes into the organising of a two day EME Conference, with the various dis-staff tours etc.
I thoroughly enjoyed the Conference and learnt a lot from the various talks. I was able to attend every one of the 16 talks over the 1&1/2 days.
I have been inspired to do some additional 'fettling' of my own dish and now it has additional bracing on the feed cage to overcome the cage drooping when the heavier RF horn and amplifiers are installed. Mainly the 6cm one.


The diagonal braces are of substantial gauge aluminium alloy and secured with M5 screws.
Laying one of my laser levels on the mount, I have checked the 'true ' of the cage and where its red dot appears on the fence. This enables me to reset the SPID RAS at intervals to overcome the inevitable SPID pulse count errors!

Monday, 15 August 2016

EME2016

This last few weeks have really all been about getting ready for EME2016, later this week.
The International moonbounce Conference is held biannually. The last one was in France and the previous one in Cambridge, UK. This year's Conference is being held near Venice.
As has become usual for me, I am offering a selection of my EME VLNA preamps, both kits and semi assembled  kits. It has been the preparation of these preamps that has been occupying my time. In addition to the VLNA preamps I have been building a number of PGA432 70cm preamps for evaluation by a number of other amateurs as well as taking one or two to EME2016 to be independently measured.
And.....the new Anglian3 transverter boards arrived last week and so I've been busy building up some of these for testing. I'm pleasd to say that they work as well as the Anglian 3 that they replace, and with some added features. Unfortunately I hve not had time to get Anglian 3 kits redy for EME2016, although I will have the first ones on show.
I've also been finishing off my presentation on failures in LNAs (too much RF - they don't like it up 'em)
The nub of the presentation is just how much abuse a HEMT LNA can take before it fails, and what happens along the way! I'm scheduld tobe the second talk. It will be nice to get mine out of the way early on, although as an ex-lecturer I don't mind standing up in front of such a bunch of established academics, enthusiasts and EME  experts.....much!
As well as all these preparations I have been trying out the new digital mode of QRA64. This is in alpha release for testing and will form part of the new release of WSJT-X. Possibly after EME2016. Joe Taylor, K1JT, and Nico Palermo are presenting at the Conference.
My testing has been with a well-known EME op, but on HF. Honestly!
QRA64 is a weak signal mode, well suited to EME, and usable at HF. It answers many of those critisisms of digital, aimed at how some of the computer processing has been considered 'cheating'. Troglodites..........
QRA64 and the new fast mode of MSK144 could quickly supplant some of the existing digital modes like JT65 and FSK441. We will see what happens over the next few years.

Sam



Sunday, 24 July 2016

Anglian 3 update

For those of you who don't subscribe to Twitter you will not have seen my progress with the Anglian 3 transverter. I have been tweeting regular updates (for anyone interested!)
The second set of Prototype PCBs were deliver last week and a second unit built up to prove the design works as it should. I'm pleased to report it all worked as planned, although there were still a few very small errors on the PCB. Version 3.1 PCBs have now been ordered and are expected in a few weeks. 
The new Anglian 3 is designed as a direct replacement for the Anglian 2, but with a few small improvements. These include transmit enable delay, better transmit amplifier gain distribution, programmable transmit IF gain (for use with ICOM rigs, with their low transverter output level), better transmit IMD, but retaining the same excellent receive performance, lockable local oscillator, separate IF receive and transmit connections and all SMD construction as the 2.
Unlike the Anglian 2 I have no plans to offer the Anglian 3 as a fully assembled PCB, as this has proven to be uneconomic for small production runs of boards with specialist RF parts.
However, I may offer partially assembled boards, depending on demand.
Also, depending on how Brexit affects component purchase (many parts are sourced from overseas), I anticipate the cost being lower than the Anglian 2.

Sam