Saturday, 25 August 2018

The QSX SDR HF from QRP Labs

QRP Labs started design and producing small QRSS/WSPR Beacon transmitters some years ago, along with a complete set of addons and other accessories that have evolved as the project progressed.  Last year, owner and designer of QRP Labs, Hans Summers, took his small company to a new success level with the launch of the QCX 5W Single Band CW/WSPR transceiver. Which has currently sold to date well over 5500 units, over various HF bands.  A fantastic project because it crammed so many full features into it's small pcb, including its inheritance from the WSPR Beacon, but with full frequency agility, CW decoder and included was a unique inbuilt test generator to aid alignment, never seen on such a low price product before.

The QCX has proved a QRP Labs British success story for such a niche product in it's own right.

Of course Hans (G0UPL) wasn't going to rest on his laurels and an SSB radio had been rumoured to be on the design board for quite sometime. Infact he had told me at the begining of this year, these projects takes a while before they hop off the design lab bench and reach fruition to complete into a working project.


So it wasn't no surprise that G0UPL has again used YOTA 2018 (Youngsters On The Air) hosted in South Africa this year, to pre launch the QSX a 10 Band HF SDR project. You could say that YOTA is used like a test bed to iron out any last minute technical and constructional difficulties, found, or encountered, before he begins to put the kit into full time mass production in a couple of months or so. Most of what the new SDR single/10 band rig will do and it's outlined specification, is set out on his website here: QRP LABS - QSX

 Photo G0UPL 



I was fortunate enough to have a short electronic messaging chit chat with Hans earlier this week, and he was able to put me well in the picture with one or two technical details about the project.

While emissions and spurs are all the talk of the town at the moment on another QRP project from another company not associated with QRP-Labs . The QSX will have "no" spuri issues!

Using 2 IRF510's in the QSX's linear HF PA, Hans reports the performance is excellent! The PA module being driven by two BS170's in Push Pull, giving an overall gain of around 26-28dB. This concludes in easily producing 10W across all HF bands using 12V.

Gain Flatness is better than 2dB across the spectrum between 2-30MHz. It is about 4dB down at 6m and 8dB down at 4m.Thus the same drive level that produces 10W across the HF bands gives a very useable 5W on the 6m band.

Hans also reports the linearity is excellent too!

Harmonics are low even before it even enters the LPF: 80m measurements 2nd harmonic is at -38dBc, 3rd -31dBc Making it very easy for the LPF to clean up what remains resulting in a very high performance radio.

All this is achieved using cheap Chinese IRF510's



Photo G0UPL


The heatsink is BIG!! Testing, it ran at 10W output for 1 hour continous 100% duty cycle, no forced air or cooling, the heatsink temperature was still reasonable about 40C over ambient.

Destruction tested at:

1) 20V supply.
2  25W output.
3) 15W 100% duty cycle for 15 mins.
4) Open load.
5) Short circuit.
6) Various mismatches.

All tests resulted in no failure.

Further reference watch the video AE4FH interviews Hans:

https://www.youtube.com/watch?v=hL6CWaY438Y

Friday, 10 August 2018

Forward thinking and food for thought.

Sorry there has been very little activity from me during the last few months, family stuff has taken up a lot of my spare time recently, and radio has been well off the menu. However I will try and get back into the Blog as our Summer comes to an end.

I was recently contacted by one of the Telford Hamfest organisers asking me to give a talk:

 We would like to invite you to give a "talk" at our "Telford Hamfest" QRP, orientated, would be great. The date for our Hamfest is Sunday September 2nd 2018. We expect to put on three "Talks". The "Talks" would last about 40(ish), minutes, with a Q&A after each, with a gap until the next talk. The timings are 11.30,12.30 and 13.30. I hope you are able to take us up on our offer Steve
--------------------

The Telford Hamfest is a Radio rally which has been held around the Telford area for many years at various venues. But for a number of years has stabilised at being held at Coalbrookdale, Shropshire, and also now incorporates the G-QRP Convention as an added bonus.

Well Stephen had already decided he wasn't going to the Hamfest this year, so it all arrived too late! But it is with interesting thought what I would of talked about, and who actually put me up for this, I could name a few?

The last lecture I gave is when I ran a Packet radio BBS and node (GB7RUG) some 20 years ago. Talks don't just come together overnight, sorry I had no real time to prepare anyway. So Telford Radio club and G-QRP thanks for asking, I might do it next year if you give me enough time to think about it?

Actually by now I have mulled it over I have even thought in my dreams what I would of chatted about Hmmm! Humm!

See you all next year :-)


Sunday, 27 May 2018

uBITX revised.

When HF Signals marketed the uBITX early December 2017, customers leapt in and ripped them off the shelf. Who could imagine the small Test facility in India that VU2ESE had setup trying to cope with the unexpected demand, or the women having to wind and test the toroids, churning them out at speed without breaking a finger nail. Even one type of toroid used had to be substituted, for another, as the world ran out and they couldn't be sourced easily, but still the uBITX production somehow was kept on track. A total to date of over 6000 uBITX PCBs sold, with very few bugs reported, apart from one batch with the faulty WX branded TDA2822 audio amp that hit the fan and must of caused an awful headache at the time.

Now that manufacturing has now caught up with demand, and there is no time lag on ordering, the uBITX becomes ex stock along with some new modifications and a new revised r4 PCB.

Could the uBITX get any better well certainly it looks like it does!


Here are the changes from Ashhar Farhan reported today on Groups.io:


1. A new, low distortion audio amplifier made from discrete transistors. This is one is optimized for head-phones and connecting to PCs for digital modes. It does work with the small speakers as well. Builders with the earlier versions can try this audio amplifier as an outboard amplifier.
2. The audio thump issue during T/R switching has been fixed.
3. At 28 Mhz, the output is about 4 watts. (this involves a single capacitor change from the earlier PCB).
4. I have included some 'jump' points to add interesting stuff like CW filters to the board. There are a large number of test points to help you debug and understand the board. 


All in all, the changes are 'backward compatible' . That is, you can hack these changes to the previous boards to get in the new functionality. I have updated the circuit diargrams on www.hfsignals.com
The earlier board's circuit diagram has moved to http://www.hfsignals.com/index.php/ubitx-r3-archived/

The bad news is that we had to bump up the price of the board by 20 dollars. We fought long and hard to keep the price down. My personal ambition was to keep the price inside (or at) $100. This is price rise has to do with three things : The recent changes in the Indian import duty and sales tax; Our own increasing costs to preorder the parts. Lastly, we also increased our payout to those who wind the coils, assemble and test the boards. They were working at the same rate for the last two years. It was about time. 

The new boards cost $129 USD with shipping. $139 USB with DHL option. 

The good news is that from now on, these boards will be available on order. The waiting queue is gone.

On a personal note, I am happy with the new audio. It is so much sweeter and cleaner on the headphones.  Far less fatigue after hours of CW work. I am also using the FT8 extensively, I have bagged almost twenty countries, testing the new firmware.

Monday, 5 March 2018

ReactOS maybe the OS you just need?

So you have run the latest Windows and found out that 10 is full of bloatware and updates to nail your PC to the ground. You may have also tried Linux, but found some things it does, and some things it won't, or impossible to be made to work, like camera drivers for example. Stuff which would work with Windows no problem. You may have tried running Windows Apps under Wine on top of Linux, some work, but some refuse point blank, or you have just found Linux too geeky and given up?

You have also discovered there is a lot more software around for Windows against Linux, especially for our radio hobby.

Also there is the no security update problem with those using ageing copies of XP, 2000, Vista and Win 7. Like myself whom will fall into the no support trap in another 18 months or so?

You also don't like paying for a new operating system and want it for free!


Well I might of found something that is being developed as an open source operating system that appears to fit the bill called ReactOS.
 
ReactOS is only up to version 0.47a, so it is in it's very early stages of development and I guess full of bugs, but it does seem to work as you would expect from a Windows operating system.

I have done a bit more research around the Web and found that only a day ago, Chris Barnatt of Explainingcomputers.com had just made a video about the product, which I have bopped the link here for you all to watch below:




This seems quite an exciting development as operating systems go, and something tight fisted penny pinching Radio Hams have been looking around for a number of years. Currently, I am not minded to move to it yet until it gets passed the beta stages, but it is something I would welcome very soon.



Tuesday, 27 February 2018

uBITX professional case

Amateur Radio Kits India, owned by VU3SUA. Is now producing a commercial grade aluminum case in a variety of different colours for the uBITX.


The case comes predrilled, with the cut out of the panel for the frequency display, ready to house the uBITX PCB. This sure makes the uBITX look the part in the shack. Complete with all the missing fittings, speaker, knobs, USB, SO239, mic skt, etc (the full list of parts is on the website).

Shipping starts early March.

Link here for:

Universal Case DA Grey


Saturday, 10 February 2018

A SWR power bridge for uBITX

A damp cold Saturday here at Rugeley, the postman has not long been and dropped off my January issue of QRP Quarterly- Journal of the QRP ARCI.

Something good has just caught my eye, especially if your into the uBITX right now.

This month there is an excellent article for a VSWR bridge for the Arduino, which confusingly KW5GP (Glen Popiel) appears to take all the credits? But it appears the article was written or most of it by KV4QB (DuWayne Schmidlkofer)? A better explaination of the confusion, might be to just nip down to DuWayne's Place  to understand what has actually gone on.


Why is this article good for the uBITX builder or users? Well at the moment there is no SWR/PWR bridge hardware built into the uBITX, although VU2ESE's Arduino code does appear to implement something for a basic S meter.

The article has  a full bridge directional coupler circuit, along with amplified outputs, which are then fed into the Arduino. Along with this, there is the code, that could be easily adapted to work with the uBITX Arduino. Anyway Duwayne, has been good enough to drop off the details along with the code at his Dropbox site here  

Saturday, 20 January 2018

BITX & uBITX resources added.



I have now added a Pages link to my blog titled

BITX & uBITX resources.


Access it from the top right handside of my Blog. 


This contains known links to groups, and support for the BITX and uBITX kits.

I will update links and details as and when I see new information appear, and of course when I have the time available.

If you know of any others please drop me a line below.


You can also access it via this link below too:


http://g1kqh.blogspot.co.uk/p/blog-page.html


73 Steve