Sunday, 7 November 2021

QRP Labs does it again - a revolutionary digital SDR transceiver - the QDX

 QRP Labs have done it again. And designed a revolutionary SDR Transceiver for digital QSOs.

The QDX

It uses SDR techniques for reception generating audio IQ signals and DSP techniques for RX, and an amazing new digital signal generation technique for TX.

Design highlights

1. Si5351 VFO with a very stable TXCO, generating directly RF IQ signals for the detectors.

2. Normal Tayloe IQ detectors, feeding an on board DSP processor for USB reception

3. Digitally switched bandpass filters for four bands, 80, 40, 30 and 20m on RX, and electrically switched LPFs for TX -  no relays!

4. > 5W output from 9 or 12V supply

5. A new transmit chain, that does not just take the audio output of the PC and send it to an SSB transmitter, as most designs today. But detects the input audio frequency and programs the Si5351 synthesiser to generate the RF tuned frequency PLUS this audio frequency for direct transmission. With an output stage which is pure digital switching. Simplicity though superb software proprietary coding. 

6. CAT emulation for TS480 

7. Integrated sound card and single Audio + CAT interface to your PC. (All in the single microcomputer chip)

This is how it is done

Block diagram

And all this in a box for $80. Remarkable, of course with the current shortage of semiconductors it is not available. But I guess I could show willing by placing my order... no I can't ordering is not open!


Friday, 5 November 2021

Can you build a 100W Auto ATU for £40? Yes

 Amazing, yet again, these Chinese suppliers can deliver an ATU kit here for £25. Just connect the display OLED (or as shown here a larger one) and apply 12V and here it is


Have not tried it out yet but if it is built onto a £9 case with a 12V socket and a pushbutton that's it Here's the display of Power, SWR and L/C values used



Sunday, 24 October 2021

My Shack

 Here is a photo of my shack.


Left to right. 

1. A home built GPS clock with TFT display (code on M0IFA.me here)

2. QRP-Labs WSPR 200mW TX for 10MHz (30m).

3. Xiegu G1M SSB/CW four band TCVR

4. ELAD FDM-DUO all mode, all band TCVR

5. Antenna switching unit (four way)

6. Auto ATU, MAT-125E

7. MacBook Air M1 used for Digital with the FDM-DUO, mainly FT8 across the bands

8 An older Macbook (x86) using Apple Bootcamp to run Windows 10 Pro for the SDR software for the ELAD FDM-DUO.

9. On the table a NanoVNA used mainly for tuning my AL-705 loop antenna and checking the SWR

So far so good, all working.


Saturday, 16 October 2021

WSPR 30m / 200mW IO92 / M0IFA and antenna update

 My Al-705 loop antenna has the capability of one, two or three loops. I will make a series of tests of WSPR reception on 10MHz (30m) with these options, with a transmit power of 200mW. 

Comparison
Now I am making a careful comparison, it will take 3 weeks! I want to see if the number of loops on my antenna makes a difference. First here is five days with 3 coils.


10MHz 5 days, 3 coils

I each case I have decided not to connect the loop directly to the QRP-Labs 200mW transmitter, but to connect via an ATU. My MAT-125E  auto ATU needs a minimum of 1W TX to tune, and so I have switched to my ELAD FDM-DUO at the same frequency 10,140,200Hz, and output a tuning signal of around 1.3W. Then switch back to the QRP-Labs 200mW output. The FDM-DUO showed an SWR of  1.5:1 on tune (down from 2.6:1 without the ATU. I checked the tuning also with my NanoVNA to see the SWR minimum at the correct frequency.


10MHz 5days , 2 coils

There is practically no difference between 3 and 2 coils on the loop antenna. May be just a little lower S/N ratio and fewer spots. 

Seems there is little difference between ,3 2 or 1 coil. Here's the one coil data


10MHz 5days , 1 coil

But more interesting might be any correlation, as you might expect, between sun spot numbers and the results. For example, the last day of one coil above shows a very poor day for 10MHz propagation. And sure enough the SN was a low 31. 

A fast way to check the propagation is a new app from N0NBH called "Solar". This runs on the iPhone but also on the new MacBook Air M1. Here is todays info:



SUN
And if you want the latest picture of the sun click here





Friday, 8 October 2021

Club QO-100 transmitter

An uplink converter (here) for transmitting to the QC-100 satellite has been built by numerous amateurs


This is the layout with individual "ebay`' items fixed to a mounting board, interconnected by SMA cables.

The Banbury Amateur Radio Society is building one of these along with the TX/RX antenna and LNB. So far we have connected up the units free across the table, and are feeding it a 432MHz input at up to 10W through a 20dB attenuator. Awaiting PSU module for +8 and +5V. No results yet, but will document as the project goes ahead.

So here's the project going ahead - it is NOT a shambles, promise

Some of the modules scattered around

And proposed box which will go outside near the dish

Just a couple of new photos as we have a club presentation about the Ofcom EMF checking we all have to do: spreadsheets and all that. I think I am exempt with max 5W TX and indoor loop antenna! Or also with my 200mW WSPR TX.

The task goes on... the antenna is proving difficult to bild as the plates keep warping when heated to solder them, tried twice so far but still a problem. This is the state of play, I'm sure something will rise out of the jungle...

We have a receiver going with a commercial LNB and dish, but it drifts quite a lot and we must xtal stabilise it. We are using an SDRplay with SDRUno software to tune to the LNB output on 739MHz.

Update: the main components are mounted on the board and we have an output at 2.4GHz from a transceiver and 20dB attenuator at 430MHz. Now to add the filters and power amplifier.


So this is what it now looks like, but building has stopped as one of the power supplies blew up and we are waiting for a replacement.

RX

There is talk of moving to an RTL dongle and I would like us to try GQRX software... as it runs on the Mac!!!

QO-100 frequencies

The tuning and TXRX frequencies are



Friday, 3 September 2021

Field day 4 Sept 21

Saturday 4th Sept was Field day and Banbury Amateur Radio Society (BARS) went to Balscote Mill to put up a /P station.

I also went along to put up my ELAD FDM-DUO and an AL-705 loop antenna.

SSB

I have updated my old MacBook 12" to run Windows 10 Pro and install the ELAD FDM-SW2 SDR suite. Looking to make any contacts on 40-30-20m.

FT8

I switched to my new MacBook Air and WSJT-X and try for FT8 contacts.

Most of the day was a disaster. We were located in a deep dip with little take off. I was heard in Croatia but no contact confirmed. The main station's G5RV  antenna broke in the centre and was irreparable!



Buying an EV?? Our needs for EV charging by 2030 (9 years away!!)

 Chucking out the peanuts

Day after day our UK government is announcing this and that million pounds for peanut initiatives for the upheaval change we must make to move to Electric Vehicles. It's a new Transport System guys...

What about 2030, just 9 years away? Will there be 6m or 18m EVs on our roads? It varies depending which part of government you ask, BEIS/Dft or Ofgem. So what? It's just chicken and egg. And here most definitely the chargers come first, for without them along our strategic road network EVs will not come, people will not buy them.

We are faced by seemingly random government actions. "190,000 home/work chargers of 7kW power by ???" "25,000 chargers, unspecified, and without declared funding, by ???" Magnificent £1.3bn declared over 4 years, for what? Not defined, but turning out to be handouts to cowboys operations putting chargers in the wrong places like McDonalds or Chester Zoo, not along our roads. Lots of talk about "£950m for rapid chargers on our roads, 6000 by 2035" (far too few). Plus a miserable £20m for Local Authorities to divide their car parks and prevent fossil fuelled cars equal access to parking, oh, and some unspecified "street" charging in 2021 & maybe 2022...

Like I said, chaos.

Pools, chargers and points

And on top of this Boris's stated bold angelic vision of charger pools "every 30 miles along our Strategic Road Network". Which, when you work it out, means 2,300 miles of motorways needing 80 charge pools, at which at least 20 pools with 10 chargers each or 9,300 points.  And even then 15m EVs will need up to 15m home/work fast charge points. We have to deliver the power, a mean of 1kW per EV by 2030 is the EU estimate for electricity suppliers.

But this is not the direction things are going. Is it? The government firmly believes in the approach of "the market will provide" (read: it's not our job, we are only the government). But the market  will not. Today few of the chargers are finding their way to motorway pools and very few, if any, to "A" roads. They are being installed at local destinations, supermarkets, fast food outlets, in town car parks. The result of which will simply be huge traffic jams as people drive in and out to put energy in their cars. And as EV's fight ICEs for a parking place.

And again just think, EVs need a 45-60 minute charge (it is getting faster but not until better battery technology comes along) versus fossil fuels cars needing just a 10 minute stop. Or 6 times as long. And the range of the EV is, not as makers claim 200-250 miles, but a realistic 150 miles, or lower in cold weather, versus a fossil fuelled car of 500-600 miles. Or four times smaller. This means many more EV stops and many more chargers. It is obviously foolish to think of just replacing petrol stations with EV charging stations. A new architecture of a revolutionary Travel System is needed, only achieved by good top down thinking and planning.

This is where our government is failing us.

It seems the only company that knows this is Tesla, with its manufacture of batteries, cars, of  navigation systems that route you to/via chargers and of an adequate national charger network.

Bad place

So where are we today? In a bad place. The useless national data base of chargers, on line as Zap Map, shows puddles of chargers. Except when you drill down to find one you need right now, right here, for example in East Anglia desert. There are more vast desserts when none can be found. Worse still are the fifty different "networks" run by 50 different cowboys, all given handouts by government to put chargers anywhere they want. All branding no substance. 

No plan, no hope.

The government financing model of handouts to stimulate private initiatives will not provide a pan-national charging infrastructure. What it promotes is seed money promoting sharing of costs with destinations. You know, "come to McDonalds and eat as we provide Rapid EV charging"... In other words the focus of the private investment is shared with destinations. No destination, no chargers. And worse, the paltry sums handed out to Local Authorities most of whom have no idea what to do with it, who employ "consultants", more cowboys, then sprinkle their patch with useless EV only parking. Some even refusing to provide on-street points for those without a private drive.