WSPR on 50 MHz

[VK2KRR]

First real day of 6m action today, with single and double hop Es, and periods of high MUF Es also around the south east of Australia.

   

In regards to the high MUF, the WSPRView software really came into its own today and made life a whole lot easier to find the higher MUF paths. When the band opens up with so many stations in on the action, it becomes very difficult to wade through all the data on the WSPRnet database page, but when you have the right parameters in WSPRView, its very easy to seek out high muf areas that may work with 144 MHz paths.

Summer is shaping up to be great fun! 

[VK4ADC]

Leigh

I have a Raspberry PI Zero on order, delivery expected today, to turn into a WSPR beacon on 50.293 as soon as I produce the low power amp/filter PCB (layout done) and get the Pi loaded up so there should be another 6M indicator source from south east VK4 soon.  Maybe the next week or two should see that on air and connected to the 6M J-Pole ( https://www.vk4adc.com/web/vhfuhf-projec...1-6m-jpole ), local circumstances permitting.

The newest release of WSPRView (1.0.0.8) has a lot of changes made inside it to accent alerts plus can generate emails through and to the likes of GMail (now inbuilt).  There is also an audible tone generation (a triple-tone burst) for those who have their WSPR-monitor PC running in their shack and that relieves them from having to watch the screen for alerts. Listen for the triple tones then look ! It should be available for download within a day or so from now.

I'll let you know when the Pi is on-air from here.. It will run off solar-charged batteries so should be available 24/7 --- except when I am on 6M in person 

Doug

[VK7HH]

Thanks Doug.
I used WSPRView yesterday too on my shack PC. It worked really well. Looking forward to v1.0.0.8 and the DX.

Regards
Hayden

[VK2KRR]

Every day is getting better and better at present. Some areas of high E MUF again this afternoon.
I was unable to find any paths across the high MUF areas and was using FM Broadcast and AIS into the Bight. There are no VK6's on 2m at present which is not helping the situation.

I downloaded the newest version of WSPRView this afternoon. Its really great.
EASY to see whats going on with the E MUF. I've taken a number of screen shots to show people a look at how I use it and what Im looking for.

I should mention that WSPRView can be used in many different configurations depending upon what your wishing to observe. Long distances or short distances or both.

For this example, im watching for areas of high E layer MUF. Mainly to then be able to proceed up the spectrum to FM radio Es and then 144 MHz Es, and possibly 162 MHz AIS.

The best way I find to do this is to have many stations or beacons on 6m WSPR. You then look for short 6m E paths between about 400 and 900 km roughly. Maybe 300 to 600 km on 6m when the E MUF is above 144 MHz. This is nice, but in practice at ranges of 400 to 900 km, you need to be able to work out what is a true E signal and distinguish that from other shorter signals like tropo, aircraft, E backscatter etc.
Using WSPR you can do this, because usually a true E signal from a station running just 5 or 10 watts will be very strong like +10dB or so. I look for them from +1dB and stonger. Usually if a signal has come via another mode like tropo, the signals over the same distance will be much weaker, usually -1dB or less.

After 7pm this evening the 6m E MUF really picked up on many paths to the Adelaide area from Melbourne and Canberra, in the +dB region. 
This is what the WSPRView screen looked like -

   

You can see paths there as short as 580 km at +20 dB. Its quite possible that 88 to 108 MHz was running across this mid point and maybe even 144 MHz. But people need to be in the right positions. For me, going across this mid-point puts signals into the great Aust Bight, and I can only investigate this with 162 MHz AIS, but this is very high and probably not running at the time. But I was watching.
The black background spots indicate an alert condition, which is great to observe at a Glance.

WSPRView 2 - 

   

WSPRVIew 3 - 

   

WSPRView 4 - 

   

Very tired when writing this, so if there are mistakes, I apologies, can fix tomorrow.

[VK2KRR]

Doug,

I forgot to comment on your Pi 6m WSPR beacon project, which sounds great! I cant wait to see how it goes.

Share with us some more details and maybe some photos when you can.

[VK4ADC]

Leigh

The critical part is operational.  The Pi Zero arrived today and I had a 16GB microSD card ready to go with Raspberrian Stretch OS. I did the update and upgrades then installed the WSPR software from the relevant GIT  A few minor tweaks and it is WSPR-ing away on 6M.   I did try it on 20M too although that isn't its destination.  I revised the amp/filter PCB layout a bit late today with the hope of producing a PCB tomorrow and getting the SMD parts onto it.  Obviously a bit of filter tuning to be done but maybe it will be ready early next week. Anticipating 400-500mW out on 6M WSPR.

Partial proof.. (left click on image to view)

   

[VK4ADC]

Leigh et all

My Raspberry Pi Zero W is alive and well and about ready for 6M WSPR use.   The PA PCB was built yesterday, tested with a sig gen at +10dBm to check the LPF action ( > 25dB down at 72MHz, each LPF section tested separately) and fed with the Pi this morning. My RF power meter shows +25dBm out of the amp stage after the output LPF, a little over 200mW.    My main concern was frequency error as it was jumping all over the place ( +/- 300 - 400 Hz) as it did the WSPR software's internal frequency correction but I have put it into free-run mode and adjusted the output frequency via the command line. Now there is just a few HZ drift noticeable at the moment over the course of the 110 seconds.  It will undoubtedly need re-calibration after it is boxed and has been running a while (so is temperature stable).  The whole assembly (Pi plus PA) runs from +12V, drawing around 300-500mA depending on what it is doing at the time (only 200mA is drawn by the PA PCB itself).

The PA PCB was designed to be the same size (65 x 30mm) and to sit over/under the Pi Zero's mounting holes and use a 10 pin header (dual 5) connector to interconnect the PCBs.  An SMA edge connector can fit to the end of the board in lieu of the current RG316 teflon coax out.  The input LPF can be set up as a 5 or 7 pole, as can the output LPF, and could be configured for any of the lower bands by changing the values of L and C.   I used the LPF calculator at http://www.wa4dsy.net/filter/filterdesign.html to work out the values for 6m, using a 60MHz Fc and a 5-pole Butterworth as that calculated as close to standard values. The SHF-0289 GaAs HFET was bought in a pack of 5 via eBay a few years ago, datasheet here : http://web.rfoe.net:8000/SIRENZA/PDF/gaa...f-0289.pdf, and while rated 50MHz to 6GHz, SHOULD work on HF too. It runs self-biassed (source resistor style) so only needs a single power supply.  The +6V three-terminal regulator is used for the PA power but was making the PCB a bit warm at +12V applied so I now have an external +8V regulator in series with the +12V supply to reduce the on-board power dissipation / temperature.

I contemplated making it multiband but the physical logistics (ie changing LPFs) was too difficult, and they are cheap enough to make to build a separate one for each band desired - OR - since the 6M LPF will pass anything up to 55MHz, why not just make up some in-line LPFs or BPFs (in small metal boxes) for the lower bands and put them in series from the RF Out connection ???  BNC or SMA in and out ??

I will "box it" in the next few days so that only power and antenna connections are required but will have a DC power switch plus a reset switch for the Pi on the outside.  It looks like it will have to be plastic as the Zero W has an internal WLAN antenna - unfortunately.

Costing : Raspberry Pi Zero W : $22 (posted),  16GB microSD card (type 10) @ $8, rest of the bits from my project box.. maybe $10-$20. All up say $50..

My command line (for now) is "sudo wspr -r -f vk4adc qg62lg51 25 50294110" to achieve an output at 50.294500 +/-. { repeat and free-run }


The images below show the details so far:

   

   

   

I will add a photo of the completed "sandwich" in the next day or two..

[VK4ADC]

I have had the Pi-based WSPR signal up on 6M for a while this morning but have encountered a few issues yet to be solved.   

For a start, it runs a number of transmission sequences then shuts down the Tx - I think I have seen a fix for this already.

A more important side effect is that the Pi beacon puts out broadband noise across HF and 6 when on Tx into the 6M J-Pole. When it drops off Tx then the received noise level is back to normal. This could be a major stumbling block to running it 24/7 as I often listen across the HF bands, sometimes operating FT8 along the way. Maybe it will be on when I am home but not actually operating / tuning around, which sort-of defeats the purpose of having it.

While not boxed as yet, the photo below shows the sandwich, Pi on top, RF amp/filter below it.


     

[VK7HH]

Hi Doug,
Maybe a shielded box and leads into/from the Pi will reduce a majority of the noise?

Also, how are you powering it? If it's via a plugpack that could be radiating noise when it's under load?

Just a couple of thoughts.

Regards
Hayden

[VK4ADC]

I will "box it" in the next few days so that only power and antenna connections are required but will have a DC power switch plus a reset switch for the Pi on the outside.  It looks like it will have to be plastic as the Zero W has an internal WLAN antenna - unfortunately.

Hayden 

WLAN won't work through a metal box  and it needs that for me to SSH into it plus it get NTP timing  corrections  
I have a nice diecast box all ready though.

It is only while transmitting that the broadband noise is present : WSPR carrier is S9+60 on the radio on 50.293 but the 'white' noise off freq (eg 50.110) and on the other HF bands is a minimum of S7 and beyond S9+.  The 3-terminal regulators (x3 : 8V [common to], 6V [PA] & 5V [Pi]) all have stability capacitors fitted so I doubt that they are a contributing factor. 

As a workaround, I have ordered a mini-HDMI and OTG adapter so that I can hard-wire in to it for monitor, USB keyboard and mouse but unless I can get a USB WLAN adapter (via OTG) to work in  lieu of the internal WLAN  then metal boxing is not going to work. At this stage it is not ruled out completely, just unlikely. Don't quite know how long they will take to arrive - late this week perhaps.

I am not going to have much more free time this week, or next, so it will have to wait.

On a different note, WSPRView V1.0.0.10 is being released shortly and the current email support problems should be resolved with it.

Doug

[VK7HH]

Oh sorry Doug...

I'm thinking regular RPi's and didn't realize it was a Zero.. otherwise I would've said just use Ethernet .

Good on WSPRView too, v1.0.0.9 has been rock solid

[VK2KRR]

Great to see this Doug, and as at time of posting was the most distant 6m signal -
2018-12-01 03:24 VK4ADC 50.294484 -19 1 QG62lg 0.5 ZL2IT RF80km 2559 km

[VK4ADC]

Leigh

Well that is the Raspberry Pi with 200-250mW PA and a 6m J-Pole in operation.  Only back at the home QTH yesterday and stoked it up this morning...

   

[VK4ADC]

I thought 6M DX was mostly finished for the summer but found these entries in my WSPR reception reports log tonight :

ZL3PX      ,  -24,   50.294465, RE66hm,  2483,  2019-02-19 03:18
ZL3PX      ,  -24,   50.294463, RE66hm,  2483,  2019-02-19 03:28
ZL3PX      ,  -22,   50.294463, RE66hm,  2483,  2019-02-19 03:38

VK7HH      ,  -19,   50.294491, QE36mx,  1782,  2019-02-28 02:24
VK7HH      ,  -11,   50.294496, QE36mx,  1782,  2019-02-28 02:44
VK3II      ,   -6,   50.294489, QF21rn,  1379,  2019-02-28 03:14

Maybe there is still some sporadic DX yet to be found..

[VK5PJ]

QRT on 50 MHz WSPR while rebuilding the shack shed after a recent shed fire caused by the battery bank exploding, hope to be on again by June - Peter, vk5pj

[VK2KRR]

Looking good today in south east Australia and across to ZL on 6m WSPR.

   

[VK7HH]

Back running 6m WSPR over winter. Beaming USA for now with 50W

[VK2KRR]

Your doing well today Doug VK4ADC (as is everyone else), 6m Winter sporadic E 
We could sure do with more VK4 stations scattered northward along the coast and ranges.

   

[VK4ADC]

Leigh

I download my WSPR spots every couple of days and have seen some odd openings  in the lists to down south over the last couple of weeks.  So it's not entirely news to me.

I'm still getting HF reports from all over the world, mainly 10 and 14 MHz but some on the 18 and 21 MHz bands, all from my measly few watts.   
Proves there is still propagation happening...

As a good news P.S., this is from this weekend's WIA News broadcast  (( From: WIA  NATIONAL NEWS FOR WEEK COMMENCING JULY 14  2019  )) :

"Reversed Polarity Sunspot
A reversed-polarity sunspot has broken through the surface of the sun, the second time this month this has happened.  This latest "backwards sunspot" could mark the official beginning of new Solar Cycle 25.

Visit the July 8 edition of Spaceweather.com to learn more about sunspot AR2744 and the transition between solar cycles.
(SouthGate)

"

[VK2KRR]

If you have or know of someone who may have a radio/antenna available to run 6m WSPR, we really could do with more stations from VK4 further north from Brisbane.

   

Brisbane is only about 1000 km from here or less, same with Sydney siders etc, so for 6m Es the MUF has to strengthen a bit to bring signals in that short, so no doubt there are numerous openings being missed from paths extending out to 2400 km from myself or Sydney area etc, same with Adelaide.

Some in VK8 particularly Alice Springs would be good too and also VK6 of course.

Even if stations could just organise to run them over the weekend, that would be a great help.