Comparing HF reception with WSPR Head2Head

After Sunday's FreeDV net on 40m, my neighbour (1km away), Richard VK3LRJ, commented that he couldn't hear all the stations I was hearing. He's on a similar 5 acre block to me. I have wire dipoles in the trees and he uses an end fed wire cut for 80m but with in-line capacitance to resonate on 40m. Richard is off grid and has significant noise from his solar power system which I'm sure is a major factor.

To test our relative reception I suggested we both run WSPR in receive only on 40m so we can compare receive signal to noise.

I did some spot checks, looking at individual transmissions received by both of us.

VK7JJ at -8 vs +13 = 21dB.

VK2NSB -26 vs +19 = 45dB. Wow.

My reception was significantly better than his. For a more long term analysis I turn to the excellent WSPR data analysis site https://wspr.rocks/ and in particular the "head2head" page. For 12 hours of operation here's the spot count for each of us.

I'm not sure of the best way to compare reception but there are several charts comparing signal to noise. This is maximum SNRs.

Ideally I'd like to be able to have software which finds the same transmission as received by both stations and subtract the SNRs (as I did manually above).

Richard's end fed no doubt has complex nulls compared to the simpler pattern of my mono-band dipole but the charts show that overall his reception is significantly worse.

FreeDV 2.1 sunday net in Australia

16 stations seen (not all transmitted though) on today's FreeDV net. Many stations have updated to the recent version 2.1 release. The Linux users, including myself, have found it solid including the FreeDV Reporter window which has been a bit unstable in past weeks. One user reported some problem with the Windows version not playing back recordings and I know there have been some headaches due to a new version of the C++ runtime being needed.

Stations see included: VK2DWG, VK3GTP, VK3JF, VK3KQT, VK3LRJ, VK3YV, VK5KFG, VK5KVA, VK3KEZ, VK3PCC, VK3CKY, VK3AWA, VK3BAL, VK2TTL, and VK3IK.

Rosebud Radiofest

The annual Rosebud Radiofest was enjoyable again this year. I'm trying not to acumulate too much gear but it's always great to catch up with friends. Waiting to enter here's Andrew VK3BEK, Dave VK3ASE, and Peter VK3YPG

Ralph VK3ZZC picked up a very nice, but not very pocketable, multimeter.

Drew VK3XU was again on hand selling some deceased estate gear.

I chatted with Peter VK3YE who made a video of all the goodies he purchased for a total outlay of $3.

The hall didn't seem as busy this year but it was certainly worth attending.

All credit to the organisers who did a wonderful and professional job again this year.

Anko streaming microphone - low cost, decent quality

One of the keys to getting the best out of digital voice over HF using FreeDV is having a good quality microphone fairly close to the speaker. Stephen, VK2BLQ, drew my attention to a "Streaming" microphone branded Anko and for sale in kmart and Target for AU$19.

It has a wire grill with a foam pop filter underneath it. There's a rather weird RGB led lighting effect that can be controlled by pushing the knob. The quality of the audio is surprisingly good! Until I looked closely at it I didn't realise it's also a USB output audio device with a 3.5mm socket under the main body.

USB Microphone:

  Location ID: 0x02122000

  Connection Type: Removable

  Manufacturer: USB Microphone

  Serial Number: Not Provided

  Link Speed: 12 Mb/s

  USB Vendor ID: 0x434c

  USB Product ID: 0x4155

  USB Product Version: 0x0100

The vendor ID isn't listed in the databases I could find and the main chip has it's numbers blanked out.

Inside it shows a nice large condenser microphone.

If you're looking for a USB microphone for very little money, I can recommend this one. I wish the mount at the bottom had the standard thread but otherwise I have no complaints.

Do you know that feeling where you have a tool, in my case a new 3D printer, and you're kind of looking for things to use it for? I designed a more compact case for the guts of the microphone.

The lip on the lid is 0.5mm smaller than the opening in the box. It's not quite tight enough to grip so I've put two cable-ties around it.

Tech Talk on ABC Radio - Valve is coming for Microsoft's games

The global video games market is worth approximately $337 billion US, 10 times the size of the global movie business. Video games have gone through massive transitions.  

Valve, an American video game developer, publisher, and digital distribution company, suggests another transition is coming, and it doesn't look good for Microsoft.  

The cost of watching Australian content on all the commercial video streaming services and competition for satellite internet is coming to Australia.

Peter Marks, mobile software developer and technology commentator from Access Informatics, joined Philip Clark and listeners to Nightlife. https://www.abc.net.au/listen/programs/nightlife/nightlife-tech-talk-with-peter-marks/106025034

 

Power tool battery for QRP Radio

Bought one of these 12V power tool battery adapters.

It has an adjustable output voltage - handy for the QRP-Labs QMX which is rather sensitive to voltage. Noise on receive seems very low. The one I bought is for Makita 18V batteries and was AU$35 on Amazon. I can see versions for other batteries. Also available from AliExpress but the price difference isn't worth the wait.

It came with a cigarette lighter socket but obviously I've changed it to Anderson Powerpole.

Aurora visible in Victoria - excellent local conditions on 80m

We are experiencing a severe geomagnetic storm at the moment. The Macedon Radio club's 80m net noticed the strongest local signals in recent memory. Eric, VK3ED, suggested that I had bent his digital S meter. 

It was difficult to detect with the naked eye - I probably didn't stay out long enough for my eye to adapt - but phone cameras these days can pick up this sort of thing with a time exposure.

The colours shifted slowly over time with reds and greens.

Interesting that local 80m signals were big because the prediction of band conditions was not looking good.

(This is not live by the way).

FreeDV Australian net - 20 stations several new

A very successful FreeDV net this morning with 20 stations at least seen. Several new stations again this week which is great. Some of us were having audio problems, low level or clipping, difficulty controlling mic levels.

One user reported that the application crashed. After much deliberation, I've decided to move the net to 7045 rather than the frequency of 7177 built in to the app. 7177 is a slow scan TV frequency which I think was selected as there's not much activity. We've found in Australia that there's often SSB activity near this frequency. 7045 is in one of the ranges designated for digital modes. I've asked Mooneer to add 7045 to the app (you can add it yourself but I think it might be nice to have it built in). There is some ongoing discussion about this.

Stations seen this morning were: VK3TPM, VK3JF, VK3BRT, VK3SRC, VK3CKY, VK5KVA, VK5LN, VK7DBX, VK3KEZ, VK3GTP, VK3LRJ, VK5KFG, VK3SPX, VK3TFD, VK5HW, VK3KR, VK3JCO, VK3PCC, VK4WGR and VK2KNC.

I will be at the Rosebud Radiofest next Sunday, as might be a few others, so someone might need to step in as net controller.