New WSPR receiver from RemoteQTH

RemoteQTH is a small company in the Czech Republic and they have just announced the release of a new receiver for WSPR. 

It can be used from 0.1 to 28 MHz and is described as follows..."The openWSPR receiver is a stand-alone HF receiver for WSPR. Just connect an antenna, internet and a DC power supply and you're ready to go! With this tiny receiver you can decode and relay WSPR messages to WSPRnet.org. 

Since the entire project is open source, receivers can be easily reprogrammed to receive signals other than WSPR. The nanoPi board inside runs Raspbian OS and several user programs, which are automated by custom scripts, making the receiver completely maintenance-free."

It is selling for €125 which at first glance sounds expensive but I guess one of the main features of this WSPR receiver is that it doesn't require an external PC or computer to run. All of the decoding is done inside the unit. All you need to do is connect the various cables, configure it, connect an Ethernet cable and it uploads the spots to WSPRnet.

Looking at the size of the box relative to the SMA or Ethernet connector then it's really small and just a few cms across.

Future products... They are also developing a separate transmitter module.

They have no information on this in terms of power output but 200 milliwatts seems to be the norm.

It's also interesting to see that they are developing a series of band pass filters...

I think these will be attractive to users of other WSPR products as well as all you need are the connecting SMA patch leads.... no construction, soldering or winding of torroids. 

The photo above shows the surface mount components inside the filter.

Nearly all of these low power WSPR transmitters have a square wave output and require some sort of filter to remove the higher harmonics. This is usually done with a low-pass filter rather than a bandpass filter which tends to have slightly more loss.

Where bandpass filters shine is with the receiver module as they keep all of the potentially large signals on the lower bands out of the front end of the receiver. I think these standalone filter modules may be of interest to anyone with a SDR receiver and who want to concentrate on one band.

Link... More info on the RemoteQTH website

Disclaimer: Just to clarify, no-one paid for this post or sent any product to me for review. These are new products that I think people will be interested in.

Addendum: Since putting up this post, someone hs asked about whether the receiver can hop between bands? Does it run WSJT-X? And what is the performance of the receiver?

I looked at the files section of the site and found a circuit diagram. The receiver schematic shows the input RF going straight into an IC without any preceding RF stage amplification. This might be ok on the bands on the lower bands like 40m or 80m but is it going to be sensitive enough on bands like 10m / 28 MHz?

The input has a single LC parallel circuit which suggests that it is intended for single band use. If these components are left out then an external band pass filter is required for each band.

Mystery US callsign spotted on WSPR on 80m to 10m in Europe

The callsign K9YO with the locator square JO22SA has been reported on WSPR on 80m to 10m since the 28th of June 2021. 

The transmitter doesn't seem to be operational all of the time and the WSPR signal has been reported by 47 stations since the 28th of June. The map above shows those who have heard this signal on 28 MHz (10M) which suggests that the transmitter was only on air for a short period.

Does anyone have any info as to why is there a US callsign in the Netherlands???

Update: The LU7AA.ORG website suggests that it might have been a balloon.

Snapshot of WSPR activity levels on various bands - Fri 2nd July 2021

2nd July 2021: For the last few weeks, I have been monitoring the WSPR frequency on 28.1246 MHz and uploading the reports to the WSPRnet website. I noticed on the 2nd of July that I was ranked 3rd in the world for 10m reception reports on that day.

This certainly isn't due to anything special on my part as I'm just using a simple CB type half-wave vertical. The 3rd place is likely due to my location in the north-west of Europe which means I was probably hearing a lot of European stations on that day and I might have a slight advantage towards North America.

WSPR activity: Looking at the data above, it gives a snapshot into the activity levels for WSPR on the various bands on what was a busy day for Sporadic-E propagation. 

The LF band down around 136 kHz has so little activity that it can be ignored. Perhaps it has more activity in Winter. Likewise for the MF band around 473 kHz.

The 70 MHz (4m) band has so few users that it is probably a waste of time using WSPR.

WSPR activity on 144 MHz (2m) is mostly confined to the SE of Australia and California. The level of activity in Europe is very low.

There is very little activity on the 432 MHz (70cms) and 1296 MHz (23cms) band.

I calculated the average number of stations heard by the five top receiving stations (>10 stns heard) on each band and this is what the chart looks like...

1.8 MHz (160m) / 3.5 MHz (80m) / 5.5 MHz (60m) ...Perhaps there is a lack of activity due to the amount of daylight during the Summer months but only 80m seems to have enough users for it to be meaningful.

7.0 MHz (40m) / 10.1 MHz (30m) / 14.0 MHz (20m) ...These are the only three bands where the level of activity is really high. I'd suggest that these are the bands that have enough users to make antenna tests and comparisons meaningful.

18.1 MHz (17m) / 21 MHz (15m) ...There is probably just enough activity on these bands to make them useful for propagation tests but the level of activity is well below the likes of 20m.

24.9 MHz (12m) ...The level of activity is very low and is probably of little value.

28 MHz (10m) ...From my experience, the level of activity outside of the summer Sporadic-E season is so low that it's pointless. Now during the Summer months however, there is a modest amount of activity but many of the propagation paths go unreported due to a lack of stations in suitable locations. In this respect, FT8 is much better at getting an idea of what the band conditions are like.

50 MHz (6m) ...Most of this activity is in Europe but the number of users is so low as to make it pointless.

In Conclusion: It might be interesting to take a snapshot again in the middle of Winter but for now, the WSPR mode is of limited use on some bands. Even though I monitor the 10m WSPR frequency every day, I can't really say it has any real advantages over say FT8 other than the fact the WSPR reception reports get stored for a longer period as opposed to 24 hours for FT8.

If you are interested in buying one of those small standalone WSPR transmitters for doing antenna tests then I'd suggest you choose one for either 40m, 30m or 20m.

Links...

1) WSPR Rocks website by Phil, VK7JJ