Tag Archives: WSPRLite

WSPRlite on 80m

After a fair amount of work yesterday I was able to get my Cobra UltraLite Senior back up with some assistance. As I said in my previous post, the tree that was holding the north end of the antenna had to come down so I needed to develop a new support plan. The other trees in the area weren’t completely suitable so my XYL suggested using the post for the basketball hoop as a support for a pole to support the antenna. I was going to fabricate a pole but a little further thought resulted in the purchase of a Channel Master 25ft antenna mast. The next problem was to develop a method of clamping the antenna mast to the basketball post. After a few minutes consulting with my older son, W9KKX he suggested using back-to-back muffler clamps. I acquired a set of three 4″ clamps and three 2″ clamps and W9KKX welded them up for me.

Clamp construction

After a little bit of paint I had three, custom pipe-to-pipe clamps:

Pipe-to-pipe clamps

Attaching the clamps to the basketball post and in turn the antenna support mast was very simple and clean.

Pole and mast

It was very easy to then push-up the mast by simply placing a ladder next to the basketball pole and running the mast sections up.

New antenna support

With the trees so close to the basketball post it actually blends in quite nicely. I placed some guy ropes from near the top of the mast to the trees behind it for support.

After replacing the halyard and support ropes in the tree at the south end of the antenna I was able to pull the antenna into position with the assistance of my younger son and one of his friends. The antenna is 140 feet long and runs over the course of about 200 feet including the support ropes in order to get the center feed ladder line positioned well. The south end is at about 35 feet and the north at 25 feet. The center feedpoint is supported with a line to another tree just to the west of the antenna. The antenna is oriented NNE to SSW.

Once the outside work was completed I went inside to check the antenna with my AA-55 Zoom and then configure the WSPRlite tranmitter for 80m. Since the Cobra UltraLite Senior is not resonant on 80m I used my Dentron Jr. Monitor to provide a match for the WSPRlite transmitter. With these preparations complete I started WSPRing on 80m with 200mW.

KA9EAK @ 200mW on 80m

Band conditions

Over the course of the night I was watching results and comparing with some other local stations. For example the station of AA9GE is just under 200 miles south and a bit west of mine and he was getting these results with 1w of power:

AA9GE @1W on 80m

The overall activity looked like this:

80m WSPR activity

A lot of the spots from Europe were US receive stations. There weren’t a lot of US stations being received by European stations with the exceptions that I found running 5w as opposed to 200mW.

WSPRing is very interesting. There obviously are a number of variables involved from propagation conditions to antennas and power. It’s not everything, but it’s something. Now that I have my Cobra UltraLite Senior back up I can do some A\B testing with my Hustler 4BTV. I’ll post results when I have them.

Now to finish up my Thirteen Colonies. I’ve got four more to go plus the GB13COL station.

Happy Independence Day!


WSPRlite on 40m

I completed the build of the low pass filter kit last night and a quick test on 40m indicates that it is working properly as indicated by a number of spots in North America and ZL1RS in New Zealand. The antenna I’m using for this test is my Hustler 4BTV with thirty 30 foot radials and the WSPRlite is set to 200mW.

WSPRlite on 40m

Current band conditions

The build isn’t difficult at all though you will get some practice winding toroids. The capacitors are very small, but thankfully not SMDs : ) , so as a nice touch for eyes that aren’t 20 anymore they package them so that old eyes can sort them out. Most of mine were on tape reels with some indication of the value by the number and\or color of lines on the reel material. One set was in a clearly labeled bag. There is a table in the build instructions to decipher the simple code for the lines. It’s a nice extra effort on the part of the SOTAbeam folks. With the capacitors, jumpers, and connectors in place the board is complete.

Low pass filter board

The three sets of filters line up across the board so configuration is as easy as moving the jumpers on the input and output headers to correspond to the filter set for the band on which you wish to operate.

As for an enclosure, given the nature of the board and the necessity to access the jumpers I think that I’ll just mount it on some standoffs and call it good. For now it’s comfortably WSPRing away sitting on my desk. The weather forecasters are predicting that the next two days are going to be mostly sunny and in the low to mid 70’s (23c) so the primary project for today is to get my CobraUltra Lite antenna back in the air. Then I can resume operations on 80m and 160m including some WSPRing.


Wind toroids or joust with lightning?

As has been the pattern this spring and now summer it’s an on and off rainy day. We’re 6″ ahead of our normal annual rainfall thus far and there isn’t any sign of slowing. That’s a lot of extra water. Today has also included mild thunderstorms periodically rolling through. With a four day weekend for Independence Day my plan for today was to work on getting my Cobra UltraLite Senior back in the air. About six weeks ago we had to take down a large tree that was arguably dead a couple of years ago but was serving the purpose of holding up one end of the antenna. However the rot had progressed to the point that one more storm was going to bring a stout limb down on the camper or a vehicle so the antenna came down along with the tree. The other trees that are close to it are tall and very full but they don’t have the substantial limbs up high enough for this antenna so I elected to move the end point to a new position and use a Channel Master 25ft antenna mast instead of a tree. This also has the advantage of moving the feedpoint a little closer so that it will fall away a bit more vertically from the antenna to the house as opposed to the more horizontal approach from the past installation.

Lightning Rod

Given the passing thunderstorms albeit mild ones, messing about with a 25 foot steel pole seemed like throwing your hat into the ring for a potential Darwin Award. So I elected to wind nine toroids instead of playing chicken with bolts of lightning. My guess is that the lightning always wins.

Out of the box, the WSPRlite transmitter supports the 20m and 30m bands. The low pass filter kit provides support for the 40m, 80m and 160m bands. As you can imagine the primary components of the low pass filter kit are a number of capacitors (14) and toroids (9).

Low pass filter kit components

So in between tending some chicken on the smoker I commenced to winding the toroids. The build instructions for the kit are very well done. One of the references for winding toroids is that of Genesis Radio which presents a very clear set of instructions for winding toroids if you are new to it. In addition, the build instructions include a simple continuity test sequence so that you can check to be sure that each toroid is soldered to the board correctly. This is a nice added touch as you can never be more than one toroid wrong as you progress.

One down, eight to go

I soldered each toroid to the board as I completed them in order to keep track as there are two different cores and six different turn counts for the nine toroids. It took about an hour to wind all nine and install them.

Toroids complete

Over the course of the evening I’ll complete the board and if the weather improves such that I can reconnect antennas I’ll do some WSPRing on 40m. Once I get my Cobra UltraLite Senior back up I’ll be able to WSPR on 80m and 160m. Stay tuned for more WSPRing, right now it’s time for dinner.


More WSPR-ing with WSPRlite

A few years ago I began to experiment with WSPR. I had recently purchased a SignaLink USB and WSPR was one of the digital modes that I used it for at that time. The radio that I used it with was my IC-718. I used the WSPR software running in Windows and the setup worked well. It was very interesting to experiment with WSPR and my antennas. I typically ran the 718 at 1 Watt.

Earlier this year I read some posts by Andrew, VK1AD and others about the SOTABEAM WSPRlite device. It’s an intriguing little transmitter that does nothing but WSPR. Configure it, connect a power source and an antenna, and you are WSPR-ing at up to 200 mW on 20m and 30m out of the box, and 40m, 80m, and 160m with an additional lowpass filter kit. I put it on my things to do list and there it sat until a box arrived this week. SOTABEAMS has an arrangement with DX Engineering to sell the WSPRlite and the filters in the US.

My favorite packing tape

Contained within the box were the WSPRlite and the lowpass filter kit:

WSPRLite and filter kit

The device itself is very tiny, about 2 inches square:


Nothing comes in the package except a thank you note and directions to the DXplorer site to obtain all manner of materials for the WSPRlite including the instructions, the configuration app, drivers, firmware updates, and the revnotes for both. I downloaded the configuration app and drivers and installed them. The WSPRlite device has a very simply interface. There is a micro USB port for comms to the configuration tool and power, an SMA connector for the antenna, a momentary pushbutton to start the device, and a multi-color LED. The LED has a few states\patterns to indicate the status of the radio.  In less than 10 minutes the WSPRlite was up and running.

Since my main wire antenna is currently down due to a recent tree removal project I was only able to use my 4BTV. I let the WSPRlite run for a bit and within a short period of time spots started to appear on the DXplorer site and the main WSPRnet site.

The purchase of a WSPRlite radio includes a license for DXplorer. There is a button in the configuration app that launches a browser with a custom URL for your callsign. The DXplorer site is interesting in that it allows you to view a table and map of your spots like the WSPRnet site but it’s real purpose is to allow comparisons between your WSPR spot data and that of other stations.

DXplorer compare

To make a comparison DXplorer presents a list of stations sorted by distance from your station. For each station you can select a map or graph comparison but perhaps more interesting is a simultaneous spot table\chart comparing S\N and power.

Simultaneous Comparison

Obviously I wouldn’t know what type of antenna was being used for the compared station but one could contact the station and ask. The WSPRlite purchase includes a one year license to DXplorer. After the first year it’s £19.95 annually. It’s interesting to play with for the moment. The DXplorer site contains a good overview in a presentation.

After letting it run for a fair while I accumulated over 1,000 spots. I got some spots in Australia and New Zealand on 20m very early in the morning but 20m to Europe was not working until much later in the afternoon. All of this at 200mW.

20m spots – 200mW

Band conditions were about as they have been as of late.

Example band conditions

Now I need to go to my bench and assemble the lowpass filter kit so that I can try this out on 40m. Once I get my Cobra UltraLite Senior back up I can do some A\B comparisons with the 4BTV.

Overall I am really pleased with the WSPRlite radio and the DXplorer site. It’s a very well done package and is a nice addition to my station. It was very easy to configure and has been reliably WSPR-ing for most of a day now. It will certainly provide some additional insight into my antennas and propagation, and the ability to compare with others is interesting. I’d recommend adding a WSPRlite to your station.

When the LED is red, you’re WSPR-ing