Here is a quick tip to always have the correct time on your PC for good WSPR reception. Website to check your time: https://time.is/ Software to always have the correct time: http://www.timesynctool.com/ You might want to change the default settings on the time sync tool, see picture: 73 //Harry

Here in southern parts of Sweden spring has finally arrived. The Magnolia tree in my garden has just opened up it's flower and it's perfect conditions for doing antenna work. If you are a Ham and live within the footprint of the newly activated Oscar 100 you probably have started planing for getting in on the action. I have put up a 50cm parabolic reflector and are in the early stages of getting my downlink put together. The down link is super easy as we can use commercial available LNBs (Low Noise Block converters) made for regular Satt-TV. The new Digital formats for TV have made the LNB manufactures shift from DROs (Dielectric Resonator Oscillator) to PLLs with crystals and this have made the LNB more frequency stable. An unmodified LNB is OK to use as a first setup. However although an unmodified LNB they can be used, if you really want correct frequency readout in your down link and if you don't want to re-tune while the LNB drifts slowly you need to come up with a way to get the LNB frequency locked to a stable frequency source. I spent some time doing research on this for two popular LNBs and have find a good solution to lock them by sending up the reference signal in the feed-line coax. I plan to design and sell modified LNBs with all the electronics needed to get a stable down link using either a TCXO or a OCXO as a reference. So now I'm in the fun stage of research and design. More news to come in a month or so. I will also do a blog write up on how to do the LNB mod. yourself and posting more of my findings, research etc. I have a working downlink with injection locked LNB that is being feed from a OCXO. I did some test to use the same reference to down mix the 739MHz signal to 2m with a ADF4351 based LO of my own design and it worked fine. I also briefly tested to build an experimental direct conversion receiver and it also worked fine. I do really like direct conversion RXs (although this would actually be a single super as the LNB has a mixer stage, the DC receiver was listening on the 739MHz IF) The DC receiver was more of a fun thing but the 2m down converter I plan to make in to a product. Using the same OCXO for both the LNB and IF mixing makes for a super stable and accurate converter/transverter. Some random photos of my experiments. Getting 25MHz from a 10MHz OCXO Sending it remotely up to a modified LNB Fun times! I'm also designing a 2.4GHz up link so I can do a full transverter for 2m. One complication is that the Swedish authorities have lowered out maximum output on 2.4GHz to 100mW!! So that will mean I have to use a 5m parabolic dish to test the up link if I can not get an exception to use more power. That will be a pretty big dish, my girlfriend said she was cool with more antennas on the south facing side of the house but I did not mention it would look like a radio astronomy site so we will see what happens :-D Please let me hear of your plans for a Oscar 100 station, I think it is super-interesting times for us! //Harry

This little amplifier will be up for sale in a week or two. Will be low cost general purpose MMIC based amp that can be nice to have in the RF experimental toolbox. It is powered from 5V USB or from a single LiPo. It has pretty decent data. I spent some time measuring the first two I built. About 21dB gain from 30kHz up to well over 1Ghz. About 4dB Noise figure over most of the range, Not bad at all. P1dB at 4dBm so will be most useful in receiver applications. More spec to follow. Price not set but will be pretty low cost as it is meant to be a simple low cost product. A LiPo daughter board that can power it will also be available, in that configuration the USB port will charge the LiPo and an on/off switch on the LiPo board will controll power to it. Measuring the Noise factor up to 1.4GHz. The somewhat blurry picture shows measurement at 100MHz. It uses the NEC/CEL UPC1688G MMIC.

For my birthday my GF surprised me with a trip and stay-over to the city of Gothenburg. The main attraction was the Radio Museum. If you ever find yourself in Gothenburg I can recommend a visit. Here are some photos. One of the first transmitters in Gothenburg from around year 1918 Receivers form the twenties and thirties and going of in the distance to more modern times. We got a guided tour and here our guide is demonstrating a unique tape player that is not magnetic, it had a pickup similar like the ones used for vinyl players and the tape was engraved with 8 tracks that could be switched between. Old brass meters, what not to love :-) Nice fifties/ sixties design radio from the Swedish AGA brand. AGA was one of these giant industrial companies that did everything from electric stoves to transmitters, to lighthouses!

This little baby is on my bench right now undergoing software and hardware tests and development. It has a GPS with built in antenna on the PCB, is controlled by the same software as my other WSPR transmitters and the Si5351 is directly feeding the antenna after low pass filtering so the output power is about 12dBm (20mW) I'm running it against an indoors dipole in my loft now. Works fine but needs an outdoors antenna. I'm now waiting for revision 2 of the PCB that should be home in a week or so. If that works fine I will create a initial series for sale in my shop. Price is not set yet but will be lower than the others. This can be run from USB or a LiPo battery so I will do some investigations in to Arduino sleep modes and see what I can come up with. Would be nice if it could go down in power saving mode if the transmission pause was longer than a couple of minutes or so. This test article will be running a beacon on 30 and and 20m band for a few days. I really need to get up an antenna outdoors again... so much to do, so little time :-) 73 all //Harry - SM7PNV

I used some copper break line and some Delrin plastic to form a small 24cm diameter three turn loop that I will use to test transmission on 17m and compare against a regular dipole. WSPR is the perfect tool for this as I can get the raw data from WSPRnet.org and export to excel for comparisons. Maybe transmit every odd day with a dipole and every even day with the loop? I can then pull a few receiving stations from around the World and see how much worse the loop is compared to the dipole. And perhaps a few test with the loop at different heights. I will probably Hoist it up my flag pole at different heights for test, currently my flag pole is on the ground for maintenance, this will be a good reason to get it up again, so much work so Little time :-) How much different do you think we will see if the loop is at the same height as a regular dipole ? minus 10dB ?

It’s good to have you here! Feel free to share anything - stories, ideas, pictures or whatever is on your mind. Here you can start discussions, connect with members, reply to comments, and more. Have something to say? Leave a comment or share a post! I will start off the discussions with a picture of the VLF transmitter located in Grimeton Sweden. It was built in the nineteen twenties and is still operational and transmits a few times per year on 22kHz. I can recommend a if you find your way up to the southern parts of Sweden. More info here: https://grimeton.org