Tag Archives: SDRplay

Using SDR Receivers to Track NOAA Weather Balloons

Found an article by the folks at RTL-SDR that shows how to recieve data from NOAA weather balloons. This look like a fun project and considering the balloons at the NWS Brownsville are launched twice a day just 2 miles from here it could be very doable.


630m WSPR

Cliff, N5CEY, has been listening to 630m WSPR stations over the past few days and has been consistently picking up three or four stations a night with his antenna system. I thought I would try the same using just the mini-whip antenna and the SDRplay receiver. The mini-whip has been fairly decent on the lower bands. I cranked up HDSDR and when I tuned to the WSPR frequency of 474.2 kHz and found a huge amount of inter-modulation products from local broadcast stations. I tried lowering the gain but they didn’t go away. Looks like I will need a low pass filter or an attenuator.

I then switched to using the SDRuno software that goes along with the SDRplay. It has some filtering features that I thought would be useful to try. The waterfall looked a lot quieter with this software for some reason and after piping the output to WSJT-X I was able to decode 630m WSPR spots from three stations overnight. This compares favorable to what N5CEY saw over the same period.

I will be playing with this some more to see if I can further optimize the receive.

Installed the RA0SMS Recieve Antenna

Installation of the mini-whip antenna wa straightforward the nice I had all the proper connectors and adapters. I tie wrapped the antenna to a 4 foot length of dowel stick and stuck it between the roof and gutter. It is up about 12 feet. I am using a length of RG-6 TV cable as a feed line to the window feed panel. Inside the shack I have a short length of coax to the bias-t and another to the SDRPlay reciever. Rigged up a power cable to provide the 12V needed to power the antenna through the coax. Did it work?

Well yes! It works quite well actually. It is marginally better than discone on 20m thru 10m and significantly better on 160m thru 40m. I’ll likely try and get some more height outside and clean up the wiring a bit. It is now my dedicated antenna for my panadapter.

The RA0SMS Mini-Whip Antenna

I just received a mini-whip antenna from RA0SMS in Russia.The mini-whip is an active receive antenna that is particularly useful in the low bands. I plan to set this up outside and up as far as I can get it. I’ll use 75Ohm cable TV feed line to bring it in the shack and connect it directly to the SDR play receiver. I have been sharing the discone with my VHF rig and the SDR play so I switch between them when I need the SDR as a panadapter. I am hoping this antenna will work well so I can dedicate it to the panadapter function on HF. The antenna consists of the external antenna and circuitry in a PVC case and a small bias-t box to send 12V up the cable to power it.Here is what it looks like after I unboxed it:


SDRplay and a Long wire Antenna

I tried some experiments today with along wire antenna for the SDRplay. I wanted to see if a length of wire through the 9:1 balun would make a reception difference. I strung up about 25 feet of wire up about 10 feet outside. Best I can tell the current setup with the discone is still better. I would have to try a a larger gauge wire and more of it.

BTW, found that using an Arrow staple gun in reverse can have a painful and unpleasant consequence.

Merry Christmas!

Merry Christmas to everyone out there and thanks for keeping up with my humble Ham Radio blog. Santa delivered a few radio goodies this year that I have been playing with since the 25th. First up was an SDRplay receiver:

blog-post1I have replaced the RTL-SDR dongle with this unit and am using it now for my new panadapter. This unit covers 100kHz thru 2Ghz in a single package powered by the USB port. This unit has simplified my wiring considerably. Performance-wise I have not noted a lot of difference between the RTL-SDR dongle and this unit. All in all I’d say its pretty equal. At first I wasn’t happy with the display I was getting with HDSDR. I had played with the setting some much they got messed up. I reinstalled HDSDR and the defaults worked a lot better

Aside from the SDRplay I also received two SOTAbeams 10m travel poles. These will be handy for portable ops as well as experimenting with wire antennas. Last up was a Ultimax 100 end fed antenna. This is an end fed wire with 24 feet of wire. Plan to try this out in various orientations.