Oktober 2025
Time to upgrade my UHF SatNOGS station with 435 MHz bandpass filter and LNA. These are the items I use from AliExpress:
Installation and testing
Some pictures from the installation and measuring:
Some more installation images
Roof mounting
Made a very simple DC switch and distribution board for all the stuff that need 13.5 V DC.
DC distribution board can be found on Aliexpress.
If the link does not work, search for ”12V 24V Car Accessories 6 Gang Toggle Switch”
With an antenna RX splitter I did some fast compare between a simple RTL-SDR v3 SDR dongle and my IC-705 on 21 MHz and 14 MHz FT8. The RTL-SDR v3 is not original designed to run on HF, but with HF Quadrature mode it is possible to use it on HF.
And I was very surprised that this very cheap SDR could decode a lot of the stations that the far more expensive IC-705 did. The spectrum was cleaner from the IC-705 and more stations was decoded, but the results from the SDR was impressive because it is such a cheap and simple device.
Used equipment:
All images below:
PSKReporter map compare – 15 minutes RX on 14 MHz.
WSJT-X window. Cleaner spectrum from the IC-705.
Logbook from PSKReporter.
Signals in dB from WSJT-X. The yellow reports are from the same station. I could notices some difference and RTL-SDR via SDR Console would often give higher dB values, but I have no idea why.
New installation of the 50 MHz Oblong in Januari 2025.
Some time ago now – but I made two EME QSOs with DL7APV (now SK) in February 2023. I used my 2* 15 el LFA X-yagi and 40 watt output from IC-9700.
See also my Tweet from this event:
Trying to receive #eme but hear nothing…. pic.twitter.com/PaPrt1dvha
— AMSAT-SM (SM0TGU Lars) (@amsat_sm) February 2, 2023
Some construction notes of my two 2.2 GHz Helix antennas I now using for my SatNOGS station and manual satellite RX.
The print scaffold set is from Dereksgc and i friend of mine did the printing https://www.thingiverse.com/thing:4980180
Construction notes from UHF-Satcom:
https://uhf-satcom.com/satellite-reception/s-band
The wire is from a RFC-400 coax cable center conductor – I just stripped one meter.
First set the wire to the printed support frame:
Then drill a hole in the reflector and mount a connector – I used both N-type and SMA-type.
In order to get good 50 ohm match I needed to solder a piece of copper tape according to the image below:
Then a lot of hot glue and UV protection spray to get it a little bit more water proof:
Finally mounted at the mast:
This is the SWR plot after mounting:
I can recommend Dereksgc Youtube channel for lot of videos about S-band antennas and RX:
Some test with the internal LNA (P.AMP) of the IC-9700 and external LNA. What combinations will give the best SNR? Note that all tests are done without any type of professional equipment – only by looking at the waterfall and listening with my ears.
I have used my VHF and UHF yagis and external LNAs Mini-2 and Mini-70 mounted just below the antennas. I have aprox. 16 meters of high quality LMR-400 cables between the IC-9700 and antennas/LNAs.
VHF – beacon SK1VHF at 144.447 MHz
| Without internal P.AMP and external LNA | Not possible to hear beacon |
| With only internal P.AMP | Possible to hear beacon |
| With both internal P.AMP and external LNA | Better SNR but needed to reduce RFGain to get good SNR |
| With only external LNA | Best SNR! No need to reduce RFGain. |
Note on VHF: The difference between using both internal P.AMP + external LNA and only external LNA is not huge, but is clearly audible.
UHF – beacon SK1UHF at 432.405 MHz
| Without internal P.AMP and external LNA | Not possible to hear beacon |
| With only internal P.AMP | Possible to hear beacon |
| With both internal P.AMP and external LNA | Better SNR but needed to reduce RFGain to get good SNR |
| With only external LNA | Best SNR! No need to reduce RFGain. |
Note on UHF: Almost the same result as VHF, but the external LNA gives better result and SNR compared to VHF.
Summary:
If you do not have an external LNA it is mandatory to use the internal P.AMP on the IC-9700 for very weak signals.
If you have a good external LNA mounted close to the antenna it is best to turn off the internal P.AMP to get best SNR.