Today (7 Mars 2026) I reached 100 DXCC stations worked via satellite but only 89 is confirmed via LoTW as this date.
Kategori: Amateur Radio
Blogs and posts about my amateur radio and satellite projects. Most posts are in english.
Kategorier
Active SAW Filter LNA 435 MHz
This is my measurement of the low cost filtered LNA with SAW filter for 435 MHz. It got it from AliExpress (link).
I used 20dB + 10dB (=30 dB) attenuators and calibrated my NanoVNA for 380 MHz to 510 MHz.
As you can see below the LNA performance well. Gain is aprox 23 dB (exact acoording to specification) and the bandwidth is aprox 15 MHz (a little bit more then the specification of 10 MHz BW).
I was curious how the RTL-SDR v4 would perform against the IC-705 during one hour of FT8 receiving so I set up and did a little test. The setup:
- One hour RX on the 20 meter HF band FT8 section
- Antenna tuned random longwire
- HF signal was split according to the image below, but I did not use the first stage ”AMP” and no LNA from the RXout from the SDRSwitch.
- SDR software = SDR Console
- Same bandwidth was used in the IC-705 and SDR Console
- Two (2) instances of WSJT-X Improved running on the same PC, calibrated to the same RX dB level
- Both instances reporting to PskReporter
Result after one hour RX
Transmitters reported in PskReporter:
– IC-705: 323 transmitters
– RTL-SDR v4: 323 transmitters
Top distance IC-705:
Top distance RTL-SDR v4:
Distance chart IC-705:
Distance chart RTL-SDR v4:
WSJT-X view IC-705:
WSJT-X view RTL-SDR v4:
Kategorier
UNUN for HF longwire
After my 80 meter HF loop antenna (SkyLoop) broke during high winds in 2025, aprox 30 meters of the loop antenna still is up and can be used as a random long wire antenna.
In Januari 2026 I connected an UNUN (DIY – maybe a 1:49, not sure…) to be able to tune the wire on all HF bands with my remote auto tuner RT-100.
I also added two counterpoise wires about 8 meters long to help reduce some common mode current on the coax and add better tuning possibility.
This is the NanoVNA SWR plot before the RT-100 tuner. The overall impedance is low so it should be better to use a different UNUN winding. But that will be some other time…
Kategorier
UHF LNA for SatNOGS
Oktober 2025
Time to upgrade my UHF SatNOGS station with 435 MHz bandpass filter and LNA. These are the items I use from AliExpress:
Also read this interesting post about low cost LNAs.
Installation and testing
Some pictures from the installation and measuring:
Some more installation images
Roof mounting
Kategorier
DC Distribution board
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”
Kategorier
RTL-SDR v3 vs IC-705 FT8 RX
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:
- 80 meter HF Loop antenna
- IC-705
- RTL-SDR v3 (aprox 40 US$ / 40 EUR)
- 0-70MHz 100W RXin RXout SDR Switch
- Y16A Antenna RX Splitter (from AliExpress)
- SDR-Console v3
- VB-Audio virtual audio device
- Two instances of WSJT-X Improved version
All images below:
- Left – RTL-SDR v3
- Right – IC-705
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.
