Adam Tests his UP-64 Upconverter with an RTL-SDR
Over on YouTube Adam 9A4QV has uploaded a video of him testing out his 'UP-64' upconverter together with an RTL-SDR. An upconverter moves low frequencies 'up' into a higher frequency. This is useful for HF reception, as normal reception on an RTL-SDR starts at about 24 MHz (without using direct sampling mode).
Adam previously manufactured and sold his UP-100 upconverter, which was an upconverter of his own design that utilized a 100 MHz oscillator. These days it has been accepted that using an upconversion frequency that avoids the broadcast FM band is generally better as it avoids the interference that can come from very strong FM signals. The 64 MHz oscillator on the UP-64 avoids the broadcast FM band for the most part unlike the older UP-100.
– The up-100 converter does not avoid the FM-BC band, since the upconverted signals start at ~0.5 MHz input and are upconverted to ~100.5 MHz. Since the The BC-Band has in Europe stations between 87.5 to 107.950 MHz any RTL-SDR will have bleedthrough from strong BC-stations
– the local oscillator used is 100 MHz and not 64 MHz (see http://4.bp.blogspot.com/-Aa0iNSR8TpQ/UFgwyB6Y9NI/AAAAAAAAByM/2YO7ToZMe_g/s1600/SDR+UP-100.PNG)
Yep but in the video he’s using the UP-64, a modified one with the 64 MHz LO. That’s what i’m referring to when I mean that it avoids the BCFM stations.
The very first upconverters back in 2011/12 were using 100 MHz oscillators, 2013 I made a short batch with 120 MHz oscillators and this one has the 64 MHz oscillator that I have from my old 1152 MHz oscillator project.
The upconverter in this video is using 64 MHz oscillator and no amplifier after the filter as I have a decent HF antenna. The idea was to avoid BCFM problems even though the 29.5 MHz is affected with the BCFM a bit.
The UP-100 PCB is quite flexible design allowing many combinations and various combinations.