The Raspberrypi and the RTL 2832U 820T/820T2 Pan-adapter

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Anne Cora Snow
5 years ago
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1 The Raspberrypi and the RTL 2832U 820T/820T2 Pan-adapter

2 First of all, why a pan-adapter? Most of our newer HF rigs, for many years now, have had this feature built in. In fact it s probably difficult to find a recently built HF rig anymore that doesn t incorporate this feature today! Being able to see the signal that you are listening to along with carriers above and below the frequency where you are operating on the band is like having some sense of sight in addition to the sense of hearing in the world of ham radio!

3 Years ago, back in the mid 60 s this is the kind of panadapter that was available. It was small in spite of the fact it used tubes! It wasn t great definition, but it worked!

4 It was possible back then to modify the Heathkit Model HO-13 Ham Scan to work as a pan-adapter for receivers such as the Drake R4B which also used tubes too! That s what I did! In the 80 s I modifed one

You generally don t need a microscope to work on this vintage of equipment either.

5 If you are like me, I happen to prefer pre-smd solid state transceivers from the 80 s, the reason being that they are relatively easy to troubleshoot and work on. You generally don t need a microscope to work on this vintage of equipment either. If you happen to have an older transceiver without a pan-adapter, what options are out there to add that capability?

With the advent of SDR, Software Defined Radio, the options abound today for panadapter choices. It s also not too difficult of a project to accomplish.

6 With the advent of SDR, Software Defined Radio, the options abound today for panadapter choices. It s also not too difficult of a project to accomplish. Of course there are different ways to approach adding a Band- Scope to your transceiver or ham-shack. This option, uses HDSDR, with a SDRPlay 2pro. It uses a Windows 10 desktop computer to run the SDR receiver. It also takes up a significant amount of room, though it does work really well! The hardware also costs $$$!

7 OPTIONS That option also requires some sort of protection to the input of your receivers, including the SDR, during transmit intervals.

8 This is my DIY Receive protection switching I can use two transceivers plus my SDR and even a noise antenna. The disadvantage is that it doesn t follow the transceiver tuning, setup this way. I can reconfigure this SDR setup to do that and I have, but I wanted to try Small and Compact!

9 Here is where the Raspberrypi and the RTL 2832U 820T/820T2 DVB-T HDTV Dongles come into play. These componets are not only small and compact, they are relatively inexpensive!

10 NooElec NESDR SMArt - Premium RTL-SDR w/ Aluminum Enclosure, 0.5PPM TCXO $24 Original RTL2832U 820T DVB-T HDTV Dongle $8 $28 NooElec NESDR Nano 3: Tiny RTL-SDR USB Set w/ 0.5PPM TCXO

The RTL2832u DVB-T chip + 820T2 Tuner Antti Palosaari, Eric Fry and Steve M of Osmocom discovered that the raw I & Q data of the RTL 2832u chipset could be directly accessed.

11 The RTL2832u DVB-T chip + 820T2 Tuner Antti Palosaari, Eric Fry and Steve M of Osmocom discovered that the raw I & Q data of the RTL 2832u chipset could be directly accessed. * This allowed this TV tuner dongle to be re-utilized as an SDR receiver, including the ability to view up to a 3.2Mhz spectrum. Today there are varieties of this dongle being produced specifically for SDR purposes instead of TV. Typical frequency range of the 820T2 Tuner is 25MHz 1700MHz *

12 Need access to HF below 25MHz? Ham-it-up 125MHz upconverter

13 $35 Raspberrypi 3 B

14 The Raspberrypi 3 B 4 Core ARM CPU 1.2 GHz 1Gb of embedded RAM. This little credit card sized computer is OK for what we are after here. If I wanted to also demodulate a signal at the same I would prefer something with more computing horsepower. However you can do that too with this tiny computer!

15 Tapping the 1 st IF DSP LPF Hi Z Buffer Amp After the 1 st Mixer Before 1 st BP (Roofing) filter

16 1 st IF Tap Point Yaesu FT1000D

17 Icom IC-751A

18 Icom IC-745

19 Hi-Z Buffer Amp These are a couple my DIY buffer amps. They are both identical parts wise.

20 VHF N Channel MOS FET Source Follower ~ 3pf input capacitance

21 Or you can buy the Hi-Z Buffer board From SDR-KITS Option: Low Pass filter OR From DX-Engineering

22 Rcv + 8 to +9Vdc Tap 1 st Mixer IF BPF Gnd Buffer output Hi Z buffer Icom IC-745

23 Icom IC-751A 1 st IF Tap No room in here for a board

24 RG-174 cable to Hi Z buffer Icom IC-751A

25 Output RG-174 Cable Input RG-174 Cable Hi Z buffer board Rcv +8 to +9Vdc Icom IC-751A

26 2.8 PiTFT Capacitive Touch

27 Tiny Python Panadapter At this time there is no provision for a zoom function.

28 7 TFT Pi Foundation Display Another 2.8 Display but it s resistive touch

29 Cubic SDR with RTL-SDR Support on the 7 Display again no zoom function

30 HDSDR supports the RTL2832u but you need a Windows computer

31 Play Video WQ7TPanadapter Youtube Video

32 If you would like to build your own version of this panadapter the files should be available via the CCARC web site once they are posted. There is very detailed pdf manual that covers everything: Parts lists and sourcing including the Hi-Z buffer Installation of Raspberry Pi images etc. Panadapter use Saving your own defaults to the panadapter

High Power Bundle for the Icom IC-7300

High Power Bundle for the Icom IC-7300 The Icom IC-7300can be connected to the KAT/KPA500 combo using the Key signal available on the rear panel of the rig. You would configure the appropriate TX port