Es’Hale uplink experiments

I had recently taken down my 40 element Wimo yagi aerial, so I put this back up on the horizontal T on the dish pole, so that its elevation would tilt with the dish. I left it horizontally polarised & gave it an azimuth off-set with the intention of it paralleling the beam from the off-set dish; I just guessed this visually.

I have added a sub-band switch to the SG-Labs transverter so that it imitates the jumper settings J1 and J2 from the four positions of the 2-pole switch. So now I can switch from 2,300 MHz to 2,320 MHz to 2,400 MHz (plus one other sub-band setting).

I’m guessing about 1W reaches the yagi.

This gave me a carrier 4-5dB over the transponder noise, so good enough for CW/morse code. Feeding into to 80cm off-set dish that I use for the downlink would be better, but I don’t have a way of doing this at the moment.

I tried re-aligning the yagi, but I did not see a significant difference, so perhaps my original visual guess was OK?

This morning I worked Severin DL9SW using morse code/CW. He was solid copy and a few dB over noise. This was my first ever satellite contact!

Update: I’m also experimenting with an Andrew linear amplifier. The SG-Labs transverter doesn’t like the match into this, but it is doing something as I get a lift of 10dB or so visible on the downlink. I’ve had a few contacts on SSB with this including Vera in Essen, who is the only woman I’ve heard on the satellite so far.

I’ve had one attempt at building a dual-band feed for a dish. I had some thin copper sheet available. The first attempt resonated around 2475 MHz (with a second resonance about 50MH up on that), so I will try cutting a a slightly larger patch, maybe with tuning screws on it.

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Es’Hail satellite downlink experiments

I have been experimenting with an Octagon LNB (Low Noise Block) which I’d obtained from the late John Roberts G8FDJ. Originally it had two outputs. John had modified this according to Bernie G4HJW’s guidance and had removed one output to allow room for an external reference oscillator input of 27 MHz. I used John’s TCXO (Temperature-Compensated Crystal OScillator) incorporating a 3MHz crystal and a 27 MHz harmonic filter. I hadn’t spotted the MIMIC buffer/booster amplifier.

I found a length of satellite coax with an F-connector on it & sealed this onto the LNB with self-amalgamating tape. I used a separate “Wi-fi” thin coax lead with SMA connectors and sealed this on the other LNB socket for the external reference input. I made a little clamp from some toilet seat bits and a bit of sailing rope and clamped the LNB close to the existing horn on the off-set dish arm. It is an 80cm diameter dish. I slanted the LNB, hoping to receive horizontal or vertical polarisation. I fed the satellite coax from John’s bias tee. The LNB output fed an RTL dongle (I’d given up with the FCD) and the data fed into GQRX running on Ubuntu Linux 18.04.

At first, I failed to get any sensible output from the LNB; I just got noise.  The LNB did not resolve anything; certainly not the GB3FNY beacon, which is very strong here. The LNB output noise lifted when I added the reference oscillator input via 40dB of attenuation. This seemed a lot of attenuation. The LNB didn’t seem to work on it’s internal crystal alone.

Barry G8AGN brought round a neat Arduino-controlled marker that he had made. I got no reading off this either. Barry did a neat job of replacing the LNB’s reference feed-in capacitor with a 1nF chip capacitor and did a general clean-up of the LNB’s board & case. We tried again. Still nothing from his marker. I took out 10dB of attenuation. A signal! It turned out that John had included a MIMIC in the reference oscillator box. Also the PLL seems quite fussy about the level of 27 MHz reference input.

Back in my lab/shack I sealed the die-cast case using outdoor Bostik sealant and put the LNB back on the dish arm. I tried 27 MHz from my signal generator. The LNB produced noise with above -40dBm input up the coax. With the reference input a bit stronger I finally found the Finningley beacon appearing about 60 kHz higher than where I was expecting it.

I adjusted GQRX to compensate for the dongle frequency error. The RTL dongle was remarkably stable. Overall the whole receiving assembly seemed as stable as my DB6NT-K3 receiver with GPSDO reference, so this looked very promising.

So I found raised noise from the LNB does not necessarily indicate PLL locking. I need a lock indicator! I settled on 26 dB attenuation in the 27MHz feed.

Peaking the dish on GB3FNY, I found I needed to dip the dish about 5 deg. to for maximum LNB signal. Azimuth, (on my sloppy rotator) seemed about the same.

190215_3cm_horn+LNB

Saturday 16-Feb-2019 I aimed the dish at Az 154 deg., El 24 deg. Nothing. I took the power off the LNB and put it back on: signals! The PLL must have locked. Fortunately, there were signals on the narrow band; the band edge beacons were switched off.

I compared the Goonhilly SDR with my LNB/GQRX output:

190217_GQRX_v_Goonhill_SDR_comparison

The top window is GQRX with a waterfall falling down. The lower window is the Goonhilly WebSDR with a waterfall falling up. The left-most trace is the lower beacon. The right-most trace is the upper beacon.

Update: I had failed to get my FUNcube dongle working with GQRX, so I bought an R820T dongle from cosycave.co.uk priced £13. This stabalises after some minutes & the frequency accuracy is much better than the dongle I have been using. Barry G8AGN showed me how to drop out the coax socket that it comes with (using my hot-air gun) and I soldered in an SMA socket and it all worked fine. A couple of days later, its little blue LED stopped working, but I can live without the LED.

R820T_dongle

GQRX on Ubuntu Linux with FUNcube Dongle Pro+ (FCD)

On a Ubuntu 14.04 PC I applied upgrades to Linux and then followed these instructions for installing GQRX. As a precaution, I did the clearing-out instructions in terminal:

sudo apt-get purge --auto-remove gqrx
sudo apt-get purge --auto-remove gqrx-sdr
sudo apt-get purge --auto-remove libgnuradio*

I added the repositories:

sudo add-apt-repository -y ppa:bladerf/bladerf
sudo add-apt-repository -y ppa:myriadrf/drivers
sudo add-apt-repository -y ppa:myriadrf/gnuradio
sudo add-apt-repository -y ppa:gqrx/gqrx-sdr
sudo apt-get update

I installed:

sudo apt-get install gqrx-sdr

I did the suggested optimisation. This took some time:

sudo apt-get install libvolk1-bin
volk_profile

With the FQD plugged into a USB3 slot, I launched gqrx fom terminal. It complained about configuration file settings and put up a configuration screen. I couldn’t see anything I could change for the better, so I shut it down. I tried launching it again & this time it launched fine. I set it to WFM an 88.6 MHz & Radio Sheffield showed on the waterfall display, but there was no trace on the upper display. I adjusted something, bandwidth?, and the upper display launched into life.

So the FCD seems to work fine with gqrx on Ubuntu 14.04 on the i5 PC.

——-

On the shack PC running Ubuntu 16.04, I used the same installation process.

With the FCD in a USB port, I tried gqrx in terminal and got:

linux; GNU C++ version 5.4.0 20160609; Boost_105800; UHD_003.010.003.000-0-unknown

Controlport disabled
No user supplied config file. Using “default.conf”
gr-osmosdr v0.1.x-xxx-xunknown (0.1.5git) gnuradio 3.7.10
built-in source types: file osmosdr fcd rtl rtl_tcp uhd plutosdr miri hackrf bladerf rfspace airspy airspyhf soapy redpitaya
FM demod gain: 3.05577
Resampling audio 96000 -> 48000
IQ DCR alpha: 1.04166e-05
Using audio backend: auto
BookmarksFile is /home/gray/.config/gqrx/bookmarks.csv
getDeviceList : Available input devices:
“FUNcube Dongle V2.0”
“PlutoSDR”
“RFSPACE SDR-IQ Receiver”
“RFSPACE SDR-IP Receiver”
“RFSPACE NetSDR Receiver”
“RFSPACE Cloud-IQ Receiver”
“RTL-SDR Spectrum Server”
“Red Pitaya Transceiver Server”
“Complex Sampled (IQ) File”
Loading configuration from: “default.conf”
Configuration file: “/home/gray/.config/gqrx/default.conf”
Crash guard triggered!

I got a “Crash Detected” message box, so I opted for ‘yes’ to change the settings, but saw nothing to change. The FCD had been recognised. I set a frequency of 88600 kHz & a bandwidth of 200 kHz.

Launching I/O device editor
firstTimeConfig
CIoConfig : Available output devices:
0 : “Built-in Audio Analogue Stereo”
saveConfig
Output device 1 : “alsa_output.pci-0000_00_1b.0.analog-stereo”
Loading configuration from: “/home/gray/.config/gqrx/default.conf”
Configuration file: “/home/gray/.config/gqrx/default.conf”
gr-osmosdr v0.1.x-xxx-xunknown (0.1.5git) gnuradio 3.7.10
built-in source types: file osmosdr fcd rtl rtl_tcp uhd plutosdr miri hackrf bladerf rfspace airspy airspyhf soapy redpitaya
Using FUNcube Dongle V2.0 (hw:2)
gr::log :INFO: audio source – Audio source arch: alsa
Opened: hw:2
Dongle sucessfully initialized
Result of Action :+++++
FCDAPP 20.03
Lna gain enabled
Mixer gain enabled
If gain set to: 15
IQ DCR samp_rate: 192000
IQ DCR alpha: 5.20831e-06
Changing NB_RX quad rate: 96000 -> 192000
New antenna selected: “RX”
********************
Gain name: “LNA”
min: 0
max: 1
step: 1
Gain name: “MIX”
min: 0
max: 1
step: 1
Gain name: “BB”
min: 0
max: 59
step: 1
********************
New audio output device:
old:
new: alsa_output.pci-0000_00_1b.0.analog-stereo
IQ DCR samp_rate: 192000
IQ DCR alpha: 5.20831e-06
Requested sample rate: 192000
Actual sample rate : “192000.000000”
New FFT rate: 25 Hz
Requested bandwidth: 200000 Hz
Actual bandwidth : 0 Hz
setFreqCorr : 0 ppm
New LNB LO: 0 Hz
Set Frequency to: 4.33985e+06 Hz, corrected to: 4339848 Hz
Lna gain enabled
Mixer gain enabled
If gain set to: 15
New mode index: 2
Filter preset for mode 2 LO: -5000 HI: 5000
Generating taps for new filter LO:-5000 HI:5000 TW:2000 Taps: 115
setFftRate to “25 fps”
New FFT rate: 25 Hz
New FFT rate: 25 Hz
setFftSize to “8192”
New FFT rate: 25 Hz
New mode index: 5
FM demod gain: 0.509296
Filter preset for mode 5 LO: -80000 HI: 80000
Generating taps for new filter LO:-80000 HI:80000 TW:32000 Taps: 19
Set Frequency to: 8.86e+07 Hz, corrected to: 88600000 Hz

I pressed the “play” arrow button. This filled the terminal box with “a0″s, non-stop! I killed the process. Buried in the stream on “a0″s is the occasional error message: “No Audio FTT data“.

So, there’s a difference between Ubuntu 16.06 and 14.04. It worked on 14.04!


1-Feb-2019: I upgraded the shack PC to Ubuntu 18.04 and re-installed gqrx. Using the FCD it failed in the same way as with Ubuntu 16.04. I’m baffled. Maybe gqrx doesn’t like my hardware?

For some reason, the No Audio FTT data error messages have gone.

I have received some help on the Microwaves groups.io forum and on the gqrx gmail forum.


14-Feb-2019 Barry G8AGN kindly lent me an RTL dongle. This worked fine using GQRX on both the i5 with Ubuntu 14.04 (in a USB3 socket) and the i7 with Ubuntu 18.04.

So the audio processing on the i7 is fine. There must be something specific to the FCDPP which causes a problem with the i7 hardware, or perhaps the volk optimisation has caused a different bit of software to be used with gqrx. I don’t know. Help!

SpectraVue on WINE on Ubuntu Linux

DRAFT:

On the Ubuntu 16.04 PC,  I inserted the FUNcube Dongle Pro+ into a USB socket. In terminal, lsusb (list usb) gave:

Bus 001 Devi6:ID 04d8:fb31 Microchip Technology, Inc.

Michael Hirsch’s blog has an entry on the topic of running SpectraVue on WINE on Linux.

I followed his instructions & downloaded Spectravue 3.39 into a new folder on my Ubuntu 16.04 PC:

~/.wine/drive_c/Program Files/SpectraVue

WINE was already installed, so I skipped:

apt install wine

I used winetricks to install the .dll files:

winetricks mfc42 vcrun2010

And I added the alias:

alias SpectraVue=’wine ~/.wine/drive_c/Program Files/SpectraVue/SpectraVue.exe’

SpectraVue launched OK under WINE.

Then I needed siqs_ftdi in order to feed the data to SpectraVue, so I installed cutesdr:

sudo apt-get install cutesdr

However I could not find siqs_ftdi and it would not launch from terminal.

————————–

27-Jan-2019:  I tried installing cutesdr via Ubuntu Software Centre on a different machine running Ubuntu 14.04. The More Info definitely mentions “this package also supports SDR-IQ/14 using an included network protocol application (siqs_ftdi) by Andrea Montefusco IW0HDV with support from Ken Hopper N9VV”.

siqs_ftdi launched fine from terminal! It did not see the FCD though.

I tried again on the Ubuntu 16.04 PC:

sudo apt-get purge cutesdr

I tried Ubuntu Software Centre, but it did not find cutesdr. So I installed cutesdr again as above. It installed fine, but siqs-ftdi would not run. It wasn’t in /bin, though cutesdr was.

Overall: there seems to be a difference between installing cutesdr on Ubuntu 14.04 and 16.04. I don’t understand why. I’ll give up on SpectraVue on Linux for the time being.

 

13cm upgrade – SG- Labs Rx/Tx and Spit Mode

In a patch of settled weather, I took down the jockey pole with its 13cm Wimo antenna and the 13cm box, so I am off that band for a while. I’m intending to modify the SG-Labs transverter for “Split Mode” operation and to add amplification on receive and transmit.

I was surprised how much muck had accumulated in the box, the only holes in it being the gap between the grommets and the cables (I hadn’t bothered with sealant) entering the box & little bleed holes underneath for releasing condensation. The chromed steel lid of the transverter had a few rust pocks on it, presumably from condensation, but internally, the transverter was fine with no condensation damage. The local birds sit on the aerials & the boxes & do what birds do. I’ve given the box a good clean.

G3YJR_13cm_jockey_pole_box

I’m planning to take out the transverter and put a Band Pass Filter (BPF) in the box, together with a coax relay & a pre-amplifier for receive and then to have separate coax cables up the pole for the 13cm transmit and receive lines. I believe a BPF is necessary to protect a wide-band pre-amp from cross-modulation effects. The Crosspool transmitter towers are very close and line-of-sight. Also, on transmit, it is important that other users neighbouring the radio amateur band do not receive interference from minor spurii, boosted by the linear amplifier.

This little box has worked well up on the pole, with contacts up into Scotland (to Jon GM4JTJ) and down to the South and to Denis G3UVR over the Pennines. It even managed one contact with Frank PE1EWR in Holland, so it has done well with its 2W output.

In the lab, I’ll mount the transverter in a box with a sub-band switch for selecting the Local Oscillator frequencies,  a switch for internal/external reference oscillator (the transverter does not default to the internal oscillator when the external input is missing – it flashes a little red light!), some monitoring LEDs, and a power output (maybe SWR) meter. I’ll add an Andrews linear amplifier indoors (it is too big a lump for the pole) with a sequencer to control the amp. and the relay up on the pole.

I intend to find a way to select 2W (the current output), 10W or 25W output for the various contest restrictions and full power (100W?) for long distance (DX) contacts.

I’m aiming to activate 2300 MHz as well as 2320 MHz (with the possibility of 2400 MHz) with some amplification on the output and pre-amplification on receive.

The picture shows the board layout near the relay, still arranged for “Rx/Tx” mode, (both receive & transmit route via the upper SMA connector on the left with the strip into), before modification for Split Mode (receive via the lower SMA, in the bottom left-hand corner of the picture).

The brown & orange wires were for forward & reflected power monitoring in the lab.

Note the little “0” ohm chip “resistor” by the orange wire. In Rx/Tx Mode, this routes the receive input away from the relay:

G3YJR_13cm_Rx-Tx_mode

Update 31-December_2018:  The “resistor” has been moved in the picture below so that the Rx input now comes straight from the SMA socket and by-passes the relay.

dscf9285

 

27-November-2018 SHF UKAC

There was some nice rain scatter (RS) before the contest. GB3FNY showed significant doppler rain scatter & the frequency of it shifted significantly as I swept the dish across the cloud.

All the RS seemed to have gone by the time the contest started at 7:30pm!

Conditions seemed poor. For the first time, I failed to work Keith G4ODA on 3cm. It took two goes to find Nick G4KUX.

1811283c

For the first time I worked fewer stations on 13cm than on 3cm: only six contacts.

18112713