Taking the Hiss out of QO-100

I’ve been on the QO-100 satellite for about 7 months now and I have to admit I love it!

Having a “Repeater In The Sky” that covers a third of the world really is a wonderful facility to have access to however, there is one thing that I find tiring and that is the high level of background noise that is always present.

Even though the signals are mostly 59-59+15dB the background “hiss” is very pronounced and gets very tiring after a while, especially if like me you have tinnitus.

Currently I’m using a NooElec Smart SDR for the receiver and GQRX SDR software on my Kubuntu Linux PC. This works great but, there is one short fall, there is no DSP Noise Reduction (NR) in the software or hardware.

To fix this I recently invested in a BHI Dual In-Line Noise Eliminating Module. The unit itself is nicely put together and has a good combination of inputs and outputs making it easy to connect up to my MacBook Pro to record QSOs and connect my headphones at the same time.

M0AWS BHI Dual In-Line Noise Eliminating Module
M0AWS BHI Dual In-Line Noise Eliminating Module

At £189.95 plus postage from BHI direct it’s not cheap but, it is nicely put together and comes complete with a power lead and a couple of cheap audio cables. The quality of the knobs and mechanisms is good apart from the little grey DSP Filter Level knob that feels cheap and is very wobbly on the switch below. I’m not sure how long this is going to last with prolonged use and will most likely need replacing with something a little sturdier at some point in the future.

Overall noise reduction is good but, the audio amplifiers on the Audio Input Level and Line Out Level distort very early on in their range and you cannot get them much above level 5 before distortion starts to appear on the received signal. This is disappointing as my headphones are of reasonable quality and are let down by the distortion creeping in from the audio amplifier in the BHI unit.

I’ve tried altering the levels on the input from the IC-705 and no matter what I cannot get a good audio signal in my headphones without some distortion on the higher frequency ranges.

Overall the device does do what I want, it reduces the background “hash” considerably reducing the fatigue whilst chatting on the satellite. Below is a recording from a conversation on the satellite showing the noise reduction performance of the BHI module.

M0AWS Example BHI DSP NR Recording

The recording starts with the BHI DSP NR off, at 00:07 the DSP NR is switched on, you can clearly hear the difference. At 00:23 the DSP NR is turned off again and at 00:36 the DSP NR is turned on again. The BHI DSP NR Module is set with the DSP Filter Level set at 3 out of 8 which appears to be the best level to use. Switching to level 4 starts to introduce digital artefacts to the audio which only gets worse the higher the DSP Filter Level goes.

With a setting above level 3 there really isn’t much improvement in noise reduction and the audio becomes progressively more affected by the digital artefacts than it does from the background noise.

M0AWS BHI Dual In-Line Noise Eliminating Module with Icom IC-705 QO-100 Ground Station
M0AWS BHI Dual In-Line Noise Eliminating Module with Icom IC-705 QO-100 Ground Station

The only other problem I have with the BHI Dual In-Line Noise Eliminating Module is that is comes in a plastic case. The case itself is solid and of good quality however, it offers no RF shielding whatsoever and the unit is extremely susceptible to RF getting into the audio chain and then being heard during transmit in the headphones and via the line out connections. For the money I would had expected the unit to come in a metal case that provides proper RF shielding. This is a real shame as it lets the unit down considerably.

As setup in the photo above I am using 300mW O/P on 144Mhz from the IC-705 into a perfect 1:1 SWR presented by the DX Patrol 2.4Ghz Upconverter via some very high quality LMR-400 Coaxial cable from Barenco but, I get terrible RF interference via the BHI unit during the transmit cycle. Considering I am only using 300mW I dread to think what it may be like if I was using a 100w HF radio. This is something I need to investigate further as it really is very annoying.

Moving the unit to a different location in the radio room does help a bit but, doesn’t solve the problem completely. At 300mW RF O/P I really didn’t expect there to be a problem with RF getting into the BHI unit.

Having a proper line-out facility on the BHI unit really is nice as it makes it very easy to connect to my MacBook Pro to obtain good quality recordings of signals on the QO-100 satellite as can be listened to above.

Overall I am happy with the BHI Dual In-Line Noise Eliminating Module but, do wish that more care had been taken over using a metal case instead of a plastic case to protect the unit from RF ingress and better audio amplifiers within the unit that don’t distort/clip so early on in their O/P levels.

Is this the perfect noise reduction unit?


No but, overall it is better than nothing and does help to reduce the background noise to a more acceptable level reducing the overall fatigue during prolonged conversations on the QO-100 satellite.

UPDATE: I tried the BHI unit with my FTDX10 on the HF bands and the RF interference is horrendous, even when using QRP power levels! This device clearly hasn’t been designed to work in an RF environment and the total lack of shielding or isolation lets it down terribly. If you are an SWL then this unit is fine but, if like me you like to monitor your transmitted audio whilst on air through headphones then this isn’t the unit for you. To prove the problem isn’t in the radio shack I put the BHI unit in the house some 30m away powered by 12v battery with nothing connected but a pair of headphones and still the unit suffered from RF interference even at QRP levels.

More soon …

QO-100 Satellite Update

I’ve been active on QO-100 for a few days now and I have to admit that I’m really pleased with the way the ground station is performing. I’m getting a good strong, quality signal into the satellite along with excellent audio reports from my Icom IC-705 and the standard fist mic.

I’m very pleased with the performance of the NooElec v5 SDR receiver that I’m now using in place of the Funcube Dongle Pro+ SDR receiver. Being able to see the entire bandwidth of the satellite transponder on the waterfall in the GQRX SDR software is a huge plus too.

M0AWS QO-100 Satellite Log map showing contacts as of 23/06/23
M0AWS QO-100 Satellite Log map showing contacts as of 23/06/23

As can be seen on the map of contacts above, I’ve worked some interesting stations on some of the small islands in the Atlantic and Indian Oceans. The signals from these stations are incredibly strong on the satellite and an easy armchair copy.

DX of note are ZD7GWM on St. Helena Island in the South Atlantic Ocean, PP2RON and PY2WDX in Brazil, 8Q7QC on Naifaru Island in the Maldives, VU2DPN in Chennai India, 5H3SE/P in Tanzania Africa and 3B8BBI/P in Mauritius.

There are many EU stations on the satellite too and quite a few regular nets of German and French stations. I’ve not plucked up the courage to call into the nets yet, perhaps in the future.

There are a lot of very experienced satellite operators on QO-100 with a wealth of information to share. I’ve learnt a lot just from chatting with people with some conversations lasting well over 30mins, a rarity on the HAM bands today.

We also had our first Matrix QO-100 Net this week, an enjoyable hour of chat about all things radio and more. We have a growing community of Amateur Radio enthusiasts from around the world on the Matrix Chat Network with a broad spectrum of interests. If you fancy joining a dynamic community of radio enthusiasts then just click the link to download a chat client and join group.

More soon …

First full power day on QO-100

The male to male SMA connector that Neil, G7UFO kindly posted to me arrived late this afternoon and I wasted no time getting it connected between the 2.4Ghz up-converter and the 12w amplifier.

Male to Male SMA connector for QO-100 Ground Station
Male to Male SMA connector for QO-100 Ground Station

Initially when I powered up the 12v to 28v converter board the output voltage was only showing 22v and so I had to adjust the onboard variable resistor to get the voltage closer to the recommended 28v for the amplifier. I decided to run the amplifier at 27v so that it wasn’t being pushed to it’s full and so readjusted the voltage converter back down to 27v. This seems to work very well with the amplifier not getting very warm at all during use.

M0AWS QO-100 2.4Ghz Uplink Hardware.
M0AWS QO-100 2.4Ghz Uplink Hardware.

Getting on air I was really impressed at how strong my signal was on the 10Ghz downlink. With my own signal peaking 5/9+10dB I was very happy with the performance of the ground station.

I made a few contacts very quickly with the first being OH5LK, Jussi from Helsinki Finland. Jussi was actually the first station I worked on CW too when I was running just 200mW, it was great to have him for both of my first contacts on QO-100.

I then went on to work a few stations from Wales, Germany, Poland and Belgium but, the one that I was totally shocked to get on my first real day of QO-100 operations was ZD7GWM, Garry (HuggyBear) on St. Helena Island, South Atlantic Ocean. This is an Island that I have never had a contact with before on any band and so I was extremely happy to get a new first especially on my first QO-100 day.

Garry and I chatted for some 25 minutes covering many topics, it was great to have an armchair copy over such a distance, something that would be impossible on the HF bands. What a great way to start my QO-100 satellite career!

One of the things I really like about the operators on QO-100 is that they have time to stop and chat, this is so refreshing and a rarity today. I’m really going to enjoy this satellite.

You can see all the details of my QO-100 contacts in my Online Satellite log.

More soon …

My First QO-100 Satellite QSO

I’ve been waiting for over a week so far for a male to male SMA connector to arrive from Amazon so that I can connect the 2.4Ghz up-converter to the 2.4Ghz amplifier. Since it still hasn’t arrived I decided to connect the up-converter directly to the IceCone Helix antenna to see if I could get a signal into the QO-100 satellite.

To my surprise I could easily hear my CW signal on QO-100 even though the total output from the up-converter is only 200mW.

I didn’t expect to be able to hear my signal since it’s a tiny amount of power that has to travel some 22500 miles to the satellite but, I could hear it and was amazed that it was peaking S8 on my SDR receiver.

2.4Ghz Up-COnverter connected directly to the antenna bypassing the 2.4Ghz Amplifier
2.4Ghz Up-Converter connected directly to the antenna bypassing the 2.4Ghz Amplifier

Being excited I put out a CQ call that was soon answered by OH5LK, Jussi in Finland. Jussi gave me a 579 report which I was extremely pleased with. He was of course much stronger at a 599+ at my end. We had a quick QSO and exchanged details without any problems at all. Its really nice to get a QRPp contact without any QSB or QRM.

M0AWS QO-100 1.1m off-set Dish and IceCone Helix antenna ground station
M0AWS QO-100 1.1m off-set Dish and IceCone Helix antenna ground station

Neil, G7UFO who I chat with regularly in the Matrix Amateur Radio Satellites room has posted a connector out to me so I’m hoping it will arrive on Monday and then I’ll be able to connect the amplifier and hopefully get a few SSB contacts.

UPDATE: I’ve since had 2 SSB contacts via QO-100 using just the 200mW O/P from the up-converter. Both times I got a 3/3 report not brilliant but, perfectly acceptable for the amount of power I’m putting out.

More soon …

Replacement for the Funcube Dongle Pro+

For some time now I’ve been using my Funcube Dongle Pro+ (FCD) as my QO-100 downlink receiver. It’s worked fairly well and has given me the ability to listen to stations on the satellite over the last few months.

During this time I have noticed a couple of things about the FCD that has lead me to the final decision to change to a new SDR device.

The first of these ‘things’ is the fact that the FCD gets seriously overloaded when there are multiple large SSB signals within the receive pass band. The only way to manage this is to constantly keep changing the software based AGC, mix and LNA settings to reduce the levels of the incoming signals so that the overloading stops. This is great except when you tune to a quiet part of the satellite transponder you have to turn all the settings back up again to be able to hear the weaker signals. After a while this becomes tiresome.

The fact that there isn’t a hardware AGC in the FCD is a major drawback when being used for satellite reception especially when it’s on the end of a very high gain LNB and dish antenna.

The second of these ‘things’ is the fact that I can’t see the whole transponder bandwidth at one time with the FCD as it has a very small receive bandwidth capability. This means that I am constantly tuning up and down the transponder to see if there are any stations further up or down in frequency.

Funcube Dongle Pro+
Funcube Dongle Pro+

Talking to more experienced satellite operators in the Matrix Amateur Radio Satellites room they recommended replacing the FCD with a NooElec NESDR SMArt v5 that has hardware AGC and is capable of receiving and displaying a much wider bandwidth.

Looking on Amazon the NooElec NESDR SMArt v5 is only £33 so I decided to place an order for one and give it try.

In typical Amazon style the SDR receiver arrived the next day and I wasted no time getting it plugged in and connected to the QO-100 ground station.

The NESDR SMArt v5 is based on the well known RTL-SDR that came onto the market some time back but, has a number of improvements in it that take it to the next level.

The first thing that I was happy with was the fact that the GQRX SDR software I use recognised it immediately on startup, no configuration or drivers were required it just worked, straight out of the box. Since I use Kubuntu Linux on my radio room PC I did wonder if I would need to get into installing extra libraries etc but, thankfully none of that was required.

Looking at the signals from the QO-100 satellite initially they appeared to be nowhere near as strong as they were on with the FCD. Looking at the settings in GQRX I noticed that the hardware AGC was off and the LNA setting was back to it’s default very low level.

I switched on the AGC and then increased the LNA setting to 38.4dB and found that the signals were now plenty strong enough on the display but, not overloading the receiver.

I then went on to adjust the display so that I could see the whole satellite transponder bandwidth on the screen. This is great as it enables me to see the low, middle and high beacons that mark out the narrow band section of the transponder and at a glance see all the stations using the satellite. This was a massive improvement in itself and one that I am very pleased with.

Using the NooElec NESDR SMArt v5 SDR it very soon became clear that it copes with multiple large signals in the pass band so much better than the FCD did. There’s no more overloading of the receiver, no more ghost signals appearing on the waterfall due to the front end not being able to cope and no more having to constantly keep playing with the settings to get things under control. The hardware AGC built into the SDR device does a great job at keeping it all under control whilst receiving a much wider bandwidth than the FCD ever could.

The satellite beacons are now received at S9+15dB without the receiver being overloaded, the first time I have seen this since starting out on my QO-100 venture.

The other thing that became obvious very quickly is that frequency stability is much better than it was with the FCD, it doesn’t drift up and down the transponder now and stays tuned exactly where I put it. It’s also on frequency whereas, the FCD was always 1.7Khz off frequency.

GQRX showing QO-100 Transponder signals
GQRX showing QO-100 Transponder signals

The NooElec NESDR SMArt v5 is very well put together, it has an aluminium case that acts as a heatsink (it does get warm!) and overall the build quality is much better than the plastic cased FCD. When I think that I paid close to £100 for the FCD and the NooElec NESDR SMArt v5 only cost £33, I am amazed at the build quality.

Overall I’m extremely pleased with the purchase of the new SDR, it slotted in perfectly as a replacement for the FCD, works great with GQRX, my QO-100 Node Red Dashboard and performs considerably better than the FCD. Overall money well spent!

You can find the NooElec NESDR SMArt v5 spec sheet here.

More soon …

UPDATE: QO-100 Node Red Dashboard

I’ve been making a few improvements to my QO-100 Node Red Dashboard whilst waiting for the 2.4Ghz hardware to arrive. I’ve added the ability to split the RX and TX VFOs so that I can tune away from the TX frequency for working split stations or for tuning to slightly off frequency stations. I also added a series of tuning buttons to the top of the GQRX side of the dashboard to enable easy tuning using the trackball connected to my Kubuntu PC. This worked well but, I really missed having a real VFO knob like a conventional radio.

As I had a Griffin Powewrmate USB VFO from a previous SDR radio I added it to the flow as well so that I had a physical VFO knob for the SDR receiver. Details on how I got it working using evtest and a simple BASH script are in the Griffin Powermate article.

M0AWS QO-100 Node Red Dashboard Flow
M0AWS QO-100 Node Red Dashboard Flow

The Node Red flow is looking a little busier with the addition of split mode and the Griffin Powermate USB VFO which has really enhanced the useability of the solution. It’s very impressive what can be achieved with Node Red with a little imagination. You really don’t need to be a heavy weight programmer to make things work.

M0AWS QO-100 Node Red Dashboard as of 07/06/23
M0AWS QO-100 Node Red Dashboard as of 07/06/23

I also put together some code to calculate the S Meter reading from the dBFS data the GQRX SDR software generates. It’s not 100% accurate but, it’s close enough to be useful.

On the IC-705 side of the Dashboard I also now display the 2.4Ghz uplink frequency so that it’s available for logging.

So with the QO-100 Dashboard ready to go live I have now started putting together the 2.4Ghz transmit path of the ground station. I have the 2.4Ghz transverter and matching 12w amplifier from DXPatrol, the IceCone Helix 2.4Ghz antenna from Nolle Engineering, some LMR-400-UF and connectors from Barenco and an appropriate water proof enclosure from Screwfix to fit all the kit into however, I’m now being held up by one simple little SMA male to SMA male connector that I need to connect the transverter and amp together.

The SMA connector has been ordered but, is taking a month of Sundays to arrive! Hopefully it’ll arrive soon and I’ll finally get on the QO-100 satellite and start enjoying the fun.

More soon …

Use a Griffin Powermate with SDR via Node Red

I’ve been gradually building my QO-100 ground station over the last few months and have had the receive path working for some time now. One of the things I really miss with the Funcube Dongle Pro+ (FCD) SDR is a real VFO knob for changing frequency.

My QO-100 Node Red dashboard is configured so that I can have the FCD track the uplink frequency from the IC-705 but, sometimes I use the FCD without the IC-705 in the shack and so a physical VFO would be handy.

Many years ago when I lived in France (F5VKM) I had a Flexradio Flex-3000 SDR, a great radio in it’s time and one that gave me many hours of enjoyment. One addition I bought for that station was a Griffin Technology Powermate VFO knob. It worked extremely well with the PowerSDR software for the Flex-3000 and I used it for many years.

Many years later I’m back in the UK and much of my equipment is packed away in the attic, including the Griffin Technology Powermate VFO.

I decided to dig it out and see if I could get it working with GQRX SDR software. Sadly I couldn’t get it working with GQRX however, I did find a way of getting it working with Node Red and thus could add it to my QO-100 Node Red Dashboard and then control GQRX with it via a simple Node Red flow.

Griffin Technology Powermate VFO
Griffin Technology Powermate VFO

Plugging the Powermate VFO into my Kubuntu PC it wasn’t immediately recognised by the Linux O/S. After a little searching I found the driver on Github. I added the PPA to my aptitude sources and installed the driver using apt.

https://launchpad.net/~stefansundin/+archive/ubuntu/powermate

Once installed the default config for the Powermate device is to control the default audio device volume. To make the device available for use as a VFO knob you need to change the configuration so that the default setting is disabled. To do this is relatively easy, just edit the config file using your favourite command line editor (Vi/Vim in my case) and add the following entry.

vi /etc/powermate.toml

# Entry to control HDMI volume with Powermate
#sink_name = "alsa_output.pci-0000_01_00.1.hdmi-stereo"

# Set powermate not to work with volume control
sink_name = ""

As shown above, comment out the default “sink_name” entry (Yours may be different depending on audio device in your PC) and add in the Powermate “sink_name” entry that effectively assigns it to nothing.

Once this is done, save the file and exit your editor and then reboot the PC.

Next you’ll need to install a small program called evtest.

sudo apt install evtest

To check the evtest program has installed correctly, plugin your Powermate VFO to any available USB port and run the following command in a terminal.

evtest /dev/input/powermate

Turning the Powermate knob you should see output on the screen showing the input from the device. You should also see BTN events for each press of the Powermate device.

Input driver version is 1.0.1
Input device ID: bus 0x3 vendor 0x77d product 0x410 version 0x400
Input device name: "Griffin PowerMate"
Supported events:
  Event type 0 (EV_SYN)
  Event type 1 (EV_KEY)
    Event code 256 (BTN_0)
  Event type 2 (EV_REL)
    Event code 7 (REL_DIAL)
  Event type 4 (EV_MSC)
    Event code 1 (MSC_PULSELED)
Properties:
Testing ... (interrupt to exit)
Event: time 1685816662.086666, type 2 (EV_REL), code 7 (REL_DIAL), value -1
Event: time 1685816662.086666, -------------- SYN_REPORT ------------
Event: time 1685816662.318638, type 2 (EV_REL), code 7 (REL_DIAL), value -1
Event: time 1685816662.318638, -------------- SYN_REPORT ------------
Event: time 1685816662.574615, type 2 (EV_REL), code 7 (REL_DIAL), value -1
Event: time 1685816662.574615, -------------- SYN_REPORT ------------
Event: time 1685816663.670461, type 2 (EV_REL), code 7 (REL_DIAL), value 1
Event: time 1685816663.670461, -------------- SYN_REPORT ------------
Event: time 1685816664.030421, type 2 (EV_REL), code 7 (REL_DIAL), value 1
Event: time 1685816664.030421, -------------- SYN_REPORT ------------
Event: time 1685816664.334389, type 2 (EV_REL), code 7 (REL_DIAL), value 1
Event: time 1685816664.334389, -------------- SYN_REPORT ------------
Event: time 1685816665.334255, type 1 (EV_KEY), code 256 (BTN_0), value 1
Event: time 1685816665.334255, -------------- SYN_REPORT ------------
Event: time 1685816665.558230, type 1 (EV_KEY), code 256 (BTN_0), value 0
Event: time 1685816665.558230, -------------- SYN_REPORT ------------
Event: time 1685816666.030161, type 1 (EV_KEY), code 256 (BTN_0), value 1
Event: time 1685816666.030161, -------------- SYN_REPORT ------------
Event: time 1685816666.182151, type 1 (EV_KEY), code 256 (BTN_0), value 0
Event: time 1685816666.182151, -------------- SYN_REPORT ------------

At this point you’re ready to stop evtest (CTRL-C) and then create the following little BASH shell script that Node Red will run to collect the O/P from the Powermate USB device.

#!/bin/bash

###############################################
# Griffin Technology Powermate control script #
# for Node Red.                               #
#                                             #
# 04/06/23 - M0AWS - v0.1                     #
#                                             #
###############################################

VAL="1"
echo "STEP-1Hz"

/usr/bin/evtest /dev/input/powermate | while read LINE 
do
   case $LINE in

      *"(REL_DIAL), value 1") echo "$VAL"
           ;;

      *"(REL_DIAL), value -1") echo "-$VAL"
           ;;

      *"(BTN_0), value 1") case $VAL in

                              "1") VAL="10"
                                   echo "STEP-10Hz"
                                      ;;

                             "10") VAL="100"
                                   echo "STEP-100Hz"
                                      ;;

                             "100") VAL="1000"
                                    echo "STEP-1Khz"
                                       ;;

                             "1000") VAL="10000"
                                     echo "STEP-10Khz"
                                         ;;

                             "10000") VAL="1"
                                       echo "STEP-1Hz"
                                          ;;
                              esac
                                 ;;
        esac
done

Once the BASH script is copied and pasted into a file called powermate.sh you need to make it executable by using the following command.

chmod 700 ./powermate.sh

If you now run the shell script in a terminal you’ll see a similar output to that shown below from the device when used.

./powermate.sh 
STEP-1Hz
-1
-1
-1
1
1
1
STEP-10Hz
10
10
10
-10
-10
-10
STEP-100Hz
100
-100
-100
STEP-1Khz
1000
STEP-10Khz
STEP-1Hz
1
1
STEP-10Hz

As you can see above the shell script outputs a positive or negative number for VFO tuning and changes the VFO step size each time the Powermate is depressed.

Getting this output from the BASH shell script into Node Red is really simple to achieve using just 3 or 4 nodes.

In the Node Red development UI create the following nodes.

Griffin Powermate Node Red Nodes
Griffin Powermate Node Red Nodes

The first node in the flow is a simple inject node, here I called it trigger. This sends a timestamp into the next node in the flow at startup to set the flow running.

The Griffin Powermate node is a simple exec node that runs the script we created above.

M0AWS Powermate exec node
M0AWS Powermate exec node

Configure the node as shown above and connect it to the inject node that’s used as a trigger. Note: Change “user” in the Command field shown above to that of your username on your Linux PC)

Once done create the third node in the flow, a simple switch node and configure as shown below.

Switch Node for Powermate
Switch Node for Powermate

The switch node has two outputs, the top one is a text output that is fed into a text field to show the current step size of the Powermate device and the lower output is the numeric output that must be fed into your VFO control flow so that the VFO value is incremented/decremented by the amount output by the Powermate device.

I’ve found the Griffin Technology Powermate USB device works extremely well with Node Red and GQRX that I use for controlling the FCD SDR radio and it’s now part of my QO-100 ground station build.

M0AWS QO-100 Dashboard with Powermate Step Display at bottom
M0AWS QO-100 Dashboard with Powermate Step Display at bottom

As shown above you can see the Powermate Step size at the bottom of the dashboard, this text changes each time the Powermate device is depressed and will set a step size of 1Hz, 10Hz, 100Hz, 1Khz, 10Khz in a round-robin fashion.

The next stage of the build is the 2.4Ghz transmit path. I now have all the necessary hardware and so this part of the build can finally commence.

More soon …

QO-100 TX/RX Dashboard

I’ve now completed the GQRX Receive and Icom IC-705 Transmit dashboard in Node Red. It was a fun project to put together and needed some javascript coding to get the functionality I wanted but, I got there in the end.

M0AWS QO-100 GQRX/IC-705 control dashboard

The dashboard looks fairly simple but, there is a lot behind the scenes to get it to this stage.

On the left is the Icom IC-705 transmit control panel. It shows the transmit frequency, power output and SWR reading. The SWR is so that I can check that the input into the 2.4Ghz transverter doesn’t have any connectivity issues. The “S0” will actually display the S Meter reading when the IC-705 is being used as a normal transceiver rather than being in QO-100 Duplex mode as shown above where the GQRX app and Funcube Dongle SDR are being used as the receiver.

The GQRX side of the dashboard shows the downlink frequency which tracks the uplink frequency of the VFO on the IC-705. This will ensure that the Funcube Dongle Pro+ SDR receiver will always be on the correct downlink frequency relative to the uplink frequency, thus I should always be able to hear my own signal coming from the QO-100 satellite.

Once taken out of QO-100 mode the two radios can be used independently on any of the HAM bands and can be switched using the buttons on the dashboard.

I also coded in a simple memory facility where a frequency can be stored in Node Red and recalled later on both the transmit and receive sides.

Looking at the dashboard it all looks simple and straight forward however, if you look at the Node Red flow it becomes obvious that this isn’t the case.

QO-100 Dashboard Flow in the Node Red Editor (Click for larger image)

There’s a lot to the flow to get the information from the receiver and transmitter so that it can be presented on the dashboard. There’s also some code to convert between Rigctl protocol used by the GQRX application and XMLRPC used by the IC-705 via FLRig and WFview. I had to also code around a bug in the Node Red XMLRPC node whereby you have to add 0.1 onto the VFO frequency for it to be passed onto the radio otherwise the information is never sent. This was a real pain of a bug to find but, with a little experimentation I found the problem and managed to code around it. The strange thing about this is that the 0.1 added onto the frequency isn’t actually passed onto the radio via the XMLRPC node, it just has to have that on input otherwise it doesn’t work at all. A very strange bug and hopefully one that will be fixed by the node developer in future releases.

All that is left to do now is add the temperature sensors dashboard to complete the dashboard. These haven’t arrived yet and so I’ve not been able to create the necessary flow to collect the data from them.

Hopefully this coming week the weather will improve and I’ll start getting the dish antenna up and the get the receive side working.

UPDATE: Further development of my QO-100 Dashboard has taken place, you can read all about it here.

More soon …

QO-100 Station – Initial parts purchase

After much reading and viewing of youtube videos I have finally settled on the parts that I want to use to build my QO-100 Satellite ground station.

Initially I’m only going to build the receive path of the QO-100 station. From the articles and blogs I’ve read online all the experienced Amateur Radio satellite Op’s recommend getting the receive side sorted first and then moving onto the transmit path.

I need to stress here that I have no experience of radio above 433Mhz (70cm), a band that I have only used a handful of times. 99% of my Amateur Radio life has been spent below 30Mhz and so this is going to be a very new experience for me.

So, what am I going to purchase for the receive path?

I’ve settled on a 1.1m off-set dish from the Satellite Super Store that should give me plenty of gain if I manage to get it pointed successfully at the bird.

I’ll pair a Bullseye 10Ghz TCXO LNB with the dish to give me a high stability receive path that shouldn’t wander too much up and down the band with temperature changes throughout the seasons.

1.1m Off-Set Dish for QO-100

The Bullseye LNB gets extremely good reviews from the HAM Satellite community, although it is a little on the expensive side compared to many others available. Since I only want to do this once I’ve gone with the more expensive option in the hope that it gives me the stability I’m looking for.

Since we’ve never had satellite TV here at home I’ve only just learnt that LNBs require a voltage feed since reading about other peoples QO-100 station builds. Most LNBs can be used for either horizontal or vertical polarisation and are switched by feeding with either 12v or 18v respectively. The LNBs also use this same voltage feed to do the frequency down conversation and some amplification of the received signal.

At the moment I’m only looking to get onto the narrowband part of the QO-100 satellite service and so I will need to feed the LNB with around 12v to ensure vertical polarisation is achieved. The easiest way to do this is to inject the 12v feed up the coax cable to the LNB.

Bullseye 10Ghz TCXO LNB

To achieve this I will need to purchase a little circuit called a Bias Tee. This relatively simple circuit consists of a capacitor and inductor combination that stops the 12v from going back into the receiver whilst at the same time stopping the RF from going back into the power supply.

Bias Tee units are relatively cheap to buy online and I have decided to get one from Amazon that has been recommended in a number of blogs posts I have read during my research.

Broco Bias Tee

With these parts ordered I now need to source the materials to mount the dish up above head height in the garden with a clear view of the sky in the direction of the satellite.

Getting the dish up high enough to be above head height will be important for when I get the 2.4Ghz uplink path in place. At these frequencies it’s important to ensure that no one is able to walk across the front of the dish whilst I’m transmitting. I’m hoping to get the dish up about 3m in the air in such a fashion that it is rigid enough to stop the dish moving around in the wind. I must admit I’ve not done any wind load calculations for the 1.1m dish so I’ll have to see how it goes over time. Fortunately where I want to put the dish is fairly well sheltered from the north wind that often howls through here so, hopefully it won’t be an issue.

More soon …

Another Begali Key!

Since purchasing my Begali Pearl twin paddle morse key I’ve been looking to get another Begali for my IC-705 portable setup. Going portable means I need a key that isn’t super shiny like the Pearl, something a little more hardy would be ideal.

I was looking to buy the Begali Simplex Basic directly from Begali as it would be ideal for portable operations however, my lovely wife spotted another Begali key for sale on Ebay and pinged the details over to me to take a look at.

Begali Traveler Light

To my surprise the key for sale on Ebay was a Begali Traveler Light, the perfect key for portable use and at a much lower price than new.

I contacted the seller immediately asking a couple of questions about the key and got an immediate response, always a good sign!

It turned out that the key was being sold by Wallace, MM0AMV up in Scotland. Looking at his QRZ page it’s clear he’s an avid CW fan as he has two Begali keys. This was backed up by the conversation we had via Ebay messaging.

In no time at all I had paid the £170.00 including postage and was the owner of my second Begali morse key.

The key was in as new condition as described by Wallace, clearly it had been looked after well.

It didn’t take long for me to get it hooked up to my IC-705 and on air. After a little adjustment of the gap and return tension I had the key setup comfortably for my weird left-handed use.

The key isn’t anywhere as near as heavy as my Begali Pearl key but, it’s plenty heavy enough to stop it moving around when in use. This is of course is helped by the two fold out legs that stabilise the key firmly during use but, protect the paddles solidly when in transit. It’s a great design and a very unique approach to making a fairly light but, solid twin paddle for portable usage.

In the garden with my Begali Traveler Light and IC-705 connected to my EFHW Vertical for 20m

Once folded the key takes very little space in the IC-705 portable case and completes the setup nicely. IC-705 radio, AH-705 remote auto ATU, Begali Traveler Light, tripod and a few interconnect cables, the perfect portable station.

IC-705 Portable station case with plenty of space for future additions

Since purchasing the IC-705 I’ve found that I’ve hardly used my Yaesu FTDX10, which is strange considering the receiver, filtering, DSP and APF combination is considerably better on the FTDX10 than it is on the IC-705. The IC-705 has a much nicer, easier to use user interface and it’s just a lot of fun to use even though it’s only a QRP rig. I can see me having many happy hours on air with this QRP station.

More soon …