Building HAM Clock on an old RaspberryPi

I’ve got a couple of old RaspberryPi computers on the shelf in the shack and so decided it was time for me to put one of them to good use. The first model on the shelf is the oldest and is one of the very first RaspberryPi 1 computers that was released. (It’s the one with the yellow analog video signal output on the board!). This particular model is extremely slow but, I hang onto it just as a reminder of the first SBC in the line.

The second one is a RaspberryPi 2, a quad core machine that is only slightly faster than the first model but, it’s powerful enough to run HAM Clock.

It didn’t take long to install a vanilla Raspbian Desktop O/S and get it configured on the local LAN. I installed a few packages that I like to have available on all my Linux machines and then started on the HAM Clock install.

The first thing I needed to do was install the X11 development library that is required to compile the HAM Clock binary. To do this, open a terminal and enter the command below to install the package.

sudo apt install libx11-dev

You will need to type in your password to obtain root privileges to complete the installation process and then wait for the package to be installed.

The HAM Clock source code is available from the HAM Clock Website under the Download tab in .zip format. Once downloaded unzip the file and change directory into the ESPHamClock folder ready to compile the code.

cd ~/Downloads/ESPHamClock

Once in the ESPHamClock directory you can run a command to get details on how to compile the source code.

make help

This will check your system to see what screen resolutions are available and then list out the options available to you for compiling the code as shown below.

The following targets are available (as appropriate for your system)

    hamclock-800x480          X11 GUI desktop version, AKA hamclock
    hamclock-1600x960         X11 GUI desktop version, larger, AKA hamclock-big
    hamclock-2400x1440        X11 GUI desktop version, larger yet
    hamclock-3200x1920        X11 GUI desktop version, huge

    hamclock-web-800x480      web server only (no display)
    hamclock-web-1600x960     web server only (no display), larger
    hamclock-web-2400x1440    web server only (no display), larger yet
    hamclock-web-3200x1920    web server only (no display), huge

    hamclock-fb0-800x480      RPi stand-alone /dev/fb0, AKA hamclock-fb0-small
    hamclock-fb0-1600x960     RPi stand-alone /dev/fb0, larger, AKA hamclock-fb0
    hamclock-fb0-2400x1440    RPi stand-alone /dev/fb0, larger yet
    hamclock-fb0-3200x1920    RPi stand-alone /dev/fb0, huge

For my system 1600×960 was the best option and so I compiled the code using the command as follows.

make hamclock-1600x960

It’s no surprise that it takes a while to compile the code on such a low powered device. I can’t tell you how long exactly as I went and made a brew and did a few other things whilst it was running but, it took a while!

Once the compilation was complete you then need to install the application to your desktop environment and move the binary to the correct directory.

make install

Once the install is complete there should be an icon on the GUI desktop to start the app. If like mine it didn’t create the icon then you can start the HAM Clock by using the following command in the terminal.

/usr/local/bin/hamclock &

The first time you start the app you’ll need to enter your station information, callsign, location etc and then select the settings you want to use. There are 4 pages of options for configuring the app all of which are described in the user documentation.

M0AWS - HAM Clock running on RaspberryPi Computer
M0AWS – HAM Clock running on RaspberryPi Computer

Once the configuration is complete the map will populate with the default panels and data. I tailored my panels to show the items of interest to me namely, POTA, SOTA, International Beacon Project and the ISS space station track. I was hoping to be able to display more than one satellite at a time on the map however, the interface only allows for one bird to be tracked at a time.

You can access the HAM Clock from another computer using a web browser pointed at your RaspberryPi on your local LAN using either the IP address or the hostname of the device.




You can also control the HAM Clock remotely via web browser using a set of web commands that are detailed on port 8080 of the device.

http://<hostname or ip-address>:8080/

M0AWS - HAM Clock remote command set
M0AWS – HAM Clock remote command set

This is a great addition to any HAM shack especially if, like me you have an old HDTV on the wall of the shack that is crying out to display something useful.

More soon …

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 …

Home-Brew 12v DC Distribution Box

I’ve been wanting to tidy up the cabling to the 12v DC PSU for some time in the radio shack as like many HAMs I have a number of radios/devices that all need a 12v feed but, only two connectors on the front of the PSU. The net result was a birds nest of wires all connected to the PSU making it impossible to disconnect one device without others getting disconnected at the same time.

Looking online I found that many of the HAM outlets stores sell nice little 12v DC distribution boxes that would be ideal however, they’re all priced somewhat high for what they are so, I decided to purchase the parts and make one myself.

Searching on Amazon I found all the necessary parts for less than a quarter of the cost of commercially made units. A couple of days later the parts arrived and sat on my desk in the shack for a few weeks. Yesterday I finally found the time to make a start on the project.

M0AWS home-brew 12v DC Distribution Box
M0AWS home-brew 12v DC Distribution Box

After much drilling and filing I had the necessary holes/slots cut in the plastic box for the 4mm connectors and fuse holders and started wiring them up. Part way through my 30 year old soldering iron decided to die and so I had to stop and wait for a replacement to arrive.

M0AWS completed 12v DC Distribution Box
M0AWS completed 12v DC Distribution Box

With the new soldering iron in hand it only took 30mins or so to complete all the joints and I soon had the box together ready to test with my multimeter to ensure I didn’t have any shorts or crossed wires.

With testing complete and fuses in place I connected it up to the PSU and then connected all the devices one by one checking for voltage drops as I went.

M0AWS 12v DC Distribution Box
M0AWS 12v DC Distribution Box

I now have my CG3000 remote auto ATU, GPSDO, QO-100 ground station and IC-705 all nicely connected in a much tidier fashion than before, all for considerably less than the commercially available alternatives.

More soon …

Antenna Analysers – The New World

Many years ago I had an MFJ-259B antenna analyser that I used for all my HF antenna projects. It was a simple device with a couple of knobs, an LCD display and a meter but, it provided a great insight into the resonance of an antenna.

MFJ-259B Antenna Analyser
MFJ-259B Antenna Analyser

Today things have progressed somewhat and we now live in a world of Vector Network Analysers that not only display SWR but, can display a whole host of other information too.

Being an avid antenna builder I’ve wanted to buy an antenna analyser for some time but, now that I’m into the world of QO-100 satellite operations using frequencies at the dizzy heights of 2.4GHz I needed something more modern.

If you search online there are a multitude of Vector Network Analysers (VNAs) available from around the £50.00 mark right up to £1500 or more. Many of the VNAs you see on the likes of Amazon and Ebay come out of China and reading the reviews they aren’t particularly reliable or accurate.

After much research I settled on the JNCRadio VNA 3G, it gets really good reviews and is very sensibly priced. Putting a call into Gary at Martin Lynch and Sons (MLANDS) we had a long chat about various VNAs, the pros and cons of each model and the pricing structure. It was tempting to spend much more on a far more capable device however, my sensible head kicked in and decided many of the additional features on the more expensive models would never get used and so I went back to my original choice.

Gary and I also had a long chat about building a QO-100 ground station, using NodeRed to control it and how to align the dish antenna. The guys at MLANDS will soon have a satellite ground station on air and I look forward to talking to them on the QO-100 transponder.

Getting back to antenna analysers, I purchased the JNCRadio VNA 3G from MLANDS at £199.96 + postage and have been trying it out on a couple of antennas here at the M0AWS QTH.

Initially I wanted to check the SWR of my QO-100 2.4GHz IceCone Helix antenna on my satellite ground station to ensure it was resonant at the right frequency. Hooking the VNA up to the antenna feed was simple enough using one of the cables provided with the unit and I set about configuring the start and stop stimulus frequencies (2.4GHz to 2.450GHz) for the sweep to plot the curve.

The resulting SWR curve showed that the antenna was indeed resonant at 2.4GHz with an SWR of 1.16:1. The only issue I had was that in the bright sunshine it was hard to see the display and impossible to get a photo. Setting the screen on the brightest setting didn’t improve things much either so this is something to keep in mind if you plan on using the device outside in sunny climates.

(My understanding is that the Rig Expert AA-3000 Zoom is much easier to see outside on a sunny day however, it will cost you almost £1200 for the privilege.)

A couple of days later I decided to check the SWR of my 20m band EFHW vertical antenna. I’ve known for some time that this antenna has a point of resonance below 14MHz but, the SWR was still low enough at the bottom of the 20m band to make it useable.

Hooking up the VNA I could see immediately that the point of resonance was at 13.650Mhz, well low of the 20m band and so I set about shortening the wire until the point of resonance moved up into the band.

JNCRadio VNA3G showing 20m Band EFHW Resonance
JNCRadio VNA3G showing 20m Band EFHW Resonance

With a little folding back of wire I soon had the point of resonance nicely into the 20m band with a 1.35:1 SWR at 14.208Mhz. This provides a very useable SWR across the whole band but, I decided I’d prefer the point of resonance to be slightly lower as I tend to use the antenna mainly on the CW & FT4/8 part of the band with my Icom IC-705 QRP rig.

Popping out into the garden once more I lengthened the wire easily enough by reducing the fold back and brought the point of resonance down to 14.095Mhz.

JNCRadio VNA3G showing 20m Band EFHW Resonance 14Mhz to 14.35Mhz Sweep
JNCRadio VNA3G showing 20m Band EFHW Resonance 14Mhz to 14.35Mhz Sweep

The VNA automatically updated the display realtime to show the new point of resonance on the 4.3in colour screen. I also altered the granularity of the SWR reading on the Y axis to show a more detailed view of the curve and reduced the frequency range on the X axis so that it showed a 14Mhz to 14.35Mhz sweep. With an SWR of 1.34:1 at 14.095Mhz and a 50 Ohm impedance, the antenna is perfectly resonant where I want it.

It’s interesting to note that the antenna is actually useable between 13.5Mhz and 14.5Mhz with a reasonable SWR across the entire frequency spread. Setting 3 markers on the SWR curve I could see at a glance the SWR reading at 14Mhz (Marker 2) , 14.350Mhz (Marker 3) and the minimum SWR reading at 14.095Mhz (Marker 1).

I’ve yet to delve into the other functionality of the VNA but, I’m very happy with my initial experience with the device.

More soon …

Just one little rain drop is all it takes!

We’ve not had rain for over 6 weeks here in Eyke, Suffolk. The ground is incredibly dry and dusty. The farmers have been pulling vast quantities of water from their bore holes for weeks to keep the crops alive and we’ve been putting extra water out for the birds and animals that visit our garden daily.

Then one night we had about 30mins of light rain, not much at all and it was consumed by the dry earth is seconds. By morning you’d never of known it had rained however, strangely the next day when I fired up my QO-100 ground station I noticed that my signal into the satellite was way down from it’s normal S9+10dB level. Checking drive into the up-converter and SWR at the IC-705 everything looked fine. I then decided to check the SWR from the 2.4Ghz amplifier output only to find that it was off the scale.

I checked inside the enclosure for water ingress but, all was bone dry as normal. I disconnected the coax cable from the output of the amplifier and the IceCone Helix uplink antenna, tested with a multimeter and found everything was fine, no short and perfect continuity.

After scratching my head for a few minutes I decided to take both the N Type and SMA connectors apart to look for water ingress. Since the inside of the enclosure was dry I wasn’t expecting to find anything.

The N connector at the Helix antenna end on the dish LNB mount was perfectly dry, no water ingress at all. The layers of self amalgamating tape I’d put over the connector had done its job perfectly. Shame I had cut the tape off to remove the plug!

Upon removing the SMA connector at the amplifier end of the coax I noticed a tiny drop of water in the bottom of the housing where the pin goes through the white plastic insulator, not a good sign.

Sure enough upon further inspection I found that the white plastic disc that is situated above the pin on the centre conductor was wet and the coax braid felt damp. I knew immediately this wasn’t good.

At first I didn’t understand how there could possibly be water in the SMA connector when the rest of the enclosure was dry. Where the coax goes into the top of the enclosure there is a water tight junction that tightly grips the coax cable and seals it, supposedly stopping water ingress.

Since there was water in the SMA connector I feared that perhaps the water had gone further and entered into the amplifier so, I decided to remove the amp from the enclosure and remove the top cover to check.

2.4Ghz amplifier with top cover removed
2.4Ghz amplifier with top cover removed

After some close inspection I found the amp to be perfectly dry and free from water ingress, a relief for sure.

Before putting it all back together I decided solder on a pair of wires to the SWR and FWD-PWR pins on the amplifier and run them down into the radio room. This would then allow me to check the SWR and power output without having to get up to the enclosure with a multimeter.

Once this was done I then set about cutting 5cm of LMR-400-UF off at the SMA connector end so that I had a fully dry piece of coax cable to refit the SMA connector to. Having to do this outside and up a ladder wasn’t the easiest but, with a little perseverance and cooperation from the breeze I managed to get the pin soldered back onto the end of the coax and the connector back together.

I reconnected the amp to the 28v feed so that I could check the SWR and power output at full rating instead of the lower 12v setting that I had been using. Checking the voltage on the SWR pin I found that it fluctuated between 0.2v and 0.44v. This wasn’t what I was expecting as the PDF manual for the amplifier states that with a 1:1 SWR you should see 1.5v on the SWR pin.

DXPatrol 2.4Ghz Amplifier Manual Page for SWR/FWD-PWR voltages
DXPatrol 2.4Ghz Amplifier Manual Page for SWR/FWD-PWR voltages

After checking all the connections and retesting and getting the same voltage reading I emailed Antonio at DXPatrol detailing my findings and asking if he could advise on the voltages I was seeing. Sure enough in no time at all he came back to me saying that the manual was incorrect and that I should see between 0.2 and 0.5v on the SWR pin for a good SWR match. Being happy that the readings I was getting were fine I emailed back thanking him for his swift reply and then moved on to check the power output safely in the knowledge that the SWR reading was within tolerances.

Checking the FWD-PWR pin I found that on SSB the voltage was fluctuating between 2v and 3v, this equates to 6w and 9w output, about right for SSB. Switching to CW mode I found the full 4v was present on the FWD-PWR pin confirming I had the full 12w output from the amp. Of course this set off “Leila” on the satellite immediately as I was a huge signal on the bird with such high power output and was a reminder to reconnect the amp to the 12v supply instead to ensure I didn’t exceed 5w output and thus keeping to a considerate level on the transponder input.

After further investigation I came to the conclusion that the water ingress could only of come from the cable inlet on the top of the enclosure, it had then run down the coax cable into the SMA connector. Somewhat annoying as the inlet is supposed to be a water tight fixing. Once I had everything back in the enclosure and securely fitted, I covered the cable inlet and coax in self amalgamating tape in the hope that this would stop any further water ingress. I also re-taped the N connector at the antenna end as well to ensure it was also protected from water ingress in the future.

2.4Ghz ground station enclosure ready for testing
2.4Ghz ground station enclosure ready for testing

I’m hoping this will be the end of my water ingress issues and that I have a dry 2.4ghz future ahead of me.

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 …