Automatic antenna tuners are expensive, manual antenna tuners are slow. So it has been a long time I dreamed of making my own automatic system.
As this year I was following a raspberry pi class and we needed to make our own project I decided to finally try to make this automatic tuner.
Summary: – Forward and reflected power are measured with a Boxa Swr bidirectional coupler combined with an ADC – SWR is calculated in the raspberry pi and displayed on an LCD – When SWR is to high an alarm is sounded in CW – after pushing a button the capacitors and the coil in the tuner are reset to 0. For the capacitors I use 2 servos, for the coil I use a stepper motor. All mechanical connections are made using 3d-printed parts. The reference point for the stepper motor is made using an infrared port. – next is the tuning operation: — the ‘transmitter’ capacitor is sweeped over it’s full range and swr is measured every degree. Then this capacitor is returned to it’s best position — next idem for the ‘antenna’ capacitor — sweeping operation is repeated for maximum 4 times, if the SWR is below 1,5:1 then tuning is stopped. If SWR is above this limit then the coil is moved to the next setting and the sweeping is repeated – built in securities: — all alarms on the LCD and in morse code — alarm when SWR is to high — alarm when tx-power is to high for tuning — coil/stepper can not be switched when there is rf-power
Remarks: – no tuners have been harmed in any way for this operation! – Was the raspberry pi the best choice for this? This could probably have been done using some microcontroller instead but the class I followed wat not arduino or esp 32 🙂
Due to the lowering in price and the low GBP vs EUR exchange rate I finally decided to offer myself a SunSDR2pro. I know, the SunSDR are not produced in the UK but the price in the UK was about 15% lower than in the rest of the EU.
These are my findings trying to start the transceiver:
23+ years in ham radio for now and I feel a complete beginner! This is so completely different from the ‘knobbed’ transceivers I have used in all those years.
first things first, installing the software. I downloaded version 1.1.2 from the Expert Electronics site.
Next came trying to connect the transceiver to the pc. It should be possible to run the transceiver over the LAN/WAN but for simplicity I chose to connect the network cable directly between the transceiver and the pc.
the user manual says to configure the pc network card so it gets its IP number via DHCP. Well… this does NOT work for me. Of course Google is your best friend and I found this Youtube movie made by ML&S explaining how to set up the pc to the correct fixed IP-address.
After watching this movie I could let the software connect to the transceiver. Finally the spectrum and waterfall screens came to life. TIP: set your PC to a fixed IP adress in the 192.168.50.*** range.
after some fiddling and attaching a small test wire to the antenna connector I could listen to the different broadcast stations in WFM. You have to start somewhere 🙂
Now was the time to connect a microphone to the rig… but alas, a complete flea market in the attick but no microphone that can be connected directly. It was getting pretty late at night so I gave up and went to bed.
still no microphone in stock so time to try something else: can I get the CAT interface to work with my DXlab logging software? No luck, DXlab’s commander gives ‘COM4 already in use’. So for some reason the SunSDR is blocking some of my COM ports. A quick search on Google and on the SunSDR forum does not yield a solution so I started a new thread on this forum.
I really need Commander to have my remote antenna switch choose the right antenna. Without Commander running all my coax cables are connected to ground.
Vassil RN6LHF the developer of the SunSDR has replied to my question. I should use the latest version of the software. And indeed v1.1.3 RC7 solves my COM-port problem. TIP: always use the latest version of the software!
So time to connect a real antenna to the rig and listen around on HF.
A quick trip to the shop today yielded me a computer headset I could connect to the MIC1 port of the SunSDR.
New problem found: the jumper cable from mini UHF to PL259 works OK but the adapter plugs I purchased separately can not be tightened correctly on the transceivers connectors. I guess I’ll have to send them back to the supplier.
After connecting my LDG AT-200ProII it’s time to try a qso and, eureka, I manage to work a belgian station on holiday in EA on 40m.
To get some decent power out in SSB using the computer headset I had to set the mic gain to maximum and compression pretty high. But that should probably work better once I get the correct interface cable to connect my Heil Pro-Set 4 to the SunSDR.
The transceiver gets pretty hot even in RX. The internal thermometer indicates 46°C at this moment. According to the user manual this should be ok. I prefer to have my electronics running cooler. So lets see if I can find a suitable ventilator in my junkbox.
For years I have been struggling to manage the 1000 memories on my FT-7800 mobile radio. Memory channels, subtones, memory banks ==SIGH==
Recently a friend (thanks Jan ON4KB) gave me the kit he bougth from Yaesu for the FT-8800 and of course, the cable was correct for my FT-7800 but the software didn’t work ==shame on you Yaesu!==.
That’s when I decided to get some help from Google and I found CHIRP, a free, open-source tool for programming your amateur radio. It supports a large number of manufacturers and models, as well as provides a way to interface with multiple data sources and formats.
I tested it for my radio and it works very well indeed! Downloading the data already in the radio, modifying it on the pc and uploading it to the radio again all in a breeze!
CHIRP supports over 60 different radios from 5 or 6 brands (including the ‘big’ ones of course) and is available for Windows, Mac and Linux.
Programming cables can easily be found on Ebay (for some €12) or you can make your own.
Franki ON5ZO recently wrote a blog ‘Why contesting sucks’. And I can’t deny I sometimes have the same feelings during or after the contests.
For example, the reason why our clubstation lost one of the last fielddays probably was because our biggest competitor probably used his home station with huge beam antennas via remote control. Okay, it’s only a suspicion and we can’t prove it but… At least since this year the rules for our national fieldday have changed and now all internet and dx-cluster use is forbidden.
And no, I probably can’t win any big contest from my average station (when speaking about contest stations).
As you already know from a previous post I purchased a Yaesu FT DX 5000 MP last december. Since then I operated in both the ARRL RTTY Roundup and in the CQ WW WPX RTTY. Time to write down my experiences:
The combo FT5K/FT990 is of course a great enhancement over the former combo FT990/TS50S :-). Even with the 500Hz filters the TS50S has a poor receiver for contesting, don’t misunderstand, the TS50S is a great transceiver for travelling but filtering in rough contest conditions is pretty poor. Moreover I was persuaded the FT990 had a great receiver but that’s because I never operated anything better… The receiver of the FT5 seems pretty unbeatable to me when compared to the FT990.
With the FT5K, narrow means NARROW! Using the the 500 Hz filter on FT990 you can see a pretty wide band in the MMTTy scope, using the with 600 Hz filter of the FT5k only a fraction of that band is left, when the need arises it can even be made narrower when using the ‘Narrow’ knob and/or when changing the settings of the RX. Sometimes I had the feeling the receiver is even too good 😉 because you get into very narrow holes on busy band to try and start a run. But it isn’t because I have a good RX that the other stations have one that is as good!
Being used to operate the FT990 it was not that hard for me to learn the basic functions of the FT5k, operation seems pretty straightforward to me.
Since I have the FT5k I made 2 RS232 interfaces so I can run both transceivers in FSK instead of AFSK, this avoids me the need to retune the level of the AFSK tx audio at every band change.
The only negative point I see in the MP version is the band scope which is pretty slow and with low resolution. The speakers that come with it are great but the scope isn’t. Guess I’ll have to go look for an SDR solution on the IF output of the FT5K.
I was pretty happy with the results in both contests! In both my claimed score beat the belgian record!
Last weekend we made our yearly ‘pilgrimage’ to the Friedrichshafen HAM RADIO in Germany. For the last few years there were always 4 of us, Andy ON7TS, Luc ON7KZ, Jan ON4KB and me. As Jan had to cancel at the last minute there were only 3 of us this year. (Jan, we missed you!)
For me it was the 18th year in a row and I can say I have seen a steady decline of the rally over the years. Every year there are less vendors at the flea market and at the ‘new’ market. I guess there are a few reasons for this: the prices for the rental of the fairgrounds and the competition of the internet sales.
This year there were only 2 halls of flea market with the second hall filled about 60%, last year it was 3 halls with the third hall filled about 50%. The following well known companies did not come back to the fair this year: Conrad, Classic International, Kabel Kusch etc. The room these companies took last year now seemed to be taken over by companies selling toy helicopters, handbags and even *very* cheap riflescopes…
As the frequent readers of this blog know I don’t own an amplifier and I like to contest. So what’s the solution to still be competitive a contest? Yes, enter the low power (100W) or the QRP-class (10W).
Every year the UBA-section DST of Diest organises the UBA Spring contest in 4 parts (each on a different sunday morning 0800-1200 local time) : 80m SSB, 80m CW, 6m and 2m.
In the UBA Spring contest there is no LP-class so I went for the 10W-class in the 80m SSB-part.
As Jan seems to be a far better writer than I am, I copied his text from the ON4KB page at QRZ.com:
ANNUAL ON4KB/P FIELDDAY OPERATIONS …
Over the last 4 years, the callsign ON4KB/P stands for a state-of-the-art SSB Fieldday operation each first weekend of September. This emergency exercise is an initiative of a team of great and competent fellow hams, mostly living in the area. In 2010 these are Hugo ON7FU, Luc ON7KZ, Jurgen ON5MF, Tim ON5HC, Geert ON7USB, Francis ON8AZ and myself, who all share the work of preparing, building the station, operating and logging. We’re also grateful to Sofie ON3SC (qrp on7kz) for the occasional help.
The team takes a fieldday quite seriously, keeping in mind the original philosophy behind the event :
To test our technical competence as radio amateurs and to combine knowledge and teamwork into the installation of a comprehensive emergency radio operation ;
To discuss technical issues and experiment in the true spirit of amateur radio ;