Again at CN3A in 2025 - CQ WW RTTY multi/multi
This year, I was really lucky and was able to spend 44 days at the CN3A superstation in Morocco. A big thank you goes to my girlfriend Lucka and all the great people around CN3A. My main goal at QTH for me is a work. Contesting is an added bonus :)
After some difficult birth pangs with both hardware and software during CQWPX RTTY, several ideas came to mind. One of them was to solve FSK keying using TNC. A very nice solution is TinyFSK by Andrew K0SM. So I made a compact PCB with Arduino and audio isolators. As a bonus, I added something that I think is very important when transmitting from a QTH such as CN3A - a PTT sequencer. This ensures timing between the TRX and PA (ANT switches, etc.).
I went to QTH as soon as I could. Team A (retirees) left almost 14 days before the contest. The plan was clear – to add more antennas. A few days before the contest, a complication showed up in the form of a fallen 20m antenna. This antenna fell on two others below it, damaging the guy rope and other antennas. These also had to be removed, everything repaired, and then gradually put back in place. It sounds easy, but in temperatures around 37 degrees Celsius, it was also a matter of health.
I also wanted to try out the RX skimmer. I prepared new BPF splitters and 2x 16-bit SDR - TRX-DUO. I modified the switching control boxes for Beverage and fed the signal for the skimmer out of them. This gave us signals from Beverage on 160/80/40. As a listening antenna for 10/15/20, we installed ordinary fiberglass with a 5m vertical wire - without a preamplifier. The location was not ideal at all, but in the end, the result was surprising. Despite the RX vertical being located only 150m from the TX antennas, it was possible to listen to 3-5kHz from the TX signal. The RTTY skimmer therefore worked even during transmission, and I will have to focus on RX using SDR next time.
We didn't have a powerful PC available, so decoding worked at about 70 percent... Even so, the RTTY skimmer sent 56,391 spots during the contest.
Sometime in the future, I would like to focus on improving RX antennas and the possibility of listening directly from SDR.
Another great news is the addition of the 6m band. Not so long ago, Jiri OK1RI looked around and decided to make another 6 pieces of 4el Yagi antennas for 10m. We discreetly added a request for a Yagi for 6m to this "crazy" plan. It's unbelievable, but the packages with the antennas arrived at the QTH together with Jiri. I wish I had as much enthusiasm as he :)
So we divided up the work, and within a few days, the new antennas were lying on the ground :)
It must be added that all antenna designs are by Jiri OK1RI. And the antenna works just as well as it is designed!
Vojta OK1GI made a one-man show on the tower and with the help of a team on the ground installed the antenna above the existing Yagi for 20m.
Immediately after instalation, Jiri OK1DO sat down to radio and classic modes - CW. But the band was quiet, there was no Es. Later we tried FT8 and in the evening the band opened to South America. It's incredible how differently the Magic Band behaves compared to the Central Europe. As a result, I was the only one who didn't go to sleep before the contest. The reason was that the Magic Band opened up and within a few hours I made about 70 stations from SA. It was a wonderful moment when JG1TSG Long Path came through! Some stations (HC) were active until 5 a.m. UTC!
Team ready for CQ WW DIGI FT8 contest :)
The newly installed antennas for 80m showed excellent parameters and directionality. Having 2x 2el Delta Loops at approximately 50m is the dream of most radio amateurs. A bigger problem turned out to be interference, which appeared every evening after sunset. Unpleasant squelching over S9 made reasonable reception impossible :( That's why, one evening while having a nice drink, the idea of creating a "aiming" team was born. Dan OK1HRA quickly made a loop antenna from kitchen tools, we dismantled one FT-DX10 and charged the battery from the car. The first listen was already interesting. There were about 10 beautiful CW signals on the band on the small loop, which we couldn't hear on the large antennas. Interference comes through the power lines :( We were lucky during the contest and the level was very low.
anti-interference hunting team
And another "monster" - a second identical system, like the one to NA. Six 4-element Yagi antennas for 10m. Stacked along the tower towards EU - JA. Jirka OK1RI and Petr OK1FFU carefully manufactured and packaged the components at home. Thanks to their precision, assembling the antennas is a pleasure! The guys assembled the antennas, connected the coaxial cables, and were ready to go up the mast. Together with Vojta OK1GI, we climb to the top and prepare "Jim's" rope. The entire antenna "lift" is named after Jim W7EJ, and thanks to that, the work is more easy.
Karel OK1JKT as a master of Jim's machines
Petr OK1FFU and Vítek OK5MM. Jiri OK1RI
Contes was a big fun. There were lots of new things:
Easy FSK box, N1MM with four decoders, several operators who had never tried RTTY before...There were a few problems during the contest. About two PCs were not powerful enough and had to be slightly optimized. On Sunday, there were problems with the electricity, and we were missing up to 80V on one phase. We found out that some repairs were being done on the power lines...
In the end, the contest was certainly an unforgettable experience, and it's a sad that there was no one left to work on Sunday... :(
3830 post by Jiri OK1RI
Our second RTTY contest on RTTY since the „reborn“ of CN3A in 2017. The plan was to work for 2 weeks before the contest to add some more aluminum and wires into the air and eventually do RTTY CQ WW. 7 people arrived already on SEP 13 – 2 left a week later but another 3 arrived on SEP20. But the plans dramatically changed after arrival – we have seen that one of our 5Y – 15m boom 20m Yagis ( we do have a tower with 3x stack into NA and 3 stack into EU+JA) third from the ground fell down and of course damaged 2 antennas bellow. Up to that we had no 80m at all since in may we decided to build one new tower to separate 80m USA and 80m EU deltaloops and make the towers a bit higher and improved the holders of the loops and the pulleys on top. Those holders (8m long) were not yet up. Up to that the completely crazy writer of these lines came with and idea that our 6x4Y to the USA on 10m works great and that we should build the same systems into EU+JA on the new tower the guys said sure let’s do it ! – so we made new antennas shipped to CN and…. Well while seeing the calamity with 20m I though forget it for RTTY maybe until SSB ??? Any way we were diligent and all this work was completed in Thursday before the contest. We have even set up a skimmer and put it into the air and set up a “small” 6Y on top of the 20m rotary antenna to give CN on 6m to the people while we are there. During our first RTTY in WPX we have seen a lot of problems inside. OK2ZAW have build 5 pcs of “tiny FSK” module with optically insulated PTT on nice SMD PCB in a tiny box – he has even contacted the author K0SM to get his permission and he said: “if you want to produce it - I am most happy since now nobody makes it”. He has not yet decided but it might appear on his hamparts.shop webside. It worked like a champ. The contest started – about half of the operators were total newbies to RTTY. We did believe that our location and 173 elements in the air will help to do the job.
The propagation was decent on all bands. We did not observe the propagation problems described by some stations. The low bands were not yet in autumn state but worked reasonably well. The new 80m delta loops now higher worked well – but as always in last few years few people there – especially the “state side” they were loud easily workable – even some QRP stations were worked there but only a few. Saturday was fine the stations called and we had fun. Well than came Sunday and the pileups slowed down significantly. We started to look around and worked not only multipliers but stations too but very few not yet worked were on the bands. In one moment OK1DO came (was on 20m around 1700 UTC) and said well I have tuned the band manually like when we were young and “bicycled” up and down investigating all the stations there and I was lucky to found only TWO not yet worked i.e. he made 2 QSOs in about 25 minutes – well I started to do the same on 10 and was lucky to find only ONE station not yet worked. While calling CQ we were going with a rate something like 20 QSOs / hour. I am sure we were reasonably well audible we were getting from the skimmers around the world over 30dB but no callers - simply there were no people – all that came were already worked.
The newly appearing multipliers were a total disaster on RTTY. For instance, OY1R showed up on 40m and was loud – if we heard good he worked only one EU station and there was a calling jam probably 100 callers - after some minutes he has written “too many stations” and disappeared. On RTTY it is complicated to distinguish in the pileups….. One observation – the skimmer. During CW there is something like 10% of busted calls. During RTTY this year there was maybe 10% of not busted calls ?!?! Maybe the authors might want to look a little into this.
Remark for P49X. We expected he is SO and knew he is not tuning the bands so we were nice and gave him (and us) all 5 multipliers. Remark – it was 5-times us calling him – but I must say in all 5 cases an easy QSO. The most magical QSO of the contest – VK9DX on 80m, the sun was already well above the horizon and was shining – complete daylight, we could not beat the both EU and NA stations already and… he suddenly appeared very loud on LP ?!?!? It was OK1JKT who found him on a dead band - who made in his “not too young” age (Being the senior of our 64 years in average group) his first RTTY QSO just this Saturday ! Also nice was a few JAs on 10m long path around 0 UTC ! How was it coming through ????
It seems we are a bit over the record – we will see after the log checking. We came to a conclusion we still do have reserves mostly “inside” and of course in the skill of the operators. So … we might appear on RTTY again. The calling is for MORE PEOPLE to come on the bands. I am sure we are able to work anybody who will show up even with a small antenna. Thanks for a QSOs and hope to work you all on SSB and CW this fall.
Antennas:
80m - 2el deltaloop @50m (into both NA and EU on two towers) loops spaced @ about 14m both horizontally fed.
40m - 2x 2x3el.full size Yagi @25m+44m 12m boom always two into EU and NA - fixed - not rotary.
20m - 3x 5el.Yagi into EU @39+27+15m fixed + 3x 5el.Yagi into NA @33+21m+9m fixed + rotary 4Y@28m (not in use much)
15m - 4x 5el.Yagi into EU + 4x5el.Yagi into NA + 5el.Yagi into 165deg + 4el.Yagi into SA - all fixed.
10m - 6x 4Y Yagi @38/32/26/20/14/8m to the USA and the same to the EU-JA, 3x 5el.Yagi fixed to EU 8+13+18m, 5Y Yagi at 35m to 120deg and 6Y YAGI at 35m into SA/JA-lp.
Thanks to Ahmed CN8WK and of course to ARRAM for long years of support. 73 !
For the whole CN3A team Jiri - OK1RI
PS – written after some investigation. I must remark – we made an unbelievable 289 5-band contacts – i.e. from people who worked us on 80m only about half did not worked us on all other bands !!!! WOW ! Some interesting calls from 5-banders….VK9DX, C37N, P49X, VP9I, VY2/WE5DX, V26OC, ZF2SS and on 4 bands 5W1SA, E2X, V55A, ZL3IO…. The best 60 min. rate was 332QSOS in Saturday afternoon. We did logged 3705 different callsigns.
See you soon again at
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