National Free Flight Society

SEN 3142

  1. Not Donkey Kong driving a Drone
  2. RF Chokes
  3. KRKA Cup

Not Donkey Kong driving a Drone

From: John Carter

Data logging , I agree the technology is hear to stay, but we should and not encourage flights to continue beyond line os sight. In fact its against drone rules in UK and assume the same applies world wide !
We do need to address the fact the models in good conditions have a far to great performance. Please lets add this issue to the timing debate .
Free Flight is not just about technology its far more .At 80 I have seen change but the challenge is always to do good flights. Lets not ruin a great sport by turning it in to a computer game
John C UK


RF Chokes

From:Ken Bauer

I’ve written about this before, but since Paul asked and in light of recent events I’ll share what I know again.

Source of problem:
Whenever any radio device transmits energy on an antenna there is an equal amount of radio energy present in the ground wire of the device and in most any wires connected to the device.  This means the wires going to the battery will be soaked with radio waves during transmissions unless there is significant filtering built into the device.  Our GPS devices are transmitting much more energy than traditional radio beacons due to the nature of the signal which exacerbates the problem.  When this energy enters either the timer or the servo or both the high frequencies are rectified into interference at levels that can cause unpredictable glitches and anomalies.

Solution options:
Best solution is to run the GPS off of a separate battery so there are no shared wires.  Note that problems can still occur with the radio signal coupling from the GPS antenna to the wires in the timer or servo or any other antennas in the model, and it is good practice to separate the GPS antenna from the other systems but this level should be much less than the case of shared wiring.  But having said that I’m a big proponent of simple and minimal systems with shared power…

When the battery is shared the use of ferrite beads is the best solution as has been discussed and practiced.  These are simply short pieces of wire surrounded by ferrite or magnetic material that allow the DC currents to pass unimpeded but suppress high frequencies starting at anywhere from about 10 to 100MHz.  Note that adding these to servo signal wires should be fine as servo signals are well below these frequencies but caution should be used to make sure servo performance is not affected.

The best way to solve RF problems is to kill the energy at the source, so the best location for the ferrites would be right at the GPS device on both the positive and negative battery wires.  But in practice placing the ferrites anywhere between the GPS source and the servo may work, but it is nice to keep the interference out of the timer as well as the servo.  It doesn’t hurt to put the ferrites everywhere, say at the GPS device, near the timer, and on the servo to really make sure the pesky radio waves are controlled.  Capacitors can also be used in places to enhance filtering as well but that is another topic.  Suffice it to say that enough ferrites in the right places should solve most of our problems.

If anyone knows of connectorized ferrite bead solutions or ready to use RF filters or chokes with our commonly used battery connectors these could be very convenient ways for people to add filtering without soldering or cutting wires.  There might be a market for tiny devices with male and female connectors on each end and ferrites in between, but not something I have time for at the moment.




From:Damjan Zulic

Dear Roger
Please, could you post the invitation in the next SEN.
Best regards
Damjan Zulic


We downloaded and auto converted it and it’s  here – but check it online if you are not certain


World cup contest
KRKA CUP 2023World Cup aeromodelling contest in free flight category


Organizer                         Aeroklub KRKA Novo mesto, Šmarješka 44, 8000 Novo mesto

Date of contest                  14. October 2023 – 15. October 2023

Classes                             F1A, F1A-jun, F1B, F1C

Participation                      competitors with valid FAI Sporting Licences

Contest Area                    Šentjernej, SLOVENIA ( 85 km SE from Ljubljana, 18 km E from Novo mesto, 55 km W from Zagreb (CRO))

Competition Rules:            FAI Sporting code, section 4

Contest Fee                     35 EUR, additional category 20 EUR, juniors 20 EUR. At registration on the flying field on the day of the contest – 50 EUR.

Contest fees are to be paid to the bank account
Bank Name:             DEŽELNA BANKA SLOVENIJE D.D., Kolodvorska 9 1000 Ljubljana
SWIFT code:            SZKBSI2X
IBAN :                       SI56 1990 6501 0768 324
Name of the Beneficiary:     Aeroklub Krka, Šmarješka 44, Novo mesto
Purpose of transfer: Krkacup entry (name of competitor)

Program and time schedule:

Friday, 13. Oct      arrival and registration at inn Pri Slavcu (Turk), Maharovec (4 km from Šentjernej towards Novo mesto, by the road) 18:00 – 20:00.

Saturday, 14. Oct             – F1A contest, flying site

round 1 9:00-09:55 max = 240 s
round 2 10:00-10:55 max = 180 s
round 3 11:00-11:55 max = 180 s
round 4 12:00-12:55 max = 180 s
round 5 13:00-13:55 max = 240 s
fly-off               16:00-16:10
prize giving on the contest site after the competition
Sunday, 15. Oct               – F1B, F1C contest, flying site
round 1 9:00-09:55 max = 240 s
round 2 10:00-10:55 max = 180 s
round 3 11:00-11:55 max = 180 s
round 4 12:00-12:55 max = 180 s
round 5 13:00-13:55 max = 240 s
fly-off               16:00-16:10
prize giving on the contest site after the competition

Prizes:         The best three ranked competitors in each class and the best three ranked juniors in F1A will be awarded with cups.

E-mail Entry applications:
(Name, Country, Class, Licence, FAI ID, Date of birth, UAS Operator Registration Number, Pilot Training Completion Number, Personal Data Agreement)
to e-mail

On line Entry application:

Application Deadline 10. Oct. 2023

(please inform us in case of cancellation of the entry application)
Registred competitors: usp=sharing

Registration point:,15.3051245,223m/data=!3m1!1e3?authuser=0&entry=ttu

Flying site:,15.3617806,749m/data=!3m1!1e3?authuser=0&entry=ttu

Use of vehicles on the flying field is allowed on roads or paths. Driving on fields or meadows is not allowed.

The organizer is not responsible for injuries or damages caused by models or participants. Participants should have liability insurance coverage.

UAS proofs:
According to the European Union Unmanned Aircrsft Systems legislation (EU 2019/947) F1A, F1B and F1C competitors are obliged to have a valid PROOF OF COMPLETION OF THE ONLINE TRAINING and a valid UAS OPERATOR REGISTRATION. Both certificate numbers are to be specified in entry applications. Competitors without both numbers will be ineligible to fly in the contest. Model aircrafts must be labeled with the Operator Registration Number.

See you on Krka cup 2023 World Cup Contest

Aeroklub Krka
Novo mesto, 30. Aug 2023