Two Metre Rule

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John Laidler

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Dec 20, 2023, 8:03:24 AM12/20/23
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I have always understood it was not necessary to seek CAA permission to launch a balloon which was less than 2 metres in height/width, including any underslung load.  There was also a weight restriction but it was quite high and won't be an issue.

What I haven't been able to find is where this is written down.  An internet search this morning proved fruitless. 

If anyone can point me in the right direction I will very grateful. 

John
M0WIV

Mike Sharps

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Dec 20, 2023, 8:25:08 AM12/20/23
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Hi John, regards 2m rule it certainly used to be the case but our recent talks with CAA indicate that all balloons with a payload require permission. 

High altitude unmanned balloon activities are defined as “unmanned free balloons”, the regulations for which are within the Standardised European Rules of the Air Regulation (EU) No. 923/2012 as retained (and amended in UK domestic law) under the European Union (Withdrawal) Act 2018. One of the requirements is that “the State from which the launch is made” must authorise all unmanned free balloons. Therefore, an organiser/operator needs to obtain CAA Airspace Regulation exemption/permission for any such launches in the UK, regardless of the balloon/payload size and weight. All applications should be submitted using the notification form. 

Link here:

Having said that this comes under commercial area of the regs but we have taken the approach that where there is doubt the more restrictive rules apply

Make of it what you will.
Mike

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Steve

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Dec 20, 2023, 5:45:51 PM12/20/23
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The 2m rule comes from the Air Navigation Order (CAP393) that sits alongside SERA.

See article 253 - which gives "small balloons" exemptions from most of the provisions of the ANO  (all but Articles 131, 138, 161, 163, 164, 165, 166, 167, 232 except 232(2)(a) and 255)

    https://publicapps.caa.co.uk/modalapplication.aspx?appid=11&mode=detail&id=226

On page 24 of the ANO a small balloon is defined as:

Small balloon’ means a balloon of not more than two metres in any linear
dimension at any stage of its flight, including any basket or other equipment
attached to the balloon;

I believe this has previously be discussed with someone in ARops and it was their view that SERA applies in all cases of balloon launch.   I'm my mind this cannot be the case as what would be the point of the Small Balloon text in the ANO. It would mean that anyone releasing a party balloon would come under SERA.  Its clear from wording that "equipment" may be attached to the balloon.  I've sought a legal view form a UK body with an interest the the ANO and they agree.

I think it would be unwise to stir this with the CAA - at the very least there is a beneficial (to us) ambiguity in the legislation. The view that was previously obtained was that of a single ARops individual.

    Steve

John Laidler

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Dec 21, 2023, 6:59:40 AM12/21/23
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Steve,

Many thanks, I thought if anyone knew it would be you.

I'm not going to raise this with anyone and if I do make a sub-two metre launch it will be one or at most two only.  I will also follow the guidance issued for previous launches, primarily not launching if the wind would take the balloon south or south west.

John

John Laidler

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Dec 21, 2023, 7:02:38 AM12/21/23
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Mike,

Thank you, I didn't see your reply before replying to Steve.  It does seem a difficult area but I guess I need to tread on the side of caution.

John

Kevin Walton

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Dec 21, 2023, 7:33:40 AM12/21/23
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Good to hear you are planning some launches John!  Any hints on what you have planned?

Cheers
Kev
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noddym

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Dec 21, 2023, 9:28:29 AM12/21/23
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All

I would just caution, ‘safety first’. As someone who is in the process of planning 5 or 6 HAB launches next year, I entirely accept that there is ambiguity between the ANO and SERA, but that is not something you want to test in court as they will ALWAYS err on the side of safety of aircraft (for obvious reasons). And as someone who also sits on the other side of the flightdeck door, we see an increasing number of balloons, one which recently came dangerously close. We are travelling at 500 mph and don’t often see them until it’s too late and having a large (even 2m) latex balloon sucked into your engine intake or blocking one of your pitot tubes is not my idea of fun! If you know that SERA requires notification (it does), then launching without doing so would likely be considered as ‘reckless endangerment of an aircraft’ and the penalties are severe.

The new SERA rules were passed in Nov 2022 and were published in Mar 2023. When I spoke to the head of AROPS back in April, they were adamant that notification is required.

Again, I just caution - ‘safety first’

Cheers

Noddy

John Laidler

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Dec 21, 2023, 1:34:10 PM12/21/23
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Thanks for all the replies, informative and helpful. I've been looking at constructing a compact HF dipole antenna for a picoballoon based on the concept of a base loaded coil design similar to the Elecraft AX1 or Super Antenna MP1C. I have one of the latter and today tried it on the 10m WSPR frequency which confirmed a theoretical calculation that 13 turns on a 30mm diameter former then 0.85m of straight wire would be resonant. The idea is to use two of these, above and below the transmitter with the upper antenna arm attached to the top of the balloon to keep everything under 2 metres. The next step, which is tomorrow's task, is to build the antenna and test it on the ground. 

Because it takes a few days to prepare a picoballoon (stretching can't really be done in advance) I think I will stay with the established procedure and seek permission for launches. I'll also continue with the compact antenna design, if it works it will make launching a lot easier. 

John

John Laidler

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Dec 22, 2023, 8:55:30 AM12/22/23
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Just in case anyone was sitting on the edge of their seat waiting for the latest news :-) first results of today's tests are positive. With a U4B tracker on low power (<10mW) and a dipole a little over 2m long including the coils, the WSPR signal was picked up about 2500 km away in Tenerife. The antenna was only about 4m off the ground. Unfortunately, I've had to stop the test as rain is in the air. 

If the weather improves, probably next year (!) I will run a longer test. Will post a few photos later. 

John

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John Laidler

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Dec 22, 2023, 11:47:04 AM12/22/23
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John Laidler
16:43 (now) 
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Here are a couple of photos of today's test, which was cut short by the weather. It doesn't represent anything like what a working payload for a flight would be like but as a test of the idea of using a short antenna the signs are encouraging.  The close up shows the 9 turn coils at the start of each 1m long dipole arm.  Everything is zip tied to a 2m length of pvc pipe with a 3 AAA battery pack for power. The U4B is mounted on a pad to keep the USB connection away from the coils. The connection would of course be snapped off before a flight and the tracker mounted level with the coils. The polystyrene the wire is wrapped around would also be much shorter. For robustness I used 0.33mm wire for the antenna, an actual flight would use wire around 0.2mm diameter. The payload wouldn't of course use a pvc pipe, the antenna would hang vertically below the balloon.

In my test I raised the pipe and payload up to about 4m above the ground, the wind was too strong to go any higher.  I only managed about two WSPR transmissions before I had to lower everything when rain arrived. In this short time EA8/DF4UE picked up the signal at -24dB in the Canary Islands at a range of about 2,500 km. More tests to follow when the weather improves. I may also try 20m which will require a coil of about 33 turns.

I need to look at testing the antenna for resonance using a miniature balun I have which might allow me to attach an antenna analyser to it through a thin bit of coax. My only worry is the coax may impact on the resonance but I'll give it a try.

Although this is designed for a picoballoon, if the proposed Ofcom changes are implemented and we can use most of the ham bands airborne then a compact antenna might be worth considering from a conventional latex balloon if anyone wants to try HF. Avoiding 10 or more metres of wire hanging from a balloon will make launches simpler.  

PXL_20231222_152807610.jpg

PXL_20231222_133356544.jpg

Philip Day

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Dec 30, 2023, 11:15:42 PM12/30/23
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Fantastic effort, thanks for sharing! Sure interesting when people innovate in the HF space. Something we need to be doing more of!

stephenb...@gmail.com

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May 20, 2024, 4:33:13 AMMay 20
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I found out a few weeks ago, one of the large red balloons from Amazon  59 Inch Big Round Balloon Latex Giant Balloon Jumbo Thick Balloons for Photo Shoot/Birthday/Wedding Party/Festival/Event/Carnival Decorations (Red) : Amazon.co.uk: Toys & Games  If filled with two cylinder's of Helium, will lift over the weight of 2 AA batteries.  And the size is less than two metre's across, when filled.  They might be worth looking at for any 'small balloon' launch, that someone may have planed.

Kevin Walton

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May 20, 2024, 7:41:17 AMMay 20
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Hi Stephen

But being latex, it will quickly grow to over 2m so still requires the notam?

"Small balloon” means a balloon of not more than two metres in any linear dimension at any stage of its flight, including any basket or other equipment attached to the balloon;”

Cheers
Kev
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