Can other planes fly at the same time?

[Bucksboy]

My BMFA club is interested in buying an FPV set up for the members to try out and we intend to comply with all BMFA guidelines.

Namely, a buddy box system for a LOS pilot.

The FPV pilot to sit down

The Plane will fly on 35mh system.

The plane will fly within the field boundaries, there will only be club members at the field as there are other restrictions about how close people can be at take off etc.

Now, will other planes be able to continue to fly at the same time on 2.4G? Or, will we have to ground other planes?

The concern is that the 2.4G from the camera system will flood the air with 2.4 and make other planes suffer from interferance and glitching.

Does anyone know the aswer? Thanks.

[Pete B]

AFAIK, even if the downlink is on 2.4Ghz rather than say 5.8Ghz, the power output is limited to 10mW, rather than the 100mW output of ground-based transmitters, so I wouldn't expect any problems.

Pete

[Martin Harris - Moderator]

There shouldn't be any problem with frequency hopping equipment and even if the link is covering the frequencies chosen by a less agile system it doesn't necessarily mean doom. You can equate 2.4 to talking in a noisy room - your conversation with someone gets through although you may need to repeat yourself a few times if it's particularly noisy.

Notwithstanding this theoretical advice I'd proceed with due caution and do some controlled practical testing first!

[Olly P]

I would do some range checks with 2.4 kit on each protocall, with the aircraft rx next to the FPV tx (ie airbourne sections) and ensure no interference.

Most frequency agile systems should cope, and all addressed systems (ie all of them) should cope as long as the signal isn't swamped out.

I would do some ground checks but would expect no issues

[Chris Bott - Moderator]

Do beware, and do the checks. I have seen 2.4Ghz video equipment that spreads an analogue signal right accross the band with not even a nod to compatibility with anything else.

[Bucksboy]

Thanks for those answers, I would have gone for the 5.8G system but I don't want the hassle of obtaining the Radio Ham Licence.

[Daithi O Buitigh]

There's a lot less hassle now in obtaining a ham license - any 'novice' callsign can legally operate at up to 10 Watts RF on all bands. Check with any local amateur for the training program or here

It's a very simple test (well to me but then I have a full(advanced) license having donw the old C&G exam.

It can prove very useful at your club for open days if there are a couple of you - you're licensed to operate all hand held radios (they're almost all 5 Watts output)

[Bucksboy]

From what I've gleaned I can operate the plane itself on standard 2.4 G. The video picture is then transmitted on a low power, 25mW, tranmitter from the plane. By using this low power system, I don't need a Radio Ham licence. We use the cloverleaf style antennas on both the plane and the ground (the aerials look like little egg beaters) and we should be ok.

Of course we'll do all the range tests we can before we commit to flight, we'll also stay within the confines of the field, buddy box etc, at most its 500 yards range. I've measured it with Google Earth so thats the furthest we'll fly.

Thanks for the earlier advice from everybody, it is quite confusing.

[Tim Chambers]

First of all 2,4 GHz is limited to 10 mW but 5.8 GHz is allowed 25 mW for airborne transmission if you want clear information then you should really ask the people doing it http://www.fpvuk.org/forum/

[Peter Beeney]

We have one member with some FPV kit that has flown a number of times. So far he’s not really wanted to actually fly the model himself, he prefers to let someone else do that and he just stands, or usually sits in a chair and watches through the visor. He’s also quite happy for any other folks to have a look.

The power for his 2.4 ground station is 12 volts I believe, so he uses his flight box battery. If he stays at the flight line and there are any other 2.4 transmitters operating, say at a distance of up to 5 metres, the adjacent 2.4 transmitter causes some problems with the ground receiver, the picture continually breaks up and becomes pixellated etc. If he returns to the pits, at 30 metres distance, there is no interference at all. So this is what he often does, the model pilot remaining on the flight-line. If he wants to stand close to the pilot and talk he just chooses a quieter time when no other 2.4 pilots are flying for a while.

In this situation there are no problems, apart from this there is no obvious interference anywhere, certainly the airborne tx isn’t an issue, but I would consider that if anyone wished to fly the model using the FPV system it would certainly be very wise to operate away from any other 2.4 transmitters, having often looked through the goggles I think any loss of vision would soon be a major concern, to say the very least.

The model is on 35 MHz and the only other caveat here is that it’s now quite an old system, one of the early ones. It’s possible they are now better in this respect, and certainly a 5.8 GHz system would eliminate any problems in one move anyway. Maybe we shall get around to fixing a buddy system for the 35 MHz tx and then we can have a go at controlling the model. Although it seems that after some initial interest most folks are not really always that keen to play with it.

Like many other things, it probably either grabs you, or it doesn’t!

PB