FPV

= Introduction =

FPV is a new way of flying RC planes via watching onboard footage. It seems to have a large interest these days so perhaps it needs its own section in our workshop.

Over the last few days there has been an increase of discussion about the legality of FPV and flying via FPV and what the rules and laws are around this. So we will be adding an additional section to cover this.

Please feel free to contribute your knowledge to this topic.

= Legality of FPV in NZ =

What should I do?
The question about the legality of flying FPV get asked often. It is not an easy topic to answer as there is nothing saying you can't fly FPV or that you can fly it.

The MFNZ is the only organisation that the CAA will recognise. As such they provide key feedback into the discussions with the CAA around these things. They have been discussing the FPV/UAV topic with the CAA for a while now and this will not change to quickly unless someone does something stupid like flying into a full size plane etc.

As such there are some basic common sense things to do.

1) Do not fly above 400 foot AGL (Above Ground Level).

2) Do not fly within 4km of a airfield/aerodrome.

These are the laws and you will be asking for trouble if you break ether of them.

Next are common sense guidelines.

1) Fly within line of sight.

2) Fly with a spotter to keep an eye out for other air traffic.

Basically the same things you would do with a normal RC flight.

It is highly recommended especially if you are new to flying FPV to do this with a buddy box setup so that if you get disoriented you have someone that can take control of the model.

NZ Frequency
So far what from what I can determine the most common setup is flying on the old FM setup of 35 Mhz with the video set up on 2.4 Ghz. This give you the best range however it is not without its problems. Most people these days have already invested 2.4 Ghz radio gear and operating a 2.4 Ghz radio and a 2.4 Ghz radio transmitter tends to cause interference which is not good.

The answer to this seems to be to run 5.8Ghz Video gear. However your video range will drop.

Other options available include.

Flying on 433 Mhz (Ham licence needed)

Flying on old crystal frequencies; 72 Mhz, 35 Mhz etc. (you do run the risk of being shot down though)

Flying on 2.4 Ghz

Video on 900 Mhz (not in NZ as far as I know)

Video on 1.2 Ghz (only certain frequencies allowed and a Ham licence needed as this a part of the amateur video band. Also be aware of harmonics on the 2.4 Ghz band)

Video on 2.4 Ghz (not if you are flying using 2.4 Ghz)

Video on 5.8 Ghz

As a rule of thumb it is best to keep your control frequency lower then your video frequency (Trappy, 2011, FPVLabs), this way your are most likely to get video static long before you lose control. It's easier to turn around with a snowy picture than watching crystal clear video and having no control.

A good link to read is this one http://www.rsm.govt.nz/cms/policy-and-planning/current-projects/radiocommunications/review-of-spectrum-allocations-for-short-range-devices/an-engineering-discussion-paper-on-spectrum-allocations-for-short-range-devices/4-wireless-local-networks#42

= Equipment =

Kneedrag's proposed setup
I have purchased the following equipment however there are cheaper sources now for the same equipment. However the frequencies that this equipment uses are in the HAM bands. As such I have now written my HAM to be legal user of these frequencies.


 * 5.8 Ghz 200 mW Tx : http://www.fpvhobby.com/31-8ghz-500mw-a-v-transmitter.html
 * 5.8 Ghz Rx : http://www.fpvhobby.com/20-4-ghz-receiver-module.html

Antenna : http://www.fpvhobby.com/55-8-ghz-7-dbi-antenna.html

Cheap camera to start with : http://www.fpvhobby.com/48-3-5v-720x576-pixels-camera.html

Still looking for a LCD display however.

I eventually bought this display http://www.jaycar.co.nz/productView.asp?ID=QM3752 however it was pointed out to me after I bought this one that there is a cheaper option here http://www.dealextreme.com/details.dx/sku.23080

That should give me a basic setup.

Just purchased the poormans OSD read more about it here http://www.rcgroups.com/forums/showthread.php?t=921467 and purchase it here http://www.nghobbies.com/cart/index.php?main_page=product_info&cPath=130&products_id=456.

The intention is to later connect it to the following autopilot system http://diydrones.com/profiles/blogs/ardupilot-main-page

So now I just need to wait for all the bits to arrive.

Kneedrag's build thread
The first flight in the ASW28 have proved that the equipment works. Now the next challenge is building a suitable FPV ship.

With the ASW everything fits but the wing loading is reaching its limit. Also you don't get enough camera angle to view the ground so judging where you are becomes very interesting if you nose down to see you dive which on a glider is not always conducive to staying up in the air.

So the plan is to build a twins cargo plane this should give me all the room I need plus extra for extra camera kit etc.

The twins is an awesome FPV platform. It is proving quite a good plane stable and slow. However I will be installing a larger wing. (She is also doubling as my C130 testbed) to increase her lifting capability. She lifts well but sinks like a brick when full loaded.

Kneedrag's attempt at building diversity on a budget
I have this idea in my head which I am going to attempt. It may be a flop but I thought I would document it here from concept to completion. That way if it works others may make use of it. If not it will be archived away for others to learn from.

A future development that I do want to make is to make it track the plane with no feed from the plane using 3 rx's. However first up is to get the diversity working.

First of all I am running on 5.8Ghz in the HAM bands. There is no reason why this will not work in principal with other rx's.

First a bill of matarial I think I will need.

BOM
- The brains an audrino US$9.29

- Some switches to switch the video NZ$0.64

- Voltage regulators LM317

- Cap 407uF

- mix of resistors

- 5.8Ghz rx modules

= Useful links =


 * ArduPilot - Autopilot : http://www.rcgroups.com/forums/showthread.php?t=1234310
 * Remzibi OSD : http://www.rcgroups.com/forums/showthread.php?t=1102975
 * NZART : http://www.nzart.org.nz/
 * RSM : http://www.rsm.govt.nz/