My Concept for a Ground Station.

[TerrorTrooper]

I wasnt going to post this, but its been quiet here recently, so i thought id contribute.
Ive spent the last couple of months Trawling.. (No!! Not Trolling guys!!!  ;D ) here and on RCG.

Ive spoke to many members, even some here.

And with exception to a Radio TX (All the good 7+ Channel ones are no longer manufactured and as such, will have to take this one day to day until an opertunity presents itself.) Apart from that, ive pretty much decided what my Ground station is going to consist of.
Ive done a fair bit of research, and contacted many manufacturers and distributors for specs and dimensions ect.

And to be totally Honest...
Im looking forward to the ground station build more than the FPV platform build.
How weird is that???

Anyway, here it is as follows.
I would appreciate any tips that any of you guys would have as im close to the build stage, pretty soon i will be selling a lot of my paintball gear and ground RC gear to fund this.
I knocked up a quick diagram for you guys, its pretty close to scale with the alluminium box im using.



I will start at the top and work my way down.

Firstly, i plan to use 5mm Black opaque Perspex/acrylic as the mounting surfaces within this box, By my calculations, (as i know the dimensions for every proposed component now) i will have 14mm between the 2 surfaces when the box is closed.

The box i will be using will have internal dimensions of 490mm x 340mm x 105mm whitch gives it a slightly lower profile than the average B&Q jobby (whitch will be problematic), but i have used them for years to keep my paintball pyrotechnics in them as they are far sturdier.
Here is a simmilar one. http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=130413359566&ssPageName=STRK:MEWNX:IT

I will have 2 Recievers from Simons wonderfull shop mounted in the lid, As these recievers have the bussiness end on one side, they will be mounted level to the edge with appropriate holes cut. one will have a 2.5 or 3 dbi rubber ducky on it, the other will have an SMA for an 8dbi Circular patch. (or a 14dbi Circular if i can source one.)
The one for the patch will also have power outputs for a Tracking system if i ever upgrade to that using a
Hobbyking 5V/6V UBEC set to 6V http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=3735

I will have a 10.4" TFT TV as a primary display. Namely this one.
http://www.onvon.com/104-inch-tft-lcd-tv-p-1402.html
whitch after several un-successful attempts to get any technical specs from On-Von, i fraudulently used a letterhead and advertising mail template from a company i used to work for that sourced such equipment and pretended i needed a supplier, after that they gave me all the specs i needed!! even pics! the unit is only 33mm from front casing to rear so gives me 4mm ventilation for my proposed installation. Also, it has a 5mm lip around it if you look closely, making it ideal to mount in my perspex. (It will bluescreen, and i will never use it really, its more for coolness and bragging rights as this groundstation build will be my pride and joy..)

I also plan to mount 4x 12V 40mm fans in it, 2 in the lid, 2 in the base.

I will use a rubber cable tidy like you get inbetween Car Doors and the chassis to link the lid and base electronics together.

The JXD 990 will be the only piece that is purely free standing and moveable. and will basicly sit there, prehaps on Velcro.
Although its not a great recorder, and has a poor bitrate, its still an awesome bit of kit for not a lot of money, and will at least be functional until i can afford something better.
(For those of you that dont know my circumstances, i am a plumber of 5 years, but recently became a fully qualified gas engineer, Spent the last 8 months doing voluntary, unpaid work in the gas industry while doing my gas qualifications, whitch i paid for myself, between them and the voluntary work, i nigh on bankrupt myself. and owe thousands. So my budget depends on what i sell.)

All my switches will be these. (Red for the main, Green for all the component switches.)
http://www.maplin.co.uk/Module.aspx?ModuleNo=218983&OrderCode=N33FB#helpfaq
at 1.2w a throw with 10A capacity, the extra ground cable makes them well worth a punt i think.

Next to the primary power switch, i will have this lovely blue backlit DC Voltmeter.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=150469788143&ssPageName=STRK:MEWAX:IT
Although its not a true LiPo monitor, ive worked with them long enough to know when they are getting low.
As for cell voltage, i will leave that to my charger to pre-empt any problems.

I will be using an Oracle Diversity from Simons FPVUK as i personally prefer visual preferance over RF stregnth preferance offered by cheaper modules. There are 2 outputs from this Diversity coder.
First will be going to my primary out to my video goggles, 2nd will be going to a four way splitter.

I have a 4 Fuse car Spade-type suse box whitch has a cover flap designed for surface mounting, fuse 1 will be the primary supply from the Bas-bars i will use for Positive and ground, 2,3 & 4 will be for other things, like the UBEC's i will need and the external 12V out whitch i will elaborate on later. Will calculate neccesary loads as needed.

I will have a 12V Video Splitter like This.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=360284376987&ssPageName=STRK:MEWAX:IT
This will be on the 2nd Diversity output.
Output 1 will go to the JXD990..
Output 2 Will go to a surface mounted phono socket for perhaps, passenger goggles.
Output 3 will go to another phono socket, Perhaps for second Recording device. (Future DV cam?.)
Output 4 will go to the 10.4" TFT Screen.
The gain adjusters will be visable from the surface as appropriate hole will be cut in perspex.

I will also have a 4 Way audio splitter such as this.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=220465156813&ssPageName=STRK:MEWAX:IT
Although i realise this is overkill, as split audios arn't as neccesary as split video outputs, id like the option, as the knobs are 8mm high, they will only protrude 3mm above the surface of the perspex once mounted under a suitable hole.
(This would be redundant with FPVUK Recievers as, although the Video TX's are capable of multi channel, the RX's only have one audio channel, so if i get a tracker, i lose audio.) But like most things in life, its the thought that counts.

**In all likelyhood, all Audio inputs ie. red and white phono's, will be bridged to allow L & R outputs as signal will be mono as FPVUK RX's are mono anyway**

I will also have a set of surfave mounted Phono's for Video/Audio input whitch will tee in on a standard Y splitter just after the 2nd diversity output to the amplified splitters so any external source can be displayed on the screen ect..
(i dont think this will affect the diversity output as its only likely to be used when the diversity is off..)

I will also have 2x USB 5V outputs below the primary Vid/Audio output for my goggles to power mine, and spectator goggles at 5V, again using the Hobby King UBEC's

I will also have a pair of 12V Female 4mm Bananna sockets on the far right of the case to feed my Imax B6 Charger to charge the likes of flightpacks. This will certainly be fused on the above mentioned box, perhaps at 5A

I will have a 3x5 Arangement for the illuminated switches for all functions. Meaning 15 switches.
A rough idea will be this.
(Admitedly, i could tie several into one switch, but i like the idea of contolling every component of my groundstation individually.)

I plan to use 12AWG Wire for the whole shebang, the ground will be a comon ring-main style return to the ground bus bar to save over complication, but the positives will likely be individual.

Main power switch      =   Red.

Receiver 01                  =    Green.
Receiver 02                  =    Green.
Diversity                      =    Green.
Monitor                        =    Green.
Recorder (Main)           =    Green.
Recorder (Back-up)      =    Green. (future planning)
Voltmeter                     =    Green.
Video Splitter               =    Green.
Audio Splitter               =    Green.
Cooling System (4x Fans) =    Green.
Back Lighting               =    Green.
External 12V  (Charger) =    Green.
External   5V (USB)     =    Green.
External 6V (Tracker)  =    Green.
Unused for now.         =    Green.

The system will be powered by either 2 or 3 20C 5000MAH Turnigy Hard cased 3S Lipo's.

Please bear in mind im a noob...
So i want honest oppinions.
I know a fair portion of my Ground Station is un-neccesary, but i want it to be my showpiece.

Thanks for taking the time to read this guys!!!!

Iain.

[Devonian]

Phew!

One thing I don't see is a 12v to 5v converter or BEC to obtain the 5v/USB power?

I used a 6A BEC - but found it was 'noisy' and added a homebrew LC filter to clean up the 5v line.

Nigel.

[Coyote]

Look the part Iain, i know what you mean by some un-neccesary parts but looking great :)

Looks pretty well thought out. The video feeds to split do need a splitter but audio really doesnt need a splitter as it doesnt degrade like video does.

As you have said you prefer the picture to switch on quality by the oracle diversity, but bear in mind if you want to incorperate the EZTracker then RSSI switching would have more benifits as the EZTracker relies on the quality of the audio not the picture to guide the antenna.

If i were you id not use the JDX990 its a bit better than the JDX318 but quality of recording still issnt brilliant so i`d spend a bit more on a better recorder if possible.

Also the bannana plugs for the charger, if your running say 3x 2200 mah 3s lipos for example even on 1C charge thats 6000mah of charge current which most charger cant output. With them being paralleled up also that might complicate the charging too especially if your charger uses the balance plugs off the lipos.

Apart from that it looks a cracker :)

[foamystuff]

I'm doing somthing similar Iain, even bought one of those blue LCD voltmeters too, so I can monitor the 12v battery that powers everything. Not that I've ever managed to run mine down, but its better to be safe than sorry..

[TerrorTrooper]

Thanks for the Comments and tips guys!  :)

one or two questions however.

Nigel.
i am planning to use the hobbyking 5v/6v UBEC's for 5v/6v lines.
What do you mean by noise?
What is it likely to affect on the base station?
(For example, say the JXD990 was on one, would it be affected by such noise? or is it something else?)
Also, is there anywhere you can buy filters as im not too sure how to make them.

Ian.
i would have thought that with something like an EZTracker would only be on the patch side, as such i would assume it would be upstream of the reciever, inbetween the patch and reciever, as such i wouldnt have thought a video diversity would affect it as the patch would keep tracking regardless of whitch feed was going to the oracle.
I guess im going wrong somewhere, im still a bit unsure of how it works.
Any tips there would be appreciated, although a tracker is a long way off, dont intend to get one for a good while.

As for the JXD990, main reason i will be using it is i can get one really dirt cheap, so in effect, it saves me buying a recorder in my initial set up. I can then save for a better quality one after im up and running while still maintaining something "semi functional" in the meantime.

On the charger that i will plug into the bannana plugs, i am not intending to do any series or parallel pack charging, just a simple single 3S pack 2200mah or so, although if the charger tried to pull more than 12V i can see that being a problem.
Perhaps some more thought on this part is required.

Thanks again guys!

[Coyote]

Ian.
i would have thought that with something like an EZTracker would only be on the patch side, as such i would assume it would be upstream of the reciever, inbetween the patch and reciever

No the EZTracker monitors the audio from the output of the reciever to get the telemetry data

as such i wouldnt have thought a video diversity would affect it as the patch would keep tracking regardless of whitch feed was going to the oracle.

Yes if it were monitoring the patch only then you could hook it up to the patch and be fine.

You cant have both audio channels from different recievers both going to the EZTracker at the same time though. Both signals would be out of sync to each other. Where as on a diversity switch the two are seperated and switched between best quality.

On the charger that i will plug into the bannana plugs, i am not intending to do any series or parallel pack charging, just a simple single 3S pack 2200mah or so, although if the charger tried to pull more than 12V i can see that being a problem.
Perhaps some more thought on this part is required.

Cool, its just i went off the diagram and it shows three in parallel

[Coyote]

This made my think last night Iain.

See i got thinking about which antena would pick up in which situation. Myself i use an omni as the secondary antenna. The idea behing the concept was that at close range or going behind the antenna at close range the omin would come into effect if needed.

But as im on a tracker also, and the 8dbi patch i use is also capable of picking up behind it almost as effectivly as the omni and its tracking all the time, what real advantage do i have from running the omni ?

The Patch is always going to be the antenna thats getting the best signal. So unless i use a yagi or a linear patch or two on diversity the diversity itself will probably be redundant.

The only use of the omni itself would be on a manual switch when i want to fly close range with no tracking effectivly.

Thats my theory anyway, but as i said, its made me think :)

[Devonian]

Nigel.
i am planning to use the hobbyking 5v/6v UBEC's for 5v/6v lines.
What do you mean by noise?
What is it likely to affect on the base station?
(For example, say the JXD990 was on one, would it be affected by such noise? or is it something else?)
Also, is there anywhere you can buy filters as im not too sure how to make them.

By 'noise' I mean the DC voltage from a lot of BEC is not very DC !
The DC has a lot of 'ripple' or voltage spikes on it caused by the switching electronics in the BEC.

Have a look here (especially post #13 and #14 for an LC schematic)
http://www.rcgroups.com/forums/showthread.php?t=1055252

On my homebrew 5.8 setup, it was very obvious in the received video (herringbone effect) - it was on the recorded video, in the goggles and the LCD screen I had connected at the time.
Homebrewed 5.8GHz FPV rig - First light.

Cured with a homebrewed LC filter on the positive DC output of the BEC
5.8GHz with improved video

It was not a cheapy BEC as it was supposed to be 'clean' - it was this one
http://www.giantcod.co.uk/hobbywing-575a-ubec-lipoly-p-402620.html

Not sure where to buy a ready made one, I almost always make my own kit where possible.

Nigel.

[TerrorTrooper]

Wow! There really is a remarkable difference there Nigel, I will have to see if i can knock a couple of them up for anything connected to a monitor or 5V line like a recorder!

Ian, your right there, Assuming a tracker was doing its job, the Omni would be pretty much completely redundant.
And the oracle will almost never switch to the omni.
As the 8dbi patch has enough pick up behind it to make it useable, perhaps you could use the 8dbi as an Omni with a directional bonus so to speak, and look at something like a 14dbi circular on the tracker.
Certainly food for thought there..

I see what you mean about the charger also, thats my bad, i wasnt clear on my diagram or description.
We got our wires crossed. (I appoligise, i couldnt let that pun go unspoken.  ;D  )
I plan to power the Station with 2 or 3 5000 Mah 3S 20C Turnigy Lipos as shown in the diagram.
The bananna sockets will be on the external of the case, but rather than being a chargeing port for the GS, they will power my Imax B6 to charge smaller flightpacks externally.

[Coyote]

This is a recording of the JDX 990 from an FPV flight :

badsound.mov

Ok the audio was fixed, but just look at the picture quality, same as what im getting, cant be worth wasting the money on. I learnt that from the JDX318

[TerrorTrooper]

Im getting it for a fiver.  :P

I do intend to get something better, But to start off, it saves me finding an extra £100+ whitch i dont have at the moment.

[Coyote]

Oh well for a fiver go for it, ive strapped mine to my Futaba now as a backup screen, the picture quality on screen is great so its not getting binned :)