wildblueyawner

Hi all,

Anyone know of a system where GPS location can be transmitted wirelessly to a PC-based topo map?

I'd like to put such a device in a giant-scale glider, in order to know its location when ranging out to distant slopes in a mountainous area where it's difficult to judge distance to the plane relative to the terrain far below.

Any help / links appreciated!

Ladyflyer

My Feedback: (2)

Yup,
Amateur radio operators do it . A GPS receiver is linked to a transmitter and the data is decoded by a PC and receiver at the other end.
If you are not an Amateur Radio OP you may have to use a transmitter on one of the license free bands,
I will try to find a website for you with more info.

Lynx

You're going to pay WAY WAY too much money for a commercial product, I know I've looked. This can't be done very easily with commercial equipment because FRS radio would have to be rigged to transmit continuously and this usually fries them in a hurry, they're not designed for 100% duty cycle. If you want a reliable link you're going to have to dive into the deep end of electronics, or find someone that can build it for you for a decent price

Ladyflyer

My Feedback: (2)

There are some low power transmitters made for video on the 900 MHZ band that operate 100% duty cycle without a problem .

I have been running one for over 2 years without a snag.

Lynx

The range on those things is pathetic.

Whirley Bird

My Feedback: (1)

I have to agree with The LadyFlyer.
I had a GPS setup going for over 2 years and no problems at all.
Also the FRS radios will run 100 duty cycle.
The final amp is built inside the thin poly antenna and that never even gets warm and I have the 2 watt version

Ladyflyer

My Feedback: (2)

It depends on WHICH one you use ,the antenna system and the RECEIVER .
We get EXCELLENT range and SOLID links.

wildblueyawner

Ladyflyer, Whirley - Did your systems display lat/lon coord's or a moving dot on a map? Although I'd prefer the latter, a display of simple lat/lon coord's is good enough. On that note, can you provide any hardware details, incl. brands & p/n's, or were your systems custom-built?

Some products I've seen on the net look like they'd do the trick, especially the stuff from http://www.u-nav.com Also, some higher-end systems that might find r/c model or UAV application from http://www.vetrak.com./

Ladyflyer

My Feedback: (2)

I haven't used the remote GPS myself. I know there is software for both options.
The application I referred to at 900 MHz was a remote video / audio link .

Hope this helps.

Whirley Bird

My Feedback: (1)

wildblueyawner
The setup I had just showed the dot.
But I didn't have the system I thought you thought I had.
The way my setup worked was when I transmitted the person at home had the topo map software in his laptop for the geographical area I was in.
He saw NOTHING intil I transmitted then a dot would show him on the screen where I was located. We live in a push button world today but I still track out with a compass and a topo map.
I never did get involved with the video part and don't intend to because I use my setup for land navigation instruction only, then resort to map and compass.
Your going with RC control and it's an area that I really have no real knowledge of.
Someone here must be much more qualified to answer the questions you have related to GPS/RC/Video

wildblueyawner

Based on that, I presume that whatever you were equipped with would be too large or heavy for installation into an r/c plane? (keeping in mind that I'd be installing this stuff into a giant-scale glider).

Whirley Bird

My Feedback: (1)

.
Well i'm a ham radio OP so I had a small 440 mhz HT that gave me 5 watts out.
Not that much weight at all but if you put it in the plane who's going to key up the TX?
The plane will not carry that much weight.
Most of the heavy stuff in on the receiving end on the ground.If you can be a bit more Specific then maybe I can help you out.
As I see it now you want to track the plane from the ground when it's out of sight

wildblueyawner

Can't the tx be left on all the time? Close - I want to be able to track the glider even when it's visible, in order to know when it's flying above certain sloped topography or ridges where lift may be present. That would be possible if I knew the plane's GPS coord's or, ideally, able to see it as a real-time moving dot on a topo map.

To put this in perspective, this glider (currently in process) is rather large ==> either 8 or 9 METERS wingspan, so it will be visible from a great distance. What is difficult, given the scale of the surrounding mountain topography, is judging how far the plane is (horizontal distance) relative to features on the ground far below it (which, in this case, can easily be a thousand feet down). In other words, "what terrain is the plane flying over right now?" Flying an r/c model amidst high mountains is one situation where a plane's distance away can be seriously overestimated, i.e. it's a lot farther to that ridge than it looks.

Whirley Bird

My Feedback: (1)

Yes,You can do that with no problem.Plus with the glider being up high your transmitter only needs to put out no more then 100 mils.
First are you a ham?
If not then what are you considering for transmitting?
You need a receiver that will be pick up the sig then that sig goes into a TMC box that will feed and deciper the carrier.
Other things you need to consider is to make sure the on board TX does not blanket out the RX so I would use something in the UHF range.
The FRS radio units will work and you can open them up and reduce some weight by just having the TX board exposed and a small switch to power it up.
I know a local ham who hits this RCU site when he feels like reading and this Guy has to be an experet in this area because thats all he does.
I'll try to get him on the repeater today.
Your not looking at much $$$ for what your doing.
I'll PM you later

wildblueyawner

Only at parties ehem, No. I haven't a clue, which is the basis for my inquiry - I don't even know where to start with this stuff, although I might be able to get going with some of the u-nav (link above) offerings. Thx for suggestion re rx interference and I do have an FRS set that I might be able to hack and work some magic.

JohnMac

This is an interesting question that you have raised. I do the same kind of cross country scale glider flying and we have often wished for such a system. However, in the UK it was illegal to transmit from an airborne object until,very recently.
A couple of alternative suggestions. I know that you can get relatively light small and low cost video systems that could give you a real-time picture of the terrain below. (or in front!)
The alternative route I have chosen is to fit a Variometer. It does not help you know your position over the ground but it tells you if you are in lift or sink which is what you really need to know, and your altitude, and your battery condition.
What it also taught me was that I am not as good a pilot as I thought. I was pretty sure that I could centre in a thermal accurately but the vario tells a different story! It makes you fly better.
Regards,

John.

Whirley Bird

My Feedback: (1)

I didn't forget you but never sent you a PM because the person i'm trying to contact was not around.
He just sold a full station last week on the local repeater for $250.00 but it was setup on the ham bands.
I should be able to contact him tonight and will PM you the info

rc bugman

My Feedback: (30)

You can solve your problem if you are a ham using a hand-held gps unit, video text overlay board, small camera and a ATV transmitter with 100 mw power on board the glider and receive the signal using a cable ready tv set (small battery powered Black/white works great).

The ATV transmitter can either be in the 420-440 mhz band, 900 band or the 2.4 gighz band. Source for both the txs and video overlay board is PC Electronics or Videolux . Cheap b/w cameras ($20) are available from super circuits (do a google search).

The small camera generates a video signal, the video overlay board overwrites the GPS information(gps coordinates, ground speed, altitude, zulu time) on the video picture and the ATV transmitter transmitts the signal. The best antenna on the glider is a simple dipole mounted vertically in the tail.

The cable ready tv receives on cable channel 58-60 depending on the frequency of the signal(420-440 mhz). The higher frequencies require a downconverter.

I hope this helps. I use this set up in many of my research planes.

Elson

Whirley Bird

My Feedback: (1)

The person who wants this setup is not a ham.
But I think he can use the FRS transmitter.
Where did you pick up a 2.4 GIG system?
At that frequency things get critical and the antenna is to short for a dipole configeration.
How about filling us out on the name and how you hooked into the GPS.
Also what GPS are you using?

rc bugman

My Feedback: (30)

All the equipment I use is off the shelf and runs at either 420-440 mhz or 910 mhz. It would be far easier to just study and become a ham at the tech level and then you can use all that neat off the shelf stuff.

I believed I had to study about a week to pass the test and I am a bug person, not an electronics buff.

Elson
K2BUG

Whirley Bird

My Feedback: (1)

The tech exam is very easy.
Thats all he really needs then he has it all with no problems.
My extra was 50 questions.
I think the tech is only 35.
I shot for the extra just so I could work the DX CW on lower part of the bands.
Really have no use for a MIC except when operating VHF & UHF

Neat call you have there.
AF2Q

Ladyflyer

My Feedback: (2)

We had a 5th grader pass the Extra class exam after studying 2 weeks cold turkey !
The new multiple guess questions are VERY easy to conquer .

Whirley Bird

My Feedback: (1)

Ladyflyer,
I think the tech is only 35 questions also and you only need a 76 to pass.
I think i'll send that person a PM and let him know he can take a practice test on QRZ.com

Ladyflyer

My Feedback: (2)

You bet ! It only takes a 75% to pass from what I recall.

As far as the written ,IF you really want to LEARN the material the ARRL has REAL study guides . Many (too many) just memorize the answers from the current question pool .

Lynx

Did that fifth grade pass the code exam? =) It's required on the Extra. Keep something in mind. The FCC is required by their own law to publicly make available the question pools for the tests. That means every question you could possibly face is available out there.