accipiterbadass

I recently bought a cheapy wireless cam and wondering if i could some how modify the antenna for better performance!
I know i could just get a better one. but its going to have to do for now. I'm only new and have seen people mentioning something about a patch antenna? please help.

yb2normal

Are you flying with the rx as high as you can get it?

The best results I have heard from folks is with the rx up on a tripod or pvc pole.

That is your best bet before messing with the antenna.

Regards,
Bill

Ursine

Here's what I put together. Get's pretty good results from my inexpensive setup. I'm saving my pennies for yb2normal's ready to fly systems.

yb2normal

That's exactly what I'm talking about!

Ursine, just sell that nice camcorder, you could buy 4 or 5 of my ready to fly systems

Ursine

no can do. I love my XL1s. I got it for work a few years ago (nice write-off). I've gotta have something to record those videos on.

Dave

Fubar-One

My Feedback: (1)

Yes, put it up on a pole as high as you can. Put it out in the open as much as you can also. Easiest thing to try. Also, with those Hongkong systems, you should remove the rx antenna while you tune it in to the tx. This eliminates those evil ghost signals you can pick up. Replace the rx antenna after you have it tuned.

accipiterbadass

Nice set up will try something similar, thanks for the idea! I now have to find a cheap enough cam corder do you have any suggestions?
Tried that and works well once again thanks for your tips
What does y2bnormal mean by ready to fly systems?

stevennh

A home-made patch antenna will help a bunch on drop-outs. I built one based on the "goof-proof-patch" instructions on the web (rc-cam). I just scaled the antenna up for operation on 1.2GHz rather than 2.4GHz. I ended up with about an 11" reflector. I built a PVC holder to mount the RX and antenna on. This greatly improved my signal by reducing drop-outs (multi-path). That being said, I think my new blackwidowAV 200mw 2.4GHz system will work much better and it will operate on legal frequencies (with a Ham license). I did not realize that the 1.2GHz systems did not operate with FCC approval in the US (wrong frequency, too much power).

Here is a comparison, the first video (crashes) was done with my normal whip antenna, the second video was done with the patch.

[link=http://s93421871.onlinehome.us/BadLandings.wmv]Standard Antenna (Bad Landings)[/link]
[link=http://s93421871.onlinehome.us/video.wmv]Patch Antenna (loops)[/link]

Steve

Nik

My Feedback: (12)

Wow!

accipiterbadass

do you have any pics of your antenna?

stevennh

No, but it is shown in the loops video in my above post (beginning of clip).

Steve

stevennh

Here are some pics...

I scaled up the GPP from www.rc-cam.com to match the frequency of my transmitter. I ended up scaling up the GPP by a factor of 2.618. I did not document my calculations, but this works fine with my hong kong rx. I used light gadge gavanized steel and wood spacers. It really made a big difference on drop-outs. Mine worked, but I make no guarantees! Since it ended up being kind of large (11.125" accross), I built a PVC stand for it.

accipiterbadass

would you be able to send some measurements?
what about the spacing between the two sheets have you increased that as well?
or everything by 2.618?

stevennh

The space between the sheets is not that critical from what I understand. I used about 1/4" (that was the height of the connector I used). I put a fe-male connector on the antenna and then used a male to male adapater to connect to the rx (rigid). I grabbed the templates on www.rc-cam.com and scaled them up to make templates to cut the metal.
I used 5 minute epoxy to glue it together after following the instructions on rc-cam...

Steve

IIVII

Thanx alot Steve

Sherak

accipiterbadass: I have one of those receivers for my DTR, I was also dissapointed when I first got it, what is it your trying to do exactly......... If you are using it with the 9v battery housing that comes with it this is a problem, if you use a 12v transformer with it instead of the battery you will increase the range 10 fold.... Just thought it was worth mentioning as there is no need to go the anntena extent if your only talking about increasing it from 10-20' to 100-150'

accipiterbadass

Trying to cut the drop outs down, better range. Do you mean the power to the receiver , at the moment it uses a 9v dc adapter 500mA . would i be able to use 12v? what would the max rating be, if you know?

mr.rc-cam

To use the GP Patch on 1.2Ghz, you would scale EVERYTHING, including the dielectric spacing, by 2.0 times larger.
For use on 900Mhz Rx, scale everything by 2.67 larger.

You need to know the exact operating freq of the system. For example, those low cost Hong Kong "1.2Ghz" systems are usually operating at 1.15Ghz. If that is the case, then scale by 2.08.

The scaling is simply 2400 MHz / YOUR OPERATING FREQ in MHz.

Sherak

Sorry, I dont know the figures I have just been experimenting with my rover, putting it in back yard and trying to control it from the front bedroom etc, initialy I used a 9v battery and you could not even recieve from the next room, so I then tried a 9v transformer and it improved performace but I still could not get a great distance through walls, so I uped and now use a 12v 1amp transformer and it is great , I have not yet checked the max distance but I can receive a good signal from about 40' through 3 brick walls on the upper floor of my house, this being the case with a clear line of sight I would expect upwards of 100'

Initialy I was little concerned as they are rated @ 9v but I dotn think there is any fine circuitry in there to blow, I just went for it cos if the 12v would have blow it I wouldnt have been using it anyway, there is little use for a Explorer cam which can only be used in the same room lol.. Anyho I was more than impressed with the results.

Dont mess with the actual cam though, there is a tiny CMOS in there which would quite easily blow if you increase the voltage above 9v so leave the cam as it is.

Hope this helps........

Fubar-One

My Feedback: (1)

I power those receivers at the field using the 12v tractor battery in my EP/Video box. This is a double decker wheeled plastic toolbox that carries the big battery, my video receivers, the BW TV, 12v battery chargers, a grip of cables, and various junk.
I am not sure what the max voltage in for those receivers is but I have opened one up and there is a voltage regulator built in.

accipiterbadass

I have a 12v 4amp adapter would i be able to use this? It would only be for at home but once i get out on the field I will have to purchase a batt of some sort. what is a car/trucks batt rating?

yb2normal

Test the voltage of your adapter. Many of them are unregulated and can put out substantially more than 12v when unloaded, or not loaded enough.

Regards,
Bill

Sherak

A car battery is 12v and does a good job of powering the Rx on the go, truck batteries are 24v so I wouldnt go powering up the Rx with that If you go to your local Halfords/Walmart you can pick up a car lighter socket and some 2 core cable and knock up a good powerfull car adapter for it. Any 12v adapter at home will do... I hav e considered trying a 15v transformer to see how this would increase but I think I would be pushing it a bit. yb2normal is right to be cautious but I wouldnt worry to much about it, any standard plug in transformer will be fine, the car battery is less acurate however I have never had a problem......

EDIT: BTW your 12v 4 amp transformer will be fine.

///samson

I LIKE MY HONG KONG 'HOBBY' CAMERA!

For what its worth and it's compact size, it's a fun camera to have. With a little TLC on making a 'better' antenna, the camera will work great for sh%ts and giggles.... This morning I mounted it on my suction tripod (shown below, but from inside the car) and filmed my journey to work. It worked out very well and I plan on using it for track events, scenic drives, and hazardous shots you wouldn't want to put a DV camera in. It might not be up to par with the $120 and over club of cameras, but for $30 it has a lot of bang for very little buck. I'll link some videos tonight.

XJet

You might want to be careful. I've got several of these receivers and some have a regulator, some don't.

The ones labeled 9V don't have a regulator, the ones labeled 12V do.

It's just a simple 3-terminal regulator but it drops the voltage down to 9V which indicates that running the unregulated unit on 12V may well be detrimental to its health.

I'd suggest that 9V is the optimum operating voltage for the unregulated units and that when you try to use a dry-cell battery, they perform very poorly because the heavy current drain drags the voltage down well below the 9V level.

The use of a good power source that will stay at 9V under load is essential for good results.