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Old Aug 27, 2008, 03:05 AM
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Danmark, Hovedstaden, Ballerup
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>Thomas didn't I read where you could adjust the power
> on the booster simply by adjusting the input voltage
>or is there another way to do it?

the most efficient way is to lower the supply voltage, but also kinda nasty with switches and different cells.

it is also possible to add an input attenuator (uha expensive)

or open the booster and lower the bias, a simple 1k lineary potentiometer
will be fine, the bias draw almost no current, you see on the booster page a zener and a 1k2 that makes the 3.3V bias, if this voltage is lowered the gain drops and the output drops too, if no bias voltage the booster is compleetly off, you have a wattmeter ? so you are welcome to experiment with this, just be sure newer to bias it over 3.3V

>do you have the filter on the transmitter as well like you do on the receiver?
>The one that blocks 2.4ghz and also some on 900mhz?

the filter on the RX input is a 4 pole bandpass filter, so it will block all frequencies we dont like, the closer to 410-450 you get, the lower attenuation you get.
the filter attenuate 35dB at 2.4GHz
but only 14dB at 910MHz (I just checked my curves :-)
the LNA amplifier I use is not good at 2.4, but still useable at 910MHz
so I suggest you perform carefull range checks with video tx on/off
to prove if any range change, more distance and different antenna polarisation will help alot if any problems are found.

on the TX side I have a lowpass filter that will make 410-450 pass with as low loss as possible 0.3dB in the booster, and 0.2dB in the 500mW.
and then I try to attenuate as much as possible at the 1st harmonic,
but you see on the curve it is -31dbc, at 7W carrier +38dBm you have 7dBm left = 5mW, ok it is under legal limits, but strong enought to jamm if you have done some really bad frequency planning and try to use a frequency that is 1/2 of your video 900MHz (or 1/5 if using 2400) simply do the math and stay at least 20MHz away and you should be fine, and also locate the booster 5-10Meters away from video receivers, and if possible use different polarisation as I have explained before.

I think ham radioes have a demand that 1st harmonic must be at least -30dbc ??
you can see this figure in your ham radio manual, then you see your test frequency 450MHz x 2 = 900MHz about 10MHz away from your wanted RX, and your IF filter is 5MHz wide x 2 = 10mhz so that is why you are jammed there, I expect any multiplum of about 5.5MHz away you will experiance jamms :-) so this is quite normal when a TX and RX are located near each other, the trick is to select the right frequencys to use,
you can change this with a serial link, I can supply you one, so you can change frequency bands as you like :-)
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Old Aug 27, 2008, 03:26 PM
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Carlyle : (you got mail ! )
just came home after visiting a club member that own a Futaba T9ZHP
and I can inform you it is 100% compatible, no problems at all.
I have also updated my web page with all the so far tested and verified RC systems,
more will follow as soon as the JR owners write the type and version number they want me to get access to and test.
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Old Aug 28, 2008, 06:27 AM
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please check you emails ! alot of parcels have left my location today !
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Old Aug 28, 2008, 06:31 PM
Torin Segstro
Alberta, Canada
Joined Apr 2008
99 Posts
Test DX7

I would like to know if the Spektrum DX7 2.4ghz transmitter works with your system if possible. I'm not sure how popular 2.4ghz is around your area.

Thanks!

Dutchboy


Quote:
Originally Posted by thomasscherrer
Carlyle : (you got mail ! )
just came home after visiting a club member that own a Futaba T9ZHP
and I can inform you it is 100% compatible, no problems at all.
I have also updated my web page with all the so far tested and verified RC systems,
more will follow as soon as the JR owners write the type and version number they want me to get access to and test.
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Old Aug 29, 2008, 02:00 AM
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the DX7 it is verry popular here, so it will be easy for me to get access to one !
I will be back with compatible info :-)
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Old Aug 29, 2008, 10:01 AM
Torin Segstro
Alberta, Canada
Joined Apr 2008
99 Posts
Thanks Thomas!



Quote:
Originally Posted by thomasscherrer
the DX7 it is verry popular here, so it will be easy for me to get access to one !
I will be back with compatible info :-)
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Old Aug 29, 2008, 01:38 PM
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Denmark
Joined Jan 2007
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Quote:
Originally Posted by thomasscherrer
thanks for the information, think about placing both antennas in a link using same polarisation, like if your wire antennas for the RC are both horizontal in the plane, your TX antenna should also be horizontal, the end of the tx antenna should point 90 deg to plane.
your video tx antenna in plane should point up or down, and your ground receiver beam should also point up/down, now you will gain 26dB on both links !!
and you have minimized the interferience (if any) from the two systems by a factor of 26db too !
15 KM beaten

More info soon..

Best Regards
Loopforever
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Old Aug 29, 2008, 01:48 PM
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ok cool, congratilations ! I look forward to send your price.
you got the last one you won I assume ?
please send the video link and pictures and so on like last time.
you did place your transmitter and receivers at launch site ? (no cheating:-)
tech info you can place here, other people might like to know what kinds of tricks you have used if any.
15km distance = 30km total flown (atleast) with a small electric plane that is really good !
you next challange will be battery power I guess ?
how much battery power was left in your pack ?
there is another price ready for the 20km record and so on !
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Old Aug 29, 2008, 01:51 PM
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Quebec, Canada
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not fair you should have waited for more people to have your system to launch your contest thomas has my futaba connector shown up yet ? cant wait to get my system !
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Old Aug 29, 2008, 01:53 PM
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tychoc's Avatar
Austin, TX
Joined Feb 2006
1,153 Posts
Quote:
Originally Posted by pratorian
not fair you should have waited for more people to have your system to launch your contest thomas has my futaba connector shown up yet ? cant wait to get my system !
I'd better hurry up an get a system before we're up to 30km....

-tychoc
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Old Aug 29, 2008, 02:10 PM
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no I am sorry that inoring futaba connector you send to me,
must have been lost in space !
I have another stocked for you, so next week I expect to be able to ship to you Sebastian (another customer send me a cable and said I could keep one end)

still plenty of chances to break the record, so dont you worry :-)
you can setup your ground station on the top of a super tall house
and have a friend launch you plane on the ground near that house,
you can use beam antennas both for up and down link,
but we need to know exactly what you did and with what equipment,
I need to see prof, like a video of the WHOLE trip, OSD with distance readout might help, but is no demand, simply send google map screenshoots with added txt so I can follow your route and prove you did it.
you can use any plane size and powered with any technology possible for you.
solar powered might get you really far and back !

I think normal hobby size planes cant fly for many hrs, so the total distance will be limited to battery/fuel tank size and weight of it all.

I can reveal: two of my crasy and rich friends are now planning to construct a plane with engine and power reserve, that will be able to fly 50km and back, the rest is secret yet.
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Old Aug 29, 2008, 03:07 PM
Torin Segstro
Alberta, Canada
Joined Apr 2008
99 Posts
Thomas,

Just so you know, I am able to use the PPM output from the DX7 to control aerofly deluxe. I'm not sure if it stops transmitting, but I can check tonight when I get home from work.

Dutchboy



Quote:
Originally Posted by thomasscherrer
the DX7 it is verry popular here, so it will be easy for me to get access to one !
I will be back with compatible info :-)
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Old Aug 29, 2008, 04:29 PM
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Denmark
Joined Jan 2007
100 Posts
Quote:
Originally Posted by thomasscherrer
ok cool, congratilations ! I look forward to send your price.
you got the last one you won I assume ?
Actuelly got the new reciever today, thanks!

Quote:
Originally Posted by thomasscherrer
you did place your transmitter and receivers at launch site ? (no cheating:-)
Errr..noo..me..cheating??!!..found some 5KM cable i used..no just kidding
Started at launch site, finished at launch site - real stuff.

Quote:
Originally Posted by thomasscherrer
>you next challange will be battery power I guess ?
Unless i get a good thermal or something yes.

What i used is a simple small foam Easystar!, fitted with 2x2400mAh 3S batterys, that can get you 30KM, if you get a good brushless motor.
(Well 15KM as you have to get home again..)

Quote:
Originally Posted by thomasscherrer
how much battery power was left in your pack ?
Used only about maybe half of the battery power, as a big thermal got me home with no power, lucky me
The trip where about 40mins, never used more than half power.

Yes, solar power can get you REALLY long!
Look at this:
http://www.qinetiq.com/home/newsroom...ephyr_uav.html

This time i have placed the TX antenne in 3.5M height - horizontally,
also fitted 2 new RX antenners with a ground wire folded back, both placed horizontally 90 degrees. Range testing without 500mW TX(NOT the 7W!!), showed some extra range with the new RX antennes.

Absolute no problems or even a small glitch with UHF system.

Video TX(whip) and RX(Yagi) antenne where both pointed upwards(vertical).

I pointed my video receiver 2.4GHz Yagi antenne too high on some of the trip,
could not understand why the picture where more noisy than last.
What i found out is that the yagi antenna got some "spot points" where is will receive better. What i mean is that moving the yagi around a little maked the signal go nearly away because i where in the wrong "spot point", but i have to move it to a whole diffent lower "spot point" to get perfect signal!

Did not use OSD, just a camera and some good ground references.
If not trained in ground spots navigation, its alot more easy to get home using a OSD if you loosing orientation - actuelly always easier..
But just sold mine OSD's(And lost another on a plane, while flying with a bad gain video antenne and murphys law came real..)

Quote:
Originally Posted by thomasscherrer
that will be able to fly 50km and.
Nice, a must have for a long range FPV


Best Regards
Loopforever
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Old Aug 29, 2008, 04:42 PM
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>Absolute no problems or even a small glitch with UHF system.

great, I am happy to hear that.
with your latest setup, it could be interesting to find out what range you have without the booster, we know the booster give you at least x 3 range
then maybe we can caluculate the max range in your area, using the 3.5m height and horizontal positions. I am happy my advice about polarizations worked, I have tried many times something similar when DX'ing on VHF and UHF bands, polarizations is important !

>Used only about half of the battery power, as a big thermal got me home with no power, lucky me

exactly ! so now you are stuck, if you want to brake your 15km LOS distance record,
then the next is 20 x 2 = 40km total distance ! that is 10km more, quite alot !
you MUST get termal at least some of the way otherwise you will use all the power and maybe loose another plane, if you can not get all the way back home.
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Old Aug 29, 2008, 11:13 PM
Torin Segstro
Alberta, Canada
Joined Apr 2008
99 Posts
Loopforever, do you have any of your record breaking video's posted on Vimeo or online someplace else? I would love to see these!
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