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Quote:
I assume something similar is happening with the 9Z Those levels are too low for using certain modules as 868mhz, etc, not to flight with usual r/c gear. |
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thanks alot, that PPM looks just fine,
are you sure it uses a fixed repeat time ? ok that repeat time will change if you change the number of channels :-) but try to move the sticks and see if the repeat time is constant. videos ? someone requested a clip, now look at the bottom of the page: http://www.webx.dk/rc/uhf-link3/uhf-link3.htm comments welcome as always. |
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the PPM pulse train varies in time when you move the sticks,
but the repeat time is constant, right ? please check ? that is normal on digital radios and a MUST to be able to use this system ! range, well it is not legal in my area to fly far far away, I spend most of my time developing and soldering, not flying (sorry) and only a few customers so far, but one had 5km, then video range problems, but still fine RC, if I calculate the line of sight range even at 500mW it gives me 100km, but those calculations think we have 100% no noise on the band, and a perfect line of sight, that is not possible in the real world :-) so in real life I think the 500mW standard version will give you 5-10km depending on installation and antennas, good/bad antenna used on the TX side, can halve or double the 5-10km range. the default standard TX antenna supplied is considered to be cheap and easy to get and small fit into parcel, but bad when it come to range, if you need over 5km range I suggest using better TX side antenna or simply use the booster option. the 7W booster option will x3 the range you had before if nothing else is changed. if you need over 5km range you have to do something special about the Video link and antennas used to get good stable and noise free pictures. |
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also added this:
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North vancouver, B.C. Canada
Joined Apr 2008
16,064 Posts
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Thomass you are a guru
I started looking for systems not too long ago and one thing told to me was, take my time, look around! One day too late for me, wish i bought yours instead I also love reading your posts very smart Thomass very smart |
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Sorry about that david, one day too slow :-) sell it used, and puchase a new ?
range cheat: if you locate the RC uplink (you) say 5km from plane take off site, then fly AWAY from your own location, that could be a good way to achive 10km distance and only use battery power for 5km. but if you fly towards yourself the first 5km is wasted battery, it is the RC RADIO range we want to see, not the plane flyning time and distance of only the plane, if that was the case simply take an open car, sit there and RC your plane while a helper drives the car, then you see how far the plane can go. |
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this makes no sense cause there are no video TX/RX to match UHF range.
esp. since 900MHz video probably won't work also powerful 2.4ghz video may drive your RX crazy unless you redesign RF section into metal can(shield). 2.4ghz mean 28mm 1/4 wavelength that can find same length PCB trace to resonate. |
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>this makes no sense cause there are no video TX/RX to match UHF range.
exactly that is why it is so perfect to use this band for long range RC systems, it is also a normal known fact: the lower frequency the longer range, so why dont we have good range on 35Mhz ? the frequency is soo low ! that is why we use 1/8 wave length antennas they are unefficient and we use really low power and at the same time most receivers dont have good sencitivity. >esp. since 900MHz video probably won't work why not ? 900MHz video is known to jamm GPS receivers, so that is bad too, and 900MHz video wont work with 868Mhz based RC systems too, frequency simply too close. >also powerful 2.4ghz video may drive your RX crazy unless you redesign RF >section into metal can(shield). 2.4ghz mean 28mm 1/4 wavelength that can >find same length PCB trace to resonate. the rf secrion of the receiver is specially designed to handle 2.4GHz video transmitters near by, no customers have been able to indicate any range loss due to video TX at 2.4, the boards them self are actually quite well shilded, removing the antennas the range is only a few meters this indicates also traces and components dont pick up radio signals well, that is quite amazing when the receiver have a -110dBm sensitivity, adding a shield case in this design is waste of cost and weight. |
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