Antenna to Extend Range on 3dr Telemetry

Archive
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Trying to extend the range on my 433mhz 3dr telemetry. Right now only getting 400-500m.

Looking for an improved ground antenna and managed to find two 433mhz RP-SMA antennas in the UK that seem suitable:

Antennas RPSMA Connectorized 1/4 Wave Whip 433MHz
uk.mouser.com/Search/ProductDeta … 2fFQ%3d%3d

Antennas 433MHz MHW Dipole RPSMA, 79’’ Cable
uk.mouser.com/Search/ProductDeta … ANtw%3d%3d

Welcome thoughts on which to go for or other alternatives.

Thanks.
Michael

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Hi Michael,

With 79 inches of cable there will be a dramatic signal loss mainly due to the low power output of the air radio, I went down a similar path not long ago and made a couple of errors which I may be able to stop you making the same ones.

One was that the SMA fitting on both the air and ground aerials had male centres, they have to be female to work with the 3DR radios.

I purchased a 9Db antennae with a similar length lead on it, where I live there is a highly experienced comms tech and he shortened the ariel cable to it’s minimum length of approx. 600mm, and put on the right SMA connector (female). The report he gave me was the antennae was good for about 4.5Db, he took 2.5 off the 9Db due to a lack of winding, and another 2Db for cable signal loss, which still gives a good improvement on the 3DR original ground station aerial. I have tested to a 1000 meters so far and I’m happy with that.

You can also have lossless cable fitted if you wish to pay the dollars, a path I might go down in the future.

Dave believed that there was no advantage going to a higher Db rating on the air radio due to the low (100mA) output.

Also Michael, good luck in trying to improve your coverage for 12 Quid, I spent AUD$120.00.

3

Genuine 3DR radios have an RP-SMA connector. SMA connectors are used by the the clones.

1 Like
4

A J-pole designed for 433 would have tremendous gain over the stock shorty antenna and would be good for the ground station antenna… http://www.hamuniverse.com/jpole.html…

Just plug in the frequency and all the dimensions are calculated…

Sandy

5

I use this calculator for my slim jims and J poles

m0ukd.com/Calculators/Slim_Jim/index.php

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Thanks for that Stefan, I wish I new that before I purchased the new aerial combo for my 3DR radios, one does pay for ones lack of knowledge.
Cheers

7

Thanks for the advice. J-Pole idea is super interesting. Sandyem16’s link has a link to a ready made Jpole.

amateurradiosupplies.com/Pro … 0&Click=74

According to the instructions, sounds like i need “50 Ohm Dummy Load”, “Coax” and a “SWR Meter or Antenna Analyzer” to get this working. Anything else i need to get this to work? Do the cables typically come with RF-SMA connectors?

I’m ok with RC aircraft…and my APM…but antenna technology is all new to me.

Thanks very much,
Michael

8

Just make a Moxon Rectangle. Much easier! Search for IBCrazy’s tutorial. You can make his Turnstile antenna for the plane, super easy build and works great for telemetry. Or buy it from ReadymadeRc.

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Looks like any discussion on antennas result in a lot of theory discussion and various DIY models proposed.
For people who don’t want to get into DIY and are just looking for standard antennas out of ebay/goodluckbuy/hobby king/etc and using the standard 3DR telemetry modules (which use RP-SMA antennas), what are the solutions to extend the range by just swapping antenna on the ground station module (and potentially on the multicopter/plane/copter itself) ?

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Get a 900 patch antenna on the ground station and you’ll be good for many miles. l-com.com/tabbeditem_mobi.aspx?id=20447

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There doesn’t seem to be much choice when it comes to 433mhz

12

The Moxon Rectangle sure seems like a potent and handy directional antenna solution. But the vertical radiation diagram looks much like a porcupine. Have you not experienced big fluctuations in the signal strength as the vehicle moves in and out of the spines of the vertical min/max?

moxonantennaproject.com/2E0RHM/2E0RHM.htm
(diagram at mid page)

/ Tom