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Old Jan 22, 2016, 06:04 AM
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Question
Frsky d4r-ii antenna shortening length for small quad?

I know that the dual antenna's are around 15cm long and that the only thing that matters is the last 31mm of inner cable length, with that in mind would it be ok to reduce the overall length of the dual antenna's to around 50mm with the said 31mm exposed and the last say 19mm the shielded bit?
I am building a small quad and it will be for park flying only (line of sight) so how will the overall range be affected by reducing the length down to 50mm overall?

Many thanks for any and all replies.

Rct
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Old Jan 22, 2016, 06:12 AM
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As long as the exposed end is the same length it should work, the shielded bit is just an extension lead. I have done something similar with a different brand of radio and it worked fine.

Range may be affected by the ability of the shortened aerials to maintain "line of sight" to the Tx, but probably won't be a problem for park flying. Just do a proper range check turning the quad at all angles to see if the signal drops.

Dick
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Old Jan 22, 2016, 06:48 AM
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Quote:
Originally Posted by dickw View Post
As long as the exposed end is the same length it should work, the shielded bit is just an extension lead. I have done something similar with a different brand of radio and it worked fine.

Range may be affected by the ability of the shortened aerials to maintain "line of sight" to the Tx, but probably won't be a problem for park flying. Just do a proper range check turning the quad at all angles to see if the signal drops.

Dick
Many thanks for the reply, I have managed to find one of my old Frsky 4ch receivers and that has a small single antenna at a length of 31mm ish and that used to work fine for my flying wings when I was park flying them so I need not worry to much me thinks.

Rct
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Old Jan 23, 2016, 05:34 AM
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The range will be affected for sure, but not in close proximity.
The antennas are 15 cm with a reason... theory say that the wave guide (cable) should be at least one wave length, which for 2.4G is 12.5 cm.
Add the 31 mm the length of antenna tip and you have the 15.6cm of the commercial antennas

The older Frsky receiver, with pigtail antenna, is rated for indoor usage, 2-300m range just for this reason
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Old Jan 30, 2016, 02:21 PM
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Quote:
Originally Posted by renatoa View Post
The range will be affected for sure, but not in close proximity.
The antennas are 15 cm with a reason... theory say that the wave guide (cable) should be at least one wave length, which for 2.4G is 12.5 cm.
Add the 31 mm the length of antenna tip and you have the 15.6cm of the commercial antennas

The older Frsky receiver, with pigtail antenna, is rated for indoor usage, 2-300m range just for this reason
Many thanks for this info as the quad is only going to be a small 230mm size I think I can get away with shortening the aerial lengths to aroun 50mm with 31mm exposed.
Rct
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Old Feb 07, 2016, 11:37 AM
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Why not route the wires on two arms, bend at the end with a generous curve, radius under 1 inch is not allowed for GHz cables bending and let the tip handing pointing to the ground ?
This would be the best reception, if you fly the platform higher than radio level.
Things change if you intend to fly at grass level.
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