Does anyone know the length of the Futaba antenna and unshielded length for the 334SBS

dk10438

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Had a crash today and the Futaba 334 was partially sheared. I think I can salvage it but need to know th4e correct antenna length and how long the unshielded portion is. I looked at one of my 304 receivers and it was 20 cm with an unshielded portion of 2.9 cm.
When I look at the 334 it looks like it used to be 15 cm?? I'm assuming the unshielded length should be the same.
 

Dan B.

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They could be different anyway, even same receiver. Hold up what’s left of the antenna and shine a bright light through it. If you lost the “hard part” at the end you need a new receiver. Sorry, man.
 

dk10438

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They could be different anyway, even same receiver. Hold up what’s left of the antenna and shine a bright light through it. If you lost the “hard part” at the end you need a new receiver. Sorry, man.
i'm going to have to disagree.

the antennas connect to the receive via an IPEX connector or something like that. What's definitely important is the "unsheathed" part of the antenna and what may or may not be important is the total length of the antenna. Antennas are definitely replaceable but you just need to get the correct one.
 

Diem Turner

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i'm going to have to disagree.

the antennas connect to the receive via an IPEX connector or something like that. What's definitely important is the "unsheathed" part of the antenna and what may or may not be important is the total length of the antenna. Antennas are definitely replaceable but you just need to get the correct one.
I just measured mine. The tip is exactly 29mm. You should be fine by just uncorking the front until you can replace the antenna.

Here's a pack of 20 antennas. If you want less or a different length, this should get you pointed in the right direction.
https://amz.run/5tRR
1661536367698.png
 

Dan B.

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i'm going to have to disagree.

the antennas connect to the receive via an IPEX connector or something like that. What's definitely important is the "unsheathed" part of the antenna and what may or may not be important is the total length of the antenna. Antennas are definitely replaceable but you just need to get the correct one.
I stand corrected. I read (and believed) that specific receivers needed specific lengths and that was that if one became damaged.
I just measured mine. The tip is exactly 29mm. You should be fine by just uncorking the front until you can replace the antenna.

Here's a pack of 20 antennas. If you want less or a different length, this should get you pointed in the right direction.
https://amz.run/5tRR
1661536367698.png
Thanks for that. So the unshielded portion is critical, but length is not?
 

Diem Turner

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I stand corrected. I read (and believed) that specific receivers needed specific lengths and that was that if one became damaged.

Thanks for that. So the unshielded portion is critical, but length is not?
Yessir, that is correct. The length of the unshielded portion is relative to the wavelength the transmitter operates on. The rest is just a mast of sorts. Raz regularly outfits his Futaba 2006 receivers with longer antennas.
 

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Yessir, that is correct. The length of the unshielded portion is relative to the wavelength the transmitter operates on. The rest is just a mast of sorts. Raz regularly outfits his Futaba 2006 receivers with longer antennas.
Thank you. And now here I go with a dumb question: aren’t all modern radios now 2.4 ghz? So as such, wouldn’t all unshielded tips need to be the same length regardless of brand?
 

dk10438

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Part of the problem is the 334 is a diversity antenna so if I install an incorrect external antenna the internal antenna will still work but I suspect the range will be limited. I may just call futaba tomorrow and ask them to send me an antenna or send it in for repairs.

Most of antennas that I saw on eBay looked like they were pre unsheathed at 32 mm

Robert
Was the 29 mm for a 334 or different receiver??
 

Diem Turner

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Thank you. And now here I go with a dumb question: aren’t all modern radios now 2.4 ghz? So as such, wouldn’t all unshielded tips need to be the same length regardless of brand?
Theoretically yes. But 2.4GHz is just the base frequency band. I suspect that there might be minor deviations between manufacturers so you might see small variations in unshielded sections.
Part of the problem is the 334 is a diversity antenna so if I install an incorrect external antenna the internal antenna will still work but I suspect the range will be limited. I may just call futaba tomorrow and ask them to send me an antenna or send it in for repairs.

Most of antennas that I saw on eBay looked like they were pre unsheathed at 32 mm

Robert
Was the 29 mm for a 334 or different receiver??
I measured both the 304 and 334. They're both 29mm. Which makes sense. They're cross compatible so I would have expected them to be the same in that regard. I think the only difference between the 304 and 334 is that the 334 supports T-FHSS SR while the 304 does not.
 

dk10438

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I contacted futaba and they sold me a replacement antenna for 5 bucks.
I'll measure the length but I believe that @DiemTurner is correct, overall length isn't critical and I'm sure the unshielded portion is going to be 29 mm.

I'll update the thread when I receive the replacement.
 

dk10438

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a quick followup. I received the new antenna from Futaba last night and it measured 21cm and the unshielded portion was 29mm. I contacted Futaba this AM and spoke with them and they confirmed that technically only the unshielded portion (29mm) was the antenna. I asked if the overall length of the wire mattered, ie 21cm v. 15 v. longer and he said not really. It had to do with the wavelength so the wire would actually have to be really long to make a significant impact....
 

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a quick followup. I received the new antenna from Futaba last night and it measured 21cm and the unshielded portion was 29mm. I contacted Futaba this AM and spoke with them and they confirmed that technically only the unshielded portion (29mm) was the antenna. I asked if the overall length of the wire mattered, ie 21cm v. 15 v. longer and he said not really. It had to do with the wavelength so the wire would actually have to be really long to make a significant impact....
Not that I would be a source above Futaba, but adding more confirmation to this thread. Only the un-shielded portion is receiving the signal.
I have in the past just put them side by side and made it close to an original without a concern for being exactly 29mm. Always worked out fine for me.

Sometimes the end gets damaged and you can simply cut it off and unshield a new section to keep using that same antenna.
 
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