Nighthawk XR700: Antenna Upgrades and Replacements

[domiluci]

Hello, friends! So I am a professional engineering scientist, but I do electronics repairs in my free time to pick up cash here and there, and sometimes even pick up sweet equipment people just give me because they think or have been told it is/was impossible to repair. I am able to repair about 95% of the things I come across, even if it means designing the replacement part myself.

But the other day, I get a call from a guy with an XR700 who completely decimated an antenna. With any other router, this would be an easy blow-and-go fix; you'd just give whoever a link to a compatible RP-SMA dual-band antenna and they could replace it themselves. Plus they'd likely add some signal gain in the process with a higher gain aftermarket antenna set. But seeing as how the XR700 employs 802.11ad with the 60GHz band, I'm quite sure I'm safe in assuming a generic dual-band antenna isn't going to work here (even though mathematically and theoretically it could). And since 802.11ad was never really accepted as any "industry standard", I can't really cannibalize an antenna from any other unit. Furthermore, I haven't found a way to get in touch with Netgear to ask if we can purchase a replacement antenna specifically for the XR700. So I'm running out of options and not really sure how to approach this fix.

So if anyone could answer the following questions, I'd be forever grateful:

1. Is it possible to get/purchase a replacement antenna from Netgear specifically for the XR700?

2. Does anyone out there know of anyone or anywhere I could get a replacement antenna specifically for the XR700?

3. Is there a compatible aftermarket antenna out there I could use to replace the broken XR700 antenna with instead?

Any help would be greatly appreciated!

[Netduma-Fraser]

I don't have an XR700 to hand but I'm not sure if the antennae are easily removable, I may be wrong about that. Regardless, I don't think you can buy any replacement antennae anywhere. Couple this with the fact that the XR700 is no longer being sold that makes it difficult. It might be best to have the customer register their router with Netgear if they haven't already and submit a ticket via http://support.netgear.com/ and see if there is anything they can do.

[domiluci]

They aren't being sold anymore? You mean through Netgear? Because I see them being sold everywhere. But I'll pass this info on. Thanks.

[Netduma-Fraser]

What I mean is they're not producing any more stock, once the stock goes it will no longer be available to purchase.

[plemans]

The other thing you could do? modify an antenna thats just 2.4ghz/5ghz and use it. The AD feature/spec was pretty much abandoned.

I don't have a XR700 to compare antenna types with but there is a video walk through of someone doing something similar. 

https://www.youtube.com/watch?v=Lzsvuo8zPSo

[schumaku]

@domiluci scratch the idea the four external antenna have anything related to the 60 GHz network. Open the enclosure band you will figure out. 60 GHz is somewhere in the mm range, around 5 mm. That's also the reason the reach is limited, and only free air can be used - it's short range technology. The 60 GHz antenna is in the middle to the R9000/XR700 front, covers about 160 degrees only, and a range of about three meters which must be free from any obstacles. When the cat or dogs are walking the way, the link is going down until the direct line of sight is free again.

Common use was and still is with wireless docking stations for notebooks btw.

When I have it right, the four external antenna are made from plain coax cable with one end connected to the PCB, and the other end (probabily scratched from some shielding). Something like this could at least serve as a replacement. The other cabling is just for some LED in the antenna "holder".

[schumaku]

For the records, the tiny PCB there is the 60 GHz phased array antenna in the front of the R9000/XR700. The copper is mostly for heat dissipation - because this is a "hot" technology:

[schumaku]

Inside of the antenna "blocks" there is the RF-module, powered and linked over the RF cables from all internal radio modules. In the upper end, there is a single antenna connctor linking to the 2.4/5GHz antenna array on the top end of the antenna PCB. 

Show us what's "broken" on the antenna you have at hand...

[schumaku]

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@domiluci wrote:

With any other router, this would be an easy blow-and-go fix; you'd just give whoever a link to a compatible RP-SMA dual-band antenna and they could replace it themselves.

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These designs require long RF cables in the box (attenuation), an RP-SMA connector (adding even more attenuation). While the loss can be overcome on the transmission path by putting up more power, the loss does weaken the receiver signal quality.

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@domiluci wrote:

Plus they'd likely add some signal gain in the process with a higher gain aftermarket antenna set.

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This is the key reason why vendors are going away from removable RP-SMA antennas: Regulations do not allow this, because these devices are already operating very near to the allowed emitted power.