Report on Alfa directional WIFI antenna

I ordered an Alfa APA-M04 directional panel antenna to replace the almost- broken original antenna on my Buffalo WHS-HP-G54 router. $9 on Ebay.

As compared to the original Buffalo antenna in the horizonal position, the Alfa antenna is either the same or worse at any testing point. Also, I don't really see any front-to-back directionality with the Alfa even though the docs say there should be some. In other words, I got the same results whether the antenna was pointed forward or backward.

So, at any point along the direction of testing, the Buffalo horizontal antenna provided a stronger signal from my router as shown by WiFi Analyzer on my Android tablet.

It's puzzling that there are a lot of positive reviews on this. So far as I can tell, it's basically no better than a normal antenna.

Well, you win some, you lose some, and some are rained out.

Reply to
Peabody
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Deduct one point. Ok, you didn't take my advice to buy a bigger and higher gain panel/patch antenna. Something like this: or build a biquad or AMOS antenna:

Yep, which suggests either that the Alfa APA-M04 is not particularly high gain, not very directional, or more likely, that the wi-fi signal is coming from multiple directions. That would explain getting the same signal levels with the antenna forward and backwards. Having a

2nd antenna (for diversity reception) inside the WHR-HP-G54 router, certainly doesn't help. The signal may not even have been received via the Alfa antenna.

Suggestion: Drag the WHR-HP-G54 router outdoors, in an area as clear as possible, such as an empty parking lot. Repeat the antenna test using Wi-Fi Analyzer. You might get better results.

Yeah, but the little panel antenna looks so cool.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

No, I didn't. But I didn't have to finance the Alfa purchase.

I guess that's true, but surely the router transmits via the external antenna, and that's what Analyzer is measuring.

There's a video somewhere describing how to convert the internal antenna to a second external antenna. But I was just hoping for some moderate improvement since the original antenna worked pretty well already when I stuck it on the right way.

Yes. However, I did take this opportunity to "fix" the broken Buffalo antenna. I keep forgetting that a hot glue gun can work well enough for very light duty repairs when the broken part has been lost. So now I can screw it all the way on, and be sure it's making contact. So I think I'm set for the moment.

By the way, this Youtube video shows what's inside the Alfa, but I think he may be wrong about it being assembled backward since mine was "backwards" too, and reversing it made no difference.

formatting link

Reply to
Peabody

What do you consider a reasonable price? I picked this because it shows what's inside, not for the price. If you want the same 2x2 Patch antenna array for cheap, try: $14.00 $16.50 $16.00 I have a few of the last item lists. They produced about 12dBi gain instead of 14dBi. Close enough. Want me to take photos of the insides so you can see the difference with your Alfa antenna?

Maybe. There are two methods. One is as you describe, where the transmitter always transmits to the Main antenna. The receiver favors the Main antenna, but will switch to the AUX antenna if it detects a low BER (bit error rate). The other method switches both the transmitter and receiver. Looking at the PCB (I can't find a block diagram), it looks like a DPST T/R switch as IC12 and IC10 (lower left of top view). That means that either algorithm can be used. Dunno. I'll try to figure it out by monitoring my WHR-HP-G54, time permitting.

There are some inherent problems with using diversity receive antennas with radically different patterns. For example: Be careful that you don't reproduce the golf course example.

I suggest you concentrate on improving the Main antenna and just ignore the Aux antenna. If you think the Aux antenna may be a problem, just unsolder the coupling cap (C50) and it will go away. It's only used if the Main antenna ends up in a null.

If it doesn't hold together, you can get replacement rubber ducky antennas all over eBay.

Thanks for making my day. I have no idea what kind of antenna that might be. It kinda looks like a common patch antenna, except that the coax center wire and shield seem to be reversed. The cute little coined "bow tie" antenna symbol does nothing. In any case, the "bow tie" is much too small to do anything on 2.4GHz. I can hardly see any detail in the dark video. The commentator also constantly moves the disassembled antenna. I may have missed something but I'm not even sure that it's a real antenna. Certainly, there's no matching circuitry near the coax end.

Caveat Emptor.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

Question for you...

Its obvious how to connect a gain antenna to a router via the RF connectors. Is there a practical way to connect a gain antenna to a device like a phone or tablet. Mark

Reply to
makolber

Why me?

Directly connect? No.

In the distant past, when there were only 2 RF bands used in phones, it was possible to hang a resonant coupling loop over the internal antenna, and amplify whatever the loop picks up with an external bi-directional amplifier. Those don't work well any more. The problem is that todays 4G smartphones have SDR (software defined radios) that cover 700, 850, 1700, 1900, and 1275(GPS), and 2400 MHz (WiFi and BleuGoof). It is difficult to build a coupler and amplifier that covers all these frequencies and switches the amps between TX and RX in sync with the smartphone. It's also rather difficult to find a single spot for the loop on the back of the phone as the antennas for the various frequencies are scattered all over the phone. So, the only thing that works is a bi-directional amplifier and antenna combination, with no direct attachment to the phone. That also keeps the FCC happy as modifying the phones antenna system is against the FCC rules-n-regs. The catch is that the antenna pointing to the cell site, and the inside antenna, need to be isolated from each other, preferably with something that blocks RF in beween: Also, in case you haven't noticed, phones no long come with antenna connectors, and the inside test connector is specifically designed to make it difficult to permantly connect a mating RF connector.

Incidentally, you can do quite well using a reflector:

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

Imagine the 48 US states with nobody in them. Then take about 23 million people. Put about a million of them in Los Angeles, spread most of the rest of them along the coast from New Orleans, east around Florida, and north to maybe New York or Boston, and then scatter the remaining ones randomly throughout the interior. Now design a cell network (or even a landline network) that lets everybody's phone work.

If you live far enough in the sticks in Australia, you can (or could?) get part of the cost of Iridium service subsidized by the government.

The "set a tire on fire" thing was official travel advice from the state of South Australia, if your car breaks down out in the boonies and you've been there a while. Apparently the smoke plume shows up real nice from the search plane.

Interesting. I didn't know that.

This was a couple of years ago, but I've heard some police dispatchers (on the scanner) get the E911 address and give it to the responding officer, but with a warning that they don't think it's a good address. Usually they come back a minute or so later (I *guess* after consulting Google Maps or equal) and tell the officer that the address is probably the tower and not the actual location of the caller.

On the other hand, it could be argued that if your cell phone provider

*doesn't* know the accurate latitude and longitude of your handset, at any moment that it is switched on, it is a feature, not a bug.

Matt Roberds

Reply to
mroberds

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