Hey Jeff, what u think the dBi is for this?

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They say 2-12? so they don't really know? or what?
Any idea what it is likely to be from indoors apartment
building? Price is kinda high.
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On Fri, 06 Aug 2010 17:24:46 -0700, in , John Navas wrote:
They actually say:
The HA12W Window Antenna boosts the antenna power of standard antennas from a minimal 2dBi to a more potent 12dBi.
In other words, 12 dBi, not a range. Price looks not unreasonable to me.
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John Navas
Not Jeff, it is stated a little clumsily "The HA12W Window Antenna boosts the antenna power of standard antennas from a minimal 2dBi to a more potent 12dBi."
They are saying their antenna is 12dbi compared to a "standard antenna".
$50 is not an unusual price for an antenna.
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Note that it's a "legacy product" which is a nice term for possible difficulties finding one to purchase.
The PDF data sheet at the bottom of the web page is a little better. .. Gain: 12dBi .. Radiation: Directional .. Polorization: Linear, Vertical .. H-Plane: 84 deg .. E-Plane: 23 deg .. Dimensions: 327mm x 80mm x 22mm
I was going to check what's inside by searching the FCC ID database, but it's a weekend, when the FCC servers usually prefer to crash. Error Executing Database Query. weblogic.common.resourcepool.ResourceDisabledException: Pool OETDataSource is disabled, cannot allocate resources to applications.. The error occurred on line 26. Sigh... Maybe some stimulus money will help.
Judging by the size, and the beam widths, I would guess(tm) that the guts might be a colinear vertical or Franklin antenna. Something like this:
but with only 3 elements instead of 5. There are many mutations of this design so I can't build a model without clues as to what's inside.
I can make a really bad guess as to the gain, by starting with a flat plate reflector and a dipole. See:
That's 8dBi gain, with an 80 degree beamwidth in both axes. If I cut the beam width in half, the gain increases about 2 dB. The horizontal beamwidth is about 80 degrees, so I can leave that alone. Cutting the vertical (E-Plane) in half, twice adds 4dB gain for a total of 8dBi + 4dB = 12dBi gain Yeah, I would say it's possible that it has 12dBi gain. Again, this is guesswork, not a calculation, or an endorsement.
Another sanity check is the length. 327mm / 125mm = 3 wavelengths The gain of a half wave dipole is about 2dBi. Double the length, and the gain increases by 3dB. So, 1 wavelength (with phasing stubs) will be 5dBi, 2 wavelengths yield 8dBi, and another wavelength will bring it up to about 9dBi. A reflector will double the signal for an additional 3dB gain, thus yielding the required 12dBi. Yep, it's possible.
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Jeff Liebermann
Or, just build your own:
Typical photo:
Hmmm.... looking at the characteristics for the AMOS-3 (3 element Franklin) at:
it has only 10 or 11dBi max gain. Close, but not the rated 12dBi for the Hawking Tech antenna. In the inverted AMOS-3, the 85 degree horizontal is right, but with only 10 degrees of vertical beamwidth, it's probably NOT the same as whatever is inside the Hawking Tech antenna. Oh well... bad guess(tm).
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Jeff Liebermann
Jeff Liebermann wrote in news: snipped-for-privacy@4ax.com:
12dBi for
Hawking Tech
Ok thanks for your calculations and replies and also to the other repliers. I am using a 1' by 1' homemade parabolic reflector behind a 5 inch whip-manila folder with pasted alum foil glued to parabolic foam shapes made from a parabolic template. What do you think the probabilities are that the Hawkins will give a significant improvement over that? The signal strength from my adapter software says it is running about 80% but the signal quality is only about 50-65%, and I am getting Rx retrys about half of Rx Oks. Actually these readings seem to bear little relation to the speed of downloading pages. Have tried moving the antenna all around different positions and different angles, am I am now getting the best I can get with this antenna. The 1' by 1' reflector is affixed to slots on the top of a small cardboard box aimed towards my window. I tried lining the bottom of the box and sides outside the reflector with alum foil, but did not improve things. I tried shielding the adapter which is right below the antenna with foil, also no improvement.
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Have you tried different channels (1, 6, 11)? Have you looked for sources of radio interference?
Reply to
John Navas
Hint: What problem are you trying to solve and what do you have to work with? You'll get better answers if you supply this information.
100%. Your antenna is probably not properly matched to 50 ohms. Your aluminum foil feed probably does not properly illuminate the dish, resulting in "over-spray" with radically different gains on receive and xmit. In short, without test equipment, a decent design, and careful construction, your home made contrivance is unlikely to provide a major improvement in antenna gain.
That being said, I'm always amazed at how crudely an antenna can be build and still work. That applies to antennas with gains of less than about 8dBi, such as coffee cans and simple reflectors. Over about 8dBi gain, things start to get critical and narrow band.
Lots of retransmissions suggests interference. Try different RF channels or run a site survey (scan of existing wireless networks). If possible use a spectrum analyzer.
Got any numbers?
I can't tell if the Hawking antenna is going to make any improvement as you haven't disclosed how you're using the antenna and radio. Are you trying to cover an area? Or are you trying to go point to point? Big difference in recommended antenna types for each of these. Also, indoors, outdoors, rooftop, folliage, through walls, etc.
Reply to
Jeff Liebermann
Jeff Liebermann wrote in news: snipped-for-privacy@4ax.com:
have to
Thanks for your reply. Sorry I am not able to converse with you at your level on this topic.
So far in my area I have found 3-5 APs, no encryption using open routers, no pw. I am sure there are more. I just want to surf the net and chat, primarily. Over months some disappear and then new ones appear. I guess they are starting to wise up that its not a good idea to run unencrypted APs with open routers. Or maybe they are just leaving it open for whoever.
ohms. Your
the dish,
design, and
unlikely to
The parabola was cut from a template that supposedly is an efficient half parabola with the rubber whip at the focal point or as near as homemade can make it. So why the "overspray", not sure what you mean by "illuminate the dish". The antenna is designed to focus the reflections off the parabola to the whip, and was intended for use with a whip. Obviously I don't know half of what you're talking about, sorry. Of course this is not factory made so I am sure that I am not reaching the dimensions and curves as closely as with factory built. As far as the 50ohm impedance, I guess can I add a resistor to generate that, and where?
antenna can be
of less
different RF
networks). If
How can I change a channel for which I have no control over the transmitter?
Only what I already gave you. The software supplied with the usb radio does not help much in determining which antenna position or even AP is providing the best throughput. For examply I can get a signal quality of 40% and have better throughput than when the bar reads 60%, or so it seems. Link quality bar is not any help either.
radio. Are
to point?
these. Also,
No I want an antenna that I can move around, directional that will find all the available open APs around me. Indoors, cannot do outdoors. Have no idea whats between me and the APs, I am relying strictly on signal strength bars, link quality bar and how fast pages load and testing throughput with online test sites. I think a true dish antenna will be too difficult to aim, so something that is directional but not too directional. Also, I have no idea how the Hawkins works or what's inside it, I just know they are claiming 12dBi and thats probably much better than what I am getting with my homemade job, IF their claims are not so much hot air.
Sorry if I am not able to give you more than my ignorance in this area (although I am learning) allows.
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In other words, you are trying to steal broadband Internet service.
Reply to
John Navas
John Navas wrote in news: snipped-for-privacy@4ax.com:
you have to
If they leave their junk out on the curb in front of their house, it's not stealing. Guess maybe you're one of the people trying to steal money by charging outrageous rates for what people can get for free?
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