That's what you get when at least the ARRL seems to be primarily interested in keeping the number of amateurs high even as society in general seems to be less and less willing to work a little for a bit of knowledge.
Significant power is still hard enough to come by at 2.4GHz that most of them will probably run out of interest or money before doing *too* much damage. :-) That being said, it's not like you need that much power to go impressive distances anyway; see:
Hi Jerry, I posted the drawing on another newsgroup called >alt.binaires.schematics.electronic< Not all ISPs carry binairy files so maybe you can't see it, if your address is good I'll email the drawing. I looked at the site and it discouraged me. One site says 34mm diameter tube another
42mm, one says a 71mm impedance match strip then another says it's longer. I have no way to measure the antenna when finished so I'd like to at least start with the right dimensions. I will say at least the site you gave does have some equipment and his measurements and reasoning make sense. What is a bridge? I plan on putting a Usb wifi adapter at the antenna. I hope to remove the smt antenna on the USB wifi card and attach the helical antenna. Thanks, Mike
Thanks Chuck, That BiQuad seems very simple and 14dbi seems like a lot for a simple small antenna. As for all the other fun stuff, not now, all I want now is internet access. But I need some gain. I'm still waiting for my USB wifi adapter card to arrive. I hope to have an antenna ready to connect to the USB wifi adapter card. Mike
I am too much 'a beginner' to be a good advisor for how to hook up devices for WiFi reception. So, I wont try to define what a Bridge is. I will do about anything (affordable) that allows the elimination of the coax in a 2.4 GHz system. I do have some experience with making WiFi systems to extend the distance at which Internet connections can be achieved. On one system I made for a guy in Ranchita Calif, who has an agricultural business about 1/4 mile from his house. I put an access point on a 4 foot diameter dish so he uses only CAT 5 cable from his home Router to illuminate the dish. I then put a Bridge on a smaller dish with CAT 5 cable to connect that dish to his lap top in the field. It worked. My objective was to be able to use highly directive antennas yet minimize coax line losses. I think the use of a USB wireless adapter (TRENDnet TEW-445UB) Would be easier than the way I made my system. Show Me cables sells reversing polarity adapters that make it possible to use normal SMA connectors to the TRENDnet USB TEW-445UB
Your project interests me. Tell me what you finally decide to do. I have rejected the Helix. They are more difficult for me to understand than a Yagi. The Helix is circularly polarized, so you loose 3 dB "off the top" of any gain (directivity) plots. The Yagi is fairly easy to model with EZNEC, so you can be fairly well assured that whatever you build will work like the model.
Jerry, I was thinking you would come back and say a bridge is the same as a usb wifi adapter, but I guess not. Have you looked at my drawing I sent you? Mike
In somewhat-simplified Ethernet-networking terms, a "bridge" is a device which joins two Ethernet segments together, by forwarding Ethernet packets from one network to the other based on the Ethernet MAC address of the system to which the packet is being sent. It makes the decision to forward (or not) without changing (or even acting upon) their contents at any higher protocol level (e.g. IP address). An Ethernet switch is a form of bridge. In most respects, a bridge is "invisible" to the systems whose packets it is forwarding - they don't even know it's there.
This is distinguished from a router, which makes the forwarding decision based on a higher-level protocol (e.g. IP address), and which is "known" directly to the systems that are using it.
An 802.11 access point tends to behave like a bridge, from the point of view of those devices which are connected to its wired-Ethernet ports. The devices whose packets are being bridged (via radio) out through the access point don't realize that this is occurring.
In most 802.11 applications, the wireless client systems *do* know that they're talking to an access point - they do all of the 802.11 protocol stuff (e.g. access-point scanning, requesting association, the client side of key negotiation, etc.) themselves, in the device adapter or firmware or driver. The USB or PCI 802.11 interfaces in these devices are *not* bridges.
However, it's possible to build a device which looks outwardly like an
802.11 access point, in that it has a radio and antenna(s) and an Ethernet port, but which implements the _client_ side of 802.11 rather than the access-point side. You can then connect this to a PC (via wired Ethernet), and *it* will establish an 802.11 connection with an existing access point, and then start bridging packets from the wired Ethernet to the access point. The PC plays no direct part in the wireless connection setup - it simply transmits packets to what it "thinks" is a hub or switch, and the "wireless bridge" sends them to the access point.
You'll sometimes see these devices referred to as a form of "gaming adapter", because they often have higher performance than typical USB or PCI 802.11 adapters and don't burden the host CPU as much... and are thus popular with players of high-performance PC videogames.
Many of the newer all-in-one "802.11 access point, router, firewall, and wired-Ethernet switch" products can be configured in this way via software... they'll take the client role in an 802.11 network just as happily as the role of an access point. Most of them cannot do both things at once - they can serve as an outbound bridge, or as an access point for a local WLAN, but not both.
So, I think you have at least three basic alternatives for how you can set up the remote/client end of a longer-distance wireless link:
- Run a big, heavy low-loss coaxial cable from your PC's 802.11 adapter antenna jack, up to your antenna (dish or biquad or helical or waveguide-can). For really low loss over long distances, plan on using something like 2" heliax (which is to say, you really don't want to do this!)
- Run a USB cable (extended as necessary with 15' "active" USB repeater cables) up to the antenna, and connect a USB/802.11 adapter there (e.g. stick the adapter at the focal point of a dish, or at the feedpoint in a waveguide can). Google for "Wok-fi".
- Run a CAT-5 Ethernet cable and DC power up to the dish, install an 802.11 bridge right at the antenna, and connect the Ethernet cable to your PC's wired-Ethernet port. It's worth noting that most methods of attaching an external antenna to a commercial 802.11 adapter are likely to void the adapter's Part
15 certification, and make the adapter techically illegal to use for transmission. 802.11 radios and their associated antennas are required to be tested and certificated as a complete system.
I've rarely heard of anyone being hassled by the FCC for doing this, though.
--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
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Why not to use an older 802.11g Usb Wlan stick (good one w/ onboard chip smd ceramic antenna, much better than w/ Pcb printed one) & some "metal" DIY "range enhancers" ? :-)
See pics & data & measures in cm to get some clues & ideas (text is in my native-slovene, so you won´t understand it; sorry, still had no time to make an english version of that articles for those UsbKey active antennas; inside URLs can be also seen at wish...)
DIY wifi USBkeY range Enhancers-boosters ´4 Dummies´ :-)
Channels 1 to 6 lie with the 13cms amateur band, which does vary a little from country to country nut in the UK is 2310-2450MHz, and there is no ERP restriction in this band just a max power to the antenna, which can have as much gain as you can muster.
For amateur radio, it's a limit on DC power to the final amplifier, which you can make as efficient as you want; it's average power, so you can run 2 KW PEP (peak envelope power) SSB, and gawd knows what kinds of pulses you're allowed to transmit on the UHF, SHF, and EHF bands, as long as the average isn't over 1 KW input to the final.
I'm sure it's all covered in the FCC regs, which should be easy to look up for anyone who's really that interested. ;-)
I thought that the FCC had abandoned the "DC input power to the final" standard quite some time ago (a decade or more, I think).
Most of the transmitter power standards for hams are in in 97.313, which describes all of the limits in terms of PEP. Duty cycle, modulation, and final efficiency are apparently no longer relevant in most cases.
For most bands, and most operator classes, "legal limit" is 1500 watts PEP. There are plenty of exceptions based on band, operator class, and modulation (spread spectrum in particular) but these limits are almost always defined in terms of PEP, which is referenced at the transmitter->feedline connection.
There are some time-averaged and/or ERP limits described elsewhere in Part 97, but these all seem to have to do with deciding when a particular station must go through an evaluation for just how much RF it's exposing humans in the area to.
--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
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"amdx" wrote in news:a590$46a7f995$18d6b40c$ snipped-for-privacy@KNOLOGY.NET:
In a nutshell, a bringe in the wi-fi sense as you should get, is a box that has an ethernet adapter and a wi-fi adapter. It is kinda like a WAP, but backwards. It allows you to use an ethernet device like your computer, on a wireless network using its ethernet connection. You would want to use that as you can locate the bridge at the antenna, and connect your computer to the bridge with as long as an ethernet cable (up to 330 ft though) as you need. USB would be quite limited.
Well, the main one is (paraphrased) that you can't be using the amateur bands for making money on a regular basis... although on-the-air swap meets, ordering pizza at Pizza Hut via the Internet, books through Amazon, etc. is certainly all kosher. Were there other exceptions you were thinking of?
As long as you don't use encryption and aren't running your business through it, in my opinion it's a perfectly reasaonble use. Heck, even QST has articles on doing so.
So in the UK, they still regulate on the basis of DC power? Interesting. I've always liked that philosophy because it promotes design of efficient amplifiers.
1.5 kW PEP, except in certain bands with lower limits (5 MHz, 430-450 MHz (depending on what your location is), etc.)
no averaging for pulses.. 97.3(b)(6) PEP (peak envelope power). The average power supplied to the antenna transmission line by a transmitter during one RF cycle at the crest of the modulation envelope taken under normal operating conditions.
You can transmit pulses on 900 MHz and 2300 MHz and all higher bands, but not 1.2 GHz (although you might be able to do pulses as part of a data or spread spectrum modulation).
Clearly, if you want to operate a radar with your amateur license, you're better off with one using pulse compression and long pulses.
Indeed? Which issue? I recall some articles about HSMM and building a slotted array with gain, but not wholesale use for extension of your internet connection.
I think that if you start to stray too far from incidental commercial use, you could get into trouble, especially if lots folks start doing it. The classic pizza over the autopatch is the example, and I suppose the occasional ordering from Amazon fits in the same category. But, if were to, for instance, check your work email, or watch pay-per-view content, you might be pushing it. In particular, if you but a PA on your access point and a directional antenna, so that your neighbor can use it too, you're likely to be stepping over the line.
It's all a judgement call, but the intent is that amateur radio not be used where there is a commercial service that can provide the same functions. This is so the commercial entities can't claim that someone using amateur frequencies is getting an unfair competitive advantage (among other reasons)
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