Re: WiFi out to 800 feet

nce,

l

What the hell? Clearly you don't do this for a living.

Generally speaking, yes. Practically speaking you can do several hundred mbps over a 2.4 link. You just need to widen the channel.

That is an absolutely correct assessment.

You can advise the OP better than I on potential Fresnel Zone issues, as he's apparently asking how best to paint a LOS location 800 feet away with the transceiver on a pole I believe.

You can run the math to explain to him how high that pole may need to be. (We do that stuff by trial and error - but you may know the math better.)

Please advise the OP on the math so he knows how high to mount the radio.

While there are 2.4GHz routers available that have a 40MHz channel bandwidth setting, I prefer not to use it because it reduces the available bandwidth to other users on 2.4GHz. If one is sufficiently clueless to use a 40 MHz channel set to CH6, it will effectively trash most of the 2.4GHz band. Since Wi-Fi pollution can be symmetrical, it also makes the receiver susceptible to more interference. Stay with 20MHz channel bandwidth on 2.4GHz.

On the other foot, the minimum channel bandwidth on 5GHz is 40MHz (depending on channel selected) with an option to use 80MHz or 160MHz for 802.11AC and AX (Wi-Fi 6). With 1024-QAM, 802.11AX can theoretically do 1.2Gbits/sec in a 160MHz channel. Your mileage will certainly be less.

The test below was to demonstrate something else. However, it does show what can be done with 5GHz. Unfortunately, the radios at both ends were only 802.11a, so the speed never went above 75 Mbits/sec at a distance of about 5 meters. It also uses Jperf 2.0.2, which doesn't work very well above 100 Mbit/sec. I should have used Iperf 3, which works well into the gigabit range: My home network is now mostly gigabit, so I could easily run some 5GHz performance tests with a later version of Iperf 3. However, no pretty graphs as nobody has bothered to port the Java code to work with Iperf3. I'm a horrible programmist, so I won't attempt it.

Anyway, the performance limiting factor is usually interference from co-channel users and noise sources. You could have all the bandwidth in the world, the most efficient modulation scheme, maximum legal RF power, and still not be able to communicate very well or far if there is an interference source nearby. In other words, one needs to do more than just "widen the channel".

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

By the way, I officially retired on Sept 30, 2020. The office is closed, the bank accounts emptied, and much of the equipment donated or sold.

Sigh. I've lost count how many times I've done that in this newsgroup. Start here:

800 ft is not far enough apart to worry about the curvature of the earth. 800ft / 5280ft/mile = 0.152 miles At 2.4Ghz, the Fresnel Zone is 9 ft radius at the midpoint of the link. Therefore, the antenna at both ends of the link need to be at least 9 ft off the ground, or 9 ft above any major obstructions (fences, trees, buildings, cars, etc). Actually, it's somewhat more complicated if I throw in fade margin, frequency selective fading, and system availability, but we won't need to go there for this example.

At 5 GHz, the Fresnel Zone radius is only 6.3 ft. Therefore, the antenna pole can be 2.7 feet shorter.

Methinks we've lost the OP long ago.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

Well done sir.

--
"I am a river to my people." 
Jeff-1.0 
WA6FWi 
http:foxsmercantile.com

Congratulations. You'll now enjoyably find everything you knew disappainting or being replaced by new kids on the block. I don't see any of those filling your shoes here and I usually only bother to lurk to see what you are posting.

I've run cantenna line-of-site over 400m reliably for years. I didn't measure the fresnel zone but a farmer's apple tree in his front must have encroached the signal line every few years and he would kindly lop a few branches, restoring normal service. I have a note of the speeds somewhere but the system gave me office access from home, home broadband via the office and all I remember is that the Wi-Fi speed was better than the rather poor broadband speed available at the end of a long exchange line.

After moving several years ago from the little hamlet (60 properties) the pathetic broadband (I think I had one of the best connections at

2mbps) was replaced by FTTP. I don't think I could have got mi Wi-Fi signal to keep up with the resulting 80Mbps broadband. Those we now Zoom with in that hamlet are always very clear and no blurring motion issues - I'm somewhat jealous. (UK in case any folk are struggling to understand any terminology or words).

--
AnthonyL 

Why ever wait to finish a job before starting the next?

Enjoy your retirement, my friend! :)

Thanks. However, it's not easy to find enjoyment while trying to adjust to Covid-19, dysfunctional government at all levels, impending economic collapse, limits on travel, increasing weather related problems, an increasing homeless problem, and probably increased taxes to keep the economy afloat. Health problems and advancing age increasingly limit my activities. I can survive on Social Security payments and the 80% that Medicare provides, but suspect those benefits to will eventually be reduced by inflation as the government resorts to printing money to finance its activities. I expect my "retirement" to more closely resemble living on unemployment with the added bonus of having no debt and a modest bank account. Since I have no children or immediate family, I could easily have obtained a reverse mortgage on my house, and lived off the cash. However, the recent fires in California might make that impossible due to increasing difficulties obtaining replacement value fire insurance, a basic requirement for a reverse mortgage. In other words, the long term prospects for an enjoyable retirement look rather grim.

However, before I blunder on into this dismal future, I have an immediate problem to deal with. I brought about 75% of the contents of my formerly palatial office to my house when I moved out. There was no time to do sorting, only time to box everything and move. I moved it in small increments because I have no garage or storage space at the house and because I had to carry the boxes up about 50 stairs. The boxes are now piled up both inside and outside the house. Much of it is covered with ash that is still falling from the trees due to the recent nearby fires. Rain will likely arrive in a few weeks and nothing outside is protected. I need to deal with that immediately, but can't during the current heat waves. At least I won't be bored looking for something to do.

Incidentally, it's now 6AM and 75F (24C) outside. NWS predicts the temperature to rise to 101F (38C) today. I might be able to do 2-3 hrs of box shuffling today. It's likely that the local power company, PG&E, will intentionally disconnect the power to prevent falling power lines from starting more fires and to reduce the load on the power grid from air conditioning.

Thanks again for the hopeful thoughts, but this is not the retirement that I had planned and is unlikely to be enjoyable.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

Given the price of real-estate, and the cost-of-living in Santa Cruz, given that you are apparently single, given that you are apparently not overly h appy about the climate, have you ever considered relocating to a more amena ble part of the country? When we moved 12 years ago (just across the townsh ip), it was akin to shedding a skin. The divestiture of unneeded *stuff* wa s pretty immense and very cleansing. We have been vary careful not to re-ac quire since. It really does make a difference. But, a more distant move in your case may solve a number of financial, physical and logistic issues all at once.

Best of luck with it. My wife is retired, my identified date is June 30, 20

22 when my major tenant ends its lease. Until then, my wife and I are busy 'feathering our nests" so that when we retired and our income drops by six figures we will have few expenses and no debt on what amounts to be two v ery nearly maintenance-free houses.

Take care!

Actually, I have done some online looking at some possible places to relocate. The exodus from California seems to be mostly to the northern and eastern states: Texas seems to be the largest, with a predictable reaction:

There are also a fair number of YouTube videos on "Why you don't want to move to [insert name of state]".

After I work out the migration pattern, the next step would be to decide if I want to move to where everyone is going, or if I want to avoid those places. Right now, I don't know. I originally moved to Santa Cruz from the Smog Angeles area in about 1973 because it was less crowded. I wanted to get away from the crowds. Before Covid-19 drastically cut down on the traffic earlier this year, Santa Cruz traffic had become as bad as Smog Angeles over the past 47 years. If I move, I don't want to become part of that problem. However, the main reasons I haven't moved somewhere else is that I don't have any urgent need to move, and that my house has some problems that will either be too expensive or difficult to fix economically. It's a can of worms I don't want to open at this time. There's also the problem of my lack of longevity. If my family history is an indication of how long I'll live, I probably won't live long enough to enjoy the change of location.

I know the feeling. Several of my friends have become minimalists. Unfortunately, I've been the recipient of some of their accumulated junk. I would say they were most successful in what they were trying to accomplish. For me, it's quite different. While I'm not quite a packrat, I do tend to accumulate "stuff". Since I don't have a family and have yet to immerse myself in public service and volunteer organizations, I tend to replace these with gadgets, things, gizmos, and goodies. I fix things, I enjoy the work, and would happily spend the rest of my continuing to save "stuff" from a premature demise in a landfill. I guess I'm an eco-freak of sorts. Moving wouldn't change much.

Nicely done. Sounds like you have things well planned and organized. I thought my plans were similarly set. Then, I had to deal with some nasty medical problems, a pandemic, wildfires, and an evacuation. The assumptions I made in planning my retirement have not gone up in smoke yet, but are likely to do so considering the circumstances I itemized in a previous rant. May your ration of luck survive and hopefully, you won't need to deal with my problems.

Thanks. Time for a fast dinner and off to a friend to fix a Brother sewing machine and a Baby Lock. As long as there are things that I can fix and that need fixing, I should be ok.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

te:

I didn't plan on becoming 100% disabled in my late 50s. My last day of w ork for someone else was the Friday before 9/11. I kept busy working on com puters for others who couldn't afford to take them to a shop. I can no long er even do that. My legs are so bad that I have to prop them up more than

10 out of 24 hours to keep the scar tissue from opening. I couldn't do it l ast night. There was a large puddle of plasma under my left foot this morni ng. I deal with it, but only having two hours a day to do everything is a r eal pain. I had two bad falls in the past year. It looks like I'm going to have to go to a walker or power chair before long. Why not open a Ebay stor e to list what you don't want to keep, as you sort out the boxes? It will help you get rid of some stuff, and hopefully give you some extra cash.

God Bless you, my friend!

Jeff, Austin TX., Portland Maine, and Madison WI. are terrific cities. If safety, beautiful scenery and incredible restaurants are top on your list, I'd consider Portland.

I see alchemy as your next hobby: Turning all that computer stuff into Gold! In which case you don't have to move any of. Rain won't hurt it.

I know it's hard to let go, but .....

-sw

So I was curious and youtubed it....This guy got $1,900 worth (about an ounce) of .99% gold from 6 pounds of clipped OLDER PCB connectors.

I suspect getting chemistry glass and HCL delivered to the Santa Cruz mountains may be difficult and raise some eyebrows. Or used to. It's kinda pointless to manufacture domestic meth anymore since it's so cheap from Mexico, so they may have deregulated that stuff.

Food for thought...

-sw

Austin, TX.

Portland, Maine.

Madison, WI.

I dunno. It appears to me that some residents are resorting to making YouTube video to discourage immigrants. I can almost visualize being greeted by a lynch mob. So much for safety.

Incidentally, I haven't been to a restaurant since late February 2020. I really miss them. I used to hang out at the local coffee shops meeting others with like interests. Zoom meetings are a poor substitute. On the other hand, my food, entertainment, and gasoline budgets have been dramatically reduced, I've lost some weight, I'm sloooooowly learning how to cook, and I've forgotten how to calculate a tip. Eventually, the pandemic will end, and I'll probably return to my former decadent and lavish lifestyle. Until then, I think I can survive without restaurants, fast food, and coffee shops.

More seriously, I've looked into selling my house and buying something cheaper elsewhere. I'd rather not go into detail, but it's not going to work for me. If I discount my house and convince a buyer to buy the house as-is (after a full disclosure), the difference between the discounted selling price and the purchase price of a replacement house, will be rapidly consumed by the sales commissions, moving expenses, repairs, deposits, etc. At best, it would be break even.

Also, I don't like cities. I grew up in Smog Angeles, which is an example of a city to avoid. If I do eventually move elsewhere, it will probably be to a small rural town similar to where I'm now living. If I want better entertainment, shopping, medical facilities, and restaurants offered by the big city, I'll just drive there. I don't need to live there.

Thanks for the suggestions.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

Afraid not. The stupid federal regulation about restricting the amount of pseudoephedrine (Sudafed) that can be sold to an individual and requiring it be sold blister packs still exists.

In dense environments, I agree. In rural areas, interference may not be a factor. In extremely rural areas, interference PROBABLY won't be a factor.

No.. The minimum 5GHz channel bandwidth is 5MHz. Not sure where you are coming up with 40MHz as a minimum. Out of several dozen transmitters, I only have two set to 40MHz (backhauls). The rest are set to 20MHz with a couple at 10Mhz.

My gear (Ubiquiti) supports 5, 8, 10, 20, 30, 40, 50, 80 Mhz wide channel= s.

Once again, sometimes. Sometimes ALL you need to do is widen the channel.=

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All he has to do is search google for "fresnel zone calculator"

At 1,056 feet (0.2 miles) the Fresnel for 5.1 GHz is 7.1 feet. (for 5.8 Ghz it would be 6.7 feet). The higher the freq, the smaller the zone.

You can intrude the fresnel by 40% (max), but I try to avoid even that.