Thursday, October 11, 2007

Easy Pocket Wizard Antenna Mod for Extra Range?

A few days ago I was cruising through Lifehacker when I saw a post on wi-fi hacks. They had instructions for a cool little cardstock-and-foil quasi-parabolic antenna reflector for wireless routers.

But it also looked like it would also fit pretty well on a Pocket Wizard. Fifteen minutes (and no money) later, I had a pair of the tin-foil hats in my grubby little hands.

More info, how-to video and test results after the jump.
______________________________

As you might imagine, this is the kind of thing that is pretty much gonna jump right to the top of my "to-do" list, shooting past "clean out closet" and "rake the front yard." So I assembled a pair of the antenna reflectors right on the spot.

Here is a video that explains the antenna and the theory:

The Missus was gone, which was why I could bail and assemble the reflectors with no rationalization of the logic of my priorities. But it also meant that I would have to wait until she got home to leave the house to test them, as the kids were in bed.

After she home I went outside to test the results. I quickly discovered that my problem was that the Pocket Wizards were too good to test in my neighborhood. They fired as far as I could separate them and still have line of sight for flash-firing confirmation. I tried two more (progressively larger) locations with the same results.

So it was not until a few days later that I had a chance to drive out to a long, straight country road with my six-year-old and test the setup properly. We set up the Pocket Wizards (with stock antennas) and flash in a line-of-site environment and found that we could reliably trigger the flash from up to two tenths of a mile, but not beyond that.

(Note to self: Any flash trigger that requires an odometer to test it is pretty cool in my book.)

After we attached the reflectors at each unit, we found that we could get a pretty reliable trigger at three tenths of a mile. Obviously, lots of things come into play to determine the range of the Pocket Wizards: Atmospheric conditions, battery condition, individual unit variances, etc. But this was an apples-to-apple comparison, with the only changed variable being the the antenna mods.

("Uh, gee, Dave, isn't two tenths of a mile enough?")

Yeah, it is. But the pont was to see if they would expand the range. And in my very unscientific test sample of one situation, it did just that. I would be curious to know whether anyone else gets extended range or whether it was just me.

More important, if it works there is no reason to think it would not work on the less robust triggers, too: Skyports, Poverty Wizards, etc.

And then there's this: Assuming you made the central support brace out of clear plastic (like material from a 2-liter soda bottle) the shiny side of aluminum foil is a very efficient light reflector, too. Mounted correctly to place the focal point of the semi-parabolic reflector at the IR receiving window of the flashes involved, this could extend the range of Nikon CLS and Canon eTTL.

Besides, until the as-yet-still-mythical Radiopopper makes an actual appearance, what else are ya gonna do to extend the range of your CLS or eTTL?

As for the specifics of the antenna, the URL of the pattern is listed below. Printing it at 100% is perfectly sized for a Pocket Wizard implementation, so no need to double it as some people do for the wi-fi boosting.

If you make one, please report back. I would love to get a better sample of info, whether it be PW's, Skyports, CLS or whatever.

______________________

:: Antenna Pattern ::
:: Top 10 Wi-Fi Boosts, Tweaks and Apps :: (Lifehacker)


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41 Comments:

Blogger Matt said...

This will NOT increase CLS range as that is IR and not radio based

October 11, 2007 12:00 AM  
Blogger David said...

Matt-

No, but it is light-based. I used foil reflectors as light catchers to increase the range of slaves all of the time.

The metal in the foil is what reflects radio waves. The shiny quality of it reflects light. Even IR light. That's the theory, anyway.

-DH

October 11, 2007 12:07 AM  
Blogger Don said...

Would anyone be interested in a Pocket Wizard compatible transceiver with a range in the 600 - 1000' ballpark, that was smaller, and with a price tag under $100? I'm thinking of building some prototypes and I'm curious if there would be interest.

I'm also toying with the idea of building a board that fits into a Vivitar 285HV, replaces the manual and automatic controls and gives you digital control of the flash from 1/1 to 1/256 power, built in optical slaving, and PW compatible wireless. Probably use the internal batteries and shoot for a range of 200' or so- (I can't see needing more than that with this particular flash). Would there be any interest?

-Don

October 11, 2007 12:15 AM  
Anonymous eyenology said...

Yes on both acccounts, I reliable tx/rx combo in that price range would be nice. Also, would love to hear more about the 285 mod. Would you sell the board with DIY instructions?

October 11, 2007 1:17 AM  
Anonymous Anonymous said...

$100 pocketwizard compatible transceivers? Heck yes I'm interested, so long at it's pocketwizard reliability within that 600'-1000' range.

October 11, 2007 1:57 AM  
Blogger David said...

Don, I expect there would be interest. Both of these things (price dependent) seem very interesting to me, and I know that at the NYC Strobist meet those of us without PWs wished there was a cheap PW-compatable trigger so that we could all fire the PWed flashes. I think a model with half that range and half the price would be even better - most of us are never more than 300ft from our flashes.

October 11, 2007 2:13 AM  
Blogger Sean Phillips said...

Don,

Of course there is interest! Sign me up...

October 11, 2007 2:35 AM  
Anonymous Anonymous said...

I think you're starting to lose the plot........... ;-)

October 11, 2007 2:58 AM  
Blogger djidji said...

Am I the only one having problems opening the url http://www.freeantennas.com ?

October 11, 2007 3:22 AM  
Blogger Jon Thornton said...

Another way to extend the range of Pocket Wizards would be to use them in relay mode. The first PW could be positioned 2/10 of a mile away. When triggered this PW could relay the fire command to the next PW 4/10 of a mile away.

October 11, 2007 3:30 AM  
Anonymous arizonavideo said...

I have made many of the reflectors for wifi. The larger the better.

To get any real performance out of them they do need to have almost perfect placement and curve.

They are vary directional so you have to aim them. If set up right you can double the range of a system.

For wifi one of the main advantages is the blocking of noise from behind the reflector.

October 11, 2007 3:51 AM  
Blogger Christopher G said...

Don-

Tons of interest right here. PW's are great, but I'm a student and need reliability, maybe 200'-300' range, nothing more, 2/10ths of a mile is overkill (unless you LOVE your 600mm and stacking 2x extenders).

Just out of curiosity, what type frequency are you looking to use, and what communication profile to wirelessly control all that input to a 285?

Cheers,
Christopher

October 11, 2007 4:09 AM  
Blogger barak said...

I do something like this for CLS and optical slaving frequently. Thing is, it doesn't even have to be as precise as the Windsurfer. I just mold the foil by hand and eyeball the shape. If I'm in the flakey range where the strobe sometimes works and sometimes doesn't, foil has never failed to get me up to 100%.

October 11, 2007 4:35 AM  
Blogger Joel said...

don -

YES and YES. You would truly be my hero. On both counts. If you need a guinea pig, I happen to be a poor college student who wants to be first in line!

I saved up, bought a pair of nikon strobes all excited about CLS, and on my first ever outdoor-with-strobes shoot I was instantly crippled by the range. It was extremely depressing.

-Joel

October 11, 2007 4:43 AM  
Blogger slickfingers said...

Don... Wrong side of the pond but definitely interested.

October 11, 2007 5:40 AM  
Blogger slickfingers said...

Don... Wrong side of the pond but definitely interested.

October 11, 2007 5:41 AM  
Anonymous Cham128 said...

So I take it in the near future we're going to see someone shooting strobist style landscape photos for the on assignment section? can you imagine...

"strobist: one sb camera right to light tree in the foreground, a second SB at full power to light the ice cap on k2 in the background"

October 11, 2007 6:32 AM  
Blogger Phil said...

I wonder if this will work with my poverty wizards, it does with the Pulsar units....hmmmmmm

October 11, 2007 6:46 AM  
Blogger Scott said...

0.2 miles to 0.3 miles in a free space field; by my reckoning, that’s a 50% improvement in range. To me that's a big deal. Not because I can set my strobes 50% further down the road, but because it gives me better punch through stuff like buildings. I recall a shot from somewhere (DH, you have a link?) of three guys in separate offices in a building ACROSS from the photog. The strobes had to have been triggered by PWs or some other RF triggers.

That's the kind of situation where the boost in performance may come in handy.

-S.

October 11, 2007 7:13 AM  
Blogger ampone said...

@don: I will DEFINITELY interessed in one!!!.

October 11, 2007 7:52 AM  
Blogger David Tejada said...

These type of articles are wonderful, I start each morning reading the daily posts from Strobist and sipping my coffee.

Really love your site. DT

October 11, 2007 9:41 AM  
Blogger Don said...

David- Half the range and half the price is a much taller order. The range doesn't affect the price as directly- the cost comes down to chips, boards, antennas, and injection molding. Injection molding does not become cost effective until you sell a LOT of units but it can be done. Actually- it might be possible to do a receive only unit for $50 - $75 with the same 600 - 1000' range and PW reliability. Fewer FCC hurdles to jump through if we aren't transmitting.

As for the reliability- I wouldn't bother making something unless it was as reliable as the PW's.

The board for the 285 would defintiely be DIY- there's no need for an expensive plastic case so that makes it a LOT easier to do.

Christopher- As for frequency- it would be the same as the PW's- 433 MHz I believe they use here in the US. The whole point would be compatibility with the PW's so people can use the PW's they already own.

I'm going to see if I can find an dead 285HV and a dead PW so I can get a feel for size and components.

Please understand this is not going to happen tomorrow :) I can put together some prototypes pretty quickly but if we want to go into production that's going to take a few months. On the other hand people can probably use the prototypes and do a bunch of testing for nothing more than the cost of the components- in the $25 area.

October 11, 2007 9:55 AM  
Blogger spence1 said...

djidji; link isn't working for me either. Maybe down on their end for some reason... will keep trying, gotta make one of these!

October 11, 2007 11:12 AM  
Blogger Joel said...

Don, did I mention you're my hero? While send/receive units would be even more amazing, if you could put together a receiver for $50-$75 the cost of a single PW wouldn't seem nearly as steep. Also the greatly shortened timeline to availability through avoiding the regulations would be wonderful, heck I wish I had a set for a shoot I want to do this weekend! Consider me your first investor!

-Joel

October 11, 2007 11:59 AM  
Blogger Will Foster said...

Would the antenna booster that you are talking about increase power, or just focus the transmitting signal? When i got my Pocket Wizards i explained to everyone about the range, and they mostly responded, "Cool, but why?" and i would explain to them that if they can work at that distance, then they will work REALLY well at shorter distances!

I tested my Pocket Wizards right when i got them. I had a friend stand next to the flash, and i jumped in a golf cart and kept popping the flash until i got out of range. It was a lot of fun, but then i was thinking, "Why would i want such a distant picture?"

Don: I love your ideas, excellent, keep going with it! It would awesome to see something come up that is compatible with Pocket Wizards! It would be nice to be able to build something like this so i can get one more flash for my setup and not spend a lot of money.

I spent plenty on my main two stands, and I wouldn't think the third needs to be fancy, just "there" haha...

October 11, 2007 12:25 PM  
Blogger bevdig said...

Don, I am a degreed engineer and professional photographer who is in a position to help you with this project. Can you contact me for further information?

October 11, 2007 12:29 PM  
Blogger Q-Master said...

Do you guys want to open a new discussion on the flickr group to better track the CLS improvements with this one ?

October 11, 2007 12:33 PM  
Blogger David said...

Don,
I think the question comes down to how closely one wants to mimic the PW. The device we were mooting would have functioned solely on one of the PW channels - a device which could select from all four would obviously command a higher premium. Having a custom injection-molded housing rather than just being a black project box with a hotshoe glued on also increases the cost (and the value). With $100 Transceivers and $50-75 receivers you run the risk of people deciding that it's a high enough cost that getting real-deal PWs is worthwhile.
Still, I'm interested, and the Vivitar 285 idea sounds really excellent. Keep us informed.

October 11, 2007 12:33 PM  
Anonymous Anonymous said...

If the parabolic reflector is used in sunlight, the antenna can get VERY hot. An RF reflector doesn't have to be shiny silver. If you cover cardboard with aluminum foil to make the reflector, bend the thing so the cardboard surface points towards the antenna, not the foil. Unless you have some unusual RF-absorbing cardboard, it will work fine.

October 11, 2007 1:38 PM  
Blogger Kyle said...

I'd be extremely interested in the 285HV mod. Any chance we could start a thread about this somewhere a bit easier to track progress or express interest?

October 11, 2007 1:38 PM  
Anonymous Chris said...

Don,
Sounds cool,
check out

http://forums.everythingrobotics.com/index.php

and

http://wiki.everythingrobotics.com/index.php?title=Main_Page

for some help from the Strobist Wireless Trigger Project.

October 11, 2007 1:53 PM  
Blogger mtreinik said...

David, sorry for spamming, since I already tried to reach you through email. It just occured to me that you might be checking the blog comments more often.

I wanted to give a small wedding anniversary present to you and Susan, but The "Make a Donation" button on strobist.com brings me to a paypal page that says Page not found.

Happy anniversary!

- Mikko Reinikainen, alias mtreinik on flickr

October 11, 2007 2:07 PM  
Blogger efrudd said...

Shucks. If you want distances greater than 3/10ths of a mile, you just need a pair of walkie talkies and a carbon-based trigger...

"Ok, ready? On three. One..two..."

The added benefit is you can easily communicate any changes in light position that are required.

Eric

October 11, 2007 2:34 PM  
Blogger Zeke said...

Don,

Please get hold of me through here:

http://www.flickr.com/photos/scipug/

Send me a flickr mail so I can get in touch with you.

Very excited about the 285HV mod.

October 11, 2007 2:35 PM  
Blogger Phil Monk said...

Q-Master,
Yes, I'd love to see what we can do to improve CLS distance and reliability, especially in sunlight, where the IR sometimes has a hard time reading the signal from the master.

Phil

October 11, 2007 3:07 PM  
Blogger Don said...

a device which could select from all four would obviously command a higher premium.

Supporting 4 channels is no more difficult than one channel- I can't imagine not just supporting all 4 channels.

Having a custom injection-molded housing rather than just being a black project box with a hotshoe glued on also increases the cost (and the value). With $100 Transceivers and $50-75 receivers you run the risk of people deciding that it's a high enough cost that getting real-deal PWs is worthwhile.

Well with custom injection mold you're talking $100 for a transceiver and $50 - $75 for a receiver only. If people just want a board they can throw into a project box then you're talking about half the cost- $50 for a transceiver, $30 for a receiver only. I'm going to jump over to the wiki and see what we can put together there. Honestly the Vivitar board interests me more than the PW replacement (though obviously it's similar technology so if I do one, I might as well do both.)

October 11, 2007 4:38 PM  
Anonymous Anonymous said...

Not that I'm complaining -- my PWs have done everything I've asked of them -- but just for the record: PW IIs are advertised as having a 1600 foot trigger range. Doing the math, 5280' in a mile/1600' = 3.3. So we should expect 3.3 tenths of a mile range, unmodified, under good conditions, not a "mere" 2 tenths!

October 11, 2007 5:17 PM  
Anonymous Anonymous said...

Dave - FYI, atmospheric conditions will NOT affect point-to-point, short-range operation at the 344 MHz frequency used by PWs.

October 11, 2007 11:55 PM  
Anonymous tuthdoc99 said...

@ Don.....definitely interested in both receiver and or transeiver. Black box is fine with me if it lowers the cost significantly.

BTW, the link on the blog page doesn't work for me either....have tried several times since it was first posted.

October 12, 2007 10:52 AM  
Blogger Q-Master said...

There is a thread going on on flicker, post you testing results there
http://www.flickr.com/groups/strobist/discuss/72157602372888347/

October 12, 2007 11:29 AM  
Anonymous Antenna Manufacture said...

GENIUS.
the strobist blog is genius.

Cheers,
Lily

October 23, 2008 3:30 AM  

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