Cactus Radio Trigger - Antenna Mod
I recently purchased a Cactus V2 radio flash controller from Gadget Infinity on Ebay. Although they worked decently out of the box, I personally wasn't getting very good consistancy or distance out of them. So following the lead of some other members of the strobist.com group, I decided to add an antenna.
I used the antenna from an old cordless phone I had laying around in the garage, because the size was perfect and all I had to do was take the old phone apart and I had everything I needed.
I simply soldered the blue wire onto the antenna on the Cactus trigger circuit board. It is a hole in the circuit board with a little silver ring around it.
Next I drilled a hole it the top of the cover to fit the antenna cover through. The antenna cover is rubber and has a square base, so it holds itself in place. The blue wire simply slides into the cover.
With this modification the reliability of the trigger improved to nearly 100%, and the distance from which it will function has grown exponentially. Formerly I could only get about 25 feet away with any success. So far I have been able to get about 200 feet and still it works perfectly. I have not tried any further than 200 feet, but my suspicion is that it will work as far as 1000 feet.
Strobist info: I shot this in a light box with modeling lamps, and put my 430ex inside the box to the left and in front of the trigger. I fired the flash remotely with my Canon STE2 in ETTL mode.
Comments and faves
photo_jeffrey, andrEtna - Andrea Fiore, Andy Brooks, airbiscuit, and 83 other people added this photo to their favorites.
Joe Templeman (61 months ago | reply)
Oooh, thats a bit interesting! Mines a bit different to that though, maybe ive not got the V2...
Josh Sommers (61 months ago | reply)
Joe, you probably have the v1 version, which are fine except for canon flashes (430ex and 580ex) which have problems with that version for some reason. However, even with the V1, I think you should be able to mod it like this. You can use any kind of antenna, or even a single strand of insulated copper wire, speaker wire, etc. I like this mod because it doesn't look so much like a mod, it kind of looks like it is supposed to be like that. Perhaps you can find an old wireless phone, or an old cellphone antenna to use?
Joe Templeman (61 months ago | reply)
Yeah, on a closer look mine is that one! Im gonna give that mod a go later =D
Ive just got to hunt round for an old antenna now!
Josh Sommers (61 months ago | reply)
Joe, I would suggest checking second hand stores, I bet that a lot of old phones wind up in those places. Either that or maybe garage sales? That is if you can't find one laying around your garage like I did! :)
Good luck!
robjwilliams.com (61 months ago | reply)
Joe,
It is not really necessary to have the Mobile phone antenna, or the black casing at least. You can simply buy some thick wire from radio shack or dick smiths and use that. I think the bigger mobile phone cover is more for looks. I have a big green wire sticking out the side of mine and it works great.
Josh Sommers (61 months ago | reply)
Yes that is true. I used the rubber antenna cover for looks, but also for protection, as a wire that is directly soldered to the circuit board and protrudes through a small hole in the case is liable to get tugged on, bend, tangled etc, eventually leading to it either coming free, or worse, ruining the transmitter. Yes they are cheap, but they take a while to arrive when ordered, and in most cases you are just better safe than sorry, IMHO.
Shahran Ali (59 months ago | reply)
are there any mods so that the radio trigger is compatible to use with canon battery pack on 580ex flash?
Josh Sommers (59 months ago | reply)
You don't need to modify the trigger for it to be compatible with any particular flash. The trigger fires the receiver, the receiver is connected to the flash. The receivers are supposed to work with pretty much any flash.
Brad Brains (54 months ago | reply)
Do you mind looking at my transmitter's guts and see if you can determine where I may be able to solder an antenna?
www.flickr.com/photos/30952310@N00/2167729042
It's not a Cactus, but I'm sure I can make this work somehow!
Herb Dunn (YosemiteJunkie) (52 months ago | reply)
This is great info to have. Thanks for putting it together. I'm planning on ordering the V2 set and had been doing a little research when I found this page. Thanks again for the information.
tigerbone (52 months ago | reply)
Does anyone know what the best wire to use? Is 20gauge solid copper wire best? Speaker wire? multistranded copper wire?
Josh Sommers (52 months ago | reply)
The wire I used was just a single strand steel wire I think. I took it out of my old cordless phone, so I'm not certain, but it wasn't copper colored, it was silver color, so whatever silver wires are made out of. :)
tigerbone (52 months ago | reply)
Thanks for the reply! I'm excited to extend the range and reliability of these puppies!
amph1on (52 months ago | reply)
Looks great, I'm going to do this. Modificaton can be done to V2s version as well, right? Does anybody have high resolution pictures so I can see where exactly I have to solder the wire.
Josh Sommers (52 months ago | reply)
amphon1- Per the caption, this IS a V2 trigger. I doubt you're going to be able to find anything that is higher res than the full size of this image. It's pretty easy and straight forward. just read the caption below the image, and look at the full size version and you should be able to figure it out.
amph1on (52 months ago | reply)
Aa, I didn't notice that there's full size image. Sorry about that. I think I'll do allright and can figure it out even if there's some difference in V2 and V2s models.
Josh Sommers (52 months ago | reply)
I'm sorry, I misunderstood your question. I didn't know there was a V2S version. My bad. Hopefully it is the same or similar. Basically you just want to look for a silver lined hole in the circuit board, that is assuming they stuck with a similar design.
amph1on (52 months ago | reply)
I did it today and it works well. Now those GI triggers are just perfect for my needs. :) There's no need to buy anything else. Atleast for now. Thanks for your help!
amph1on (51 months ago | reply)
I have a problem with the mod. It works fine when it's not attached to my camera (Canon 40D). But when it's attached it doesn't work well if I don't touch the antenna. If I touch it, it works great. Any ideas? I'll try to change the batteries and perhaps I'll try to go with a heavier antenna, one from wireless router or so.
If somebody knows what's wrong, I'd really appreciate a few tips.
Josh Sommers (51 months ago | reply)
I think that could mean that the length of your antenna is wrong. Unfortunately I am not any good with wireless technology or signals, etc. I just copied what I heard someone else did, and luckily for me it just happened to work. I would suggest that you poke around the many postings on this subject in the Strobist.com group.
amph1on (51 months ago | reply)
Yeah, I've tried to do that. My antenna is 15cm long, how long is yours? And mine is pretty thin wire... I woudn't like to solder it several times, but I try to do some tests. :)
Josh Sommers (51 months ago | reply)
Mine is about 8cm.
amph1on (51 months ago | reply)
Oh, ok. I think I could try to shorten it a bit. Cut - test - cut - test etc. Mine is 15cm, so it's a lot longer. The whole thing sounds a bit weird. :)
Eugeniu (51 months ago | reply)
can anything be done to the receiver to increase range ?
Josh Sommers (51 months ago | reply)
You don't need to change anything on the receiver to increase range, you need to add an antena to the transmitter to increase range. The receiver will receive any signal that reaches it, you need to change the transmitter so that it sends a stronger signal, and that will increase the range.
chrom4te (50 months ago | reply)
Works for me , range is better, misfires are less.
djjohnmonreal (49 months ago | reply)
just got my GI kit. il try to do this mod. :)
peterkangaroo (43 months ago | reply)
Hmmm.
The length of an antenna is fairly critical to get maximum efficiency.
If it's the wrong length then most of the transmitted power can be reflected back down into the transmitter.
So theoretically any added antenna needs to be approximately the correct length.
Calculations will give the full wavelength of a device operating at 433 MHz at around 665 mm or just over half a meter. But most antennas are not full wave (too long) and are a fraction of that. 1/4 wave being the most common. This then equals 166 mm (16.6) cm which is still too long so going for a 1/8 wavelength we get 8 cm for maximum efficiency. 1 or 2 cms either side can drastically reduce performance. So there you go. And a thick solid copper (or aluminium) wire would be better than multistrand.
I'm about to try it myself.
Josh Sommers (43 months ago | reply)
The wire I used isn't multistrand, it's the antenna wire taken directly from a cordless phone. I guess I must have lucked out because it made a huge performance increase.
GingerMan2 (43 months ago | reply)
Perfect I saw the tutorial on You Tube nice to know this actually worked for someone else also.
nicolasbdotnet [deleted] (42 months ago | reply)
Must doing this for mine.
photocraft01 (41 months ago | reply)
mod equipment cam be purchest here e-bay uk item
cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem& ssPageName=S...
Josh Sommers (41 months ago | reply)
Cactus is releasing a new v4 trigger this month that has a built in antennae.
Fabio Aro (39 months ago | reply)
can you tell me if they do work with e-ttl II or not??
thanks!
Josh Sommers (39 months ago | reply)
Fabio- No, they do not. If you want to use ettl, you need to use either the canon steII or radio poppers, I think those are your only options if you want to use ettl. Personally I do not care for ettl, I much prefer setting the flash manually.
Fabio Aro (39 months ago | reply)
Hey Josh, thanks for answering....I'd rather using manual also, but one of my speedlites does not have manual function, so it wouldn't work at all..
As far as I searched, the only ones that works with e-ttl are the pocket wizards, and some brazilian ones that are called 'radio flash'
Josh Sommers (39 months ago | reply)
For canon speed lights you can use the STE2 for infrared wireless communication with the flash, using ETTL.
For others you can use "RAdio Poppers"- so I've heard. radiopopper.com/
Fabio Aro (39 months ago | reply)
Yeah, I use the ST-E2 for about a year, it's good, but outdoors it gets limited sometimes, specially when you can't aim the flash body to the camera (like when you are using umbrellas, and they point the same direction as the flash body...in other words, if you aim to the subject, it won't fire because of the infra-red beam...
Josh Sommers (39 months ago | reply)
Yeah, I know, I have the STE2 also, and i never use it because it doesn't work very good at all, especially outdoors or with an umbrella like you said.
lilvietkhoa (38 months ago | reply)
hello, what kind of wire were you using?
I have a red wire with 600 volts.. I wonder if that will work, i believe it's copper?
Josh Sommers (38 months ago | reply)
I don't know. Like I said in the caption, I just used the antenna from an old cordless phone. The wire was not copper though, I think it was aluminum.
lilvietkhoa (38 months ago | reply)
where did you get the blue wire?
Josh Sommers (38 months ago | reply)
Seriously? Lol. I JUST USED THE ANTENNA FROM AN OLD CORDLESS PHONE!!!
By the way, the new version already comes with an antenna...
hi_spd_lens (38 months ago | reply)
1.) The color of the plastic wire jacket DOES NOT MATTER.
2.) 600v (volts) means the plastic jacket (cover) is good enough to insulate YOU from electrocution if you chose to run 600 volts of electricity through it.
3.) One single solid wire ( inside the plastic jacket) will perform better than muli - strands inside the plastic jacket.
4) Thicker wire should work better than thin wire, but this is a small
device and the wire must be somewhat flexible to allow the exterior cover to be reassembled. Note: wire thickness is measured by "guage" - lower numbers are thicker than higher numbers-
Example: 18 guage wire is thicker than 24 gauge wire. 20 gauge wire seems to be common, and works well for this mod .
Hope this helps.
Josh Sommers (38 months ago | reply)
Thanks hi_spd_lens- That should be helpful for anyone who is wanting to mod their v2.
My professional advice though: Forget about modding the V2 and get a V4- they don't need to be modded, and they work 100x better than the v2, and are only slightly more expensive.
hi_spd_lens (38 months ago | reply)
You're welcome Josh.
The basic wire "thing" can be confusing sometimes, and when I saw lilvietkhoa struggling with "red wire / blue wire" I had to comment.
Also, glad to hear the v4s are that much better. Thanks !!
foCuseD-Photography (37 months ago | reply)
I have done it with my as well... works just brilliant!!!
Thank you very much for this.
Carsten
dduncombe (37 months ago | reply)
thank you times ten million peterkangaroo! I was looking for that info on the length forever. Really appreciate the calculations.
Diji's Photography [away] (33 months ago | reply)
My cactus v2 Does not trigger the Vivitar 3200 flash guns! what could be wrong? is there any compatibility issue? works well with canon 430
Josh Sommers (33 months ago | reply)
I don't know. Lots of things could be wrong. Are you connecting via hotshoe or sync cable?
Peter Mars Photo (27 months ago | reply)
I have an RPS Studio 4-channel unit, similar to some of the others mentioned here. It however has a basic antenna printed onto the PC board, but only had a range of 25'. It also had a special hole to attach an antenna right in the circuit board. So I added a small screw and nut and attached a coiled up wire to it. Wire is 20 gauge, solid core, and about 8" long. I wrapped the wire around a small drill bit I had handy, and flattened the coils slightly so the cover would fit back on. Works great, no wire hanging out, and it now gives me about 200' range... absolutely amazing!
www.hostzombie.com/flashtrigger/antenna1.jpg
www.hostzombie.com/flashtrigger/flash-200feet .jpg
noypi2 (8 months ago | reply)
no
Josh Sommers (8 months ago | reply)
yes
Antoine Grid (4 months ago | reply)
Awesome image! 5.