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 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.

  • Josh Sommers PRO 6y

    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 6y

    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 PRO 6y

    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.
  • Fabio Aro 6y

    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 other words, if you aim to the subject, it won't fire because of the infra-red beam...
  • Josh Sommers PRO 6y

    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 6y

    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 PRO 6y

    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 6y

    where did you get the blue wire?
  • Josh Sommers PRO 6y


    By the way, the new version already comes with an antenna...
  • hi_spd_lens 6y

    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 PRO 6y

    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 6y

    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 6y

    I have done it with my as well... works just brilliant!!!

    Thank you very much for this.

  • dduncombe 6y

    thank you times ten million peterkangaroo! I was looking for that info on the length forever. Really appreciate the calculations.
  • Dijaraj Nair 6y

    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 PRO 6y

    I don't know. Lots of things could be wrong. Are you connecting via hotshoe or sync cable?
  • Peter Mars 5y

    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!
  • noypi2 4y

  • Josh Sommers PRO 4y

  • Antoine Grid 3y

    Awesome image! 5.
84 faves
Uploaded on June 3, 2007
This photo is in 1 group
This photo is in 2 albums

Additional info

  • Viewing this photo Public
  • Safety level of this photo Safe
  • S Search
    Photo navigation
    < > Thumbnail navigation
    Z Zoom
    B Back to context