Weird China RF triggers


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chanjyj

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Apr 8, 2007
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#1
The cheapo China RF triggers I have (bought one set and one extra receiver, then not happy with quality control, thus went to change for another brand new receiver) all exhibit WEIRD characters.

BAH. I am going to stick to the higher end ones from now on. Wasted my cash :mad2:

  1. It takes 1/40s!* for the signal to be sent from trigger to receiver at 20m** distance! This is weird ain't it? I never knew know that RF signals (433MHz) move so slowly. Or am I missing something here?
  2. The trigger is useless beyond 15m (Even at 15m missfire occurs roughly 20% of the time). At 20m it is pretty much a touch and go affair.

*(You ask me how I know - well, at 1/60s I fire the camera shutter. I can see the flash fire, but in the final photo the flash is not seen. I.e. shutter closes before the flash fires!)[/B]
**At closer ranges like 5m this is no longer a problem, and I can safely trigger up to 1/200s. But then, at 5m range I might as well use CLS i-TTL right? :rolleyes: (Doesn't apply to studio strobes. For Canon E-TTL I am not too sure


Image for your reference. 15m
 

chanjyj

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#3
一分钱,一分货。
Distance wise, if the thing cannot work beyond 15m I will still accept it. But...


It takes 1/40s!* for the signal to be sent from trigger to receiver at 20m** distance

what kind of stupid nonsense is this? And is it physically possible anyway?!
 

chanjyj

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This one, strangely, pass the test.
Forgot to mention though, that they did not pass the test of close proximity. Keep at least 40cm apart.
 

Jan 23, 2005
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#7
Distance wise, if the thing cannot work beyond 15m I will still accept it. But...


It takes 1/40s!* for the signal to be sent from trigger to receiver at 20m** distance

what kind of stupid nonsense is this? And is it physically possible anyway?!
It doesn't take 1/40 s from transmitter to receiver. It may take the receiver 1/40 s to react to the signal. By evaluating the signal for a relatively long time, the receiver gains immunity against electrical noise and interfering signals.
 

chanjyj

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#8
It doesn't take 1/40 s from transmitter to receiver. It may take the receiver 1/40 s to react to the signal. By evaluating the signal for a relatively long time, the receiver gains immunity against electrical noise and interfering signals.

What you say would make sense had the flash not fired at speeds of up to 1/200s at 10m. Why the sudden increase in reaction timing at 20m leaves me bemused.
 

chanjyj

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#9
Thinking back... I did alot of testing (alot means I blinded the whole neighbourhood).

the final part of my testing was at 20m. It may be possible that the 1/40s speed at 20m is due to a low battery. I'll get round to testing it sometime.

Have been thinking of zhnging it and adding an antenna too :think:
 

chanjyj

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#10
Used a coiled piece of wire (5.5cm, should be ideal for the 433mhz frequency, engineers pls correct me if I am wrong ;p)

Works ok now (I no more energy left to walk to 20m again and test at this time of the night) ;p

Strangely, straight piece of wire is useless, wire wrapped round transmitter also useless... only this shape seems to be able to trigger reciever. Really weird. REALY WEIRD JUJU :dunno:
 

chanjyj

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#14
Disappointed. After adding the extra antenna, (despite theoretical increased range of 30m), range remains the same and the furthur you go, the slower the flash responds. By the time I reach 11m, shutter speed has to be approx 1/60s (which means I cannot overpower the sun) and that is, if the stupid receiver fires the flash at all. (I would say failure rate of 50%).

Any engineer here who can advise me on the antenna? I really at a loss now. According to science, I have already done everything right.

(It is not the transmitter or receiver problem. I have already went to change for a new set. Problems are identical)
 

chanjyj

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#16
search the strobist think there is a mod for it. I did it too does improve the signal but I switch to something which is never fail and longer distance. :dunno:
I saw those mods. I use them as a basis for my own mod but realised that their antennas all don't work with mine although we all using the same chipboard.

I had to make a curly shape for the darn thing to work (and must circle around 2 times somemore).
 

chanjyj

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#20
I just let it come out of the casing, you can have mine to test it. After the mod wow it is shoik but still can't beat the real one. :dunno:
I just modded another one. Fed up. This time I just took one antenna and stick on the stupid transmitter. (when I shoot I extend the transmitter antenna up by 3 times).

Look like some stupid alien :angry:

Your real one is what? Pocket Wizard, Bowens or Elinchrom?
 

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