I have both the GT-301B and the YHDC-B. While the Transmitters appear to be the same, they are not compatible with one another. I can not fire a GT301B receiver from a YHDC-B transmitter for example. Nor can I fire the YHDC-B receiver when using the GT301-B transmitter.

The GT301-B receiver has a PC connector, a phono-plug and switches to set the channel.

The YHDC-B receiver does not have the PC connector or switches. It programs its self to match the settings of the transmitter when you push the "test" button on the transmitter. It is not known if the test button sends the same signal as when triggered by the hot shoe or not. I like to use the test button off camera to set my lights and metering. This may be a problem with the YHDC-B.

As far as sensitivity goes I have fired them from 150 feet with no problem. However they do work better with some flashes than other. SB-800 works fine, PZ-5000 not as reliable.

I was hoping I could mix and match these units, but they are not mixable. I think the GT301-B is a more versatile. The programmable channel switches and PC connector are worth the few dollars.

My SB-800 has a standby mode. It goes to sleep after so many seconds. If the flash goes to standby the flash will not trigger on the first trigger from the receiver, so you may need one firing to wake it up (use the test button) and then trigger from the camera.

Not to crazy about the cost of shipping from either Carol Ho or Joe... but that is their way of making a profit I guess.

As far as service goes; Both Carol Ho and Joe sent the units very promptly.

I just received my YHDC-B unit. Both the transmitter and recevier have DIP switches to set the channel. The receiver has 1/4" phono plug and the transmitter has an 1/8" phono jack. I've been trying a few different configurations and though some of these were worth noting:

1. Triggering Canon 420EX: The receiver can repeatedly trigger my 420EX. This is different than trying to use a simply optical trigger for the 420EX. With that, I could trigger it once, but then I'd have to power the strobe off and on again. I been triggering 420EX with some hotshoe adaptors and a PC cable. I was only triggered the strobe about 2/3 of the time. So far, using the YHDC-B, I've trigger the 420EX every time.
2. Daisy chaining: I successfully trigger two strobes from one recieved unit. I haven't tried more than two yet.
3. Optical triggers and 420EX: I tried triggering the transmitter using an cheap, generic, optical slave. I could trigger the optical slave and see the LED on the receiver light up briefly, but the strobes on the receiver never triggered. I know the optical trigger was working because I also had a strobe connected directly to the trigger and then to the tranmitter via a PC cable. Plus like I said, the LED was firing on the receiver. I could trigger the system using the test button the transmitter and everything fired. I'm guessing that the pulse is pretty short from the optical slave and it gets sent, but by the time it gets to the 420EX it wasn't long enough or strong enough to trigger it. I don't have any other optical triggers. I was able to use this same setup to trigger my JTL160 and my 430EZ with no problems.

I somehow got curious about the actual "internals" of these flash triggers. Finally yesterday afternoon I looked inside the GT301-B transmitter & receiver.

These devices are relatively sophisticated and well built considering the price. Both transmitter and receiver are controlled by a microprocessor. (As opposite to general purpose "Garage Door Opener" Integrated Circuits usually seen in cheap Chinese radio devices.)

I'm not sure about the other models, but at least my GT301-B's seems to operate on 315MHz band set aside for "remote keyless entry systems" here in the US.

However, it is a serious issue for folks using these devices in the European Community countries: The 315MHz band is definitely not a license free band within the European Community. On the contrary, 315MHz band is specifically set aside for Earth-to-Space satellite uplinks.

Using the 315MHz version of the GT301-B would be a violation of R&TTE 1999/5/EC directive in any European Community member state.

However, having seen several companies in the European Community offering exactly the same looking products as my GT301-B's, I suppose Shanghai Jinbei Photographic Equipment Co., Ltd is also making European market versions of these devices.

That is to say, "wireless flash trigget kits" operating on the 433.92MHz band. 433.92MHz is a popular license-free band in the European Community, set aside for similar purposes than the 315MHz band in the USA.

(I suppose a properly educated person could guesstimate in which band their wireless flash trigget kit is operating in by opening the transmitter (just like replacing the battery) and looking at the markings on the SAW-transmitter crystal [about 0.4"/1cm diameter metal can on the circuit board.] By my limited experience, marking 315 usually means 315Mhz while 434 usually 433.92Mhz.)

But it should be noted that working on the right frequency is not enough!

The Manufacturer/importer/seller is by law demanded to verify the compliance of the product with the R&TTE 1999/5/EC directive before offering any "license-free" RF device to the public.

Additionally, they have to provide a "Declaration of Comformity" in the product manual (or similar), and both the product and the packaging have to bear proper "CE" markings.

The bottom line is that if your "wireless flash trigget kit" (or any consumer RF device, for that matter) doesn't come with a proper "Declaration of Comformity" and/or the product/packaging fails to bear "CE xxxx" label (xxxx = four digit Notified Body number) -- then it's NOT complying the aforementioned European Community directive.

DISCLAIMER:
I am not a lawyer nor a qualified RF engineer – and I don't even play one on television. So, any of the information on this post may be factually incorrect. Do not hold me liable for any consequences arising as a result of however you use the information posted.

THE DEVICE DOESN'T SYNC AT A SPEED HIGHER THAN 1/45 and only up to 30 ft. Fuji s2/s1, visatec solo 800 flash/ac-30 slave, Radio Slave 4-channel / Flash Trigger / Battery type (YHDC-B)??????

@ami,
I had the same problem with mine. Put in a fresh set of batteries and it should work fine. I couldn't get over 1/45 either, after the batteries I could sync at 1/200 the roof for my Canon 10D.

The Chinese text on the box reads:

Product Features:
microprocessor encode/decode very good interference rejection ability microprocessor controlled; long distance remote controlled low trigger voltage and current; trigger current only 0.01 mA; will not hurt camera standby sleep mode; super low power consumption long lasting battery; can standby for 1 year or trigger 20,000 times

After reading a lot about this radio slaves i still have one question. I know that in the slaves the maximum sync is around 1/1000 and in my 20D 1/250. My question is: Can i use high speed sync (HSS) or FP of a 430EX with those radio transmitter to achieve 1/1000?

I don't have any flash yet (and my budget is low) so I'm trying to find the best way to work remotely and at high speed shutter (if possible). I had already studied the ST-E2, but 4-5 meters don't work in my case.
Thanks in advance.

@Pedro C.
No, these unit do not support HSS/FP (or any of other the sophisticated features that are part of Canon's and Nikon's dedicated flash systems). All it will do is allowing you to fire a flash remotely, by radio.

Hey guys.
For all of you out there frustrated with the 1/4" male plug, here's a great answer. Paramount cords offers custom built cords on their web site. I was able to get three cords for my units with a 1/4" female on one end and the Nikon screw lock (I prefer this to the standard pc for security reasons) on the other end. They work great and delivery was less than one week! Check the website www.paramountcords.com for options and pricing.

I purchased one transmitter and two receivers on eBay from GadgetInfinity (total with shipping $47). I was very impressed with delivery (8 or 9 days) and email followup. The receivers worked well with Canon 420EX and Vivitar 265 but did not work with Minolta Autoflash 360 PX.

I had several email follow ups with the company and they suggested new batteries (did not help) and offered to modify the voltage on one of the receivers (at no cost and no shipping cost back to me) because they thought that might solve the problem. I chose not to pursue this because the trigger voltage of the Minolta and the Canon are almost identical (4.3 volts), while the Vivitar is 199 volts. They asked another question regarding current draw that I could not answer. They did not have another suggestion.

I do not put to hard use, but so far so good. Trips every time, no misfires.

Their web site provides details about which flashes will not work with them and DIY tips for flash misfires with the Canon 430EX and 580EX.

I'm surprised no one has mentioned this issue about the cheap Chinese RF radio triggers: I bought 2, they worked fine for a while, when crapped out. The problem? The sync connector socket on the receiver is held in place with a knurled nut inside the unit. As the cord turns in the socket, the nut loosens, the socket turns, and the wire to the center of the socket came loose. I got it soldered back on (tight quarters, and you'll need a soldering iron with a really, really small tip). To prevent problems try this:

1. take case apart (2 small phillips-head screws), and use silicone calk or some such adhesive to prevent the knurled nut from turning. or
2. quick fix, and effective: use gaffer's tape to tape down the sync cord to keep it from turning.

Hello,
Great review and discussion everybody. Thanks.

I have been researching building my own rf trigger.

It appears that the transmitter would be a TLX 434 chip or similar. These are digital tranmitters which can send data as well (10kbs). These are low power transmitters typically 3db/10ma which is way below the fed regulations.

Adding a large antenna would increase the range (add one to both units) or a smaller if one of the smaller units is not already included on the circuit board.

Decreasing the trigger time will depend upon the resistance in the wired sections of your circuits. Use gold connectors wherever possible and clean oxide off the contacts.

False triggering will more likely be the fault of the camera or nearby interference like another photographer with the same unit! (less likely unless you're in a paparazzi huddle).

To lower the 'theoretical' trigger speed is not really possible with these units. To achieve a lower speed a higher frequency system would be required. Portable phone and bluetooth spectrums of 2.4 Ghz would need to be considered.

I think for the money these would be great little units.

Thanks for all the great info, but I'm probably more confused than ever.

When I work with my Broncolor Impacts, infrared is great when it works, but then there are alarm systems that interfere, even had some problems with existing office lights on location that kept triggering (client swore there was no alarm system).

With battery lights, I reverted to photosensitive slaves, great when you're the only photographer, but now everyone is shooting, so my lightman covers slave, and we try to grab shots, lots of luck. Used GVI (now quantum) very quirky, they work great when I'm home testing them, the minute I get to the job, problems, wireless DJ's interference etc. I worked with early PocketWizards, noticed same problems (any better now?) And which ones? I saw some with LCD readouts instead of 4 position switches. But for a setup with 3 lights they cost a small fortune. It seems I always reverted to hard wiring lights (ok for in home portraits, unthinkable at weddings). For the price I guess I'll try these new Chinese remotes.

Thanks again for the review.

– V. Nicoletti (still wired in a wireless world).

I have a solution to offer for those having constant misfires. Not sure if anyone has suggested or tried this, but since flash triggering is accomplished with a simple 2-wire connection acting as a basic momentary contact switch, any connector scheme you like will work. I have noticed however that polarity matters greatly. I have Norman studio flash equipment that uses standard AC-type plugs to connect flash cords and reversing the plug stops misfires… so reversing polarity at the receiver/flash unit connection, should provide correct functioning. I would say that if you have not changed the transmitter/camera connection from its manufactured configuration, then look at reversing the Receiver/Flash connection polarity.

For more insight here: I always touch my outer PC cable connection (outer shield around the center-pin PC connection to camera) to ground metal on my Norman Power packs before attaching to the camera, to make sure that the flash does not fire. If it does flash, polarity is wrong. Continued flashing and misfiring is the main symptom of reversed polarity.

Good Luck

I solved the cheap pc jack problem by soldering a 1/4" female jack to a Vivitar connector. I just plug the 1/4" plug into that. The problem is that one of them stopped working with my Vivitar 285 (it also misfires rapidly) so now I'm down to just one radio slave. My overall experience has been that these things work OK for about 6-9 months and it's downhill from there (but then again, what do you expect for $30 including shipping?).