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Four channel radio triggers

Review of a low cost radio trigger for flash
by Gisle Hannemyr
Published: 2005-06-17.

Update: The Jinbei GT301B that is the the subject of this review was the first low cost radio trigger widely available. It caused a sensation in strobist circles when it first appeared on eBay in the spring of 2005, and became the original “poverty wizard”. It is no longer available, but the design of the Jinbei GT301B is very similar to the cheapest 4 channel 315 MHz/433 MHz triggers still available on eBay and elsewhere.

(Search eBay for low cost triggers).

For an introduction to wireless triggers, you may also want to read our general articles about radio triggers and optical triggers.

1. Introduction

When it comes to battery operated wireless slave flash systems, PocketWizard is the top brand. With 500 meters (1600 feet) reach, and super reliability, they provide very powerful capabilities. The downside of PocketWizard is cost, the top of the line MultiMax costs around $ 295, and the budget model, Plus is $ 165.

There now exists low cost alternatives to PocketWizards with a more limited range and without the bells and whistles. These are sometimes referred to as Poverty Wizards or FleaBayTriggers. The subject of this review is one such low-cost alternative.

The first of these to become available was a simple 4-channel radio slave made in China by Shanghai Jinbei Photographic Equipment Co., Ltd., sold on eBay under the name GT301B and YHDC-B. I first noticed it on eBay in the spring of 2005.

Price for this unit vary between vendors. At eBay, you usually pay amount $20 for a new transmitter/receiver pair (the actual amount vary from auction to auction). However, some vendors may charge as much as $130 for the same item.

As far as I am able to tell, all the vendors sell a similar unit, from the same Chinese manufacturer. However, several versions exists with small design differences, and with different channel signatures.

The items reviewed in this article (one trigger and five receivers) is a 433 MHz, 4-channel model designated GT301B, and was purchased from eBay in April 2005.

2. Compatibility

Do not expect different versions of the same unit to be compatible with each other, even if they bear the same model designation.

For instance, there exists both a 315 MHz version and a 433 MHz version of the GT301B. These are not compatible with each other. The simplest way to ensure compatibility is to order all the units you need with from the same vendor at the same time. Otherwise, you will need to communicate with the vendor to make sure that any additional units you buy are compatible.

There are additional user comments about compatibility in the comment section below.

3. Product

The phot below show the box he unit came in:

GT301B boxed.
The GT301B box.

Most of the text on the outside of the box is in Chinese, and reads (thanks to peter for the translation):

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.

The transmitter uses a 23A/LRV08 alkaline 12V battery (included) rated at 20 000 flashes. The receiver uses two standard AA/R6 1.5V alkaline batteries (not included) rated at 30 000 flashes.

The trigger voltage of the GT301B transmitter is less than 6 V (my unit measured 4.96 V), which makes it safe for all modern digital cameras. According to the vendor, the receiver is capable of handling old flashes with high trigger voltage up to at least 200 V. It worked fine with my old Vivitar 283 that has a 107 V trigger voltage, as well as my Nikon SB-600 (2.7 volt) and my Canon 550EX (around 6 volt).

While being made from plastic, the unit appear to be of good quality and well constructed for the price. When I accidentally dropped one of the receivers from a height of about one meter on to a hard, wooden floor, it broke open at its joins. However, there was no breakage and after I've reassembled it, it was as good as new.

Some users has reported that dry soldering has stopped units from working. Opening the unit up and re-soldering dry connections has fixed the problem.

Below is a picture of the four items that comes with the basic kit:

GT301B kit components.
Inside the box.

The item on the left is the transmitter. It normally mounts in the camera's hot-shoe, but also have an 3.5 mm mono-plug socket for cameras without a hot-shoe. Included is also a 30 cm (12") cord with 3.5 mm mono-plug at one end and male pc-plug at the other. The item on the right is the receiver – it does not have a hot-shoe, but has a cable with a 1/4" mono-plug for studio flashes. There is also a 1/4" to 3.5 mm mono-plug adapter included in the basic kit.

Pc-socket
A pc-socket is located at the back of the receiver unit.

On the back of the receiver unit is there a standard 1/8" pc-socket (close-up image image of the pc-socket on the left). The pc-socket can be used to connect the receiver to most portable flash guns.

There is no manual included – just an one page “Troubleshooting”-guide. I had no trouble setting it up. After I'd loaded fresh batteries and connected the units, I was ready to shoot.

Operation is simple and intuitive. There is no on/off switch. The transmitter has a “test” button on top (which does what you expect), and the only other controls are two micro-switches which selects one of four channels.

The units seem, however, to be sensitive to battery voltage. There is no “low battery” indicator. Even freshly charged rechargeable NiMH batteries, and slightly run-down alakalines, give poor reliability and reduced firing range. If one experience problems in these two areas, replacing the batteries should be the first thing to try.

It should be noted that the GT301B can only be used to trigger the flash remotely. There is no way to remotely control flash power, as with the more expensive radio systems and Canon's E-TTL II and and Nikon's i-TTL systems. This is an obvious limitation. When you use this unit, you will to work out the flash power settings by hand or by using a flash meter. If you want a complex lightning layout, you also have to walk around to adjust each flash by hand.

4. Connections

The receiver is obviously constructed with studio lights with 1/4" mono-plug socket connector in mind, as is evident from the non-detachable cord with a 1/4" mono-plug at the end.

GT301b receiver and Vivitar 283
The GT301b receiver connected via pc-socket.

However, to connect the receiver to portable flash units, there is a standard 1/8" female pc-socket at the back of the receiver.

The image on the left shows how to connect the receiver to a standard portable flash unit (as opposed to a studio light) via the pc-socket.

Connecting the Vivitar to the pc-socket works well as far as trigging the Vivitar goes, but it leaves the non-detachable 1/4" mono-plug exposed. When I do this, all 107 volts of trigger voltage appear on the exposed metal of the mono-plug, and will give me a nasty shock when I touch it. I've resolved yhis by putting insulating tape over the metal on the exposed plug.

GT301b connected via adapter
GT301B receiver connected via a hot-shoe adapter.

If the flash does not have a pc-connector nor a 1/4" or 3.5 mm mono-plug socket, you need some sort of adapter to get the receiver connected to the flash.

I use a simple two-contact shoe hot-shoe adapter with an 3.5 mm mono-plug-socket. The image on the right above shows a set-up using such a mono-plug to hot-shoe adapter. You plug the receiver's mono-plug into the hot-shoe adapter by means of the 1/4" to 3.5 mm mono-plug adapter.

For studio lights that uses a HH-prong, Paramount Cords sells various adapters.

I've noticed that newer types of cheap radio triggers now come with a standard hot-shoe as part of the receiver. This is obviously a much better solution if you want a trigger for portable flash units.

5. Tests

All tests uses as its subject an ordinary indoor scene (my living room, with a nice white ceiling for bounce). The tests were conducted after dark, so that the flash was the sole source of light. I use the histogram in Photoshop CS to judge exposure.

Timing tests

For my first, simple test, I used a vintage Vivitar 283 and a Canon Powershot G5 with a central shutter. The G5 was set up in manual mode, f=7.2mm (35mm FOV equiv.), ISO 100, shutter speed set to 1/250 second (the maximum x-sync or flash synchronisation shutter speed according to the G5 manual), and aperture f/2.8. The Vivitar was set to bounce against the ceiling in auto mode with an aperture f/2.8.

The GT301B radio slave kit performed as advertised. The exposure was spot on. Lowering the shutter time resulted in identical histograms, which means that the unit is fast enough to keep up with at least a shutter speed of 1/250 second. Increasing the shutter speed beyond 1/250 second resulted in more and more underexposure.

I then tested the kit with a Nikon D80 with a focal plane shutter. This camera has an x-sync speed of 1/200 second. Firing a Nikon SB-800 Speedlight with the camera's shutter speed set to 1/200 second worked fine. However, firing a Nissin Di866 with the camera's shutter speed set to 1/200 second resulted in an image where part of the flash was blocked by the shutter blade. I had to lower the shutter speed to 1/160 second to to be able to use the GT301B kit to synchronise with the Nissin Di866. This is because the Nissin Di866 is slower to respond than the Nikon SB-800, and with the extra delay introduced by the GT301B, this makes a difference.

Here are some other timing tests: Dan Jeter, using a Nikon D2x with a focal plane shutter which has a x-sync speed of 1/250 sec., has posted test images (now gone) that shows that setting shutter speed to 1/250 sec. results in a noticeable shutter blade shadow, and that 1/200 sec. is the top speed that produces reliable results on a Nikon D2x. J.R. Sprawl, using a Nikon D70 with an electronic shutter writes: “With the radio slave, usable sync speed is limited to 1/640 sec. – at 1/800 sec. there is about a 1-stop exposure loss.”

Exposure tests

Again, I used the Vivitar 283 and Canon Powershot G5. The G5 was set up in manual mode, f=7.2mm, ISO 100, shutter speed set to 1/250 second and aperture f/2.8. The Vivitar was set to bounce against the ceiling, auto mode, and aperture f/2.8. As in the previous test, the exposure appeared to be correct.

I then changed the head position of the Vivitar to provide direct flash. This, however, resulted in a 1/2 stop overexposure with noticeable burnt out highlights.

Conclusion: Auto does not always result in the right exposure. If you have the time, make a test shot and check the histogram. If necessary, adjust the exposure.

Range test

The units are not reliable if placed to close together. You need at least two feet between two receives, or a transmitter and transceiver, to stop them from interfering with each other.

My range tests for long distance was conducted outside with fresh alkaline batteries in the receiver. I sat the flash with the receiver attached on a tripod and then moving away from it. Distance was measured by counting paces (not a very accurate method, I admit). I found the unit to work reliable up to about 100 meters (300 feet). Beyond that, it became more erratic and stopped working altogether at around 200 meters (600 feet).

Indoors, I found it capable of working through at least three wooden walls, which is the maximum size of my apartment.

With worn-down batteries, range and reliability is significantly reduced.

While its range is clearly more limited than PocketWizard (500 meters) it is also much better than its rated range (25 meters). I find the range it offers adequate for my needs.

For a more accurate range test, see this user report by FotoFlip posted in the DPreview Lighting Technique Forum. He uses GPS to measure distance accurately.

6. Conclusion

The GT301B slave transmitter and receiver appear to be reasonably well constructed (for its price) and it works as advertised. The top synchronisation speed is less than advertised, but adequate for most users. You may need to work with the histogram or flash meter to get correct exposure in some situations.

With fresh batteries, the units are very reliable. With run-down batteries, reliability is significantly reduced.

In the connections department, the receiver is a bit of a kludge if you intend use it with something that does not come with a 1/4" mono-plug socket or a standard pc-connector.

The main utility of this item is to let users of modern digital cameras use old, cheap and powerful auto flashes such as Vivitar 283 without having to worry about high trigger voltages damaging the camera. It also lets you move the flash unit away from the hot-shoe for more flexible lighting technique.

For complex lighting arrangements using multiple triggers it has obvious limitations, in particular when compared to more sophisticated and expensive flash systems. If you are a professional photographer requiring absolute reliability in all situations, this is not the solution. However, the price is nice. If you are on a tight budget, the low price may more than make up for its lack of bells and whistles.

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15 responses:

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GT-301B vs. YHDC-B

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.
RF regulations

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.

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Bad performance

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.

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Text on the box

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

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High Speed Sync

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.

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@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.

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Connections

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 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.

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Loose sync cord fix

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.
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Building my own rf trigger

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.

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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).

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Reversed polarity

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

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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?).

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