Serious Interference Issue with Wireless G2

R

rszebras

Well-known member
I just received my Sennheiser Series 100 G2 ENG kit from B&H. So I scan for channels and all four are open on every bank. Set up the transmitter and adjust the sensitivity. Eveything seems to be going okay but then I start getting serious interference issues. So I track it down and here's what is happening. If I put the receiver within eight to ten inches of my camera, it's loaded with interference. As a matter of fact, if I turn off the transmitter and put the receiver next to my camera (an HV30), every channel has static. If I scan for free channels, not one single channel is available. Move the receiver away a foot or so and no more interference.

As this is my first wireless system, I am at a loss as to what's going on. Is my HV30 giving off so much electrical noise that it can't be used with a wireless system? Is there a problem with the G2 I received?

I have to confess that when I opened the box from B&H, it looked as if the unit had been used. Just an odd feeling I had. Then I noticed sticky substance on the metal belt clip on the transmitter, as if someone put tape on it, and the clip was bowed out too as if it had been used. And the unit was not set to factory defaults. Odd. And I'm not really happy about it.

Here are photos so you don't think I'm nuts. The green light indicates a signal -- close to camera it's on, away from camera it's off.
 

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Try it with the viewfinder flip-out screen closed. I have something like the same interference from a Sony TRV-950 at the office. With wired mics, even.
 
Richard Crowley said:
Try it with the viewfinder flip-out screen closed. I have something like the same interference from a Sony TRV-950 at the office. With wired mics, even.
Click to expand...

Even with the viewfinder closed there's too much interference to use the unit close to the HV30.

As for whether the unit was used, here's a question for those who have purchased new units. Does the manufacturer seal the receiver and transmitter in plastic? With mine they were just in the box loose. The mic and cables were factory sealed though. Maybe it was a refurbished unit or demo?
 
I have never used our G2 portable receiver with an HV30, but i have used it on our GL2, and got no interference, so I think it's safe to say that something is wrong with one of these components.

With regards to whether you got a new or used unit... Sennheiser stopped making the G2's at least six months ago, maybe a little longer. B&H shows all their G2 systems as "Discontinued," with only a few individual components still available. Personally, I find it hard to believe that there are any new G2 systems still out there. That said, while I have certain issues with B&H, I don't consider them dishonest. As John Willett suggested, I think you should get in contact with them.
 
Yeah, I noticed the G2 units were discontinued too. But every now and then units would be available on the B&H website. The last time I saw it available I ordered. I just thought maybe Sennheiser was producing a limited amount and B&H got some. Now I suspect this might have been a return, demo, or refurbished unit. And that was not listed on the B&H site. It was represented as new with a two year warranty. But if this is an old unit maybe there is some problem with it.

I suppose it's possible there is something wrong with my HV30. But I plug in my Rode Videomic and I get great clear audio with very little hiss -- nearly imperceptible. I plug in the G2 and there's a lot of hiss even when the unit is 10 inches away, out of that persistent interference range. Anything above -20db on the transmitter and -18db on the AF Out and the hiss is quite unacceptable. And that's with the mic set to manual and set at 25 to 30 percent level in camera. Again, with the VideoMic there's no issue with hiss using the same settings.
 
You will always get static if you turn off the transmitter. Also you are going in with an 1/8" connection. One really needs a juicedLink type XLR conector on their camera, and use the sennheiser's XLR cable, which is balanced and more robust about defeating rf hits.

Really you need to return the used unit, kick down 100.00 more and get the G3, which has diversity antennae. It's passive diversity, but having both I tell ya, I have not had one RF hit with my G3. Why cheap out for a measly 100.00? For that 100.00 you are saving, you have bought hours of possible audio restoration work to fix potential static. Or worse you could lose a whole shoot over the sound. I'm not saying the G2 isn't great, but it makes no sense to intentionally buy a unit that has a much better decedent (G3) for only 100.00 more.
 
Although something might certainly be wrong, electronics can have varying amounts of RF "spray," even on the super-high end (although such manufacturers usually issue fixes quickly). For a while even pro sound men had to really futz with the placement of wireless Tx/Rx units around a certain brand of field recorder due to similar issues.

If things improve with the distances you show in your pix, and you can't determine the specific units at fault (I'd exchange what you can to test, or borrow identical units from local suppliers to test/troubleshoot), you may need to use a workflow that involves using the receiver on your belt while holding the camera; your body itself may also help shield the Rx if you clip it to the back of your belt.

Be sure to test all permuations as best as you can: Swap cables, borrow another G2 Tx, another G2 Rx, another HV30, test with different freq's, and test IN OTHER PLACES (testing in your home may have totally different results than testing in some other location!)...if you can replicate the problem with other units of the same model, it's probably an unfortunate combo and not faulty gear!
 
rszebras said:
As this is my first wireless system, I am at a loss as to what's going on. Is my HV30 giving off so much electrical noise that it can't be used with a wireless system? Is there a problem with the G2 I received?
Click to expand...


All electronic devices have 'noise'. Digital devices generate lots of noise. Depending on the shielding, depending on how well the shielding has held up, more or less noise will 'leak' through. One of the most readily available 'noise generators' is a GSM based phone. One can hear the 'clack-itty-clack' on old phones because the unshielded wires and coils act as antennae, but I've heard it on 'behind the scenes' material shot using more modern cameras. The Wife can't use GSM because the interference is so great with her hearing aid... it als picks up 60 Hz power hum 'pretty damn easily' in certain circumstances...

The thing is, once you determine that the G2 'cleans' up a foot or so away from the camera, you have 2 basic choices. 1) Find a device, perhaps pay more, that works closer, 2) always locate your receiver at 'some disance' from the camera, ok, maybe 3... 3) replace camera...

At this point the cheapest is just don't get close to the camera.

You did mention that the unit looks 'used'... if it is... who knows where it's been and why it was returned... like for an unsolveable noise problem...

As a note, noise can 'leak' in through a number of pathways, and so, connectors that don't fit quite right, or have a bit of corrosion, or are 'broken' somewhere not obvious, can lead to the shielding being 'less that good'.
 
I've had time to test the system and decided to keep it. It's not the G2 that has been causing the interference but my HV30. On other cameras and into mixers the G2 works just fine. However, when I plug the AF Out cable into the 1/8" mic input on the HV30, that's when this interference begins in earnest. Of course, the 1/8" mic input is not a balanced input so I guess that's why I get the RF interference.

However, I did find a workaround. I use the 1/8" to xlr cable that came with the G2, then I connect an xlr to 1/8" stereo cable to the mic in. This gives me a couple feet of cable. I then let the G2 receiver hang directly below the HV30. In that position it is out of the zone for RF interference. I then get crystal clear audio. If I try to mount the G2 receiver on my tripod, I still get interference even though I have it about two feet away from the camera.

I set the mic in to manual in the HV30, adjust to about 25% to 30% (so the mics preamps don't have to do too much work), and this gives me a good hot signal peaking at about -12db to -6 db. The sound quality is actually quite good. I'm working on a project right now.

I haven't had a chance to call Canon tech support to see if this level of RF interference is normal for the HV30. Also, I plan to do some research to see if there is some type of electrical connector that could isolate the RF interference and prevent it from transmitting down the cable to the G2 receiver.
 
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