problems with sennheiser signal etc

[Ben.]

am currently working on a rather interesting gig, but having problems with signal cutting out on my radio mics.

 

We are using 10 sennheiser e300 g2 transmitter packs and recievers.

 

2 of the recievers are using their own antenna, the other 8 are using the sennheiser paddles.

the 2 recievers using their own antenna seem to be working a lot better than the other 8, however I think this shouldn't really make any difference.

 

the show is all sat on a small ( 6" ) raised platform, with 9 x 8m box truss at a height of 4m. acting on the round.

the paddles are located around shoulder height on 2 of the corners, with paddles sat vertically on mic stands, square on toward the middle of the stage. we have tried all sorts of orientation for the paddles, however nothing has improved the signal.

 

please give me some suggestions as to why or anything that I can do to improve things.

its getting desperate measures, the show goes up weds eve, however I really need to get this sorted before then.

 

Thanks.

 

Ben.

[Shez]

What kind of cable (length & type) are you using between the paddles & ADU?

Do you have boosters at any point in the line?

[Ben.]

we are using bnc connections, so running down co-ax cable we have no boosters in the sig chain, cable length of about 8-12m, we have since my original post tried to seperate the power lines and the bnc lines as far as we can, this has improved things a lot, but there are still a few issues.

[mackerr]

we are using bnc connections, so running down co-ax cable we have no boosters in the sig chain, cable length of about 8-12m, we have since my original post tried to seperate the power lines and the bnc lines as far as we can, this has improved things a lot, but there are still a few issues.

The real question is what kind of coax? There should be no metal objects near the antenna, and the paddles should be pointed at the acting area like an arrow head. what kind of antenna distribution system do you have for the 8 receivers using the paddles? If it is active, are you sure it is getting power? I have made that blunder and it's hard to admit. It is important that the coax is a double shielded low loss variety, not RG58 or 59.

 

Mac

[Bobbsy]

It's probably worth having a look through THIS THREAD where lots of potential problems were discussed.

 

Beyond that, things to look at are: (and I'll likely be repeating some of the advice above)

 

-I note you mention ten channels. Be aware that Sennheiser only recommend 8 channels on a single UHF TV channel, i.e. 69. I suggest you download their SIFM software (free on their site) and check the frequencies you're using (and have it recommend better if necessary).

 

-Make sure you're using high quality, low loss, 50 ohm antenna cable (something like RG213 at the least). RG58/59 runs over a couple of metres are often the cause of problems.

 

-Separate your remote antannae as much as possible. On a true diversity system, the farther apart the two antennae are, the better the chance that at least one will have a good signal.

 

-Try hooking up some of the "problem channels" direct to the antennae without splitters. Passive splitters can be lossy; cheap active splitter and boosters can introduce nasty phase jitter which upsets receivers.

 

-Make sure the transmit antennae aren't getting hooked up/bent under the actors' costumes. This can reduce performance significantly.

 

I'll likely think of more later, but that should be enough to be getting on with!

 

Bob

[errol]

If you mean A1031-U as your paddles(antenna), these are omnidirectional, so orientation is not that important, what is important for them is that you get them as close to the transmitters as you can and keep them away for metal work.

 

I assume that you are using two Sennheiser ASP2 to divide the antenna signal to your receivers with out an amplifier. If so then your problem could be a lack of signal. The ASP2 divides the signal up to five ways so each receiver only get 1/5 of the original. One way to fix this is to use an antenna amplifier (Sennheiser's AB2) to make up for the loss in the ASP2. These should be added at the antenna end and not the receivers as there is no point in amplifying the signal after you have lost a bit in the cable.

[Ben.]

Thanks all for your suggestions on solving my radio mic dropout.

We are half way through the show and have had not problems so far.

In order to fix the problems we tried to decrease the signal cable length and use higher quality sig cable,

we have also tried to keep the paddles as far away from the metal work as possible.

Antenna amplifiers have been kept as close to the paddles as possible, and after manually tuning in all the transmitters and recievers things seem to be working well.

 

So thanks very much for all your suggestions.