Radio mic problems

[soundspider]

Hi,

 

Really sorry if this has already been posted, but searched and couldn't find anything.

 

Basically we're having nightmares with radio mics in our church since November. We had a Trantec S2000 which worked perfectly for about 8 years, then started making fistling sounds, surges in volume then dropping out. Since then we've tried 2 different Trantec 4.4's, an AKG PT40, and a SmartWireless U100B, all of which have had the same problem (we're on a budget, as you can tell). We have moved the receiver up to the front of the church (so within about 5m of the transmitter), but didn't help. I've watched the RF levels esp on the 2 Trantecs and they completely drop out at times for no reason, giving the audible problems mentioned above.

 

I borrowed an old mic (about 7 years old) from another church - I think its an old version of the AKG PT40 - and it has worked perfectly, oddly, irrespective of positioning of receivers etc. They won't let us keep it ;)

 

We're amazingly confused, especially with 1 mic being fine, and pretty fed up as you can imagine, so would be great if you had any insights as to either how to diagnose the problem, or get round it!

 

Thanks.

[smalljoshua]

How are you powering them? New Alkaline Batteries or Rechargeable ones?

 

Josh

[J Pearce]

I'm guessing the old mic you borrowed is a VHF, whereas the ones you mention are all UHF (except your original S2000), and UHFs are more sensitive to surrounding metalwork and static.

 

But, also look for any change when it all started going wrong.

 

Has the layout of the church changed? New furniture?

Has the vicar or their clothing changed?

Have any new buildings gone up around the church?

[Dmills]

What frequencies are you using, and has digital telly or Tetra just come on line in your area?

 

Regards, Dan.

[soundspider]

Thanks for the replies - will try to answer as best I can.

 

We're using new Duracell Procell batteries in them, so don't think that should be an issue. The old mic is a UHF - the only VHF is the old Trantec. Frequencies tried are 863.15, 863.725, 864.15, 864.85, and the VHF was 173.8. As far as I know, digital telly has been on in the area for ages (I don't actually live that close, so not exactly sure) and, erm, I don't know what Tetra is!

 

No new layout in the church, we did start using an electric heater at the time, but the problem has happened even when it has been switched off. Same old vicar, and he told me he got a new suit around the time, but only wore it twice and the problem has happened with his old clothes as well. No new buildings either around the place.

 

I was wondering if things like I-phones and blackberries could have an effect on it? Saw a wee thread about wifi interfering with radio mics. Having said that, I don't know if anyone in the church has one or not - I certainly don't!

 

Does that help?

[Bobbsy]

The interference you describe sounds like what you'd expect if something else was on the same frequency(ies) as you. Is there another church/pub/club/school nearby that could be trying to use the same four de-regulated frequencies?

 

Bob

[soundspider]

We're reasonably isolated, being up on a hill with no buildings within about 100m of us, but to be honest we haven't checked if anyone else is using radio equipment nearby. The old AKG that works is using one of those frequencies too I'm pretty sure - should it not get the same interference as well? Will check it out anyway

 

Is it in anyway a sensible approach to just try different radio mics to find one that works or is there a more scientific way of working out what the problem is? I noticed an earlier thread where the contributor said essentially radio mics are of the devil - I'm beginning to believe him!

 

Thanks again