I finally moved up to the wireles mic age, but admit I have problems. Two weeks ago I DJed a Car Cruise I had the amp on a platic milk carton (on the ground), and the mic transmitter on table behind the mixer and of course I got feedback, then last weekend I did a city wide pool party. So I thought OKAY I know what happended last time so I will do it different, same results FEEDBACK. This last time I put the mic transmitter on the plastic milk carton and the amp on the table...what am I doing wrong?? I ended up usuing a wired mic and no problems go figure!!!!

Hard to tell without knowing what model or type of wireless mic you have. Assuming the unit has a gain control on it, you might want to turn this down <50% and use your mixer to control the overall level and feedback control, just like a corded mic. Is your unit a UHF, VHF or FM transmitter? How many channels do you have available? Have you tried switching over to a different channel? Hope this all helps/makes sense.

ROQ out.

Where to begin.

Perhaps it wasn't feedback but rather noise due to signal loss.

There are many reasons. Poor antenna placement, cheap wireles gear? Condenser unit, dynamic unit, polar pattern? Frequency response? Channels, are they fixed channels or selectable? Interference? Frequencies compatible with your area? Signal strength? Diversity? True Diversity?

And like the other guy said, gain. Gain on the transmitter itself? Gain on the receiver unit to the console or mixer?

Personally speaking, I have my gain on my wireless transmitters CRANKED(weak female vocalists, man I hate them!) and by default, I have my transmitter outputs cranked up all the way since it matches to line leven. Then I usually have to use a 20db pad on the console(matching a line level to a mic level is why), and then bring up the gain at the console just a tad. I NEVER have feedback problems except in high SPL environments where they insist on being in FRONT of the speaker at close range. Mic selection always plays a big part. A Shure SM58 is a great mic, but isn't the best mic for all people. For most girls(and especially girls with thin and weak voices), I find using a handheld condenser, be it wired or wireless, works much better on getting their voices captured with more gain and less feedback. Heck, I'm about ready to just go all condenser!

I did a show a few years ago with some cheap VHF wireless units and it wasn't feedback that was killing me, it was the poor signal reception, which sounded like feedback. That's where I would START looking. Those units went right back to the store. I was so angry with those. My more expensive VHF worked fine as did my(then) 2 UHF units.

Also, put your antennas HIGH!! You want if possible as clear of a line of sign between transmitter and receiver. ALWAYS!! I use remote antennas and an antenna splitter/amplifier/distributor unit since I have 4 UHF units. I save my VHF unit for "emergencies". I plan on getting 4 more UHF units and 2 more VHF units. Use the VHF for on-stage wireless, the UHF for vocals and mic'ed instruments. I have to run my wireless from front of house since I also have to do monitors and having both UHF gear AND the external antennas and that distro really help a lot.

I think it's cheap VHF units with too much interference and/or distance. It's not the microphone. It's the wireless units and your placement choice.

Sorry, but your words like "amp on table, receiver(not transmitter) on milk cart", wow. I never did that sort of thing. All my gear has always been and always ever will be in racks. But I've never been a DJ and I've always been a pro sound company. Remember, the handheld or body pack unit is the transmitter, while the bae that plugs into your mixer is the receiver.

make sure whatever mic your using is UHF and has true diversity.

That's not a 100% true statement.

I can get better results using VHF in certain environments and am glad I've stubbornly held onto my VHF system as a result. Saved me many times.

You've got to think multiple things:
As clear a path as possible between transmitter and receiver
Distance from transmitter and receiver.
Antenna positions and angles, especially taking into consideration if the antennas are full, halft or quarter wave antennas and are they directional.
Absorbtion of signal. All those meat bags walking around and the like can "soak up" a signal.
Metal, mainly in regards to metal to ground issues, and also metal not to ground issues.
Transmitter strength. Is this variable? Do you have a high and low setting? I set mine to high. Batteries are cheap, just do it.

On a stage for instruments, depending on the instrument, due to signal companding, a VHF can outperform a UHF, especially when it comes to lower frequency response. Guitars also tend to often be a tad more receptive to VHF as well for similar reasons. Go from transmitter pack to on-stage rig. This leaves anything that goes DIRECT to a console is using UHF and no way they signals are stomping all over each other.
As been mentioned before: Signal availability. Is this signal open in your area? Is your system "frequency agile"? Do you have a choice of a few frequencies? UHF systems, such as my Audio Technical 1400 series are UHF, but are fixed frequency systems, and as such, aren't going to be able to work everywhere and as a matter of proof, there is some television station operating outside their allocated range and is causing grief on one of these two systems. But, my Audio Technica 3000 series are "frequency agile" and I can change them through a fairly decent range. My VHF, however, is on what is called a "Travelling frequency", which means it SHOULD be able to be used everywhere. My problem was at one event, they were also using that frequency for the video slacker, so I was able to listen in since I had nothing better to do during that point in time.

True diversity is a must. That doesn't merely mean two antennas, it means active electronics in the unit itself that will differentiate between the signal arriving at both antennas and choose the stronger and less phased signal of the two signals received. Sometimes, two antennas can just mean more "signal reception area", so don't use that as guideline. Unit that use true diversity will say so flat out with no imagination required.

So, get your receivers up as high as you can, use remote antennas if you can and quality signal cables, set your transmitters for high power mode, make sure your frequencies aren't being used and you are starting in the right direction.

Wireless looks easy. It can be, but when problems crop up, wireless can be your worst enemy.

I am moving from 5 channels of wireless microphones to 10, plus adding up to 8 channels of wireless in ear monitors. That's a LOT of wireless. Gotta keep everything under control, and that's OK until I go somewhere and have to change frequencies and don't have a fancy software based control system. But, I will when I get there.

Also, have the people speaking INTO your microphones actually give you something to work with. But that's another issue!

Why does this Chris person go on and on and on...can't he answer in a sentence or two??

Why do I go on and on and on(and on)?

Because simply put, you're asking questions that don't have simple answers. And on top of that, the people asking the questions refuse to provide basic details such as "what model, what frequency, where do you live, structural issues, cabling" and all sorts of things.

But people don't want an answer of:
You're using junk gear. Trash it and buy something better than what came free on your box of Cracker Jacks, OK?

With Mad Mikey saying "use UHF and true diversity" sounds good, that's not sufficient. Is all the UHF used up in the region? How large are the guard bands? VHF can be equally reliable in areas with low VHF saturation. And case and point, VHF has less frequenc roll-off, making it many times more suitable for guitar and bass instruments for on-stage wireless usage.

I see people saying "use this, use that" and not quantifying the statement.
There's a thousand reasons why wireless might not work. But if you want to take a cheap dig at me, then please, by all means do so, if that is what feeds your ego.

In the meantime, I'm giving useful advice that completely and thoroughly aswers questions. If that is a crime, then please convict me now and put a bullet in my head. Life's too short for bad sound. Seems people are gunning for me anyways. Like I care. Steal 10K worth of my stuff. Fine. I'll get by, despite having to now grovel and have my wife's birthday, my birthday, Christmas and my vacation ruined. But hey, that's life. I enjoy losing half a million dollars in busines apparently because some bottom-feeder can't figure out how to respect the property of others.

So, if you get off trying to give a one-liner, let me say this:

I am glad you are a person who speaks their mind. It is also obvious you are a person of very few words. Good thing you don't have all that vocabulary jumbling around in that skull case, you might get hurt.