So I read the best way to start setting up your G2 when on a shoot is to scan for available frequencies in your area. You do this by leaving the transmitter off, turning the receiver on, and then going to "scan" in the menu.

So, seems like the last several times I've done this, and mind you, this is all different locations in the Houston TX area, and I've always got "00 channels available".

Is this where we're at now? My G2 doesn't even operate in the ill-fated 700Mhz range, it's in the 500s (or is that even worse????), but I never get even one channel/frequency listed as available.

Now, you may say, how's the actual interference issue? Usually fine, though in some buildings I've had the little hits now and then (sounds like static or something smacking the mic for a split second but no, it's interference) but sometimes it's fine all the time. Still though, this 0 channels thing has me a little worried.

Have you changed the 'bank'?

Ah. Maybe. I never got super duper familiar with the system, and might have done something dumb somehow at some point.

Yeah, you have to change to another bank, there are eight banks, (+1 user set bank) four frequency channels per bank. I can always find a usable channel even in midtown Manhattan. (aka, RF hell)
Setting up the G3 is a little different..

Josh, maybe this will help, from Sennheiser's site: Find Available Frequencies (http://www.sennheiserusa.com/FindFrequency/)

You can search for available frequencies or those with the least RF strength in the area you are working.

Ok. That bank thing sounds vaguely familiar from that one time I looked at the manual back in 2004. There was no social networking, I had more hair, and the world had not yet been introduced to the likes of The Office, Lost, or Battlestar Galactica.

Is the squelch switched off? If so, the scan won't work properly - as every frequency step has noise on it. Set the squelch so you get silence, not noise as an output, then do the scan again.

The only danger with the auto-scan is that here in the UK, it often means the suggested frequency to use is not one of the ones listed on the license - and even in the non-regulated part of the spectrum, there are only enough channels for 4 simultaneous users, and you could come in half way between causing interference to two other users? It also means here, that many users who don't even know they need a license are working on frequencies not available to them - which is an offence. Unlikely that you'd get the equipment seized, but wipe out a licensed user at the olympics and expect the on-site authorities to take action pretty quickly. For a single user, scan can find a nice quiet space between maybe TV transmitters or other users, but a clear space doesn't always mean a legal one!

I'll look at the squelch thing.

I don't think I'll be working in the UK in the near future, but I'll keep it in mind.

Get your self one of these RF analyzers.... Mine has got me out of so many problems with RF set ups, last used on a 14 radio mic job (various makes on several RF bands) with 2 RF IFB sends, RF TB to / from cameras FM +crew.
It helps to know what's where and where the holes in the spectrum are, and for the price a GREAT investment for anyone into radio mics.

RF Explorer model WSUB1G [TES82252P] - $129.00 : Seeed Studio Bazaar, Boost ideas, extend the reach (http://www.seeedstudio.com/depot/rf-explorer-model-wsub1g-p-922.html)

http://www.dvinfo.net/forum/all-things-audio/500753-spectrum-analyzer-working-wireless-mics.html

Thanks. Looks like it was definitely the bank thing (I think). changed banks, tried it out at my house, bam, 4 channels available.

Yeah, you have to change to another bank, there are eight banks, (+1 user set bank) four frequency channels per bank. I can always find a usable channel even in midtown Manhattan. (aka, RF hell)
Setting up the G3 is a little different..

Yep, that's how it works for me. I'm actually in midtown Manhattan as I write this, doing some interviews at a conference. Did a scan and turned up a number of acceptable channels, but had to move up a couple of banks from the first bank to get to them. I'm using a G block G3 set. Works like a charm.