Wireless channel sets A, B or C -- any preference? at DVinfo.net

Tom Tomkowiak · October 6th, 2005, 11:44 AM

After a bad experience, I finally decided to switch from VHF lav wireless to UHF. So now I see I have a choice of Channel Sets A, B, or C from Sennheiser.

Maybe I've been checking the wrong places, but I can't find a general explanation what advantage (if any) there is to select any particular Channel Set.

I realize that if I already had other wireless UHF equipment, or, if purchasing additional wireless in the future, the frequency range of my existing equipment would be important. But, since I'm starting from scratch, does it make any difference if I pick A, B, or C?

Greg Bellotte · October 6th, 2005, 12:19 PM

each frequency group covers a UHF tv station channel number (or numbers). sony actually uses the channel number itself. point is, if you are using mics in the frequency of channel 67, in a city that has a station broadcasting on that channel-you are going to have trouble. i'll see if i can put the groups into channel numbers for you when i get back home tonight

after you get your mics, always listen to the reciever channel with the transmitter turned off to see if it is clear first. it does you no good to pick a channel where something already exsists.

Pete Bauer · October 6th, 2005, 01:42 PM

Hi Tom,

I asked the same question before buying the "C" range. I live in suburban Houston and haven't had to adjust the frequency since it came out of the box last year. Links to the Sennheiser frequency charts are in this thread:

http://www.dvinfo.net/conf/showthread.php?t=31301

Some of the audio professionals who post here seem to have a preference for the Audio Technica wireless system, but as an amateur I've been entirely happy with the Senn G2 -- has surprisingly good sound from that little lav.

Tom Tomkowiak · October 6th, 2005, 01:58 PM

Greg,

Are tv stations the only broadcasters in the area I would need to be concerned about? The low end of the A channel set is 518MHz, which is 'way above FM, so I guess radio stations wouldn't be a concern.

Other than tv stations, is there anything else normally to be found in the 518-662MHz range that I need to be aware of, like air traffic control? (big airport nearby)

So, bottom line, there is some logic to picking out a specific channel set for a wireless mic system.

Tom Tomkowiak · October 6th, 2005, 02:08 PM

Pete,

Thanks for that link. Even though the thread is a year old, it answers my questions perfectly.

Greg Bellotte · October 6th, 2005, 06:45 PM

Quote:

Originally Posted by Tom Tomkowiak

Other than tv stations, is there anything else normally to be found in the 518-662MHz range that I need to be aware of, like air traffic control? (big airport nearby)

Tom,

I wouldn't worry about airports, they are usually between 110-240 Mhz. The radar can sometimes be an issue, but that is usually cyclic as it rotates and will disrupt a wide range of freqs when it happens. It has been my experience that many illegal/unlicensed radio transmissions exist. Most probably aren't fully aware of the rules, and low power things are hard to identify/track down. There just isn't enough manpower to police it all. Most cites have a person called a "Frequency Coordinator" designated by the FCC. It never hurts to check with these guys, but most of the time they don't care about stuff as low power as a wireless mic.

ALWAYS check your frequency for traffic first, BEFORE you turn on a transmitter. There's nothing like starting a shoot with a wireless lav, only to hear through your wireless receiver-that housekeeping is out of towels or something. :-)

So as promised, Senn Grp A (518-554) MHz covers TV channels 22 thru 27. Grp B is ch 40-45, and C is 59-64, but it looks like you figured that out in the previous link. Check to see which group has the most unused channels in your area and start there. Don't forget to check for the new digital HD broadcasters, they are most offen on a UHF channel that DOESN'T match the number of the station. Inside of each Grp there are over a thousand possibilites to use for the mic, with patience you should find some clear space to use your mic. And now you know why having the ability to change channels is so important...happy shooting.

October 6th, 2005, 11:44 AM	#1
Tom Tomkowiak Major Player Join Date: Sep 2005 Location: On the NC Crystal Coast Posts: 203	Wireless channel sets A, B or C -- any preference? After a bad experience, I finally decided to switch from VHF lav wireless to UHF. So now I see I have a choice of Channel Sets A, B, or C from Sennheiser. Maybe I've been checking the wrong places, but I can't find a general explanation what advantage (if any) there is to select any particular Channel Set. I realize that if I already had other wireless UHF equipment, or, if purchasing additional wireless in the future, the frequency range of my existing equipment would be important. But, since I'm starting from scratch, does it make any difference if I pick A, B, or C?

October 6th, 2005, 01:42 PM	#3
Pete Bauer Wrangler Join Date: May 2003 Location: Eagle River, AK Posts: 4,100	Hi Tom, I asked the same question before buying the "C" range. I live in suburban Houston and haven't had to adjust the frequency since it came out of the box last year. Links to the Sennheiser frequency charts are in this thread: http://www.dvinfo.net/conf/showthread.php?t=31301 Some of the audio professionals who post here seem to have a preference for the Audio Technica wireless system, but as an amateur I've been entirely happy with the Senn G2 -- has surprisingly good sound from that little lav. __________________ Pete Bauer The most beautiful thing we can experience is the mysterious. It is the source of all true art and science. Albert Einstein Trying to solve a DV mystery? You may find the answer behind the SEARCH function ... or be able to join a discussion already in progress!

October 6th, 2005, 12:19 PM	#2
Greg Bellotte Major Player Join Date: Sep 2005 Location: SLC, UT Posts: 291	each frequency group covers a UHF tv station channel number (or numbers). sony actually uses the channel number itself. point is, if you are using mics in the frequency of channel 67, in a city that has a station broadcasting on that channel-you are going to have trouble. i'll see if i can put the groups into channel numbers for you when i get back home tonight after you get your mics, always listen to the reciever channel with the transmitter turned off to see if it is clear first. it does you no good to pick a channel where something already exsists.

October 6th, 2005, 01:58 PM	#4
Tom Tomkowiak Major Player Join Date: Sep 2005 Location: On the NC Crystal Coast Posts: 203	Greg, Are tv stations the only broadcasters in the area I would need to be concerned about? The low end of the A channel set is 518MHz, which is 'way above FM, so I guess radio stations wouldn't be a concern. Other than tv stations, is there anything else normally to be found in the 518-662MHz range that I need to be aware of, like air traffic control? (big airport nearby) So, bottom line, there is some logic to picking out a specific channel set for a wireless mic system.

October 6th, 2005, 02:08 PM	#5
Tom Tomkowiak Major Player Join Date: Sep 2005 Location: On the NC Crystal Coast Posts: 203	Pete, Thanks for that link. Even though the thread is a year old, it answers my questions perfectly.