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Antnenna splitters for wireless coms

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Justice C. Bigler:
I'm looking for a powered antenna splitter for wireless coms, analog UHF Clearcom WBS 680 or HME Pro850. I'll have four receiver/base stations (i.e. 8 antennas) and up to 16 belt packs. I'd like to have a pair of antennas close to the base units, and a pair in a remote location. The long cable run is going to be a good 300 feet for the remote antenna location. Basically I want four antennas total, two local and two remote, to split and connect to four different base units (4 in, 8 out?)

I seem to remember seeing something by Lectrosonics that would do the trick, but I'm not finding it on their website.

Mac Kerr:

--- Quote from: Justice C. Bigler on June 28, 2011, 05:09:39 PM ---I'm looking for a powered antenna splitter for wireless coms, analog UHF Clearcom WBS 680 or HME Pro850. I'll have four receiver/base stations (i.e. 8 antennas) and up to 16 belt packs. I'd like to have a pair of antennas close to the base units, and a pair in a remote location. The long cable run is going to be a good 300 feet for the remote antenna location. Basically I want four antennas total, two local and two remote, to split and connect to four different base units (4 in, 8 out?)

I seem to remember seeing something by Lectrosonics that would do the trick, but I'm not finding it on their website.

--- End quote ---

For the transmit side you can use a PWS GX4 IEM transmitter combiner feeding a passive transformer splitter. On the receive side you need 1/2 of a wireless mic antenna combiner, with the 2 antennas going through a passive antenna combiner before going into the antenna DA. On the end of that 300' run you want to use directional antennas to get some passive gain to make up for cable losses. You will also need to use very low loss cable. If this is a permanent install you might opt for LMR600 instead of LMR400 to get a little less loss.

Mac

Karl Winkler:

--- Quote from: Justice C. Bigler on June 28, 2011, 05:09:39 PM ---I'm looking for a powered antenna splitter for wireless coms, analog UHF Clearcom WBS 680 or HME Pro850. I'll have four receiver/base stations (i.e. 8 antennas) and up to 16 belt packs. I'd like to have a pair of antennas close to the base units, and a pair in a remote location. The long cable run is going to be a good 300 feet for the remote antenna location. Basically I want four antennas total, two local and two remote, to split and connect to four different base units (4 in, 8 out?)

I seem to remember seeing something by Lectrosonics that would do the trick, but I'm not finding it on their website.

--- End quote ---

The Lectrosonics unit is the UMC16B: http://www.lectrosonics.com/Multicouplers-Adapters/umc16b.html?qh=YToxOntpOjA7czo2OiJ1bWMxNmIiO30%3D

but it is only an active splitter - 2 in, 8 pairs of outs. It sounds like you'll need to combine your two antenna sets first, using a passive combiner.

We don't make any combiners, but AT does: http://www.audio-technica.com/cms/accessories/7dcbc90353fbf2e0/index.html

You'll probably also want RF amps at your remote antennas to drive the 300' of cable. http://www.lectrosonics.com/182-UFM230/View-details.html?qh=YToxOntpOjA7czo2OiJ1Zm0yMzAiO30%3D

That said - are these com units sending AND receiving RF? If so, the above suggestion won't work - the UMC16B is a receiving antenna splitter, not a combiner for transmitter signals.

-Karl



Henry Cohen:
As per Mac, but with a few comments: How many outbound intercom channels (buses) are actually required, and how does that translate into the number of outbound RF channels based on bandsplits? The point is, you'll want a good quality IEM transmitter combiner, but you want to either turn off one or both transmitter(s) in each base station (and use a 4-way combiner), or get base stations that break out the two transmitters separately (and use an 8-way combiner) so you don't amplify (via the IEM transmit combiner) after the combining of amplifiers (inside the base station).

Start with one TX antenna deployed with a completely unobstructed near-field (6-8 wavelengths), up high. The choice of antenna will be based on coverage pattern required. Walk the entire operational area just listening to the transmission (via some signal source connected to the aux input); you'll be surprised at the propagation possible when the electromagnetic wave can properly launch from the radiating element. If the coverage is in fact inadequate, simply add a high powered passive two-way Wilkenson splitter and run your 300 feet of low loss coax (.4"OD, i.e. 9913, LMR400, CQ102, CQ106) to another antenna. Make sure the two antennas are RF isolated from each other by at least 20dB.

On the RX side, again ensure use of large diameter low loss coax and at least 20dB RF isolation between antennas. As Mac said, if this is a permanent install, LMR600 would be preferable on the RX side, especially over an RF amp, but that's easily determined by calculating out your RF gain structure.

Justice C. Bigler:

--- Quote from: Henry Cohen on June 29, 2011, 12:02:24 PM ---As per Mac, but with a few comments: How many outbound intercom channels (buses) are actually required, and how does that translate into the number of outbound RF channels based on bandsplits?
--- End quote ---
I think I understand what you are asking. We have a two channel com system currently. However, the wireless com stations only run single channel. With our replacement I would like to give wireless access to both of the com channels. So, two channels, with up to 16 users on both channels. After rereading the HME Pro 850 specs it appears that I can use a single base station for up to 16 belt packs if I do not enable the latch function, which provides full duplex communication. Although I would like the system to operate exactly like the hard wired Clearcom system. But I'm not opposed to telling people that they have to push-to-talk.


--- Quote ---The point is, you'll want a good quality IEM transmitter combiner, but you want to either turn off one or both transmitter(s) in each base station (and use a 4-way combiner), or get base stations that break out the two transmitters separately (and use an 8-way combiner) so you don't amplify (via the IEM transmit combiner) after the combining of amplifiers (inside the base station).
--- End quote ---
Perhaps I'm making this too complicated on myself? I guess there is no off the shelf product to combine and/or split antennas for wireless coms across several base stations?


--- Quote ---Start with one TX antenna deployed with a completely unobstructed near-field (6-8 wavelengths), up high.
--- End quote ---
Just so that I know I'm workng in the right direction. Our current wireless com system, and older HME 800 runs in about the 471MHz range. For that system, to obtain a 6 to 8 wavelength clearance from any hard surface, I would need about 16 and 2/3 feet distance from any walls or floors or ceilings? Or am I misunderstanding you?


--- Quote ---The choice of antenna will be based on coverage pattern required. Walk the entire operational area just listening to the transmission (via some signal source connected to the aux input); you'll be surprised at the propagation possible when the electromagnetic wave can properly launch from the radiating element. If the coverage is in fact inadequate, simply add a high powered passive two-way Wilkenson splitter and run your 300 feet of low loss coax (.4"OD, i.e. 9913, LMR400, CQ102, CQ106) to another antenna. Make sure the two antennas are RF isolated from each other by at least 20dB.

On the RX side, again ensure use of large diameter low loss coax and at least 20dB RF isolation between antennas. As Mac said, if this is a permanent install, LMR600 would be preferable on the RX side, especially over an RF amp, but that's easily determined by calculating out your RF gain structure.

--- End quote ---

Our current system is installed in the sound booth in the back of the hall. The antennas are on the back wall of that same hall, just on the other side of the sound booth. I would gladly relocate the receivers, but all the hard wired com stuff ties into that booth. Would it be possible that I would get better propagation back stage and downstairs where the dressing rooms are if the antennas were located on stage? Saving me the hassle of having to set up a remote antenna run and distribution?

I guess it's time to fire up the spectrum analyzer and see what's really going on.

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