jkowtko
Well-Known Member
I just wanted to share my recent experience adding an antenna splitter using cheap components --
I have four AKG WMS450 wireless systems with handheld D5 transmitter, using these as emcee and solo mics for choir, orchestra and jazz concerts.
The AKG systems normally mount the 1/4 wave whip antennas off the back of each unit, but that location doesn't work with standard rack mounting ... instead each unit is shipped with rack ears that will mount a single receiver in a 1U rack space, and provides holes to mount the antennas on the front panel. However this only allows you to mount the receivers one per rack space. The receivers also have tandem mounting hardware, however you lose two of your antenna mounting holes, leaving you with only two mounting positions per pair of receivers. So the obvious need for splitters if you want to keep both A and B antennas outside the rack.
AKG sells expensive splitter/power units in the $500 range. I've always wondered about using cheap splitter components but never tried until now ... I spotted on eBay an aftermarket antenna splitter kit for Shure, that used simple BNC T connectors and short BNC patch cables. So I dropped by the local electronics store last week and bought exactly that ... 2 BNC T 50ohm connectors, and four 1ft RG50 BNC patch cables ... plus tax it came out to $21.
At the event I hooked up the splitter to one pair of receivers, and left the other pair set up with their dedicated antennas, so I could get a good A/B comparison. I still used the 1/4 wave whip antennas, did not change to 1/2 wave. Figured I might as well start with the worst case (and lower cost) scenario.
Signal strength -- no noticable difference by using the splitter. Walking around the room with three mics in hand, the two that were sharing the splitter, and one that had it's own antennas, talking into them all at the same time. Up to 100 feet away the signal was at full strenght, dropping a bit when talking, but the same behavior for split and non-split receivers. During the walkaround test we monitored audio quality with solo headphones, and I listened to the concert recordings afterwards ... no noticable difference.
Antenna choice -- I have both Band 1 and Band 7 receivers from AKG. The Band 1 are the original bands and have the black plastic whip antennas at 650-680mHz ... Band 7 is one of the newer bands at 570-600mHz and have the chrome antenna. Since these antennas are supposedly designed to length to match the frequency band, I though it would be interesting to use the Band 7 antennas on the Band 1 receivers to see how much worse the reception would be. In fact, the reception improved a bit! So my take on this is, not only does AKG not cut the antennas to length per band, but the chrome antennas are likely a design improvement over the black plastic ones. And these antennas look to be very cheap, simple construction if you want to go back to the idea that a coat hanger or piece of steel wire will do just as well.
My tests were with handheld transmitters so I don't know if this will translate well to bodypacks (although theoretically it should) ... but it does leave me believing more than ever that a lot of the antenna component design, packaging and pricing is just marketing hype, and if pressed for funds you can likely do very well with inpensive materials from Radio Shack and Home Depot.
I have four AKG WMS450 wireless systems with handheld D5 transmitter, using these as emcee and solo mics for choir, orchestra and jazz concerts.
The AKG systems normally mount the 1/4 wave whip antennas off the back of each unit, but that location doesn't work with standard rack mounting ... instead each unit is shipped with rack ears that will mount a single receiver in a 1U rack space, and provides holes to mount the antennas on the front panel. However this only allows you to mount the receivers one per rack space. The receivers also have tandem mounting hardware, however you lose two of your antenna mounting holes, leaving you with only two mounting positions per pair of receivers. So the obvious need for splitters if you want to keep both A and B antennas outside the rack.
AKG sells expensive splitter/power units in the $500 range. I've always wondered about using cheap splitter components but never tried until now ... I spotted on eBay an aftermarket antenna splitter kit for Shure, that used simple BNC T connectors and short BNC patch cables. So I dropped by the local electronics store last week and bought exactly that ... 2 BNC T 50ohm connectors, and four 1ft RG50 BNC patch cables ... plus tax it came out to $21.
At the event I hooked up the splitter to one pair of receivers, and left the other pair set up with their dedicated antennas, so I could get a good A/B comparison. I still used the 1/4 wave whip antennas, did not change to 1/2 wave. Figured I might as well start with the worst case (and lower cost) scenario.
Signal strength -- no noticable difference by using the splitter. Walking around the room with three mics in hand, the two that were sharing the splitter, and one that had it's own antennas, talking into them all at the same time. Up to 100 feet away the signal was at full strenght, dropping a bit when talking, but the same behavior for split and non-split receivers. During the walkaround test we monitored audio quality with solo headphones, and I listened to the concert recordings afterwards ... no noticable difference.
Antenna choice -- I have both Band 1 and Band 7 receivers from AKG. The Band 1 are the original bands and have the black plastic whip antennas at 650-680mHz ... Band 7 is one of the newer bands at 570-600mHz and have the chrome antenna. Since these antennas are supposedly designed to length to match the frequency band, I though it would be interesting to use the Band 7 antennas on the Band 1 receivers to see how much worse the reception would be. In fact, the reception improved a bit! So my take on this is, not only does AKG not cut the antennas to length per band, but the chrome antennas are likely a design improvement over the black plastic ones. And these antennas look to be very cheap, simple construction if you want to go back to the idea that a coat hanger or piece of steel wire will do just as well.
My tests were with handheld transmitters so I don't know if this will translate well to bodypacks (although theoretically it should) ... but it does leave me believing more than ever that a lot of the antenna component design, packaging and pricing is just marketing hype, and if pressed for funds you can likely do very well with inpensive materials from Radio Shack and Home Depot.
