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Sound Devices SL6 RF distribution

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Hi,

I have heard that the SL6 RF distribution is passive and that the RF signal loses 6 dB. 

Has anybody measured it ?

Does it mean that the wireless range is not as good as when the antenna is plugged directly in the receiver ?

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Testing with my rf explorer there was no change when I went through the SL-6's rf distro vs. attaching the antenna directly to the RF Explorer. Also, the distribution doesn't seem to be passive as when I power down my 688 the rf explorer stops getting signal from the SL-6

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from the manual:

Using Antenna Distribution Two BNC antenna connections (A and B) are provided for attaching antennas to the antenna distribution system. Antennas with an SMA connection may be used with a BNC to SMA adapter, which is included with the SL-6. The antennas on the SL-6 provide improved diversity performance due to wider spacing than those directly mounted on the receivers. This can reduce the instances of signal dropouts due to destructive cancellation of reflecting RF signals. Good performance will be obtained when antennas are mounted directly to the SL-6 BNC connectors. Quarter wave whip antennas are typically used in this scenario with the SL-6 housing providing the reference plane. Better performance will usually be observed with a higher elevation of the receive antenna. This can provide a more direct line of sight to the transmitter which improves signal strength. Shoulder mounted antennas are one example. Care should be used with antenna selection in this scenario. Some antennas, such as quarter wave (also known as quarter wave whip antennas), require a ground plane (metallic reflective surface usually perpendicular to the antenna). Others, such as a half wave antenna and log periodic antenna (Also referred to as paddle antenna), can be remotely mounted and do not require a ground plane. For best performance, Sound Devices recommends directional remote antennas. Independent 12 volt antenna bias for powering active antennas is provided at each SL-6 antenna BNC connector. Many variables are involved with a successful RF link. As such, results for each operation may vary. Antenna Bias Power If needed, 12V bias power may be provided to each antenna. To supply bias power to an antenna: 1. Press the MENU button to access the Main menu. 2. Do one of the following: X Turn and press the Headphone encoder to select SL-6 > Antenna A Power. X Turn and press the Headphone encoder to select SL-6 > Antenna B Power. 3. Turn and press the Headphone encoder to turn bias power on or off. 11 SL-6 POWERING AND WIRELESS SYSTEM Radio Frequency (RF) Filter The SL-6 provides RF filtering which can allow operation in the presence of interfering signals such as cell phones and TV stations. Selection is provided for four different frequency ranges of operation. To enable the RF filter: 1. Press the MENU button to access the Main menu. 2. Turn and press the Headphone encoder to select SL-6 > Antenna Filter. 3. Turn and press the Headphone encoder to select a filter range.

This may not answer your question,but for more info mail Casey Luft at sound devices.

PS. I own and use a SL6 in conjunxtion with either Lectro block 21 antennas when in bag mode, and RF Venue sharkfin when in cart mode: both work fine!

 

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Thanks for your answers. So it seems that there is no signal loss. Good to know.

Has anybody measured it ?

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Testing with my rf explorer there was no change when I went through the SL-6's rf distro vs. attaching the antenna directly to the RF Explorer. Also, the distribution doesn't seem to be passive as when I power down my 688 the rf explorer stops getting signal from the SL-6

I am unsure about your methodology. When going through the SL-6 how did you measure its rf outputs? Or did you just compare the readout of your rf explorer with of the SL-6?

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On 2/13/2016 at 6:16 PM, Constantin said:

I am unsure about your methodology. When going through the SL-6 how did you measure its rf outputs? Or did you just compare the readout of your rf explorer with of the SL-6?

I turned on a transmitter and placed it 6 feet away. Then, using the antenna that came with the rf explorer, I first took a reading with the antenna attached directly to the top of the rf explorer. Then I attached the antenna to the "B" bnc on the SL-6 and the RF explorer antenna input to one of the "B" sma cables that you would normally attach to your receiver. 

IMG_1968.thumb.JPG.fee102aa0ffad772c3322

IMG_1971.thumb.JPG.411251a1fa200b387b421

In these pictures the signal going through the SL-6 is actually 1dB stronger but they were both hovering around the same level. 

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So with the additional selective filtering-  is the RF performance better than Venue?  I know this is broad question- but i see some have dropped their venues for Sl-6 setups....   

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