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JonG

SRb + PSC Rf Multi SMA?

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" I know the logical thing to say is that they (production) are asking too much, but I cant change the way they see things, "

this seems to be a recurrent theme...

you cannot change the laws of Physics.

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I'm also thinking about a system to optimize the reception of my three SRb in my Petrol bag.

 

Considering that the EU versions of the transmitters have only 50 mW, I have reached the conclusion to use two SRA600 each connected to a UFM230 and then a ZFSC41 that connect the outputs of the whip antennas of SRb.

 

I'd like to know if this could theoretically give me some improvement in areas with a moderate crowding compared to using only the whips. 

 

Sergio.

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" I'd like to know if this could theoretically give me some improvement in areas with a moderate crowding compared to using only the whips.  "

maybe!

 

depends on which TV antenna you use...

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As I said, the antenna is a Lectrosonics SRA600.

Do you perhaps mean the SNA600? Anyway, boosting the receiver signal is similar to using a higher mW on the tx, in that you are likely to increase your problems. But at least this way wouldn't be illegal. The amp is meant to compensate for signal loss due long cable runs. Do you expect long cable runs? Otherwise just try it out. It may work well, or it may be a desaster.

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Are the Lectro antennas on the SRb and SMQVs 1/4 wave? Maybe a 1/2 wave antenna would be better for reception? Any thoughts?

 

Steve Wytas

www.audio911.com

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Are the Lectro antennas on the SRb and SMQVs 1/4 wave? Maybe a 1/2 wave antenna would be better for reception? Any thoughts?

Steve Wytas

www.audio911.com

Yes, and yes

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" Any thoughts? "

optimizing antennae (sic) has been an issue since the pioneering days of Marconi wireless.  It involves lots of physics.

it has also involved lots of trial and error, lots of trials, lots of errors.

there are many things that can, and will, improve antenna performance.  and especially diversity antenna systems' performance.

a good easy one to begin with is physical separation... (this sometimes also involves distribution)...

when an antenna is near another antenna, they end up affecting each other, sometimes for the better (Yagi, LPDA) but often not.

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I'm also thinking about a system to optimize the reception of my three SRb in my Petrol bag.

 

Considering that the EU versions of the transmitters have only 50 mW, I have reached the conclusion to use two SRA600 each connected to a UFM230 and then a ZFSC41 that connect the outputs of the whip antennas of SRb.

 

I'd like to know if this could theoretically give me some improvement in areas with a moderate crowding compared to using only the whips. 

 

Sergio.

Hi Sergio,

Adding gain to an antenna does no good for reception if you don't have  cable or splitter losses to overcome. The amplification gains up the noise at the same time as it gains up the signal so your SNR remains the same. However, directional (gain) antennas "look" at a smaller segment of the world and so pick up more signal and less noise. So if you are in a noisy environment ("moderate crowding"-your words) the only solution is a directional antenna or less distance between transmitting and receiving antennas since you can't use a higher powered transmitter above 50 mW.

Best,

Larry F

Lectro

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Hello Everyone!

I've been using the PSC RF MULTI SMA running 4 SRbs + Lectro SNA600a dipoles with great results for the last 8 months, but very recently the SRs are being sprayed with excessive RF garbage every time I power on the Multi unit. I'll present the specs and the troubleshooting I've tried so far in the hopes that someone here has some advice to get my system back to its proper performance.... 

Nomad + 4 SRb + RF Multi routed through AudioRoot power distro. 

Started with SR Blocks 19/21/25/25 using 2 SNA600a antennas (dialed in to middle freq) and all was good for 8 months. 

Recently changed to Blocks 19/19/20/21 and tried 2 Lectro ACOAXBNC antennas (BK20) - which is when the RF garbage kicked in. I figured it was the ACOAX antennas so i switched back to the (retuned) SNA600s and the unacceptable RF noise continued unabated. 

I've tried other SMA, BNC and power cables, but no change. Even though my Multi has a 13xxxxx serial number I tried a brand new unit with my same setup and still the noise is overwhelming. I've even tried powering the SRbs from a separate power source in case there was a ground issue but the results remain the same. 

Am I missing something? I've heard conflicting reports about terminating the open SMAs on the Multi (which I am not doing) but I didn't have an issue before so I don't think that's the problem.

I'm on a pretty intense shoot that doesn't leave me too much time to keep breaking down, rebuilding and reworking my bag so any pertinent advice would be a greatly appreciated. 

Cheers,

Evan Meszaros

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I also used SNA600's with my RFmulti and all was fine, then Up'd my game to Lectro ALP620's and it's been amazing( 3 SR's, 3 411's) ...however whenever I switch back to the SNA600's (smaller run bag setup/ dump the 411's) they don't seem to play nice any more. 

I would try and get a different antenna (LPDA?) into play and if problems persist I wonder about the RF Multi... also try to disconnecting (one at a time) each sma input to RFMulti, it may pinpoint if theres a bad sma cable, or connection. I assume scans are clear when on whips, just not enough range for you?

Just my 2cents...

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2 hours ago, EnotsMedia said:

I also used SNA600's with my RFmulti and all was fine, then Up'd my game to Lectro ALP620's and it's been amazing( 3 SR's, 3 411's) ...however whenever I switch back to the SNA600's (smaller run bag setup/ dump the 411's) they don't seem to play nice any more. 

I would try and get a different antenna (LPDA?) into play and if problems persist I wonder about the RF Multi... also try to disconnecting (one at a time) each sma input to RFMulti, it may pinpoint if theres a bad sma cable, or connection. I assume scans are clear when on whips, just not enough range for you?

Just my 2cents...

I'm into trying new antennas - but the ALPs are a little to unwieldy for my bag. 

I've tried the one-at-time cable disconnect in every possible way. And a since PSC lent me a brand new Multi to test I don't think it's my unit. The whip scans are significantly more clear than the dipoles. 

Cheers,

Evan

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From my experience the Src seems to have a more sensitive Rf front end than the 411 when I use it with the RF multi 

Maybe Larry has some info about this? 

 

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3 hours ago, chris_bollard said:

From my experience the Src seems to have a more sensitive Rf front end than the 411 when I use it with the RF multi 

Maybe Larry has some info about this? 

 

The SRC or SRB? I've had great results with the Multi and my SRBs for months. Suddenly it's awful. Two of my SRBs just came back from Lectrosonics after a tune-up so everything should be good on their end. 

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