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4x SRc on whips in a bag. Can I get away without RF distro?


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How many receivers is too many in a bag before RF distro becomes necessary?

 

My regular bag is two SRc receivers on whips.  I find reception acceptable but not great.  Am I screwed if I add two more SRc on whips for one scene?  How much of a chance am I taking to run all four SRc receivers on whips in a bag?  I would distribute the receivers on the outside of the bag in holsters (I have an old Petrol bag that lets me do this).

I know I should ideally use RF distro to use two external antennae for all four receivers, but I'm having trouble justifying the added cost and complexity for one scene.

In addition to Lectro receivers, I have Zaxnet Tx (2.4Ghz) and a Comtek Tx (216MHz) in the same bag, plus a likely camera hop Tx close by.

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2 hours ago, Dejan Ceko said:

AC/RF distro would be nice investment and problem solver for your future work.

Bunch of parallel whips in the bag are "RF disaster" :D


I think I would add two things here. A RF distro is a good problem solver, but it can also be a problem adder.

 

And I disagree that a bunch of whips are a RF disaster. What’s wrong with a bunch of whips?

 

They said that they will have other TX in the bag, such a camera hop which will likely be quite close in frequency range to their receiving antenna. In a bag situation - with antennas not remoted -, the likelyhood of overloading a compact, low-current, high gain RF amp increases drastically, especially if using one without an RF overload indicator. The intermod products of a distorting RF amp aren’t exactly great either in a bag.
 

So I think that’s seriously worth keeping in mind.

 

The question was, would you be fine just adding two more SRc receivers with whips to your bag. I don’t see a problem there. 
 

Would you be able to get more range out of the system with remoted antennas by using a dipole or sharkfin with an antenna distro? Very likely yes.

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Why I would go for the system with the distro :

1. RF / Better , more controllable and more stable . This could be achieved via combinations of adequate antennas (dipole,lpda,heli...) , low loss cables ,  filtering , gain compensation (or attenuation ) ...

2. Power / Most of your system (if not all) can be powered via one source .

3. Other / Moving to "On the Cart" type of working is very easy (One 3-4 meter long stand for the antenna's , chair , table ...and coffee ) . Cleaner look of the bag .

 

Cheers.

 

 

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Thanks!  The antenna farm is exactly the problem I'm trying to avoid by adding RF distro.

 

And Jason Porter's real world experience is what I'm looking for in terms of what I can get away with.  I know 8 whips on 4 dual Rx isn't a good idea.  I want to know if I can get away with it.  It sounds like if I remote my camera hop & IFB Tx, maybe I can.

I agree, it's not a bad investment to make, but it's not an investment I *want* to make ... 99% of the work I do is 4ch or less, and my long-term plans would involve a different recorder & different receivers if I were to build a cart system, which would mean investing in a different variety of RF distro than what I need for this one scene.

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I think loads of us have probably used 4 receivers in a bag with acceptable performance.  bags change shape with job needs.  I've used 3 with whips many times, 4 less often, but often enough.  Unless you need max performance on everything you'll be fine (i.e. if you're near the scene/subjects and they aren't 150m away).    I also us an RF distro, but keep my whips in the bag if everything gets overloaded...usually if everyone is in close proximity. I wouldn't worry too much about it.  You said it was short term, right?  go for it.  

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Can someone please explain why an antenna farm is a bad idea? How does adding another pair of whips affect the performance of anything else?

 

I moved from whips to 2 dipoles and a PSC RF Multi SMA because you really do see and hear a difference in range.

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1 hour ago, BAB414 said:

Can someone please explain why an antenna farm is a bad idea? How does adding another pair of whips affect the performance of anything else?

 

I moved from whips to 2 dipoles and a PSC RF Multi SMA because you really do see and hear a difference in range.

 

The reason being is that the antennas create an EM wave from the from the current that is passing through the antennas that can interfere with neighboring antennas.

 

https://www.rfvenue.com/blog/antenna-farms

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How much range do you need?  I've done doco audio for decades with 4 411 RX in a bag on their own whips, so 8 whips total.  I'm not doing reality TV etc etc but in general use it works fine if I've been careful about freq coordination.  Think carefully before adding a complex system to a run-gun setup.   For longer distances, as in cart-recording for drama etc,  shared (big) directional antennas with RF distro are the bomb.

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On 9/11/2022 at 5:05 PM, The Documentary Sound Guy said:

I know I should ideally use RF distro to use two external antennae for all four receivers, but I'm having trouble justifying the added cost and complexity for one scene.

 

You're just renting in two more SRc to supplement the two SRc you already have, just for the day for this one scene?

 

Yeah, don't bother with an RF Distro, especially as all the talent will be close by to you it sounds like. (just do sensible scanning and frequency coordination beforehand)

 

Only if you were buying the extra two SRc then would I suggest you should be considering more seriously getting an RF Distro, as you'll be having an using your four SRc many times more during the future years to come. But if it is just a one off event for the day? Keep it simple. 

 

On 9/11/2022 at 5:05 PM, The Documentary Sound Guy said:


In addition to Lectro receivers, I have Zaxnet Tx (2.4Ghz) and a Comtek Tx (216MHz) in the same bag, plus a likely camera hop Tx close by.


What block are your receivers on vs your camera hop TX? Keep those blocks as far apart as possible, and keep the TX physically as far away as possible too. 

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7 hours ago, IronFilm said:

 

You're just renting in two more SRc to supplement the two SRc you already have, just for the day for this one scene?

 

Yeah, don't bother with an RF Distro, especially as all the talent will be close by to you it sounds like. (just do sensible scanning and frequency coordination beforehand)

 

Only if you were buying the extra two SRc then would I suggest you should be considering more seriously getting an RF Distro, as you'll be having an using your four SRc many times more during the future years to come. But if it is just a one off event for the day? Keep it simple. 

 


What block are your receivers on vs your camera hop TX? Keep those blocks as far apart as possible, and keep the TX physically as far away as possible too. 

I have a small stingray bag that makes keeping the Tx far away a pain. But I got the 1/4 wave antenna which I feed up through my harness and that does the trick.

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My receivers are B1 (mainly in 21 & 22).  My Tx are Zaxnet (2.4GHz), Comtek (216MHz), and Sennheiser Block A (518-554).  So it's really just the Sennheiser that is seriously in the way.  I'll remote it and leave it at that I think.  The SRcs will all hang off the outside of the bag; they aren't all clumped together, so it should work out ok I think.

Thanks for all the advice.  I'm glad to hear other people are using 4 receivers without serious issues.  I'm sure it will be fine for one scene.

BTW ... does anyone know if the antenna farm issue remains a problem even when the receivers aren't active?  I would think the current would be induced regardless of whether the system is on, so my guess is yes, but I'm not 100% clear on that point.

 

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It can be done.  Back just before covid, we did a four or five camera round table style shoot, and one of my A guys did 11 channels, using SR's on whips(maybe a 411A or two, too), out of two bags.  Amazingly enough, there was not a single hit, drop-out or other audio problem.  I'm sure there was more than one prayer said...  I just wish it had gone as smoothly for us on the camera side.

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