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Dipole Antennas on bag/Harness


KGraham045

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Hello,
 I guess I am confused. I assumed that you are using the 2 SNA600a dipole antennas to feed what ever receivers you add to you bag. It seemed like the kit would need a splitter for each dipole, with each dipole output being split to one of the two antennas on each receiver.
 


Thats exactly what i have going there. Two combiners, one over the other.


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On February 12, 2017 at 8:43 AM, alenK said:

Hello and thank you for addressing the question.

It has been my impression that using a better or better placed antenna system results in a net increase in signal even with the drop on a passive split. I am trying to learn about this stuff and still confused about many of the details.

I have assumed  that is why some engineers explain that an active stage is only necessary on a long cable run. Does this advice only apply when using the dipoles or sharkfins on a single receiver?

Is it routine for people using extra antenna systems and multiple receivers to use active splitters in over the shoulder bags?

What products are people choosing to use?

Thank you.

Micplexer2 for both zaxcom and lectro receivers, whips or dipoles outside bag on selfie sticks mounted to the sides. Best flexible setup for range i have ever owned 

-Ken

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I have a Lectro Quadpack, and i attach 2 dipoles to just one sma connection on each of my SRbs. On the other connection, I keep a whip on. My experience is much better range than just whips. Wondering if from mathematical-technical perspective, this makes sense, or am i experiencing the placebo effect?

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  • 2 months later...

I appreciate this thread very much. I have recently incorporated dipole antennas into my bag. I have found that my range has increased, which is great; but also, unwanted rf sources are more prevalent too -- AND, my receivers seem more susceptible to interference. I receive more "hits" when talent wearing mics moves around the room, for instance, and when I scan, more TV stations or rf "noise" show up. I do not have a filter in the system, so perhaps this is my problem, as Rado wrote earlier in this thread. 

I ask the people who really like their dipole-in-bag setups, are you using filters? Would the Lectrosonics PF25 be a good idea? 

Here is my current setup: 2 Lectro SNA600's connected to the PSC Multi SMA, which then connects to an SRb and 411A on block 19; and an SRc in the block 21-23 range. 

I see that if I add two PF25's on block 19 between the dipoles and the Multi SMA, I would need to remove the SRc (which does not cover block 19) from the dipole setup since its frequencies would be filtered.

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I thought the SNA could only cover 100 MHz at a time (about 4 blocks), so how is it you're making it work from 19 through block 23 for a total of 5 blocks of bandwidth?

5 hours ago, Ben Turney said:

I appreciate this thread very much. I have recently incorporated dipole antennas into my bag. I have found that my range has increased, which is great; but also, unwanted rf sources are more prevalent too -- AND, my receivers seem more susceptible to interference. I receive more "hits" when talent wearing mics moves around the room, for instance, and when I scan, more TV stations or rf "noise" show up. I do not have a filter in the system, so perhaps this is my problem, as Rado wrote earlier in this thread. 

I ask the people who really like their dipole-in-bag setups, are you using filters? Would the Lectrosonics PF25 be a good idea? 

Here is my current setup: 2 Lectro SNA600's connected to the PSC Multi SMA, which then connects to an SRb and 411A on block 19; and an SRc in the block 21-23 range. 

I see that if I add two PF25's on block 19 between the dipoles and the Multi SMA, I would need to remove the SRc (which does not cover block 19) from the dipole setup since its frequencies would be filtered.

 

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18 hours ago, BAB414 said:

I thought the SNA could only cover 100 MHz at a time (about 4 blocks), so how is it you're making it work from 19 through block 23 for a total of 5 blocks of bandwidth?

 

The SNA 600 has what are called fat elements (arms). If they were narrow wires for elements, they would be sharply resonate at a single frequency. Being "fat", the bandwidth is spread out over about 50 MHz. Ideally, you would center the arms between the two contiguous blocks you were wanting to use.

Why does the SNA  antenna work well over 4 blocks? It is the definition of "well". There will be 4 or 5 dB of sensitivity loss when you exceed the 50 MHz bandwidth. When you consider that RF levels jump up and down by 30 to 40 dB as you walk around and the usual setup has excess RF signal of 50 dB or so (50 dB more than minimum usable signal), it is obvious why a mis-tuned antenna will still perform.

In a long distance setup, with low signal levels and little RF noise in the surroundings, (Flat Rock, Montana), the properly tuned antenna will give you a slight edge in range. For 98% of the time in typical use, a coat hanger bent in interesting shapes soldered to a BNC would work just fine. For those of us that are anal and use both belts and suspenders, having the whole RF chain as perfect as can be is comforting.

If you really want to cover all four blocks perfectly, a truly wide band antenna such as an LPDA (Lectro ALP600 or others) is a fine solution. Walking around with a pair of paddles on your shoulders will result in good solid RF and knowing glances from those working around you. So, tune the SNA 600 to the middle of your blocks and go onward. Or cut a coaxial antenna to the middle of the blocks. Or there's the coat hanger option also.

Best Regards,
Larry Fisher

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  • 2 years later...

Here is my attempt for mounting two SNA600s in my ORCA OR-30 bag. 

For me it´s important to keep my bag as light as possible (it´s heavy enough) so I unmounted the black heavy blocks from the antenna and put some 3M dual lock on it and attached it to a hardplastic piece from the hardware store. For prevent the plastic to move around some normal velcro is attached on the upside. When the sides are closed it locks the holders in position.

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  • 2 weeks later...

Well here is what i did, 19" flexible gooseneck ($10), i was radio ham in Argentina and work on broadcast radio, i know i need to clear space and elevate the antennas. This option give me a fast and easy way the change the antenna. LECTROSONICS SNA-600 and LPA WA5BJV 400-1000 i build.

I need to try this on real shoots!!!

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Hey guys,

I use Lectrosonics SNA600 Dipole antenna's for my run and gun kit. 

I have 2 Lectrosonics ZSC-24 2-Way Passive Splitters at the bottom of my bag feeding 2 Zaxcom QRX100Q receivers.

The SNA600 antenna's are mounted using a 3D printed clip designed for my bag. The velcro just gives more support from getting knocked (had too many camera operators knocking it out.)

This setup has improved my range over whips by about 50%.

And if I need more range I just put the mount onto a c-stand.

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I am trying to find the photo that I took and i believe i had posted here somewhere… When I had an orca bag i used selfie sticks with my sna600’s that I bought at Walgreens for $10 apiece. I mounted two of them on the front of my bag on the aluminum frame via cable ties and added cold shoe mounts. I recall it working really well in run and gun situations and also could drop the bag and extend the antennas high about 3 feet above the bag. 

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