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Antenna Distros in the bag


Tim Hays

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Coax antennas look like a great option for changing over from cart antenna to bag antenna quickly but only if your receivers are in the same block, no? Or at least within a couple blocks?

My understanding about dipoles: the more "focused" you are, the best. If you start tuning your antennas for a middle frequency that's to cover for three blocks, you better keep the quarter waves on each receiver than use a distribution system.

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Jason, on this show I'm really limited on the amount of things I can bring, and mobility is key. Using a k-tek traveler pole allows me to keep it in my luggage when we travel, and is there in the event that I do have to boom something. I rarely just stand there, I am often hiking through the Forrest or something keeping up with the cast. Sometimes they venture over a mountain and I have to be on the other side to get reception.

This setup works really well for this show, but other shows I work on could benefit from the antenna system, just not up on a pole. Finding a good way to mount them on the harness would be great for many of the more run and gun type jobs that I do where the cast sometimes does get away from me, or worse, when they split up and A and B cam follow two different groups while I have to get both simultaneously! Haha

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" you better keep the quarter waves on each receiver than use a distribution system. "

I disagree with your "understanding", and suggest that folks are overestimating the differences in and for reception /ant-tuning /Q

...but if you got, say, receivers in blocks 470, 21 and 26 and want to use two antennas to cover that spread of blocks, how's it done with dipoles? Middle freq of it all and hope for the best for blocks at the extremes ?

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You need to experiment boom boom.  As i said, i have 470 ( cam hop ) and 22-24-26 ( as talent mic ).  When i did my experiment, i measured and cut the coax dipoles to block 24 ( in the middle of my talent block ).  I did not feel like i had affected block 22 or 26 reception but spreading from 470 to 26 might be asking for a lot.

 

But there is nothing like trying it.

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I think there is a lot of confusion about that hybrid antenna, so it would be nice for people to chime in who use it, explain their scenarios, and the blocks they are using.

 

In my case, I was using the PSC passive shark fin which is broadband, and the Lectro SNA600 dipole. The SNA does allow you to tune it, and I tuned it to handle the 500 mHz block, which was a good place for coverage. In the first two seasons of the particular show Ive been doing, I was using blocks 21, 22, and 25. I was really blown away by the kind of reception that I could get using those antennas and the PSC RF Multi SMA (or the mini circuits splitters with the Lectro UFM230s). Either way, lile the Senator says, it has a great deal more to do with your ability to get your antennas up in the air.

 

When I was working on a different show and this thread popped up, I scooped up the only Shure broadband dipoles I could find in town and decided to try them out. Since, like you can see if my first posted photo in this thread, they were mounted on my bag, my reception was about as good as if I were using standard whip antennas. But once I raised them into the air, my reception was a great deal better. Still, my theory is that only using these broadband omni antennas will open you up to a lot of problems if you are in a largely congested area such as Los Angeles or New York.

 

I would still very much like to see some good mounting techniques for antennas for bag based work. I think that a great number of us here would much rather have fewer items in our bags weighing them down (using such things as duel receivers such as the Lectro SRb), but need to get our antennas up and out of the bag to get better reception. Productions are demanding more and more range capabilities, but those of us interested in continuing our careers for longer than 10 years need to consider our backs, so the real race here is to get lighter bags with better reception/range (at least for as long as we are allowed to use the radio space, license or not).

 

Hopefully this thread hasn't tired everyone, and people are still reading it, so that we may get some responses, possibly with photos (hint hint!)

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Again what makes a receiver get more reception and better range, as far as this conversation is talking about, his bringing the antennas up in the air and away from obstacles.

Do a simple test, rig a tx on a stand with its antenna up in the air in the middle of a field ( wide open space ) and walk away from it 200 feet. If you are line of sight ( receiver and transmitter see each other with nothing in between ), and reception will be most likely perfect. Now add a couple of people in front of you blocking the receiver view of the transmitter, and most likely your reception is affected if not heavily affected. Now stay the same way but mount that transmitters on a person with its antenna against the person skin and in there lower back ( person is now in between the tx and the RX ), and bang no more range. But if you where to take your bag and bring it up in the air and bang again tx is back in business. That's exactly what you do with the antennas up in the air. It's all about clearing the space in between tx and RX.

Now I have been thinking about mounting a set of coax dipole ( super light weight ) on a set of telescoping rabbit ear antennas ( not using them as antennas but as mount for the coax dipole ), I could mount antennas maybe 4 feet over my bag temporally and easily and quickly collapse them when needed. Just an idea.

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Usually when I'm having reception issues I will hand hold an antenna over my head. Either an sna600 or a lpda. Obviously not a permanent solution, but when booming I'm generally close enough to talent to not worry about it. Its just when I'm far back listening to a bunch of lavs run around that I need the height.

I've considered sewing a set of coax whips into the top of a hat, but haven't gotten around to trying it out.

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Even with the dipole setup that I'm using now, dipoles on my harness and across the chest, I notice a great difference in reception as compared to if they were mounted on the front of the bag. Although I definitely get lots if questions like, "what are those things?" and "isn't it bad to have those so close to your head?"

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post-402-0-26491000-1376320337_thumb.jpg

 

So here is how i had attached the coaxial dipole to myself ( headphones, harness or whatever i felt like ).  I used very small coaxial cable to make the antenna, then put a large plastic tie wrap at the end and shrink wrap the antenna to the tie wrap, this way i had a flexible antenna.  I then attached a paper clip to it and used that to clip it to me.

 

Sorry no telletubby pix...

 

Thanks

 

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SNA600 ( Standard Lectrosonics Dipoles ) and coaxial dipoles ( homemade ) are not equal, the SNA does have a bit more success. What I did like about the coaxial version is that it is really portable.

Again, once you have established a distro setup that is at unity gain ( 0 in equal 0 out ) then it is all about positioning the antenna in a free space with the least obstacle.

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