KGraham045

Dipole Antennas on bag/Harness

80 posts in this topic

Just trying this as a quick release mount for SNA600 on the side of an Orca OR41 using Smallrig coldshoe components -

So far so good. :)

http://smallrig.com/

Cold Shoe Mount 1593

SMALLRIG Cold Shoe Mount 1593

Cold Shoe Adapter 3/8 inch screw 1275

Cold Shoe Adapter 3/8 inch screw 1275

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cold-shoe-1.thumb.jpg.81b4bbaed4119e9ba7

cold-shoe-2.jpg

Elegantly executed. Kudos!

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Great, Smallrig make nicely made useful bits at very reasonable prices.

The only thing that worries me is my SNA up arrow is pointing down, will my sound be upside down :)

LOL, you can adjust the mounting block on the antenna!  Remove those 4 screws, reorient the block with the threaded hole where you need it (if I recall correctly!)

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The only thing that worries me is my SNA up arrow is pointing down, will my sound be upside down :)

Just invert the phase on your input and you will be fine.

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I was working with Gordon Moore last year on a harness friendly dipole but we did not get anywhere.

I tried to modify myself "picture bellow" but it does not work very well.

The antennas have to be perpendicular to the circuit board.

 

 

11742637_10207143004113366_2431703770759

 

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Pindrop, very nice solution. After a nightmare ENG job running around with shark fins in my bag, I went with the

Lectro SNA600's and never looked back. I use the PSC RF Multi SMA with my RX and will try your method of mounting the antennas.

Thanks to all of the folks on this forum that help share their creative ideas. I really enjoy learning new tricks.

Todd

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pindrop, what does the cold shoe mount screw in to? what's behind it in your orca? are there just nuts on the screws, or do they go into some kind of plate for better rigidity? 

thanks! 

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#: 57   Posted (edited)

pindrop, what does the cold shoe mount screw in to? what's behind it in your orca? are there just nuts on the screws, or do they go into some kind of plate for better rigidity? 

thanks! 

Hi, the bolts with hex inserts in the photo, came with the Smallrig coldshoe mount, and they're just long enough to go through the side of the ORCA 41 and get a washer and nut on the other side (1/4"). The nuts were not supplied and I used some I already had. The bag side panel has some fairly rigid re-inforcing insert inside, which is sufficient to hold the mount rigid enough. I drilled through with a standard high speed drill on low speed.

Having now used it now on a couple of jobs, I've found it's not that easy with bare hands to get the locknut on the mount tight enough, to be sure of it staying in place. So I've got some slightly larger diameter locknuts that came with a K-Tek shark mount bar, which I'm going to try. What I did today was use small cable ties which was easy enough, but defeats some of the purpose of it being quick release. Basically though it works as a mount well enough, and I didn't find there was any danger of the leverage from the SNA's being too much, either for the SNA's themselves or the coldshoe.

Edited by pindrop

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Thanks that's really helpful. I need to mount them on my Petrol 614 at the moment. Not as rigid as the Orca but I'll find a way. 

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#: 59   Posted (edited)

Thanks Jim, food for thought indeed.

I meant to mention that the SMALLRIG Cool Cheese Bar with 1/4 inch and 3/8 inch screw holes, the pairs of 1/4" threaded holes, line up exactly with the two holes on the Cold Shoe Mount 1593. So for those who might like additional rigidity on their bags this could work, to fix the cold shoe mount.

http://smallrig.com/smallrig-cheese-bar-with-1-4-and-3-8-screw-holes.html

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cool-cheese-bar-with-1-4-inch-and-3-8-inch-screw-hole-1091_05_1.jpg

Edited by pindrop

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#: 60   Posted (edited)

Inspired by all of your ideas and for also for those that still use Petrol bags (as I do) that come with these handy Mod-u-Lox locking systems.
I took the idea of Suso Ramallo's L shaped aluminium bracket for his Zaxnet antenna and just screwed one of these lockable cold shoes adaptors

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Edited by efksound

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Two photos of SNA600s on a selfie-stick rig. Selfie stick with threading adapter to K&M stereo bar. Can be collapsed and lowered or widened and raised up.

SNA600s can also have their mounting hardware removed and velcroed flat onto the bag or other surface. Hand-sewing velcro onto an existing bag is doable. Some bags have rain cover velcro attachments that work. 

ORG_DSC01551-01.jpeg

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For those using either the sna600 or the DIY dipole, how many of you are simply using passive splitters like the lectro zfsc successfully?

Secondarily, why not just put some Velcro on the SNAs and on the front of the bag and mount them that way? Easy pull off when packed. That was my plan.

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Hello,

 I have a similar question; How are you distributing the antenna output to your collection of receivers?

Thank you.

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Not quite a bag mount or harness mount, more of a machine mount but there you have it. Square dabs of snot tape in just the right places.

5a0399e6cfe7be2dbd119f80867cd60f.jpg2768157514b0588a9a14ab0aab2056b1.jpg

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2 hours ago, fieldmixer said:

Not quite a bag mount or harness mount, more of a machine mount but there you have it. Square dabs of snot tape in just the right places.

5a0399e6cfe7be2dbd119f80867cd60f.jpg2768157514b0588a9a14ab0aab2056b1.jpg

Wow, Your dipoles are all but integrated into your nomad. Are there any ill effects from being so close to the recorder? Makes me wonder, is the next step the antenna full integrated into a bag/recorder/SL6, especially now bags are using some aluminium in their structure. Eg stingray.

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Is that a passive or active splitter?

Thank you.

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11 hours ago, fieldmixer said:

Not quite a bag mount or harness mount, more of a machine mount but there you have it. Square dabs of snot tape in just the right places.

5a0399e6cfe7be2dbd119f80867cd60f.jpg2768157514b0588a9a14ab0aab2056b1.jpg

 I'd be surprised if you didn't get any stray RF from your nomad having it literally being on the chassis of the recorder!  Good for you if it's working. :-)  I had to get my dipoles out of the bag on the outside. 

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 I'd be surprised if you didn't get any stray RF from your nomad having it literally being on the chassis of the recorder!  Good for you if it's working. :-)  I had to get my dipoles out of the bag on the outside. 

 

I havent noticed but, i havent worked much with it on jobs requiring much range yet..

id like to hear more about what you noticed in your experience? With nomad spray on dipoles.

Is that power distro on the right side?

Yes. Switchable power distro with three discreet switches built into the machine. 10f32ca81ec15ccd586824710d45e2ac.jpg
Is that a passive or active splitter?
Thank you.

Passive combiner

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48 minutes ago, fieldmixer said:

I havent noticed but, i havent worked much with it on jobs requiring much range yet..

id like to hear more about what you noticed in your experience? With nomad spray on dipoles.

I've just noticed that if my Nomad and QRXs are powered on but without any TXs on, and my dipoles were that close to everything, I would get a couple levels of pixels of stray RF across the scan. If my dipoles are outside of my Stingray bag, I can get clean freqs without any stray RF pixels on my QRXs. 

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7 hours ago, fieldmixer said:

Passive combiner

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.

 I have been trying to learn what actual RF distribution products people are using. For example; are people using two separate 1x4 splitters or are there some 2x(1x4) splitters available.

 I have seen the PSC RF Multi SMA 2x(1x8) splitter and it looks nice but seems like possible overkill for a small bag mount system with a few receivers.

 I enjoy seeing all the bag and harness mounts for the antennas and I am wondering what choices people are making for RF distribution.

Thank you.

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 I have been trying to learn what actual RF distribution products people are using. For example; are people using two separate 1x4 splitters or are there some 2x(1x4) splitters available.
 I have seen the PSC RF Multi SMA 2x(1x8) splitter and it looks nice but seems like possible overkill for a small bag mount system with a few receivers.

When you consider that for example the Sennheiser 1:4 splitter has a signal loss of, I believe, 10 or even 14dB, it makes a lot of sense to use an active design with an amp for make up gain.
I don't think the PSC is overkill, even if you only have 2 receivers. And physically it's not much bigger than two passive splitters. And it can also power your rf amps, should you ever need them.
The same applies to other active splitters, by the way.

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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.

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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?

The loss is always there, as soon as you split or adapt or whatever. Sharkfins on the other hand boost the signal, so the sum may be the same. But if you use sharkfins in a bag, you may need every dB you can get. Otherwise you'd be using something more handleable.
I don't think there is a general rule about using an rf amp. The PSC, by the way, only makes up its own loss, so it's not an amp per se. In bags I would say an amp is usually not required, but if you are having problems with reception you may wish to add an amp, bearing in mind that this will also boost problems.
I think something like Zaxcom's micplexer or the similar thing from Audio Wireless os probably the best bag solution.

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