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[Tom Simenauer]

Hi i am about to by a Sennheiser rig with the receivers going into a ASA-1 with 2 Sennheiser A1031-u omni antenna's.
How far can i run the A1031-u's without a booster?

[Henry Cohen]

Hi i am about to by a Sennheiser rig with the receivers going into a ASA-1 with 2 Sennheiser A1031-u omni antenna's.
How far can i run the A1031-u's without a booster?

This will depend on a number of factors:

- Type of coax. Your subject line indicates RG58; I would strongly recommend a low loss coax sized sufficiently for the length needed. It's far better to run a larger, low loss coax than add the noise and potential intermodulation distortion that comes from adding an amplifier stage. Preferred coax recommendations are Belden 9913F7, Times Microwave LMR400 / LMR400UF and PWS S9046.

- Average signal strength from the transmitter reaching the antenna. Unless extenuating circumstances are present, you're better off moving the antennas closer to the transmitters and using a larger, low loss coax.

- Type of antenna. Omni or directional? And if directional, how much [passive] forward gain?

[Keith Broughton]

Hi i am about to by a Sennheiser rig with the receivers going into a ASA-1 with 2 Sennheiser A1031-u omni antenna's.
How far can i run the A1031-u's without a booster?

Loss per 100' of RG58 at about 500 Mhz is around 12 db. I don't use more than 25' of RG58 (if that's all I can get)and that's with directional antennas.
As Henry stated, use a better cable especially considering you are using omni antennas.

[Tom Simenauer]

Loss per 100' of RG58 at about 500 Mhz is around 12 db. I don't use more than 25' of RG58 (if that's all I can get)and that's with directional antennas.
As Henry stated, use a better cable especially considering you are using omni antennas.

thanks

[Tom Simenauer]

Loss per 100' of RG58 at about 500 Mhz is around 12 db. I don't use more than 25' of RG58 (if that's all I can get)and that's with directional antennas.
As Henry stated, use a better cable especially considering you are using omni antennas.

thank you

[Jason Glass]

Hi i am about to by a Sennheiser rig with the receivers going into a ASA-1 with 2 Sennheiser A1031-u omni antenna's.
How far can i run the A1031-u's without a booster?

Everyone else's suggestions here, so far, are best practices. If you're stuck with RG58 and can't get low loss cables, here's rule of thumb. A1031-U antennas have approximately 3.1dB of axial gain, omnidirectional and perpendicular to their physicl axis. Approximately 25 feet of RG58 has 3dB of loss at 585MHz (the middle of the UHF TV band), so 25 feet is your practical limit.

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[Tom Simenauer]

Everyone else's suggestions here, so far, are best practices. If you're stuck with RG58 and can't get low loss cables, here's rule of thumb. A1031-U antennas have approximately 3.1dB of axial gain, omnidirectional and perpendicular to their physicl axis. Approximately 25 feet of RG58 has 3dB of loss at 585MHz (the middle of the UHF TV band), so 25 feet is your practical limit.

Sent from my Nexus 5 using Tapatalk

Thanks, 25 ft will do me fine.

[Kevin Graf]

There are many different coax cables that have the generic type RG58 designation.
From my old Belden catalog, the losses at 1000 MHz (the only high frequency that all the cables spec) the losses range from 10.9dB to 21.5dB. There is a lot more to choosing a coax than just the RG type number.

[alex.cerutti]

Does the same apply, with IEM's ie, it's better to have your TX antenna closer to the performers and having longer cable the short, presuming that in both situations each antenna has free line of sight?

[Jason Glass]

It's a balancing act between a specific cable's loss vs. antenna gain - free space loss - polarization mismatch loss - multipath loss. Be mindful of Fresnel zones. High loss cables such as RG58 can be lossier than free space, while modern low loss coax can be far less.

http://www.timesmicrowave.com/calculator/

https://www.pasternack.com/t-calculator-fspl.aspx

http://www.antenna-theory.com/basics/polarization.php

http://www.radio-electronics.com/info/propagation/multipath/multipath-propagation-basics-tutorial.php

https://en.m.wikipedia.org/wiki/Fresnel_zone

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[Keith Broughton]

It's a balancing act between a specific cable's loss vs. antenna gain - free space loss - polarization mismatch loss - multipath loss. Be mindful of Fresnel zones. High loss cables such as RG58 can be lossier than free space, while modern low loss coax can be far less.

http://www.timesmicrowave.com/calculator/

https://www.pasternack.com/t-calculator-fspl.aspx

http://www.antenna-theory.com/basics/polarization.php

http://www.radio-electronics.com/info/propagation/multipath/multipath-propagation-basics-tutorial.php

https://en.m.wikipedia.org/wiki/Fresnel_zone

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Thanks for the links

[Jason Glass]

Thanks for the links

You're welcome!

BTW, it may seem counterintuitive because a lossy cable that isn't faulty will almost always have less total loss over a given distance than free space over the same distance.  Where it gets weird is when you compare different lengths of cable and free space as portions of a given path distance.  I hope these graphics help.

[brian maddox]

It's a balancing act between a specific cable's loss vs. antenna gain - free space loss - polarization mismatch loss - multipath loss. Be mindful of Fresnel zones. High loss cables such as RG58 can be lossier than free space, while modern low loss coax can be far less.

http://www.timesmicrowave.com/calculator/

https://www.pasternack.com/t-calculator-fspl.aspx

http://www.antenna-theory.com/basics/polarization.php

http://www.radio-electronics.com/info/propagation/multipath/multipath-propagation-basics-tutorial.php

https://en.m.wikipedia.org/wiki/Fresnel_zone

Sent from my Nexus 5 using Tapatalk

This with its links could easily be a sticky.  So much great information....

[Keith Broughton]

Those loss charts really support the idea of good quality cable with the antenna closer to the transmitter.

[Lyle Williams]

The reception game is about signal-to-noise, not just raw signal power.

[Jason Glass]

The reception game is about signal-to-noise, not just raw signal power.

That's correct, but neither can be ignored and optimization of both is the secret to solid performance.

FWIW, in systems where I've done exhaustive path loss calculations to predict that IEM receivers have no less than 1500uV at their furthest expected distance from the TX antenna, none have had dropout issues. Some have had audible noise issues due to nearby emitters such as video floors and LED drivers, but having signal strength to spare is what allows one to use RX RF attenuation to mitigate those types of problems.

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[Jason Glass]

Those loss charts really support the idea of good quality cable with the antenna closer to the transmitter.

I think we agree but I'm a little confused because it depends on whether you refer to an IEM system or a microphone system.

It's safe to say that it's best to cover as much of the distance between TX and RX as you can with modern low loss cable and as little free space between them as possible.

Before someone pipes in about RF overload, IMHO that issue is far less likey to cause real world trouble than insufficient RX signal strength, especially if you place antennas in a way that prevents TX and RX from getting within 10 feet of each other.

edit: OK, so not strictly as close as possible.   More like minimal while maintaining even performance area coverage.

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