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External antennas for 2.4 GHz wireless?


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Are there ways to improve the antennas of 2.4GHz wireless receivers such as the Deity Duo-RX?

It has standard SMB connectors for both antennas, though.

 

I wonder if some kind of directional antennas will improve the range for stationary gigs.

Or if these do even exist.

 

I plan to build a 4x TX wireless with the Deity Connect early next year.

But I need to do some tests to be confident about these guys working correctly.

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Yeah.

Four antennas might sound a lot, but if these guys are that cheap - no problem.

 

I think I'm gonna check this as soon as I receive the first Connect set.

I see there are lots of simple directional antennas out there.

As you said, most of them with RP-SMA for WiFI routers and such.

 

How long shoould the cable be max?

I think as short as possible?

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In Germany talk to WiMo. They have a good assortment of antennas and they sell both to hams and professional users. 

 

 

14 hours ago, kavenzmann said:

 

How long shoould the cable be max?

I think as short as possible?

 

As you can't install an amplifier close to the antenna (the "receiver" in digital systems such as Deity is actually a transceiver) keep the cable as short as possible. 

 

Another advantage of Wimo is that they can build a pigtail to your specification and they have a good selection of low loss coax cables. Also bear in mind that a splitter will add losses by itself.

 

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23 hours ago, Rick Reineke said:

There is a formula for 5/8, half-wave ect.,, but I do not recall it, nor can I find it. I think our esteemed friend Larry from Lectro posted it a while back.

5/8 wavelength and 1/2 wavelength (4/8)  antennas require additional matching whereas a 1/4 wavelength is a good match to 50 Ohms directly. Here's a easy to read article on 5/8 wavelength antennas:  

https://www.electronics-notes.com/articles/antennas-propagation/vertical-antennas/five-eighths-wavelength-vertical.php

 

As I remember, a 1/2 wavelength antenna looks like a high impedance load, i.e., much greater than 50 Ohms (a bad thing) and requires lots of matching for poor results.

 

At 2.5 GHz, a corner reflector antenna is reasonably sized and has excellent directivity and fairly high gain. They are available from a variety of antenna shops since they are used to extend wifi. See Borjam's post below.

 

Watch out for cable losses. At 2.5 GHz they can be a decibel per foot so choose your cable wisely and keep it short.

Best Regards,

Larry Fisher

Best Regards,

Larry Fisher

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Larry:

This might be a thread detour or more of a Karl question but since you are talking about it, do you foresee the possibility of a potential 2.4Ghz product for Lectro in the near or far future? 

I have the Deity system and a Røde Video Wireless, both are sort of prosumer-ish, I get it. but they aren't bad, most of the time although limited obviously.
As limited as 2.4Ghz systems seem to be, it would be interesting if a top line product like Lectro threw their hat into that technology ring with a pro product.

 

I am concerned about the FCC's culpability and responsibility to not keep auctioning off the UHF spectrum to the highest bidder, which will never be us wireless mic users.
Less spectrum plus more users isn't forecasting a bright future for UHF for wireless mic users. Thoughts? 

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2 hours ago, Dan Brockett said:

Larry:

This might be a thread detour or more of a Karl question but since you are talking about it, do you foresee the possibility of a potential 2.4Ghz product for Lectro in the near or far future? 

I have the Deity system and a Røde Video Wireless, both are sort of prosumer-ish, I get it. but they aren't bad, most of the time although limited obviously.
As limited as 2.4Ghz systems seem to be, it would be interesting if a top line product like Lectro threw their hat into that technology ring with a pro product.

 

I am concerned about the FCC's culpability and responsibility to not keep auctioning off the UHF spectrum to the highest bidder, which will never be us wireless mic users.
Less spectrum plus more users isn't forecasting a bright future for UHF for wireless mic users. Thoughts? 

I would hope not. 2.4 is becoming a swamp on set with all the other depts running gear on it 

 

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The 2.4 GHz spectrum is a mess. I would bet for a properly regulated cognitive radio approach on the traditional UHF bands or even TV channels exploiting the fact that the whole band is not busy everywhere. 

 

As for the 2.4 GHz antenna, remember that it can be challenging to build a good one. Tolerances are tight and it must have quite a usable bandwidth. 

 

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Maybe worth mentioning, there is the,  not so cheap, RF Venue CP Beam 2.4Ghz. Rf Venue claims it is optimized with some "tech" for transmitting audio, opposed to WiFi.

I am skeptical, if it will improve the deity system significantly in a classic bag/cart situation by putting some sort of directional antenna on the RX side.

The Deity system uses a feedback channel for remote commands, resend requests and channel negotiation.

The performance of the radio link will probably not improve equally in both directions. Things may be different though, if there are directional antennas on both sides in a fixed directional radio situation.

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22 minutes ago, DanieldH said:

Maybe worth mentioning, there is the,  not so cheap, RF Venue CP Beam 2.4Ghz. Rf Venue claims it is optimized with some "tech" for transmitting audio, opposed to WiFi.

I am skeptical, if it will improve the deity system significantly in a classic bag/cart situation by putting some sort of directional antenna on the RX side.

The Deity system uses a feedback channel for remote commands, resend requests and channel negotiation.

The performance of the radio link will probably not improve equally in both directions. Things may be different though, if there are directional antennas on both sides in a fixed directional radio situation.

 

I think some improvement can be expected. For starters, the transmissions won't be symmetrical with more bandwidth being used for audio from the transmitter to the "receiver" compared to the feedback signal sent from the "receiver" back to the transmitter.  So, a properly aimed directional antenna would at least help reduce interference on the most critical point. 

 

Unless, of course, the worst offender is aligned with the RX and the TX. In that case, miracles don't exist ;)

 

 

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7 hours ago, borjam said:

The 2.4 GHz spectrum is a mess. I would bet for a properly regulated cognitive radio approach on the traditional UHF bands or even TV channels exploiting the fact that the whole band is not busy everywhere. 

 

As for the 2.4 GHz antenna, remember that it can be challenging to build a good one. Tolerances are tight and it must have quite a usable bandwidth. 

 

+1...  That's why people are looking for directional antennas and RF amplifiers to make their systems work at 2.4 GHz. Both of which are against FCC regulations.

 

We might look at 2.4 GHz for remote control but not for production sound. It is way too line of sight, too busy with wifi and used by a variety of non-audio devices.

 

If you want good, clean spectrum look at the 941 MHz band. It was set aside for wireless mic users when all the other part 74 bands were being sold or chopped up. Legally you need a license for 74 use but it keeps all the part 15 users away.

Best Regards,

Larry Fisher

7 hours ago, DanieldH said:

[snip] I am skeptical, if it will improve the deity system significantly in a classic bag/cart situation by putting some sort of directional antenna on the RX side.

The Deity system uses a feedback channel for remote commands, resend requests and channel negotiation.

The performance of the radio link will probably not improve equally in both directions. Things may be different though, if there are directional antennas on both sides in a fixed directional radio situation. [snip]

Actually, it improves the exactly same amount in both directions. A good receive antenna is an equally good transmit antenna. If it has 10 dB of gain as a receive antenna, it has 10 dB of gain as a transmit antenna. This is for an antenna without amplification of course.  

Best Regards,

Larry Fisher

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Hey all,

 

Luckily directional antennas for 2.4Ghz devices are super small. Like the palm of your hand small. I run several and have one I will use for long range or difficult to pickup transmitters that gives me great range and punches thru walls no problem.

 

This is a 2.4Ghz Yagi PCB antenna with a semi-rigid coax cable soldered directly to the PCB and into a SMA connector. This little guy cost a whopping $8, an an afternoon of soldering. The guy who makes them is in Dallas Texas.  If you can't solder or have access to this type of coax wire, if you email Kent over at WA5VJB they can put together one for you a little extra cost.  https://www.wa5vjb.com/products2.html

 

05a6daf8c3b6e98b9946cb3401eb0823.jpg

 

I screw it on, point it, and i'm getting 4 out of 5 bars with a transmitter punching thru  2 walls behind the choir loft where the PA system was. I had the transmitter sitting next to a microwave, nothing fancy.

 86491061_10162802519480214_4100314387393282048_o.jpg20200215_163831.jpg

 

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On 12/11/2020 at 4:09 PM, LarryF said:

 

Actually, it improves the exactly same amount in both directions. A good receive antenna is an equally good transmit antenna. If it has 10 dB of gain as a receive antenna, it has 10 dB of gain as a transmit antenna. This is for an antenna without amplification of course.  

 

True, but I was thinking about the non linear effects, ie, receiver saturation. In a link with enough interference to cause intermodulation on the receiver the directional antenna may be more beneficial on the receiver, as it will attenuate off axis interference (unless Mr. Murphy makes the powerful interference exactly on axis) ;)

 

And in this particular application there is more bandwith from the "transmitter" to the "receiver" (audio) than the reverse (feedback/control signals from the "receiver" to the "transmitter"). 

 

Just from a theoretical point of view :)

 

As for the 941 MHz band, can you use it for wireless microphones in Europe? I have checked quickly at the current Spanish regulations (and it's more or less the same in all the EU) and except for low power wireless telephones I don't see other applications, but I have just checked on the latest update, more on this later).

 

At least the Spanish regulation mentions the 863 - 865 MHz band for wireless microphones, but preferably non professional applications.

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I've had solid results the RF-Venue CP Beam 2.4 for a long time as a Zaxnet antenna. 

In fact, I got a loaner from them to test out years ago, and I liked it so much I bought.  It is a soft version of the current molded ABS version.

They make good stuff, I own a Diversity-Fin too.  The cheaper $8 yagi board is worth a look, on cost alone.

 

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