Which antenna to increase the poor nominal range 7m

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yellowsky
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Which antenna to increase the poor nominal range 7m

#1 Post by yellowsky » 19 May 2017, 12:12

Hi everyone,
i have a lot of visonic door sensor (MCT-320 not 302) in 868Mhz

I have a RFLink mount by Nodo with an antenna from the nodo shop.

Unfortunately, the range of detection of sensor is 7 m in open area with the RFLink software under windows. I suspect the antenna to be not so powerful.
Indeed my alarm central system see the visonic sensors at more 10m with a lot of heavy wall/floor so i think the sensors are ok (while they work correctly for years).

Have you got some idea to increase the power of signal detection?
I try R46 and R45 (but in the case of R45 firmware the signal detection is worst <2m)

Thank you

costo
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Re: Which antenna to increase the poor nominal range 7m

#2 Post by costo » 19 May 2017, 14:50

yellowsky wrote:
19 May 2017, 12:12
Hi everyone,
i have a lot of visonic door sensor (MCT-320 not 302) in 868Mhz

I have a RFLink mount by Nodo with an antenna from the nodo shop.

Unfortunately, the range of detection of sensor is 7 m in open area with the RFLink software under windows. I suspect the antenna to be not so powerful.
Indeed my alarm central system see the visonic sensors at more 10m with a lot of heavy wall/floor so i think the sensors are ok (while they work correctly for years).

Have you got some idea to increase the power of signal detection?
I try R46 and R45 (but in the case of R45 firmware the signal detection is worst <2m)

Thank you
You do not mention which antenna it is that you use.

If it is the dipole antenna then not much can be done except change the orientation.

If you use this nice looking antenna https://www.nodo-shop.nl/en/antennes/12 ... -nodo.html , which is actually a coil-antenna inside a rubber tube, you can improve things.
Replace this antenna with a copper/iron wire of 172 mm. Connect a second plastisized/isolated wire of about 172mm to ground right there where the antenna connection is. The wire may/can be bent around the RFLink case. This modification will turn your simple wire antenna into a dipole like antenna.
Instead of a second wire you can place the RFLink on a metal ground-plane (about 20x20 or 30x30 cm) and eventually connect this plate with ground.

p.s. with ground I mean the common electrical point and not the actual ground in your garden :lol:

yellowsky
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Joined: 10 Dec 2016, 20:09

Re: Which antenna to increase the poor nominal range 7m

#3 Post by yellowsky » 19 May 2017, 15:24

In fact i have this one:
https://www.nodo-shop.nl/en/antennes/16 ... 68mhz.html
It is for 868Mhz devices (and they don't sell any other antenna)

I don't understand where plug the first or the second wire? Have you got a picture?

Thank you for your help

yellowsky
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Posts: 30
Joined: 10 Dec 2016, 20:09

Re: Which antenna to increase the poor nominal range 7m

#4 Post by yellowsky » 19 May 2017, 15:39

AddOn, i have this product:
http://www.dx.com/p/rtl2832u-r820t-mini ... ack-170541

I sniff the data at a frequency between 868.84 and 868.91 in function of the device, could be related?

In another hand could i use the antenna of the dvb-t device tu use it with RFLink (because in this case this antenna seems all frequency)

costo
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Re: Which antenna to increase the poor nominal range 7m

#5 Post by costo » 19 May 2017, 16:15

i have a lot of visonic door sensor (MCT-320 not 302) in 868Mhz
Right, you did mention it is 868MHz, my mistake.

Because for 868MHz the frequency is doubled, the antenna wire lengths must be halved for that frequency.
So 86mm is the right length. The Nodo antenna has probably a strait wire of 86mm inside, so nothing can be improved by changing it with a 86mm copper wire.
A second wire connected to ground may improve the signal strength, it should be soldered right where the screen of the SMA connector is located and the orientation must be experimentally determined.
Using a metal plate (15x15 to 20x20 cm) as groundplane will likely improve your signal most.

yellowsky
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Posts: 30
Joined: 10 Dec 2016, 20:09

Re: Which antenna to increase the poor nominal range 7m

#6 Post by yellowsky » 19 May 2017, 17:00

i have a lot of visonic door sensor (MCT-320 not 302) in 868Mhz
No problem ;-)

Concerning the plate and the second wire connected to the ground what is the physical explanantion of the higher level of detection?

costo
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Re: Which antenna to increase the poor nominal range 7m

#7 Post by costo » 19 May 2017, 17:36

yellowsky wrote:
19 May 2017, 17:00

Concerning the plate and the second wire connected to the ground what is the physical explanantion of the higher level of detection?
That it looks more like a groundplane antenna .
Because a whip antenna placed on a car (= metal plate) works much better than the same whip antenna without a groundplane
But on 868MHZ and a Nodo plate it is hard to see if anything can be improved that way because the Nodo plate already functions as a sort of groundplane.

For me on 433MHz and a separate tranceiver module , a second grounded wire improved the reception of my outdoor weather sensors significantly.
The antenna wire of 172mm (433MHz) was connected to the antenna point and a second wire of the same length is soldered to the ground connection next to the antenna connection.

liverock
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Re: Which antenna to increase the poor nominal range 7m

#8 Post by liverock » 25 May 2017, 05:38

433 MHz diapole.

Any photos to illustrate what it actually look like?

Mies
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Re: Which antenna to increase the poor nominal range 7m

#9 Post by Mies » 18 Jul 2017, 09:53

I also have a lot of Visonic sensors which I want to reuse.
The Visonic frequency is 868,95 and the Arduino frequency is 868,3.
Could that be the problem that is is not working correctly ?

Regards,
Mies

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Stuntteam
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Re: Which antenna to increase the poor nominal range 7m

#10 Post by Stuntteam » 18 Jul 2017, 11:26

Yes, this will limit the range.
We are working on support for additional transceivers that will have other frequency ranges.
-=# RFLink Gateway Development Team #=-
Introduction: http://www.nemcon.nl/blog2/
Generic Support forum: http://www.esp8266.nu/forum/viewforum.php?f=8

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