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Range issue of xbee 900 hp with hogh gain antenna

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Hello everyone,
I am having a problem with the range of xbee900 pro hp (Xbp9b-dmst002).
I have two of them.
I used xctu to configure them with firmware version 8067 (not the latest).
I am using transparent setting with PL = 4
I also have two high gain antenna. The guy whom i bought these antennas did not gibe me their product name but said that they are around 14 dbi antenna. One of them is a black duck antenna (for transmitter) and the other is a slightly thin and has a helical (for receiver).

I did a range test using two different laptop and cbee were powered by fundino usb adapter for xbee (thiss seems to be the issue as usb port does not provide mich current).

All i am getting is around 40 ft range outside with one or two trees in between.

I know i am doing sth wrong. Please guide a bit.
Thank you
asked Mar 27, 2017 in RF Solutions and XBee by arsh New to the Community (3 points)

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1 Answer

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Do you have any specs for the antennas? Are they made for the proper frequency of the 900 HP?
answered Mar 28, 2017 by DystopianFerret Veteran of the Digi Community (363 points)
No but the guy grom whom i bought these said that they are for 900 Mhz.
I checked with and without antenna. Without antenna i get a range of abt 3 to 5 ft whereas with high gain antenna on both sides and sparksfun regulated board, its giving me a 50 ft range on line of sight. I mist be doing sth wrong
What's the voltage of the adapter? How high off the ground are antennas? The ground might be absorbing the signal if they are not high enough above the ground.
btw the current on both sides (during transmission and reception) was around ~30mA. Which is very low as compare to what the datasheet mentions. This is also very low noticing  that I have got around ~9-10 inch long , high gain antennae on both sides.
I am doing the range test with a laptop in my hand and walking . My group mate does the same on the other end. So I would say that the antennas are like 4 5 ft above the ground.

I have got two Sparkfun Regulated Breakout Board for Xbee. I power them up with a 12V 4.5Amp Long Battery after regulating the voltage to 5V through lm338 on both sides (thought I was not supplying enough power from Fundino USB Adapter).

I connected the xbee to explorer board which is connected to the software Serial of arduino then arduino is connected to the laptop. But the explorer board are powered by the regulated voltages from the battery. I have also attached the battery ground to Arduino ground. These are the hardware setups for both sides

Things I have done:
1 - I have updated the firmware on both xbees (for Xbee 900 Pro HP S3B, XBP9P-DM)

2 - I checked the current consumed by the Xbee on transmitting and receiving sides by simply attaching a multimeter in series with the 5V line.

3 - I have done the Range test in XCTU.

I am really out of options. Btw I needed on ~700m range. I have a s2b (8 s2b sending data to one master-s2b) and this 60mW master s2b is providing me more range than this 250mW Xbee pro 900.

I don't know what else to try?
If you're getting better range on an XBee S2B, then it sounds to me like the antennas you have are not the right ones.

Make sure the antennas match the operating frequency listed here in the 900HP manual:
https://www.digi.com/resources/documentation/digidocs/90002173/Default.htm#reference/r_specs_900hp_general.htm
Also, 900 MHz requires a much larger Fresnel Zone than 2.4 GHz products, so you may need to get the antennas even higher off the ground.

See this site to calculate the required antenna height in relation to distance: https://www.everythingrf.com/rf-calculators/fresnel-zone-calculator
Well i did a range test of both xbees with above mentioned scenario and it failed to receive anything.

I strongly believe that my xbee 900 are broken but if they were why would they communicate in shorter range?

And if my antennae were not working? Why would xbees give me more range with antenna as compare to without Antenna?

One more thing i dont understand is a channel mask. I have set it to default value. Digi should at least make a tutorial for these 900 modules as their settings in xctu are totally different than the xbees working on 2.4Ghz ..

Still miserable with such short range.
I don't understand one more thing, why the transmitting xbee is taking such low current (30mA) when I connected a multimeter in series with the 5V of Regulated Explorer Board. I thought that they'd consume more than 250mA of current when transmitting. But this is not the case.
How can I check the frequency of antenna?
I mean the guy said that the transmitter and receiver's antennae are of 900 Mhz and their impedance is matched beforehand.

As you mentioned the height, I am going to put both the xbees on the roofs of two 2-storey buildings (LOS) and check if its giving a better range. the buildings are around 70 to 90 meters from each other.
Thank you for the suggestion. Can you think of any other reasons why they are not giving me a better range?

As for antennae, I know that they are working because I checked the range with and without antennae and without antennae, xbees were communicating with a range of about 3 to 4 ft, where as with antennae their range increases to ~40 ft.
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