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macsrwe
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LHG 5 awful tx signal

Thu Feb 22, 2024 9:43 am

I posted this in the wrong forum and got zero replies, so I'm trying here.

Monday, I erected an RBLHG-5nD to feed two Ring security cameras only 190 meters away. The aim seems to be on the money, and the LHG is seeing -53 and -59 from the cameras. However, the cameras are seeing -74 and -72 from the LHG, insufficient to operate. Upon examination, the LHG seems to be stuck in (6dBm) channel mode. I used to be able to jar them out of that mode by selecting high-range frequencies and outdoor/any operation, but I can't get that to work with this unit. I have tried every combination of indoor/outdoor/any with both low and high frequencies, and the highest tx power I can achieve is 6dBm. What am I doing wrong?

I'm in regulatory-domain (no other choice), united states3, on v7.13.2.

One oddity: since I had two cameras I needed to serve, I had to upgrade the unit to an L4 license so I could run ap bridge. Did I screw myself in doing that? I have tried all of the above combinations in straight bridge mode as well, but of course that doesn't downgrade the license to PTP.
 
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Re: LHG 5 awful tx signal

Thu Feb 22, 2024 10:19 am

wait, you have only 1 lhg acting as AP? or each camera has it's own lhg in station mode so you have 1 LHG AP and 2 x LHG clients?
 
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Re: LHG 5 awful tx signal

Thu Feb 22, 2024 3:00 pm

With ROS 7.12, for "united states3" we have .... 30dBm EIRP power (=radio+antenna gain in the peak direction)
 /interface/wireless/info> country-info 
country: united states3
  ranges: 2402-2472/b,g,gn20,gn40(30dBm)
          5170-5250/a,an20,an40,ac20,ac40,ac80,ac160,ac80+80(30dBm)/indoor
          5735-5835/a,an20,an40,ac20,ac40,ac80,ac160,ac80+80(30dBm)/outdoor
The LHG has 24.5dBi antenna gain. If ROS takes 24dBi, then the radio is indeed limited to 6 dBm

Device is probably locked to outdoor only , so the usable freq is probably only 5735-5835.

Antenna gain works in 2 directions. Send (with reduced radio power) and receive.
That's why the receive signal is stronger (signal +24dBi from antenna) , and the transmit signal is limited at what is allowed in the region. (30dBm total).
The camera's have a much weaker antenna gain, but still are allowed to emit a total peak of 30dBm, what explains the -53 versus -74 dBm difference.
 
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Re: LHG 5 awful tx signal

Thu Feb 22, 2024 3:36 pm

Also that AP has only 7° antenna beam width, not the best candidate for multiple clients, this AP is build for P2P links.
 
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macsrwe
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Re: LHG 5 awful tx signal

Thu Feb 22, 2024 7:46 pm

The two cameras occupy the same post, the east one two feet above the west one (photo), so directionality of the LHG should not be an issue. Both cameras are returning quite adequate signal to the LHG. The cameras run on internal batteries with a solar panel and have their own internal radios. There is no power at the post to power a MikroTik (otherwise this would be way easier). This is why I resorted to using an LHG as a "highly directional AP." I am serving other Ring cameras on the property in this way, though all at shorter distances.

The LHG is not locked to outdoor only, and seems to work on all channels. But the power limitation information is bad news. At 190m I'm seeing an RSSI at the pole (measured on my iPhone) of only -78 at best. I can't imagine this sort of performance being adequate for any serious outdoor application, so I have to believe something else is wrong here.
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Re: LHG 5 awful tx signal

Thu Feb 22, 2024 9:48 pm

I understand the frustration. One very strong AP is not what is enough for longer distances. The antenna gain must be at both sides.

https://mikrotik.com/products/ptp

Eg a "SXTsa5 ac" would already do wonders. (16dBi).
Or a MT AP with external antenna (eg like with mANT15 S) would as well.

5V powered , or battery powered via DC Jack does exist with MT. There is no search criteria, but
However using a RBMQS only to convert 5V to PoE injected power for a long time is not the intended use.
But like RBMQS, also the mUPS is discontinued: https://mikrotik.com/product/mups
 
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macsrwe
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Re: LHG 5 awful tx signal

Thu Feb 22, 2024 10:27 pm

One very strong AP is not what is enough for longer distances. The antenna gain must be at both sides.
Well, certainly, I agree. I'm familiar with this principle (I blogged about it back in 2012). However, as I mentioned, the -55 signal FROM the cameras is more than adequate. It's entirely the signal from the AP that is lacking.

And I'm somewhat distressed to see 190m characterized as a "longer distance" -- in my younger days, I could have practically thrown a rock from these cameras to the AP. I used to use LHGs as CPEs a km away from my towers. Even the chart you link to shows superb performance up to 5km, and acceptable for my purposes over 100km (but I bet this chart assumes tx power not so strictly artificially limited).

I do use SXTs for this purpose elsewhere on the property, but I chose the LHG here for its ability to collect incoming signal from a greater distance, knowing I could do nothing to improve the camera radios. I'm assuming that even if I replaced it with a vastly superior (according to the chart) LHG XL HP5, I would gain nothing because the tx power would be even further reduced for compliance. (Boy, do I wish I had saved some of my older LHGs.)
 
igorr29
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Re: LHG 5 awful tx signal

Fri Feb 23, 2024 8:38 am

can't you leave it like this? you don't need signal TO the cameras, it's just a few kbit of data anyway. you need good RX signal, and you have that.
that said, you should downgrade to 6.48 for example and see if tx power will increase.
 
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Re: LHG 5 awful tx signal

Fri Feb 23, 2024 9:14 am

The LHG tx is so poor that it can't even maintain registration with the cameras for more than a minute or so at a time.

The idea of dropping to v6 is interesting -- I thought the regulatory limitations were baked into the unit at a lower level than the OS, but I suppose there's no reason not to try it. Now I have to figure out how to downgrade it without taking it down off the mast. I don't relish trying to make Netinstall work from the base of the tower instead of from my workbench, but it is what it is. I think I remember how to make it trigger without having to hold down the physical button.
 
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Re: LHG 5 awful tx signal

Fri Feb 23, 2024 9:51 am

Try setting the antenna gain parameter to 0
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igorr29
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Re: LHG 5 awful tx signal

Fri Feb 23, 2024 10:00 am

no need to netinstall
https://help.mikrotik.com/docs/display/ ... g+RouterOS

also if you DO need to netinstall, you can do it remotely by telling it to try ethernet instead of nand for the next reboot,and then run netinstall and reboot it.
 
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macsrwe
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Re: LHG 5 awful tx signal

Fri Feb 23, 2024 10:01 am

Yeah, that old trick failed me -- there IS no Antenna Gain field anymore!
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macsrwe
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Re: LHG 5 awful tx signal

Fri Feb 23, 2024 10:04 am

Ooh! Super-great catch! I've never seen that. That's fast and easy enough for me to do tomorrow morning. I think you just saved me a lot of grief. Thanks!
 
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Re: LHG 5 awful tx signal

Fri Feb 23, 2024 10:45 am

Or set up a super channel
Screenshot_16.jpg
Or use the terminal command
/interface wireless
set [ find default-name=wlan1 ]  antenna-gain=0 
PS Usually reflashing via net install removes the region lock and the superchannel appears
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macsrwe
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Re: LHG 5 awful tx signal

Fri Feb 23, 2024 7:47 pm

Or use the terminal command
/interface wireless
set [ find default-name=wlan1 ]  antenna-gain=0 
Bingo! 🥳
I'm really surprised (but so grateful) that they left that in the CLI!
Thank you!

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