Basic newbie questions about setting up an RB411/R52n-M as a WiFi card in a desktop computer at home

RouterOS Beginner Basics
1

GOAL:
I would like to ask some basic newbie questions about setting up an RB411/R52n-M as a temporary WiFi card in a desktop computer at home.

  1. What is the difference between the pigtail on the RB411/R52n-M being on the LEFT versus RIGHT connector?
  2. Why does the antenna seem to be set up for 2.4GHz but the radio will only “see” my 5 GHz access points?
  3. Both PTP and CPE seem to work; so which setting is the one I should use for this application, and why?
    And, most important:
  4. What do I need to do to get the setup to be for 2.4GHz and not for 5GHz?

SITUATION:
I have borrowed a Windows desktop for a few months from a friend who went to Europe where the desktop doesn’t have a WiFi card so I figured I’d use a spare RB411/R52n-M as a temporary “wifi adapter” while I am using the desktop. My SOHO Wi-Fi router at 192.168.1.1 is a typical Netgear n router, with both 2.4GHz and 5GHz access points, where it’s about 30 or 40 feet away through a few walls so the 5GHz signal strength at the computer is only about -75dBm to about -85dBm (although the S/N is about 35dB).

I’d like to use 2.4 GHz because it penetrates walls better (or so I’m told).

Of course I tried the obvious thing, which is I moved the pigtail from the LEFT side of the RB411/R52n-M to the RIGHT; but when I did that, nothing works. It only works in the LEFT side. So I don’t know how to get the radio to be 2.4GHz and not 5GHz and even so, the antenna seems fixed at 2.4GHz (according to the label on the antenna anyway).

QUESTIONS:
This is what my RB411 routerboard and 2.4GHz (I think) antenna looks like (it was given to me for free by a neighbor who changed WISPs)

My first question is what is the difference between when the antenna is connected to the LEFT RB411/R52n-M pigtail connector (as shown here)?
Please note that all the handwriting is mine, and it could be wrong, as it’s just a guess, and for the connectors on the left and right, I think it is wrong - so disregard the handwriting on the box!

Versus when the antenna is connected to the RIGHT RB411/R52n-M pigtail connector?

The reason I ask is I’m confused in that the ANTENNA seems to be set for 2.4GHz as far as I can read on the label.
And there doesn’t seem to be any setting for the antenna to be 5GHz anyway, even though there must be a way to get the R52n-M card to output 5GHz, isn’t there?

Even though the antenna I inherited from my neighbor seems to be labeled for 2.4GHz, the Winbox software seems to indicate it’s 5GHz and not 2.4GHz because the only access points it sees in “CPE” setting are my 5GHz access points (and not my 2.4 GHz access points).

My other question is whether I should use PTP or CPE settings for the purpose of using the radio & antenna as a WiFi card in the desktop computer?

So, in summary, I have three newbie basic questions that I would like advice on please.

  1. What is the difference between the pigtail on the RB411/R52n-M being on the LEFT versus RIGHT connector?
  2. Why does the antenna seem to be set up for 2.4GHz but the radio will only “see” my 5 GHz access points?
  3. Both PTP and CPE seem to work; so which setting is the one I should use for this application, and why?

And, most important:
0. What do I need to do to get the setup to be for 2.4GHz and not for 5GHz?

2

It’s possible that you’ll have to leave Quick Set (I can’t say for sure, because I don’t use it and don’t know about everything it can possibly do).

  1. If you go to Wireless menu, open properties of your wireless interface and select HT tab, you’ll see options Tx Chains and Rx Chains, both with checkboxes chain0 and chain1. Chain0 is left connector and chain1 is right connector. And it controls which one should be used for receiving and transmitting. It defaults to chain0 (left connector) for both. In short, don’t touch it and keep pigtail in left connector.

  2. Same start as in 1), but select Wireless tab. Then check Band: (second option from top). It controls used frequency and modes.

3

I left quick set and followed your instructions. Thanks.

Thank you for clarifying that the LEFT pigtail connector on the RB52n-M PCI board is TX0 and the right pigtail connection on the RB52n-M Wi-Fi board is TX1 - and - thank you for letting me know I should leave the settings alone! :slight_smile:




Thank you for clarifying that the frequency of the RB52n-M PCI Wi-Fi radio board is set in the Wireless tab of Winbox!

So the main problem is solved, which was how to set the radio to 2.4GHz since that penetrates walls better than does 5GHz.

4

Thanks to the answers from “sob”, I have the radio set up in Wireless B/G/N mode at 2.4 GHz, which the antenna seems to also be set up as (based on the sticker on the antenna) and where I get signal strengths of around -50dB at 2.4GHz instead of around -85dB at 5GHz without moving the antenna or the Netgear n SOHO router.

There are some curiosity questions I’d like to ask that remain, where I’ll try to ask only one question per post.
Here is my question for this post.

QUESTION:
Given that the SOHO router is a Netgear n (2.4GHz & 5GHz), what setting is best to set the Winbox “Wireless” tab to?
(And why does it say “2GHz” instead of “2.4GHz”?)

  • 2GHz-B/G/N <=== the answer is probably either this?
  • 2GHz-only N <=== or maybe just this?
  • 2GHz-B/G
  • 2GHz-only-G
  • 2GHz-B

So my first quick question is whether it actually matters if I set the Winbox Wireless tab to B/G/N or just to plain N?

5

The second question is whether to set the Mikrotik RB411/RB52n-M to “CPE” or “PTP Bridge” settings?
(What’s the difference in this type of setup?)

Here is the results of a CPE setup where 9 access points are found & the 2.4GHz n SOHO router AP is -47dB:

Here is the results of a PTP setup where 7 access points are found & the 2.4GHz n SOHO router AP is -36dB:

QUESTION:
Since both CPE & PTP work, how do I decide which one to use?
(And why are the number of APs and signal strength to the SOHO router AP so different?)

6

My third question is related to the antenna hardware.

While I now know I can set the Mikrotik R52n-M board to either 2.4GHz or to 5GHz using the “Wireless” tab of the Winbox utility, how do I know whether this antenna can handle both 2.4GHz and 5GHz?

QUESTION:
What is the set frequency of the antenna?
Is the antenna 2.4GHz only?
Or is this antenna both 2.4GHz and 5GHz?
Or, is the antenna adjustable (presumably by moving the feed in or out of the hollow square tube)?

7

Should I ask the hardware questions in a separate thread each?

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  1. If your router/AP uses “n” mode, you definitely want selected band on client to include “n” as well. I’m not good enough with wireless to tell you what difference there will be between B/G/N and only-N. Probably not much, but it’s just a guess. Take “2GHz” as short name, the important thing is that it works correctly.

  2. I’m not really sure. I’d expect some config differences between CPE and PTP Bridge mode, other than wireless settings, mainly regarding bridging or routing. But there’s also CPE/Bridge mode… Manual does not seem to be very detailed here, so you’d probably have to try both, export complete config and look what exactly is different. Signal levels can change a lot (e.g. someone can sneak around antenna and it’s enough), I don’t think it’s related to this. In both cases, the signal is more than good enough. In fact, this antenna of yours is probably an overkill for your use.

  3. I don’t think this kind of antennas supports both bands, only one.

9

Thanks for taking a stab at answering the noob questions!
How does this summary look?

Q: What does the 2GHz mean in the frequency selection pulldown list?
A: The 2GHz is just a short way of saying “2.4GHz”.

Q: For an “n” SOHO router, what is the best choice for frequency on the radio connected to the desktop as a Wi-Fi adapter?
A: Nobody knows yet, but it sure as hell should at least have an “n” in it! :slight_smile:
[u]- 2GHz-B/G/N <=== the answer is probably either this?

  • 2GHz-only N <=== or maybe just this?[/u]
  • 2GHz-B/G <=== but not this
  • 2GHz-only-G <== nor this
  • 2GHz-B <== and certainly not this

Thanks for advising me on this basic beginner questions because I don’t really understand why both CPE/Bridge and PTP work in this situation, and the signal levels seem to be the same whether I’m in CPE/Bridge or PTP mode. The only difference is:
a. CPE/Bridge => sees 9 other access points (all of which are known to me)
b. PTP => sees only 7 other access points (all of which are a subset of the above)
So clearly, PTP is better, but only marginally so.

Q: What is the better configuration for use as a WiFi Adapter, CPE/Bridges or PTP mode, and why?
A: Nobody knows why, but PTP is better, but only marginally so (because it sees more access points).

Thanks for that explanation, which is what I would have thought, although, it may be that only the FOCAL POINT needs to be changed to go from 2.4GHz to 5GHz.

On whether I should use 5GHz or 2.4GHz, it seems that in this case with the radio being used as a Wi-Fi adapter for my desktop computer, the received signal strength seems to be pretty consistently far better at 2.4 GHz than at 5GHz, where nothing else has changed in between. So I think the 2.4 GHz penetrates the house walls FAR BETTER than does the 5GHz signal (assuming the EIRP radiated at the router is the same for both frequencies).

So that makes this the Q&A:
Q: Which frequency is better for penetrating about 40 feet including walls between a SOHO router and the radio set up as a WiFi adapter?
A: 2.4GHz is FAR BETTER than 5 GHz for penetrating walls, at least with this antenna it is.

10

a/B/G/N/ac at AP has to be set accordingly to the clients you expect that will be connected. Sometimes according to the local conditions when you need to keep stable link with worse signal. Nothing in WiFi world is singlecriterial decision.

11

PTP /CPE is definitely not about how many access points does it see…

12

WiFi adapter is more common term. You are talking about adapter but you mean it’s networking role as a client.

13

@woodrock
WiFi propagation sample picture … as you can see it is not an easy problem:
comm-v103.jpg
taken from https://people.ucsc.edu/~warner/heat-map.html

14

That antenna is normally unusable for 5g regardless the focal point. Look how big are 5g waves and how big are the holes in the grid…

15

Result about the wall penetration is good but the assumptions and logic is totally false. You should rather spend some time studying these topics before making such judgements, because someone could believe them…

16

Router is network role. Access point and client radiate the signal from their antennas feeded by the radios in their adapters.

17

Ah! THANKS! That’s the kind of real-world experience I was looking for.
I didn’t know how to tell just by looking at the antenna if it was 2.4GHz or 5GHz or both.

What you’re saying is that the grid is unsuitable for 5GHz (due to the smaller wavelength going right through the holes).
[] The antenna grid is about 6 inches long and about 3/4 of an inch wide
[] 2.4GHz frequency is about 4.9 inches wavelength
[*] 5GHz frequency is about 2.4 inches wavelength

Hmmm… it seems that both 5GHz and 2.4GHz are far larger than 3/4 inch (so I’m confused by your statement that the holes are too large).

Thanks for all your great advice!
I agree that, if the antenna is the wrong antenna for 5GHz, then that, alone, could account for the HUGE difference in received signal strength between 2.4GHz and 5GHz.

I think I will just set the RB411/R52n-M radio hooked to the computer to be “n only” since I don’t need B or G as far as I know.

Just to clarify, the SOHO router is 802.11n which as a 5GHz access point and a 2.4GHz access point.

The desktop computer has the RB411/R52n-M connected to the computer Ethernet port as a “Wi-Fi adapter”, but I’ll call it something else if you think there’s a more appropriate description.

I don’t disagree with you that there MUST be “something” different between CPE/Bridge and PTP, but my question is which do people recommend for this setup.
All I know when I tested it out is that everything is the same, with the only exception that I know of being:

  1. CPE/Bridge sees 9 access points.
  2. PTP sees 7 access points.

What else should I look at to figure out if PTP or CPE/BRIDGE is best for this setup?