Go to the Wireless page on your Host (Access Point).  Under frequency/channel, do a survey of radio frequencies in your area.  Find a frequency that is the lowest possible frequency and select it.    Then, set your Client to the same frequency/channel.

The CPE210 is a 2.4 MHz unit.   Likewise, the 2.4 MHz frequency is very commonly used in many residential areas.  Therefore, by fine-tuning the unit (above) to a frequency that occurs at a low level, you will minimize the amount of interferrence your units will incur.     Also, turn on MaxStream in your Access Point

@88inall 

Thank you all for this very useful information.  Could anyone think of the reason(s) that the following connections drop to 1Mbps on the Negotiated Rate?  Thank you in advance.

cpe220 and cpe210 are bad at link stability they just dont seem to retain the link for more than 24hours.
i have done everything test_mode, @ 20mhz, spectrum analisys, on-off some settings. tried different firmware.
NOTHING
not very good for business.

band-aid fix is doing a watch dog on the cpe and set the ip of the base ap.
this will reboot the clients if the link is unstable.
but i have found there is a 30minute window that the cpe reboots and reboots before all the links are stable.
this happens around 1x every 1-2days.

cpe510 are better and the links are very very stable.
longest ive seen is around 2weeks.

The CPE210's work on 2.4GHz, which is a very crowded spectrum.   You might try doing a spectrum analyzer, which you can find on the 'Wireless' tab.  It will show you what the most crowded channel frequencies are.  Once you do that, then you 'may' be able to select a 'channel' which is less crowded.

The CPE510's work on 5 GHz which is a far LESS crowded frequency, and that is why you have had better luck with it.  Whether you use a CPE210 or 510, you should always do a spectrum analysis (in the Wireless tab).

Hope this helps.   

Kent

@KentRda 

i am using test_mode and i also did a spectrum analysis which is why i am on channel (23 / 2552MHz)

again i have mirrored all settings from the cpe510 to the cpe220. NOTHING.

the best i can get is a stable 15-20hours link then all the cpe experiences massive packeloss (they have watchdog so they just reboot every 5mins if the base ap is not pingable)
after around 30mins the link stabilized.
then it repeats againg after 15-20hours.

all cpe (220 and 210 mixed) are on firmware 2.2.3 UN.

and the base AP is currently on 2.2.1 UN (was 2.2.3 before then i downgraded to 2.2.0)

Do you have an ethernet tester? It's starting to sound like you are losing the connection to the CPE(s).  Did you install the RJ-45 (ethernet) connectors on the cable?  If you don't have an ethernet tester (which is a great tool to have) you can get one for very little money on Amazon. 

@KentRda 

its not the cable (and i have a lan tester btw)

if i reboot the base ap or change the channel the wireless link will be stable again (for about 15-20hours)

i have cheaper branded device at 2ghz band (Comfast cf-314n and cf-130n) which has frequency of 2.3 to 2.7ghz (wider freq than tplink cpe220 and 210)
i can see them reach 50+ hours link status. much more stable. no customer complains.

Good Day Sir.  

I was just looking at your signal to noise ratio.    Signal to noise is actually a very complicated measurement.  However, simply put,  if you and I were talking in a noisy room, the level of our voices, compared with the noise in the room would be the signal to noise ratio.    Even if we were standing close to each other,, if our voices (signal) were close to the same level as the noise in the room, it would be very difficult for us to hear and understand each other.  With radio, it is ideal to shoot for a S/N ratio which has a difference of at least 50 db between the S ignal and the N oise.   

When I look at your S/N rations, that 50 db is not there.   Therefore, the radios are having a hard time hearing each other, even though the signal is good.  Unfortunately, the noise level is high in your environment.  This often happens at 2.4 GHz because there are so many devices operating on and around that frequency.   Therefore, when you do a spectrum analysis, look not only for a good signal level, but also look for a difference of 50 OR MORE db difference between your Signal level and your Noise level.  

I believe that this wlll also explain why you have had better luck with the  CPE510's (there is less noise in the 5GHz range.)   Also note that TP-Link also makes a CPE-710, which is also a 5GHz unit.  However, the dish configuration focuses the signal which not only gives you more Signal, but it also rejects much more of the noise from the surrounding environment.

So, start out by trying to find a frequency with a greater difference between S ignal and N oise (look for a difference of 50db or more).  If you can't find that with the CPE 210, then I would advise usings the CPE 510 or even the CPE 710's.

Good Luck Sir.

Kent

@KentRda 
SNR almost the same with CPE510 @ 43-46

it is not the snr. probably the firmware is faulty or faulty design of the v3 cpe220 base ap.

again the link goes haywire for 30mins (if i don't intervene) then it is again stable for 12-48hours.
today it almost got to 2days before the problem came back.

if i reboot the base ap or change to the next lower or upper channel the link once again is stable (for 12-48hours)

i read a post in this forum that the hardware ver2 was stable and they only saw the problem with hardware ver3.

I've been using V2 and V3 with many of these units for a number of years and have had zero failures.