Antennas gain and RSSI

Hi,
we are using 1240 AP and now have changed antenna to 1728 (Gain 5.2dBi) to increase signal strength, but as show Wi-Fi scanner (inSSIDer)
RSSI stays the similar with old and new antennas.
What's wrong? in AP configuration I changed diversity and external antennas gain.
Valentina

Hi, I have captured with inSSIDer and Xirrus: both programs show similar results (pictures are attached). Signal strength was measured from one place and it should be higher with higher gain antenna (distance is about 1 m in these pictures, but similar results with longer distance). Should we some addtional configurations in AP - and where if yes?
(the highest blue line in both pictures with dipole and then 1728)
Valentina

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SNR and RSSI Values.

HI ,
What is the tha average ,minimum and maximum values of SNR(Signal to noice ratio ) and RSSI (Received Signal Strength Indicator ) in cisco access points   .
And how it is depends on the client connectivity with the Access point.
Thanks & Regards,
Sinjish.K

I am not really sure what you asking here, but My guess is your trying to get a grasp on what SNR and RSSI
values are how they relate to clients, and how they relate to connectivity. If this is the case read on. otherwise well ingore this post..
SNR (Signal-to-Noise Ratio) is a ratio based value that evaluates your signal based on the noise being seen. So let's look at the components of the SNR and they see how to determine it. SNR is comprised of 2 values and is measured as a positive value between 0db and 120db and the closer it is to 120db the better: Signal Value and Noise Value typically these are expressed in decibels (db).
     So we will look at the Signal (Also known as RSSI) first this value is measured in decibels from 0 (zero) to -120 (minus 120) now when looking at this value the closer to 0 (zero) the stronger the signal is which means it's better, typically voice networks require a -65db or better signal level while a data network needs -80db or better. Normal range in a network would be -45db to -87db depending on power levels and design; since the Signal is affected by the APs transmit power & antenna aswell as the clients antenna (I'll explain this later.)
     Now to the Noise side of this equation, noise is any signal (interference) that is not WiFi traffic such as cordless phones, microwaves, radar, etc. This value is measured in decibels from 0 (zero) to -120 (minus 120) now when looking at this value the closer to -120 (minus 120) is better because that means there is little to no interference. Typical environments range between -90db and -98db.
     So to calculate your SNR value you add the Signal Value to the Noise Value and it generates (or should) a positive number that is expressed in decibels (db); for example lets say your Signal value is -55db and your Noise value is -95db.
                    -55db + -95db = 40db this means you have an SNR of 40, my general rule of thumb is that any SNR above 20 is good.
RSSI (Recieved Signal Strength Indicator) is a more common name for the Signal value; meaning it is the strength that the device is hearing a specific device or signal.RSSI is most common used in bridge links where on client laptops they just call it Signal.
As for your question about the maximum and minimum supported by cisco access points that is hard to answer because the antennas attached to the access points also factor into it. In general the Cisco APs have the following maximum transmit powers: 802.11a/n is 40mw or 14dbm, 802.11b is 100mw or 20dbm, 802.11g is 50mw or 17dbm; although in some cases countries and specific channels can alter these limits.
The last three things I will kind of explain is the EIRP, Free Space Path Loss, and Client side.
EIRP (Effective Isotropic Radiated Power) is the actual amount of signal leaving the antenna and is a value measured in db that is based on 3 things:Transmit Power (db), Cable Loss (db), & Antenna Gain (dbi). To determine EIRP follow this equation: - Cable Loss + Antenna Gain = EIRP. For example we have a Cisco 1242AG access points running at full power with a 6dbi antenna on the 802.11a radio and a 2.5dbi antenna on the 802.11bg radio.
802.11a EIRP = 17db (40mw) - 0db + 6dbi = 23db = 200mw of actual output power
802.11bg EIRP = 20db (100mw) - 0db + 2.5dbi = 22.5db = 150mw (approx) of actual output power
based on the example above in theory if you were to measure it right at the antenna you could get an RSSI of -23 or -22.5 respectively.
Free Space Path Loss is a measure of how much signal power you lose over a given distance typically you lose about 0.020 db per foot in an outdoor or wide open office; doors, walls, glass, and etc. affect this. This is why as you walk away from an AP your signal gets weaker.
All this relates to the client because it determines the signal the client recieves, also keep in mind that when looking at the client you have to account for it's antenna as well. much like the EIRP... So if a client card has a 2 dbi antenna (although they are typically either 0dbi or 2.2dbi) that boosts the incoming signal. as shown here assuming the actual raw RSSI signal being seen is -68db (not the value displayed in the client window).
Actual RSSI + Antenna Gain = Displayed RSSI
-68db + 2db = -66db
I hope all this helps with your question...
Please rate useful posts.
Thanks,
Kayle

Do i have to configure the antena gain in a controller?

hi, i am using antennas of 5dbi for some aps and 2.2dbi for the others aps. so i would to know if i should configure in the controller the antenna gain? or the controller does this automaticaly?

Do you have it setup on the controller for "on demand" or "automatic"?
You can specify it per AP from the controller if you like , or the let controller do it for you automagically. If your APs are spread out somewhat uniformly in a given area - automatic may be the way to go. If you have APs strategically positioned and/or are using external antennas such as directional patches, you may want to do some tweaking. Try tweaking the power levels on a few APs and see how the other APs in the area react and how the user environment is affected.

Question about Antenna Gain

Dear Frends,
Could any one can explain me the usage of "Antenna Gain" field in Cisco WLC software v4.2 (Go to Wireless > Accesspoints> radios >802.11b/g/n Cisco APs > Configure - page in Gui)
if i'm using an 2.2Dbi cisco antenna, which value should i mention there? 2.2 or 4.4 ?
Anybody can suggest me any white paper or any documents regarding the mentioned page ?
Thanks in advance
Raj

You would use the gain of your antenna, 2.2dBi.
Just because there are two antennas does not mean the value doubles. The other antenna is for diversity purposes; in the event a signal recieved is weaker due to a host of reasons, the other antenna is exactly 180 degrees out of phase of the first antenna and would most likely be in a better position to receive the strongest signal.
With diversity on, the AP constantly determines which antenna would be the best antenna at that moment in time to recieve signals. They flip on and off all the time.
The only way to increase gain would be to use a higher gain antenna. Depending on your original intent and your surrounding environment, this does not necessarily equate to better; sometimes it equates to worse.
You type it in so the WLC knows what you stuck on the end of the radio so it can act accordingly, supposedly.

LWAPP/CAPWAP Antenna Gain Setting - label only?

When configuring an AP external antenna gain (from a WLC), is the gain assigned purely a label to show its gain, or does it actually wind down the transmitter output by the dB amount that is input in to the gain field?
For instance, my Tx power is set to 2 (17dBm), and I attached a 2.2dBi antenna.
My ERP would now be 19.2dBm.
Does the antenna gain value I enter (4 x 0.5) actually cause the AP to lower its output power by 2.2dB to cater for the fact that I have attached a 2.2)dB antenna and maintain its 17dBm output? (...OK, I know 4 x 0.5 will give 2dB, but lets talk in round numbers)
So in summary:
AP tx pwr = 17dB
Physical antenna gain = 2.2dBi
AP configured antenna gain = 4 x 0.5 (2dB).
What is the effective radiated power? 19.2dBm, or auto-lowered to 17dBm?
Thanks
Nigel.

This setting effects the heat map predictions in WCS. It also comes into play with the RRM calculations and with some AP's will be considered for controlling the RF power.

What's the relation between Gain and transmitted power with coverage area?

what's the relation between Gain and transmitted power with coverage area?
if we want add coverage area, could we just add antenna's gain only or add transmitted power only?

That information can be found at: http://www.cisco.com/warp/customer/cc/pd/witc/ao350ap/prodlit/agder_rg.htm

Foreign exchange gain and loss

Short Text
Foreign Exch Gain / Loss to be booked to a diffr cost center
Long Text
The transaction booked with the following parameters
Step 1:-Transaction booked trough FB60
Foreign currency CHF @ 40/ruppee
Expenses debited (1000-cost center)
Vendor Credited
Step 2:-Transaction paid through F-53
Foreign currency CHF @ 50/ruppee paid
Vendor Debited (Clearing the open item)
Bank outgoing account Credited
Foriegn exchange gain and loss Debited
In ECC 6.00 Version:- The open item clearing inherits the CO objects
from step one except for "Foreign exchange agin and loss line item"
Note:
1) In above scnerio, if foreign exchange gain and loss booked to some
other cost center other than Step one:- Cost Center (Expenses booked).
2) If the foreign exchange gain and loss line item booked to same cost
center as specified in Step one:- Cost Center (Expenses booked).The
below error does not occur.
3) The requirement is to book different cost center for the Foreign
exchange gain and loss line item.
The following error occurs during FB05 transaction execution for
transfering the line item in Bank outgoing account to Bank Main account.
Error Details occur during FB05 transaction execution:-
Start----
Ex.rate diff.accts are incomplete for account 0002500062 currency CHF
Message no. F5063
Diagnosis
The accounts for posting exchange rate differences could not be
determined. For the specified G/L account and the specified
currency
key, the accounts are only specified incompletely. Either the
accounts
for the implemented exchange rate difference, the accounts for the
valuation differences or the balance sheet adjustment account are
missing.
System Response
The system cannot generate the exchange rate difference posting.
Procedure
By pressing ENTER, you achieve that the document is reset to a
status
without automatic posting. In another window, you can complete
default
settings for exchange rate differences and post the document
afterwards.
END----
Configuration already in place:-
1) Bank outgoing and main account "ONLY BALANCE IN LOCAL CURRENCY" is a
ticked
2) In OBA1 Foreign exchange gain and loss and valuation gain and loss
GL's are defined for respective Reconciliation account.
Regards,
Sathya

Hi,
Is your problem solved, I am also facing the same issue when transffering from Incoming/Outgoing to Main Bank Account. Exchange gain/loss is being calculated by the system.
Please share with me the solution to the above problem.
Thanks & Regards,
Jyoti

I am trying to create a PDF document that calculates Gains and Losses in Mutual Funds. The calculation scripts are repetitive from line to line. The scripts work well until I reach the line 32. Script stops calculating...

I am trying to create a PDF document that calculates Gains and Losses in Mutual Funds. The calculation scripts are repetitive from line to line. The scripts work well until I reach the line 32. Although I am using the same script as the fields above in the columm, the script eventually stops calculating and I can't figure out why. Is there a limit of how many calculation scripts you can enter? I will attempt to attach my pdf as soon as I figure out how. Thanks.

For e31 :
var e30 = +getField("e30").value ;
var c31 = +getField("c31").value ;
if ( (e30 !== 0) && (c31 !== 0) ) event.value = e30 + c31 ;
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for e32 :
var e31 = +getField("e31").value ;
var c32 = +getField("c32").value ;
if ( (e31 !== 0) && (c32 !== 0) ) event.value = e31 + c32 ;
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var c33 = +getField("c33").value ;
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Java console doesn't show any error... That's why I am wondering if it's not a limitation issue... or memory issue, because they are maybe too many rows or something....
The c value is not calculated.

Issue on Gain and Loss account in F110 document

Hello SAP Guru,
I would like to ask your assistance regarding our accounting document. The document was produced on F110 transaction.
Now the problem is Valuation Balance sheet adjustment, realize gain and loss are in one document.
25 - Vendor - 727,843.35
50 - Clearing Account - 801,874.76-
40 - Valuation Balance sheet adj - 159,734.84
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40 - realize loss - 0
How this happened? Realize loss and gain in one document, and why valuation balance sheet adjustment was used? I thought it is only use for open items?
Thanks in advance!
Jhero

Hello SAP Guru,
I have other question, I have maintained KDB accounts in OBA1. How could I test it? I mean what transactions do you have to perform to use the accounts I maintained.
Eg.
1. Post document FB01 - using Foreign Currency - Vendor + GL
2. Chnage the FX rate - to have FX valuation
3. Run FAGL_FC_VAL
Something like above
Thanks!
Jhero

The gain and loss from asset retire ment

hi
The Gain and Loss from a retirement is booked to the cost center where the asset is located, is it possible to override the cost center so all will be booked to the same cost center?

Hi
Change the Cost Centre or
Go to TCode OKB9 and enter your new Cost Centre
Srinivas

Gain and loss account

Hi,
My scenario is Mae to order, when i m going to make new Finished material , i put 1 INR in with Price control "S".Then Created sales order - creation of BOM - production order - confirmation of production order - Then Dispatch the Finished good.Then updating MR21 for price.Then in when i m going to see the accounting document there is Gain and loss account hited.Please suggest reason behind this.

Hi,
That's right! Because you changed the standard price of the finished good with t-code MR21, system had to re-calculate the stock value again, it led to update the stock account obviousely, so debit(credit) stock account and credit(debit) Gain & Loss account to balance the financial balance sheet.
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Tao

5500 sport,Antenna Coupler and Holder incompatabil...

I have a Nokia 5500 sport which is causing some grief in relation to finding and appropriate antenna coupler and a suitable phone holder. I am wanting to install a CK- 7W car kit with an external broomstick antenna but am limited I think to a universal holder CR-39 because of the phone. I already have the CK-7W but need some advice as to which cradle I can get that will support an antenna coupler and what model of antenna coupler I should purchase. The dealer has sold me an AX-15s coupler and a CR-39 holder but the two do not match!
thanks in advance

The only company which i know of that do a cradle for the 5500 sport is THB Bury, but you will have to buy a full new car kit for this not a ck-7w, although it dose have antenna connection and charging.
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Need info about Antenna gain settings

I could see that antenna gain setting under 802.11b/g ap showing 0 valu. However, the antenna connected to that AP is AIR-1728 which has 5.2dbi. Please let me know if it shows 0 then will I get the Maximum power ? or do we need to change ito some value to get the maximum of the antenna power.

Not really, with a value of 0 the WLC assumes a standard 2.2dBi of gain, IIRC. Putting in the correct value for the antenna gain, allows the WLC to make better power settings.
HTH,
Steve

Can We Change Realized gain and loss account in system option Receivables

Hi All,
As part of our month end processes we are posting a manual journal each month to clear this GL account down to a nil balance.
Looking at the activity they all look to be automated AR postings on foreign currency transactions.
Is there any way we could get these to automatically post into account 01.2201.4901 instead of 01.9000.9757? This would save us having to do the manual journal and avoid the situation of missing any which we did last month.
Regards,
Raju.

Hi Raju,
option 1
You can change the Realized Gain and Loss Account from the System options form in Receivables, but this will be effective only for all new transactions that are going to get created and not for the existing one ...
Option 2
If you do not want to modify the system options, you can override the values at the accounting time frame by configuring an Accounting Derivation Rule for the Realized Gain and Loss Journal Line Type. Again this would take effect on new transactions only
Option 3
You can disable 01.2201.4901 and state its replacement is 01.9000.9757 in General Ledger module, so whenever system would use the replacement account for automatic processing ....
You have to keep running the Accounting analysis report in General ledger for the account string 01.9000.9757 every month to cross check whether you have passed all Manual Journal Vouchers to make the balance NIL ... i am not sure whether there is any other way of performing a cross checking and minimizing the time that is being consumed at present ....
Regards,
Ivruksha

Currency gain and losses

Hello,
Is there a report where I can get the currency gain and losses from the exchange rate in a specific period?
Regards,
Barbara

Hi
You should run the foreign currency valuation program in order to obtain the profits or lost ..
Check this out
http://help.sap.com/saphelp_erp2004/helpdata/EN/a6/004940f0030272e10000000a155106/frameset.htm

Antennas gain and RSSI

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