Guys,
Does changing among 802.11b frequencies affect the range for the same power used? I mean if I changed my channel frequency from ch6 to ch1 with the same booster will that decrease my range?
thanks
Atheer
booster?
Jwcn → booster == Amplifier
let me put it in other words: Using 802.11b 500 mili Watt AP, if I changed my transmission frequency from channel 6 (2.437 GHz) to channe 1 (2.412 GHz), how would this affect the following:
1-bit rate.
2-range.
3-reliability.
hope I can find any answer here…
Atheer
What type of wireless radio and amp are you using?
in most radios yes, you will see a slight decrease in power on channels 1 and 11 as opposed to channel 6. The radio’s are tuned to work best in the center of the band, to balance performance between 1 and 11, in a good radio, this differece may hardly be measurable, but in a lower quality radio it may be as much as 2 db drop.
That said, you’re probably going to see a bigger difference in the tuning of the antenna then the difference in transmit power of the radio. We don’t do much in the 2.4 band so I don’t have much experience with it, but in the 5.8 band with cheap antenna’s, we see as much as 4-5dbm of signal loss from the center of the band to the edge channels, due to performance differences of the antennas
Jwcn,
well I said it is 802.11b (2.4 GHz), but if you were asking me about my AP then it is Wireless Interactive WI24001W with Power Over Ethernet unit that supply 1 Watt to My AP, and my anntena is Omni with 15 db.
ForePoint,
thanks a lot for these info,it was helpful… but do you know any site or something where I can find answers?
anyone else can drop us a line here?
Atheer
you’re already at one… 
you’d have to be alot more specific as to what kind of answers you’re looking to find.
Dear Normis , I would appreciated if you share your thoughts with us
thanks
Atheer
this has been discussed many times. an amplifier works only if you have a perfect signal, no noise and a free freqency (basically if you are alone in the area). Otherwise it will amplify the noise and things will get much worse in all aspects.
Normis,
Where I can find that discussion? do you have any link to such posts?
aside from noise amplification, does reducing the frequency affect my range? currenly I transmit up to 700 meter, will that be less with the new freq?
I know that low freq is more stable than high one from the bit rate point of view…
am I correct?
thanks
oh, lots of them. this is common knowledge.
http://forum.mikrotik.com/t/best-mpci-b-g-for-a-public-hotspot-with-amplifier/9930/1
http://forum.mikrotik.com//viewtopic.php?t=7643&start=0&postdays=0&postorder=asc&highlight=1watt
http://forum.mikrotik.com/t/perfect-signal-smtp-traffic-bombing-out/7136/1
http://forum.mikrotik.com/t/cm9-with-1-watt-amplifier/6701/1
http://forum.mikrotik.com/t/faustrating-issues-on-performance/5416/1
http://forum.mikrotik.com//viewtopic.php?t=7643&start=0&postdays=0&postorder=asc&highlight=1watt
Thnks Normis, those posts were really helpful..now I hate those amplifiers !
Ok now forget about amplifiers, if I just changed the channel frequency from ch4 (2427 Mhz) to ch1 (2412 Mhz) what things that would be affected due this change? or let me be more specific, how this change will affect:
- range distance
bit rate
reliability
I do need answers to those questions and I would be grateful to you if you could help me with that.
Atheer
it highly depends on the environment you are operating, which channel is free and what nose (interference) you have there.
if you are all alone you should not feel much of a difference if any.
Ok, here are my opinions on the topic. Obviously lower frequencies go through things better and higher ones have smaller fresnel zones amongst a million other variables, but the change between 2427 Mhz and 2412 Mhz really doesn’t give you any noticiable differences. I mean, we’re only talking 15 mhz difference between the center frequency. Even the difference between 5100 mhz and 5800 mhz is hardly noticable.
The real only difference between all of the frequencies in any given band is the noise from other equipment operating on that same channel. If you happen to switch to a channel with less noise, all 3 of the things you mentioned will be better. If the noise floor is the same, you probably won’t notice a difference.
I should mention that some equipment has a more tight filter or is more tuned to a specific frequency. For example, a 2.4 ghz antenna and radio are probably tuned to work best in the center of the spectrum (channel 6), so when you get to channel 1 or 11, you could be down 1 or 2 db. I personally have never really noticed this minimal effect and rely more on finding a clean frequency to operate on.
Joe
well well well…
i m working in a very heavy interferene environmet..
and i also hav almost same setup i mean a omni and a 200 mw seano 2611 cb3 an i hav 25 usres connected to it…i m having this setup for last 3 years…and i m new in mikrotik..offcourse i hav 10 % knowledge of mikrotik..i always keep on playing wid channels…wht i noticed is when i shift my ap to ch1 two or three users get dissoconted..which are located in the eastern part of my tower…while…the west side users get remarkabale improvement in each aspect..but..on the other reming two sides the performance is not real satisfactory one…though users are not disconnetd..but one more thing its not permanet performance…i know after 2-3 months i hav to again change the channel…i m sure..it all depened upon the physical envorionment at tht place..
Janisk
That is absolutely right, it highly depends on the environment and how much noise and interference is there…
jcremin
Thanks a lot for those opinions. I like really found them very helpful. So, not that noticible difference I should encounter. therefore I should focus on more clear channels than low or high bands…
wireless12
very ture…it all depends on interference and noise on that channel you choose…
guys, I have to thank you all for this fruitful converstion..I learned a lot and now I can decide what to do..
thanks again.
Atheer