I have been trying 4 a long time to get a link up with a good signal strength. I am using compex cards (WLM54AG). I think its 65mW output power. On either end of the wireless link, I hav a compex WLM54AG connected to a 22dBi flat panel antenna (with specs that suit a point-to-point i.e. beamwidth ~ 20 degrees). The flat panel antenna is optimised SNR at 5.7GHz (pretty even SNR for ± 100MHz). I’m working with 5745 MHz. Initially I started off with using LMR100 series cable, cudnt establish a connection, and a scan wud pick up the AP at -92dBm. I replaced the cable with an even less loss affected cable (the thicker WBC400, pretty sure its similar specs to LMR400 in terms of shield quality and internal core wire). This however improved it slightly, as now a connection was established but at -89dBm. Can ping to the remote side and work with a slow telnet seesion. Not good for the sort and amount of traffic that is to traverse the link. I really need some help with this, tried replacing radios. Got one side up with a SR5 but that too didnt make a significant difference. The distance between the two points is exactly 8km. Please note, there is clear line of site between the two sites. I have an 8.5km link on 2.4GHz range (prism cards NML2511) with signal strength at -76. Working on the 5GHz is frustrating (higher frequncies, greater attenuation).
Oh and just another question, not as important now, but just buggin me to ask… any1 know y we are able to receive at frequency channels of 5MHz and 10MHz but not transmit at such… Guess wat I’m asking is… wat is the point? To be able receive at a certain frequency shudnt u hav to transmit remotely at that same frequency… For example: We kno, we cant transmit at 5775MHz, but apparantly can receive at the frequency. i may not b thinking about something. My RF knowledge is not the best.
For the signal strength in your link, I would strongly recommend not to use any cable such as lmr-400 or such, I would recommend to place the card rigth next to the antenas on both ends of you link see… if you use coax cable this will result no only in signal loss but most important it will result in sensitibility loos, this means the cards will not be able to transmit at high rates eaben with a strong signal, put your radio on an outdor box close to your flat pannel antena, then run your UTP cable to your equipment using power/ethernet and you will see the difference
How long is your LMR cable run?
65mW radios with 22dbi antennas will not give you a very good signal over 8kms unless you are well above your LOS obsticle line.
If you wish to run a length of cable for 5.8 you should use a minimum of an LMR 600 or an even lower loss cable such as LMR900.
For the cost difference of a 400mW radio I would suggest you upgrade your radios.
If you have lightning arrestors, be sure they are rated upto 6GHz.
The LMR400 RF cable i’m using is 1m (my radio is next to the antenna in a box on the mast). I am running power over ethernet and have clear LOS. I have a lightening arrestor rated at 5.8 GHz. I am hesitant to replace the radio to a higher powered radio, because I already have two higher powered radios on the same routerboard (SR2 and SR5). It may cause too much heat dissipation and hence problems may arise. I am using a routerboard 532 that contains the 2 high powered radios and a daughterboard RB564 that contains for now the compex low powered radio.
