hi guys
anyone here have tried bandpass filter to see how much effect it has on speed on very noisy locations?
thanks
It depends entirely on what the nature of the very noisy location is.
If the noise source is within your passband, they won’t help.
If it’s something really powerful just outside your passband, they can work wonders.
We have never had to use one in 5gig, and only once in 2.4. In that case, we had an old lynx right next to us, and we were playing channel tag. The filter did not really help our SNR much, but it did clean up our own sidebands, which was enough to stop the channel war. We used one of those little “tunable” electronic filters, but if we had really cared all that much, a actual cavity is much cleaner (and doesn’t add to the noise at all, unlike the electronic ones).
In 900Mhz, however, we absolutely need them. At one location, there is a ~2Kw paging system nearby sitting at about 932Mhz. It was saturating our recievers all the way down to 905Mhz, causing very poor performance. Adding a 6-pole cavity improved our SNR by ~35dB, making it a very usable system.
If you are fighting powerful out of band interferance, then they are worth their weight in gold.
Otherwise, they are probably more trouble than they are worth.
–Eric
very good answer.
since I dont have signal analyzer I must try and see what is my noise source first
thanks again