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Operation with hot signals?

Posted: Fri Nov 05, 2010 6:23 pm
by tackerman
Can anyone comment on their experience with "hot" signals using either mtik or ubiquiti radio cards?

I'm looking for anecdotes regarding any success or failure with either the in channel (i.e. actual link) signal being hot or an out of channel transmitter in the same frequency band injecting a hot signal at either end of a link.

I have "gut" ideas about what constitutes a "hot" signal but I'm also wondering what the long term effects are to the radio cards. Is it possible to have a hot enough signal that physically damages a radio card.

I am specifically not talking about subjecting the radio cards to unreasonable conditions such as having them run without a load.

Mikrotik, if you have any recommended operating conditions regarding your radios and the long term effects of hot signals (e.g. how hot and how long the radios can be subjected to the hot signal), we're all ears

Thanks

Re: Operation with hot signals?

Posted: Fri Nov 05, 2010 10:04 pm
by 0ldman
Just during short term testing, mostly when configuring routes and testing end to end in the office...

I've found that anything better than a -50 is detrimental to speed and reliability. -38 will barely associate, when it does it is 1-2mb instead of A/G/N speeds.

Long term, I have no idea.

Re: Operation with hot signals?

Posted: Fri Nov 05, 2010 11:53 pm
by adrianatkins
Running more than 1 watt EIRP is illegal where i am (Spain) and that is the max on 5Ghz > 5450Mhz.

On 2.4 it's 100mW.

It's also basically stupid to have your radio running 'Hot' or Over Powered because it forces the final stage(s) of the radio card into un-designed-for areas.

They make Noise, and lots of it.

In places where people think BIG is Best, the airwaves are horribly poluted, and the normal reaction is to Turn It UP, which causes further noise, and so on.

In WiFi, and other areas, i find that Bigger Ears win every time over Shouting.

Re: Operation with hot signals?

Posted: Sat Nov 06, 2010 7:41 am
by 0ldman
I may have misunderstood, but I thought he was talking about rx signal strength, not necessarily blowing the tx power out of proportion. That is what I was talking about anyways...

Re: Operation with hot signals?

Posted: Sat Nov 06, 2010 10:01 am
by adrianatkins
Maybe i misunderstood it too.

Re: Operation with hot signals?

Posted: Mon Nov 08, 2010 9:07 pm
by tackerman
Yes I'm speaking only of RSSI.

It doesn't matter what the transmit power is set to or what kind of antenna is used, could even be a lab situation where the radios are coupled directly with cables and attenuators. Only that a radio is receiving a "hot" signal.

Anyone see a radio get physically damaged from a hot signal?

Re: Operation with hot signals?

Posted: Mon Nov 08, 2010 9:16 pm
by tackerman
Just during short term testing, mostly when configuring routes and testing end to end in the office...

I've found that anything better than a -50 is detrimental to speed and reliability. -38 will barely associate, when it does it is 1-2mb instead of A/G/N speeds.

Long term, I have no idea.
Which model of radio was that?