Dave said:
Ummm... those are *not* the same signals! The ATSC is on a different
RF frequency than the NTSC (quite possibly in an entirely different
band - e.g. NTSC might be on VHF low-band and the corresponding ATSC
up in the UHF region), at a much lower power, from a transmitter in an
entirely different location.
I've heard some stations do that (not so much in our area though) but
that sets them up for a serious black eye. Viewers buy new converter
box, most don't have analog pass-thru, they tune in ... nada ... whoops
.... numbers go down ... ad revenue goes down ... pink slips. In the
current economic condition that almost amounts to suicide from a
business point of view.
Comparing "Channel 6" NTSC and "Channel 6 ATSC" one-to-one is
comparing apples and oranges. Without further information (e.g. look
at the actual RF spectrum with an analyzer) you simply don't know
whether the signals are of similar strengths or not, or whether they
have similar amounts of multipath, or whether your antenna is dealing
with them in a comparable way.
Ch29 digital is where Ch48 used to be. On the analyzer it almost pegs to
overload. But signal strength can mean nothing in this area.
A 30-to-60-second outage is more than I would expect from an
occasional packet loss. It strikes me that something different might
be going on in your situation. It sounds more to me as if your PC is
completely losing its assocation with the AP and is having to
re-negotiate.
But it's all of them
First practical suggestion - have somebody observe the AP lights in
the office, while you do something to precipitate this problem (or
just wait until it occurs). See if the AP seems to be doing something
different than normal during the "dead time". Specifically, see if
its LED sequence suggests that it is rebooting.
Did that already. It just keeps its beacon going. Traffic slows to a
crawl. Seems to be trying but can't get through.
I had a problem somewhat similar to this a few years ago, involving an
Apple Airport 802.11 base station. It worked fine during light use,
but if I tried to download a large file I'd lose the signal for 30
seconds or more.
Turns out it was crashing under heavy load. The culprit: Apple was
one of many victims of the "capacitors with pirated, corrosive
electrolyte formula" problem. The main power-supply bypass caps in
the AP were rotting and had gone high-ESR. The AP worked OK under
light load, but when it started transmitting lots of data and drawing
more current from the power supply it would brown-out and reset.
Replacing the caps cured the problem.
Ah, thanks! Time to open it up and hanging the scope onto the rail. It
appears to have a buck switcher that takes a wide input range. Of
course, if the cap before the buck can't hold its water then it's all hosed.
I wonder whether your AP is having somewhat-similar problems... it
sounds as if it might be getting old enough. If it's boosting its TX
power on the fly in order to push a signal "through the walls" to your
living area, it might be overstressing itself.
Can you borrow another AP from somebody, substitute it for your
current one (with no other changes) and see whether the problem is the
same or different?
Not in this neighborhood, it's rather rural. But if I can't fix this
quickly I'll just buy another one and try that.
Interference remains a possibility - in particular, microwave-oven
interference. Some years ago I used a 2.4-gig audio/video sender to
distribute a composite-video signal from a TiVo DVR to a TV in another
room. It worked well most of the time... but whenever anyone in any
of the houses in our cul-de-sac started microwaving dinner, the video
became un-viewable and the audio roared loudly enough to hurt our
ears. 802.11b is vulnerable to similar problems. Possibly the
drop-outs correspond with somebody nearby turning on a microwave?
I've also tried at night where all the lights were off at the neighbors.
Unless one of the kids snuck out and reach into the freezer ...
Surely you can figure out how to install one in a concealed location?
The only option would be outdoors here. Inside it's like a metal maze
from an RF point of view.
Quite possibly they do - that's entirely up to the firmware.
If it *is* a multipath problem, installing another AP closer to your
living area is probably the best solution... even if it's unpolitical
and requires physical concealment of the AP behind a potted fern named
Fred.
Yeah, it might be needed. But right now it has to wait. My wife just
started ripping out the floor in the next office. Meaning a slight hint
"Hey, get over here with them tools, will ya?" If I was a bachelor I'd
have left the old flooring in there and not moved a thing. But ...
