Wireless antenna question

Hello,
To have a more stable wireless connection with my router, i replaced
2dbi standard antenna of my router WITH Digitus 5dbi antenna:
http://www.digitus.info/scripts/digd...00&showpfad=ja

After replacing, i wasn't supposing too much signalling quality
increasement, then it was so that the signalling quality did not
change, stayed at with the same level of the previous 2dbi antenna.

So, what's the purpose of purchasing or producing 5dbi antennas which
are certainly more expensive than standard 2dbi ones?

Is it normal not to increase signal quality or noise reduction?

I'm thinking, this type of antenna replacement can be useful for
extending wireless range coverage? Is it right?

If you clarify i'd be happy...

Thanks....

kimiraikkonen wrote:
> i replaced
> 2dbi standard antenna of my router WITH Digitus 5dbi antenna:
>
> So, what's the purpose of purchasing or producing 5dbi antennas which
> are certainly more expensive than standard 2dbi ones?
>
> Is it normal not to increase signal quality or noise reduction?
>
> I'm thinking, this type of antenna replacement can be useful for
> extending wireless range coverage? Is it right?

Not really, that's only a 3 dB increase. It takes a SIX dB increase to
double your range. A 3 dB increase will help a little big, but not all that
significantly.

On Aug 5, 3:17 am, DTC <no_spam@move_along_folks.foob> wrote:
> kimiraikkonen wrote:
> > i replaced
> > 2dbi standard antenna of my router WITH Digitus 5dbi antenna:
>
> > So, what's the purpose of purchasing or producing 5dbi antennas which
> > are certainly more expensive than standard 2dbi ones?
>
> > Is it normal not to increase signal quality or noise reduction?
>
> > I'm thinking, this type of antenna replacement can be useful for
> > extending wireless range coverage? Is it right?
>
> Not really, that's only a 3 dB increase. It takes a SIX dB increase to
> double your range. A 3 dB increase will help a little big, but not all that
> significantly.

Besides not to get "higher" signal levels, signal level fluctutas very
quickly, but doesn't drop to low signal levels when compared previous
2dbi antenna. WhY?

No comment more? There's no router and adapter positioning change but
also signalling level is still same maybe worse maybe same, but
definetely no signal level increasement after upgrading from 2dbi to
5dbi anntenna...

On Aug 7, 5:32 am, kimiraikkonen <kimiraikkone...@gmail.com> wrote:
> No comment more? There's no router and adapter positioning change but
> also signalling level is still same maybe worse maybe same, but
> definetely no signal level increasement after upgrading from 2dbi to
> 5dbi anntenna...

Well, welcome to the real world of antenna design. I'll hit the
highlights.

1. Your theoretical gain increase is allegedly 3dB. That's good
for a 1.4 times increase in range. You probably won't notice it
much.

2. The "5 bars" signal indicators are very granular. I was going
to measure the signal levels that correspond to each bar in a
probably futile attempt to achieve some semblance of calibration.
It's about as futile as doing that on a cell phone. I have one phone
that shows 3-5 bars for everything except a total loss of signal,
but garbles calls regularly. I also have a PDA phone, that shows
zero or 1 bar regularly, but works just fine at those levels.

In short, the number of bars don't mean much and certainly not
for comparing different client radios or antennas. I'll make a
very bad guess that the 5 bars cover the dynamic range of
the receiver. That's about an 80dB range, which makes one
bar worth 80/5 = 16dB. You're not going to see a 3dB change
when each bar is worth 16dB.

3. The bars may not even measure signal strength as RF level.
Some chipsets use the bit error rate as an indication of signal
strength. It's suppose to be an indication of signal quality, but
they just take the baseline noise level, add the signal quality,
and call it the signal strength. Saves on hardware and CPU
cycles, I guess(tm).

4. Measuring antenna performance indoors is also futile. There
are more reflections than signal. Same with going through
walls, corridors, and close to the ground. What you're actually
measuring is the RF reflective quality of the room, not the
direct signal. I was running antenna tests in my palatial lab,
the swept gain results were varying +/- 2dB by just me moving
around about 1 meter from the antenna.

Those lovely symmetrical gain plots you see on the antenna
manufacturers web piles are nothing even close to reality.
The gain pattern is affected by literally everything in the area.
Give a single antenna to several test labs, and you'll get
ridiculously different patterns and result. Your two antenna
have a max gain of 2 and 5dBi only on a simulator.

5. Antennas are also very frequency sensitive. This is normally
not a problem with low gain 2 or 5dBi antennas, which have a
fairly flat VSWR curve. However, the higher gain antennas (24dBi)
often barely cover the 83.5Mhz of the Wi-Fi band and are often
quite different on low and high channels.

However, the low gain antennas offer another complication.
They are very crudely constructed. Look inside and they are
mostly coax cable and brass tubing. The driven element is
commonly just the exposed center of the coax. When 1Mhz
is only 0.052 mm, it's fairly easy for production variations
to cause problems. I've tested a box of allegedly identical
5dBi rubber ducky antennas and found the resonant point
to wander all over the 83.5Mhz of the band. About 1/4th were
outside the band.

6. I suggest you give up on your quest to find the ultimate
omni antenna. They have their place but directional antennas
and reflectors work better if you can tolerate the directionality.
I'm also a big fan of homemade AMOS/Franklin sector antennas:
<http://pe2er.nl/wifisector/>

Hi Mr. Liebermann,
Thanks for the tips and experiences, actually i've got it to get rid
of wireless drops although the connection is seemed as "connected" in
Windows taskbar or my Broadcom's utility, but it didn't help, still
having drops if i move notebook away from router, the shown speed is
about 24mbps or 11mbps and it drops although seemed as "connected".

However i haven't changed adapter or router, only changed antenna from
2dbi to 5dbi, which did not help...

On Aug 8, 12:32 pm, kimiraikkonen <kimiraikkone...@gmail.com> wrote:
> Thanks for the tips and experiences, actually i've got it to get rid
> of wireless drops although the connection is seemed as "connected" in
> Windows taskbar or my Broadcom's utility, but it didn't help, still
> having drops if i move notebook away from router, the shown speed is
> about 24mbps or 11mbps and it drops although seemed as "connected".

Ok, now we know what you're trying to accomplish. I'll assume a
Windoze XP laptop and some sort of internal MiniPCI card. I'll
pry the details and the router model out of you later.

Try this simple test. Run continuous ping from your laptop.
Don't move it during the test. Also try it with various antennas.
For Windoze it's
ping 192.168.1.1 -t
What you should see is delays of about 2-5 msec. Less if
you have a decent router. The actual value is not terribly important.
The variations between ping times are an indication of how reliable
your connection is running. If you get larger variations in ping
times,
you might have a interference problem, sick router, old firmware,
buggy driver, or as I found in another similar thread this week, it's
time to reboot your computer.

If you're really ambitious, you can use IPerf to determine your level
of impairment. Setup a 2nd computah, with a direct CAT5 connection
to the router. Run the server part or Iperf as:
iperf -s
On your wireless laptop, run:
iperf -c ip_address_of_server
and see what manner of speed you get. It should be about half the
wireless connection speed. Anything less or highly variable means
you've got a problem.

Whether a better antenna will solve the problem is dependent on the
exact nature of the problem. Go find the cause. Then we can discuss
the solution.

>
> However i haven't changed adapter or router, only changed antenna from
> 2dbi to 5dbi, which did not help...

On Aug 8, 1:21 pm, Jeff Liebermann <je...@comix.santa-cruz.ca.us>
wrote:
> you might have a interference problem, sick router, old firmware,
> buggy driver, or as I found in another similar thread this week, it's
> time to reboot your computer.

See:
<http://groups.google.com/group/alt.i...ss/browse_frm/
thread/be0f100b187d5a37/#>
for the thread on analyzing ping results. If you get something
awful, like the initial message shows, you have a problem,
somewhere.

On Aug 8, 2:32 pm, kimiraikkonen <kimiraikkone...@gmail.com> wrote:
> Hi Mr. Liebermann,
> Thanks for the tips and experiences, actually i've got it to get rid
> of wireless drops although the connection is seemed as "connected" in
> Windows taskbar or my Broadcom's utility, but it didn't help, still
> having drops if i move notebook away from router, the shown speed is
> about 24mbps or 11mbps and it drops although seemed as "connected".
>
> However i haven't changed adapter or router, only changed antenna from
> 2dbi to 5dbi, which did not help...



Try putting a reflector on either of the antennas. That will help
more than going from 2 to 5 . http://www.freeantennas.com/projects...te2/index.html

Steve