Hi all,

I am transmitting in channel 3 of 802.11b, centered at 2.422Ghz.
Details aside, let me just say that it is very important for my
application that I sharpen up the spectral mask beyond that of the
802.11b standard. To be specific I need to purchase a bandpass filter
such that I get attenation of greater than 60dB at +- 15Mhz from the
center, i..e outside of [2.407Ghz, 2.437Ghz]. I am looking for
suggestions on where to purchase such filter(s) with the usual
parameters in mind, cost, lead time, etc.

I did see the filters that hyperlink sells, but it would take many of
their 8 pole filters in series to get what I need and they additionally
don't sell filters for one of the channels i would need. Maybe I need
to go custom on this? Any suggestions are greatly appreciated.
Thanks,

Kevin

You don't need to go custom. You need to understand the impossibility of
what you are asking for.
Jim




wrote in message
oups.com...
Hi all,


Maybe I need
to go custom on this? Any suggestions are greatly appreciated.
Thanks,

Kevin

Sorry I mispoke earlier. Let me restate this. Hyperlink has an 8pole
filter for several of the 802.11b channels that has the mask -3db at +-
10Mhz, -5db at +-15Mhz, -20dB +- 20Mhz.

Essentially I want to keep 2.417 to 2.437 Ghz, so one of their filters
centered at 802.11b, channel 4 would be ideal, except that they only
sell centered at the standard channels (channel 3 and 6 are the
closest), so in short I was wondering if anyone knows of a vendor that
sells such a filter centered at 2.427Ghz. Thanks for any suggestions.


RST Engineering (jw) wrote:
You don't need to go custom. You need to understand the impossibility of
what you are asking for.
Jim




wrote in message
oups.com...
Hi all,


Maybe I need
to go custom on this? Any suggestions are greatly appreciated.
Thanks,

Kevin

Hello Kevin,


Sorry I mispoke earlier. Let me restate this. Hyperlink has an 8pole
filter for several of the 802.11b channels that has the mask -3db at +-
10Mhz, -5db at +-15Mhz, -20dB +- 20Mhz.

Essentially I want to keep 2.417 to 2.437 Ghz, so one of their filters
centered at 802.11b, channel 4 would be ideal, except that they only
sell centered at the standard channels (channel 3 and 6 are the
closest), so in short I was wondering if anyone knows of a vendor that
sells such a filter centered at 2.427Ghz. Thanks for any suggestions.


That looks like you'd have to call them for a custom version which will
probably be lots of $$. Or roll your own which requires a lot of
RF/microwave knowledge. Or hire a consultant :-)

Problem is, if you are most likely the only one needing this there won't
be an existing market and chances that any other company has the right
product could be close to zilch.

--
Regards, Joerg

http://www.analogconsultants.com

wrote in message
oups.com...
Sorry I mispoke earlier. Let me restate this. Hyperlink has an 8pole
filter for several of the 802.11b channels that has the mask -3db at +-
10Mhz, -5db at +-15Mhz, -20dB +- 20Mhz.

Essentially I want to keep 2.417 to 2.437 Ghz, so one of their filters
centered at 802.11b, channel 4 would be ideal, except that they only
sell centered at the standard channels (channel 3 and 6 are the
closest), so in short I was wondering if anyone knows of a vendor that
sells such a filter centered at 2.427Ghz. Thanks for any suggestions.


Can't you do this at IF?

Tam

Tam/WB2TT wrote:


wrote in message
oups.com...
Sorry I mispoke earlier. Let me restate this. Hyperlink has an
8pole filter for several of the 802.11b channels that has the mask
-3db at +- 10Mhz, -5db at +-15Mhz, -20dB +- 20Mhz.

Essentially I want to keep 2.417 to 2.437 Ghz, so one of their
filters centered at 802.11b, channel 4 would be ideal, except that
they only sell centered at the standard channels (channel 3 and 6 are
the closest), so in short I was wondering if anyone knows of a vendor
that
sells such a filter centered at 2.427Ghz. Thanks for any
suggestions.


Can't you do this at IF?

Tam

He might with a hi Q cavity.

--
Baron:

wrote in message
oups.com...
Hi all,

I am transmitting in channel 3 of 802.11b, centered at 2.422Ghz.
Details aside, let me just say that it is very important for my
application that I sharpen up the spectral mask beyond that of the
802.11b standard. To be specific I need to purchase a bandpass filter
such that I get attenation of greater than 60dB at +- 15Mhz from the
center, i..e outside of [2.407Ghz, 2.437Ghz]. I am looking for
suggestions on where to purchase such filter(s) with the usual
parameters in mind, cost, lead time, etc.

I did see the filters that hyperlink sells, but it would take many of
their 8 pole filters in series to get what I need and they additionally
don't sell filters for one of the channels i would need. Maybe I need
to go custom on this? Any suggestions are greatly appreciated.
Thanks,

Kevin

Perhaps you could get one of the hyperlink models and modify it.

wrote:

Hi all,

I am transmitting in channel 3 of 802.11b, centered at 2.422Ghz.
Details aside, let me just say that it is very important for my
application that I sharpen up the spectral mask beyond that of the
802.11b standard. To be specific I need to purchase a bandpass filter
such that I get attenation of greater than 60dB at +- 15Mhz from the
center, i..e outside of [2.407Ghz, 2.437Ghz]. I am looking for
suggestions on where to purchase such filter(s) with the usual
parameters in mind, cost, lead time, etc.

I did see the filters that hyperlink sells, but it would take many of
their 8 pole filters in series to get what I need and they additionally
don't sell filters for one of the channels i would need. Maybe I need
to go custom on this? Any suggestions are greatly appreciated.
Thanks,

Kevin

Send your spec to these guys, they should be able to help you or at least
tell you whether it can be done. I hope you can afford their products.
Their tunable notch filters are very nice and might be one way of avoiding
a custom design, though I don't know if they cover your frequency.
http://www.klmicrowave.com/index.shtml