I'm curious to know if you're taking about transmit amps or receive  
amps. When you say noise are you meaning transmitted noise (meaning  
spectral impurity such as distortion, or do you mean unintentional  
radiation of the desired transmitted signal?) or do you mean receiver  
noise such as a higher noise floor, or signals considered to be noise  
which are being picked up by the higher sensitivity receiver? I'm  
assuming you mean transmitted noise of some kind as a result of the  
transmit amp but I just want to clarify. Thanks!

What's the point of these router boards that have multiple radio card  
slots if you can't have the radio cards that close together?

Greg

On Apr 29, 2009, at 9:20 PM, Tom DeReggi wrote:

> There is nothing wrong with lowering the power on them.
> I personally love SR5s.
>
> The facts are though that cards with add-on amps embedded have the  
> potential
> to be noisier than one that does not.
> How much noisier, I can't say. That was part of tthe goal, to  
> determine if
> XR5s are as clean as CM9s, and if there is a distinguishable  
> difference or
> not.
>
> Tom DeReggi
> RapidDSL & Wireless, Inc
> IntAirNet- Fixed Wireless Broadband
>
>
> ----- Original Message -----
> From: "Kurt Fankhauser" <k...@wavelinc.com>
> To: <wireless@wispa.org>
> Sent: Wednesday, April 29, 2009 6:30 PM
> Subject: Re: [WISPA] RB333/433 eliminating self-interference test
>
>
>>
>> Whats wrong with using XR5's and lowering the TX power on them?  
>> They are
>> more rugged and have better RX sensitivity than many other cards.
>> --
>> Kurt Fankhauser
>> WAVELINC
>> P.O. Box 126
>> Bucyrus, OH 44820
>> 419-562-6405
>> www.wavelinc.com
>>
>>
>> --------- Original Message --------
>> From: WISPA General List <wireless@wispa.org>
>> To: WISPA General List <wireless@wispa.org>
>> Subject: Re: [WISPA] RB333/433 eliminating self-interference test
>> Date: 04/29/09 16:31
>>
>>>
>>> The first question is &quot;why are the 4 mpci cards in teh RB600  
>>> seeing
>> each
>>> other so loudly&quot;?
>>> There lies the problem needing fixed, because of course we want to  
>>> use
>>> one
>>
>>> RB433, instead of 3 RB433s, to accommodate 3 mpci cards.
>>> (even if different channels and freqs).
>>>
>>> First question to you... &quot;am I assuming correct that you  
>>> still kept
>> the
>>> dummy loads on each of the mPCI cards, when testing all in teh same
>> RB600&quot;?
>>>
>>> What is a bot disturbing is that you said you used a XR5. That  
>>> means the
>>> card had a single antenna connector and a MMCX style, which is  
>>> supposed
>>> to
>>
>>> give better isolation.
>>>
>>> (note: some have advocated that Ufl is as good as mmcx, regarding  
>>> rssi
>> loss,
>>> stating that the UFl connector itself has less loss than the gain  
>>> MMCX
>> adds
>>> by enabling thicker pigtail cable. I always still prefer MMCX  
>>> because it
>> is
>>> more rugged abd less likely to break pigtails connectors in things  
>>> like
>>> Rootenas that are not easy to access with short pigtails. But  
>>> surely I
>>> thought mmcx would also add better shielding/isolation from outside
>>> sources.)
>>>
>>> So using XR5s, it would infer that the cards saw each other because
>>> either
>>
>>> loss from pigtail cable, loss from mmcx connector, or simply the  
>>> cards
>>> electronics.
>>> The next relevent info might be to determine if it is the amp  
>>> circuitry
>>> driving this interference. Just like a pair of PC speakers can  
>>> sometimes
>>> pickup music radio.
>>>
>>> For years Lonnie (StarOS) gave teswtimonials for lower power CM9s
>> performing
>>> better than Amplified cards (SR5) for short range applications,  
>>> because
>> they
>>> were quieter.
>>>
>>> So there is about 8db difference between a SR5 and a CM9. I wonder  
>>> if you
>>> repeated your tests, but used CM9's instead (no ext embedded amps),
>> whether
>>> you'd just hear the other adjacenet radios at 8db lower,  
>>> proportional to
>> the
>>> spec of the radios, or if you hear the otehr radio much much less,
>>> because
>>
>>> it doesn;t have the amp to pcikup the interference?
>>>
>>>
>>> Tom DeReggi
>>> RapidDSL &amp; Wireless, Inc
>>> IntAirNet- Fixed Wireless Broadband
>>>
>>>
>>> ----- Original Message -----
>>> From: &quot;Kurt Fankhauser&quot; &lt;k...@wavelinc.com&gt;
>>> To: &quot;'WISPA General List'&quot; &lt;wireless@wispa.org&gt;
>>> Sent: Wednesday, April 29, 2009 10:33 AM
>>> Subject: [WISPA] RB333/433 eliminating self-interference test
>>>
>>>
>>> &gt; About a week ago there was some discussion about 5ghz radio's  
>>> being
>>> &gt; installed in the same board and causing self-interference on
>>> adjacent
>>> &gt; channels and possible even on the entire band thus decreasing
>> throughput
>>> &gt; on
>>> &gt; backhauls. Because even if you were operating on frequency's  
>>> 5745
>>> and
>> 5825
>>> &gt; the two radio's would have side lobe harmonics that if  
>>> installed in
>> the
>>> &gt; same
>>> &gt; enclosure they would still &quot;hear&quot; each other at  
>>> that short
>> of separation.
>>> &gt; I
>>> &gt; decided to combat this problem and find a solution and share my
>> experience
>>> &gt; with the list.
>>> &gt;
>>> &gt;
>>> &gt;
>>> &gt; I installed a single XR5 card into 3 different RB433's with  
>>> indoor
>>> &gt; enclosures. I also installed foil tape which I obtained from  
>>> the
>> local
>>> &gt; True
>>> &gt; Value store for $2.49 on all the vent holes and unused bulkhead
>> connector
>>> &gt; holes. This was done in order to prevent RF side lobe leaks  
>>> from the
>> three
>>> &gt; radio's that would escape from the indoor enclosures  
>>> themselves.
>> Having
>>> &gt; only
>>> &gt; 1 card inside each enclosures I should not have a heat  
>>> problem as
>>> the
>>> &gt; outdoor box will not be in direct sunlight.
>>> &gt;
>>> &gt;
>>> &gt;
>>> &gt; I then stacked all 3 enclosures on top of each other with dummy
>>> loads
>> on
>>> &gt; each of the N-bulkhead connectors and did some testing. This  
>>> is what
>> I
>>> &gt; found:
>>> &gt;
>>> &gt;
>>> &gt;
>>> &gt; I set the bottom board as AP and the middle board as Client on
>> frequency
>>> &gt; 5825. Even with this close of separation the two XR5's could  
>>> only
>>> see
>> each
>>> &gt; other at -83 on the same channel. With the top board  
>>> connecting to
>> the
>>> &gt; bottom board they could only see each other at -90. Keep in  
>>> mind
>>> this
>> is
>>> &gt; on
>>> &gt; the same frequency so adjacent channels should be much less  
>>> than
>>> that
>>> &gt; possibly even in the -100 ranges. Wish I had a spectrum  
>>> analyzer.
>> With two
>>> &gt; boards separating the AP and Client there was no link at all.  
>>> The
>>> two
>>
>>> &gt; boards
>>> &gt; could not even see each other in an AP scan.
>>> &gt;
>>> &gt;
>>> &gt;
>>> &gt; Just as a comparison with the same radio's installed all on a  
>>> RB600
>> not on
>>> &gt; top of each other but in the adjacent mpci slots the radio's  
>>> were
>>> all
>>
>>> &gt; seeing
>>> &gt; each other at -30's. So I gained roughly -55 db of separation  
>>> by
>> doing it
>>> &gt; this way. So all I would have to do now is make sure that the
>> antennas on
>>> &gt; the tower have at least 10 foot of vertical separation and the
>>> &gt; self-interference problem should be gone and I should be  
>>> enjoying
>> much
>>> &gt; more
>>> &gt; throughput!
>>> &gt;
>>> &gt;
>>> &gt;
>>> &gt; Thoughts anyone?
>>> &gt;
>>> &gt;
>>> &gt;
>>> &gt;
>>> &gt;
>>> &gt; Kurt Fankhauser
>>> &gt; WAVELINC
>>> &gt; P.O. Box 126
>>> &gt; Bucyrus, OH 44820
>>> &gt; 419-562-6405
>>> &gt; www.wavelinc.com
>>> &gt;
>>> &gt;
>>> &gt;
>>> &gt;
>>> &gt;
>>> &gt;
>>> &gt;
>>> &gt;
>>>
>>>
>>>
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