No obvious way to crack one open and I don’t have any dead ones yet - but 
spring is coming.   Should not be too long before Thor comes to visit.

Mark

> On Mar 28, 2019, at 3:26 PM, Ken Hohhof <[email protected]> wrote:
> 
> I’m busy configuring a licensed link or I’d snap a photo.  But here’s a 
> Cambium video of assembling a 450b high gain, maybe you can glean enough from 
> this.  Note that there is an optional radome that snaps onto the front of the 
> dish, they don’t show it in the video, but some of us like the radomes for 
> aesthetics/windload/snow.
>  
> https://www.youtube.com/watch?v=z88P-0nZkZ8&feature=youtu.be 
> <https://www.youtube.com/watch?v=z88P-0nZkZ8&feature=youtu.be>
>  
>  
> From: AF <[email protected] <mailto:[email protected]>> On Behalf 
> Of [email protected] <mailto:[email protected]>
> Sent: Thursday, March 28, 2019 1:54 PM
> To: 'AnimalFarm Microwave Users Group' <[email protected] 
> <mailto:[email protected]>>
> Subject: Re: [AFMUG] [*] Re: [*] corrective optics
>  
> Yes, I could probably google it, but I would like to have an image of the SM 
> and reflector or whatever that is underperforming.  
>  
> From: Ken Hohhof 
> Sent: Thursday, March 28, 2019 12:17 PM
> To: 'AnimalFarm Microwave Users Group' 
> Subject: Re: [AFMUG] [*] Re: [*] corrective optics
>  
> I think he meant a photo of a Cambium 450b, or something relevant to 
> improving the antenna performance thereof.
>  
> What were you thinking the topic was about?
>  
>  
> From: AF <[email protected] <mailto:[email protected]>> On Behalf 
> Of Carl Peterson
> Sent: Thursday, March 28, 2019 1:05 PM
> To: AnimalFarm Microwave Users Group <[email protected] 
> <mailto:[email protected]>>
> Subject: Re: [AFMUG] [*] Re: [*] corrective optics
>  
> "What would you like to see?"
>  
> I'm OK with the spam, but if this thread goes the wrong way I might need to 
> unsubscribe.  No offense, just not my bag.  
>  
> On Thu, Mar 28, 2019 at 11:06 AM Mark Radabaugh <[email protected] 
> <mailto:[email protected]>> wrote:
>> What would you like to see?
>> 
>> Mark
>> 
>> On Mar 28, 2019, at 10:26 AM, Chuck McCown <[email protected] 
>> <mailto:[email protected]>> wrote:
>> 
>>> How about some photos.
>>> 
>>> Sent from my iPhone
>>> 
>>> On Mar 28, 2019, at 6:58 AM, Ken Hohhof <[email protected] 
>>> <mailto:[email protected]>> wrote:
>>> 
>>>> If you ever do the experiment again, it would be interesting to rotate the 
>>>> antenna to see if there’s some kind of sidelobe pointed toward the ground 
>>>> or something.  Obviously you can’t install it rotated or upside down 
>>>> (unless you really trust that cable gland to seal against rain), but it 
>>>> would be interesting to see the results.  Like you said, maybe some 
>>>> component in the feed horn is blocking the RF.
>>>>  
>>>> Cambium is in a better position to investigate this, it’s disappointing if 
>>>> they aren’t taking it seriously.
>>>>  
>>>>  
>>>> From: AF <[email protected] <mailto:[email protected]>> On 
>>>> Behalf Of Mark Radabaugh
>>>> Sent: Thursday, March 28, 2019 6:19 AM
>>>> To: AnimalFarm Microwave Users Group <[email protected] 
>>>> <mailto:[email protected]>>
>>>> Subject: Re: [AFMUG] [*] corrective optics
>>>>  
>>>>  
>>>>  
>>>> 
>>>>> On Mar 27, 2019, at 10:11 PM, Ken Hohhof <[email protected] 
>>>>> <mailto:[email protected]>> wrote:
>>>>>  
>>>>> In another thread, Mark Radabaugh posted:
>>>>>  
>>>>> “For your next product….   Corrective optics for 450B high gain CPE!”
>>>>>  
>>>>> Mark, I’m not sure if you were serious, I suspect yes.
>>>>  
>>>>  
>>>> Yes - but I’m not sure what is possible with the design.
>>>>  
>>>> 
>>>>>  
>>>>> I know it’s frustrating that the antenna gain is lower than the old 
>>>>> reflector dish, Cambium dropped the number on the spec sheet to 24 dBi, 
>>>>> but I think even that is optimistic, I think it’s about 2 dB less than 
>>>>> the old combo which was supposed to be 25 dBi.  Lower antenna gain is 
>>>>> going the wrong way!  I don’t care if it does have higher xmt power, that 
>>>>> does nothing for the downstream direction.
>>>>  
>>>>  
>>>> Changing the spec sheet to match what they ended up with was a pretty big 
>>>> cop out when the product failed to meet design expectations.   
>>>>  
>>>> 
>>>>>  
>>>>> In calling for corrective optics, do you have any info or even a gut feel 
>>>>> for whether the problem is in the feed or the dish?  Is it as simple as 
>>>>> the dish is just too small?
>>>>  
>>>>  
>>>> I suspect that they managed to block part of the antenna feed horn with 
>>>> other components.  
>>>>  
>>>>  
>>>> 
>>>>>  
>>>>> Also, is it just the gain is low, or does the 450b hi gain have other 
>>>>> issues?  Like poor F/B or sidelobe performance or something?
>>>>  
>>>> It seems like if the 450b high gain is far away from other surfaces it 
>>>> works mostly to spec but when mounted in the typical locations near 
>>>> rooftops it seems like it either picks up more destructive multipath 
>>>> interference than previous designs or the antenna pattern distorts badly.  
>>>> For a long time I thought they didn’t manage to get the feedhorn in the 
>>>> focus of the dish but Cambium assures me that it’s right.   We are seeing 
>>>> decent performance under 5 miles but it seems to fall apart much quicker 
>>>> over 5 miles than would be expected.
>>>>  
>>>> We set up a test with the bucket truck and drove it out and measured every 
>>>> mile to 10 and it came back fine - but that was 50’ in the air with 
>>>> nothing around.   Yet swapping out standard 450 SM’s with beehive or KP 
>>>> dishes with 450B’s at >5 miles routinely fails with poor signal.   The 
>>>> difference is often far more than the 2dB the spec sheets would indicate.  
>>>>  Sometimes it works if the antenna is well away from all other surfaces 
>>>> like on a tower but for the majority of installs the swap fails.   Why 
>>>> were we doing that anyway?  We wanted to start using 5.1/5.2.
>>>>  
>>>> 
>>>>>  
>>>>> I know the 450b mid-gain is frustrating because apparently Cambium 
>>>>> doesn’t think a tight vertical pattern is important.  I keep wondering if 
>>>>> a top and bottom flap like on the old 2.4 Stingers would correct that.
>>>>>  
>>>>> Cambium seems to be sharing antenna designs between ePMP and 450, so the 
>>>>> same issues probably exist in the corresponding ePMP products.
>>>>> -- 
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>>>>> <http://af.afmug.com/mailman/listinfo/af_af.afmug.com>
>>>>  
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>  
> -- 
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> PORT NETWORKS
> 401 E Pratt St, Ste 2553
> Baltimore, MD 21202
> (410) 637-3707 
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