Long as the TX of one radio is not in the RX range of the other radio at
the same site you should be fine. With the issues you are seeing I would
recommend turning the power down a little bit -39 may be a little hot
for you to run a higher modulation without errors. It would probably be
better a few db less.
On 4/16/2016 10:56 AM, Faisal Imtiaz wrote:
I am not familiar with the hardware nor the intricate specifics.. However I
would make a general statement ..
There are a lot of old wives tales associated with licensed link, there may be
some context to these old wives tails, most folks in the industry tend to take
it for face value, very few end up examining it for merit of correctness.
Comments made by folks in the public forums can be the best or the worst of
such examples.
From the sounds of it, you have done everything right, and you have the link
working, then anything else would be an old wives tale.
BTW, if you were able to get 2x80mhz channels in 11ghz, take a look at what
Mimosa B11's can do with them.... and yes these folks did challenge the
accepted status quo in licensed links..
Regards/
Faisal Imtiaz
Snappy Internet & Telecom
7266 SW 48 Street
Miami, FL 33155
Tel: 305 663 5518 x 232
Help-desk: (305)663-5518 Option 2 or Email: [email protected]
----- Original Message -----
From: "Craig Baird" <[email protected]>
To: [email protected]
Sent: Saturday, April 16, 2016 11:32:09 AM
Subject: [AFMUG] PTP820S 2+0 configuration
So a few months ago we purchased an 11 GHz PTP820S 2+0 link. We
recently installed it, and it appears to be working fine, aside from a
little bit of frame loss that we are investigating. While looking
into this frame loss issue, I stumbled across something that concerns
me. On Cambium's support forum there is a post that states that when
dealing with 2+0 links both radios must be in the same sub-band.
There is no explanation of why this is the case. In our situation,
the radios are in separate sub-bands. When we did the frequency
coordination, the only two 80 MHz channels available were in different
sub-bands. I passed those channels along to our vendor who worked
with Cambium to get a BOM. At no point did anyone say that this was a
problem. So now, fast forward a few months, and I stumble across this
post, and now I'm wondering what the implications will be. Both links
are up and running. Signal on both is right where it should be (-39
on one, -40 on the other). Both are running at maximum modulation.
There are no defective blocks shown on the radio interfaces. There is
no indication that this sub-band mismatch is causing any issues, aside
from possibly this frame loss thing. However, if I mute the radios on
one link, the frame loss persists, so I don't think it's related.
In case it matters, the two links are oppositely polarized. On one
side we've got a 2 foot dish with an OMT combining the radios. On the
other side, we've got an 8 foot dual-pol dish.
So I'm wondering if anyone knows why Cambium says that you can't use
radios from different sub-bands. Are we in for trouble at some point?
Craig
