[HamWAN PSDR] Baldi Deployment Report: Part Deux

Bart Kus me at bartk.us
Tue Jun 16 12:21:26 PDT 2020

Better late than never!

We visited Baldi instead of Rattlesnake last Saturday.  Both sites were 
in rain, and Baldi had the easier set of tasks, so we opted for the 
safer option.  Here's the work report:

1) Baldi has had a server so old for so many years that it's RAID 
drivers are no longer supported by HPE for management within ESXi. It's 
also had very little RAM (8GB) and drive space (RAID1 of 73GB drives).  
I took one of my spare servers to serve as a new hypervisor up there.  
It has 48GB RAM and 4x250GB SSD in RAID10 (500GB space).  After install, 
I discovered iLO had somehow lost all the credentials I saved into it.  
It took all of Sunday to setup a special PXE environment + OS to finally 
gain control of iLO from the server side (not network side).  Everything 
here is finally working as it should, and VMs will be migrated soon so 
we can decommission the old server.

2) The switch in "Building 2" at Baldi was full!  We managed to install 
a new 24-port gigabit switch, pictured here: 
https://photos.app.goo.gl/8a98D44dDxkeqJn37  This switch is important as 
it links "Building 1", and "Building 3".  We also discovered the UPS 
powering all the repeaters and the network gear was overloaded.  It 
would beep when things were transmitting.  We re-arranged the load so 
that it's only backing up the network gear now, and the repeaters will 
need their own larger UPS.

3) We installed the shield on the CampMurray facing dish.  Over the last 
week I noticed the VPol signal on the link was really low (-94dBm) 
whereas the HPol was just fine (-65dBm).  Prior to shield install on the 
dish, I inspected the connectors for any water ingress.  I did not find 
any.  However, I did find what looked like crusty build-up on the center 
pin of the VPol RP-SMA-to-N adapter. This adapter was re-used from the 
old 3ft dish.  That dish had a split-open HPol connector (likely caused 
by ice expansion), which I suspect allowed water to pool in the feedhorn 
and probably drip down to this adapter, causing it to build-up whatever 
this grey substance is.  We did our best to clean up the connector with 
the tools at hand.  After re-installing and re-aligning the dish, VPol 
is now reading -84dBm instead of -94dBm.  While this is a 10dB 
improvement, there's still clearly a problem.  We need to return with a 
new adapter, and a method to properly clean the female N connector on 
the antenna to remove any residue which might still be there. Possibly 
re-compress the pin if it was split open too much by the residue.

Another thing which might be affecting VPol is misalignment of the 
corresponding dish at CampMurray.  That dish was never aligned with 
Baldi for lack of ever hearing a signal.  If it's severely off-axis in 
the horizontal, the VPol transmission might be getting shunted by its 
shield (conductive vertically when azimuth is off).  Both things need to 
be addressed before this link can be considered done.

4) We had serious Ethernet link stability problems with the new 
Rattlesnake.Baldi dish.  Its cable is routed just a few feet from an FM 
broadcast antenna, and several repeater antennas.  We installed a 30m 
(100ft) run of multimode fiber to connect the Rattlenake.Baldi modem to 
the switch in Building 3.  The link came up and has been rock solid.  I 
also suspected there might have been water in the original RJ45 leading 
to these Ethernet link outages.  This was inspected and the connector 
was found to be dry, so there's no worry of corrosion due to PoE 
voltage.  While the cause of the CAT5 link failure is not known, I think 
we can narrow it down to either RFI or a bad crimp job on the tower-side 
connector.  The shack-end connector was re-done twice with no change in 
link failures. Anyway, this modem is now happy with the fiber and has 
great signal to Rattlesnake (-55dBm)!

Now let's hope for some nice weather for the next visit to Rattlesnake, 
which requires work at about the 150ft level of a tower.


More information about the PSDR mailing list