Helical resonator duplexers can be almost as good as quarter wave duplexers and
much smaller.
From: George Skorup
Sent: Wednesday, June 07, 2017 5:56 PM
To: af@afmug.com
Subject: Re: [AFMUG] Interference on a repeater at 149 MHz
We have a local school district co-located with us on a water tower and they're
complaining about noise on their input. I pretty much told them they're SOL
until we need to add or replace cables since they're all in an 1-1/4" PVC. So
we'll have to run temp cables up, rip all the cables out of the pipe and pull
new ones. The village said we have to be in conduit. And we do have a couple
cables in use that aren't shielded. They didn't offer to pay for it, so too bad.
They're running a Kenwood repeater in an outdoor cabinet. Maybe 12U. Obviously
that's not going to fit the proper large can cavity duplexer like a Sinclair.
Plus they have >4.5MHz split, so no doubt that let them use a smaller
rack-mounted duplexer.
So I'd be curious to know what the setup is on this 149MHz repeater. Are they
using a small crappy duplexer with a large split, too?
On 6/7/2017 5:55 PM, Lewis Bergman wrote:
I don't think so. I am assuming they probably didn't install some connectors
correctly. Unless they are using some extremely crappy gear the RF portions of
all half decent repeaters are shielded very well. Unless they modified the
repeater leaving some shielding off the connectors are the most likely source.
I guess there could also be punctures or some such in the coax as well.
On Wed, Jun 7, 2017 at 5:51 PM Jaime Solorza <losguyswirel...@gmail.com>
wrote:
Lewis. You are assuming the VHF gear was properly installed...few folks do
right first time... someones laziness or lack of knowledge is another's
opportunity to make some cash
On Jun 7, 2017 4:41 PM, "Lewis Bergman" <lewis.berg...@gmail.com> wrote:
Has anyone checked their connectors/connections between all RF points?
Antenna to cable, cable to duplexer, duplexer TX/RX to repeater.
Most of the time I have seen Two Way equipment either be interfered with
or interfere with someone else it is a connector issue. The only other case I
have seen issues should be able to be determined by an intermod study. I doubt
it has anything to do with intermod. My bet is a faulty connector. I would
assume it is the RX side so I would check the RX Repeater port to the RX port
on the duplexer and then the rest of the connectors.
Not saying it can't be the the CAT5, just that if all is good on the
antenna system I haven't ever seen an issue and I have a lot of sites with both
two way and 900, 2.4, and 5GHz operating on all kinds of speeds both POE and
not.
