Steve
There have been many documented problems with the RP4000V.
One thing is to test for desense - this snip from
a message by Steve NU5D, covers it well:
Its very simple to listen to the receiver discriminator with an audio
monitor while injecting an FM tone into the receiver, and key the Tx by
applying 3 vdc to the TXE lead - basic tests for any FM repeater,
receiver desense, isolated TEE, spurious TX are all standard tests.
Also if there is a common power supply, noise on the buss or sagging
voltage during TX ? Repeater TX into a dummy load while listening in
the TX shack ?
Before going digital, maybe do the simple analog tests first ? Also get
the gateway completely out of the picture - just repeater and controller.
Best luck,
73, Steve NU5D
Second - if there is desense look at the internal
jumpers in the repeater module - Icom used RG58,
single sheilded crap for the jumpers between the
rear panel and the boxes containing the transmit
and receive modules. Replace them with Hardline or double shielded cables.
In our K1XC stack we also added a preamp (the
Icom units are deaf) to all the modules - we use
preamps from Angle Linear - http://www.anglelinear.com/
Chips units work very well in the repeater
environment - Our 70 and 23 CM preamps were
purchased as part of the Duplexer set - the 2M
preamps added with a "N" barrel connector in the
receive input of the repeater. I'd also avoid
preamps with BNC connectors (way too much RF
leakage on some BNC connectors) - stick to Type "N" connectors.
Use only double shielded cables between the
Repeater and the duplexers, RG214 or something like it.
Lastly use monoband antennas for the repeater. we
noticed a great improvement when we changed out
the 440 antenna from a Comet Dual Band antenna
GP-9N to a commercial 16 bay folded dipole array
cut for 70CM. We use a comet CA-CAB 23 for 2M
and a pair of Comet GP-21 antennas on the 23 CM
voice and Data Modules. I initially tried a
Comet GP 95, Tri Band antenna with a triplexer -
an absolute disaster for a repeater but works
great at my home station on all 3 bands.
Finally use Hardline from the antenna to the
Duplexers - we use LDF 4-50 as the runs are under
25' to the antennas - over that I'd go with LDF 5-50 or larger.
VRY 73
Bob Cumming
W2BZY
Repeater Chair - Orlando Amateur Radio Club
K1XC and W4PLB D-Star repeater systems
QRV 160M - 9CM + 3CM (5760 next)
from EL98hr
At 02:36 PM 8/9/2009, you wrote:
Is there an adjustment for receiver sensitivity
on either the RP 2C or the RP4000V? Once a
transmitted signal gets more than about 100 or
200 yards away from the site we can not key the
repeater. We have checked antenna, duplexer,
and feed line and all of those seem to be
working well. Once the repeater is keyed, the
transmit side is great with an excellent
coverage area. The issue is at the input side.
Can anyone point me to where an input signal
threshold might be set? A second question is
can anyone suggest a good way to measure the
signal required to âkeyâ the repeater?
Feel free to contact me with suggestions here on
the list or on at the above email address.
Thank you in advance!
Steve Mercure
WU5PIG DStar System.
