On 4/6/2010 3:17 PM, James Earl Wells wrote:
This sounds pretty good. My problem is that D-Star is not all that far
from me but I cannot talk on it while I am at my home. However I can
walk yes, walk less than a block and talk all day on it. Some of this
I can understand because of some of the things that block my path to
the repeater. However what bugs me is to listen to people who talk on
the same repeater who are 40 miles and some more away from it and are
talking on a HT like me. I do not know if a different kind of antenna
would help me.
If you don't know, we probably don't either. ;-) But we can offer
ideas. The legwork's up to you...
What kind of antenna are you using? How many "things" block your path?
The rules of RF haven't changed any yet, that I'm aware of. You either
have a path or you don't. You didn't say if the repeater's VHF or UHF?
(Heck, if it's 1.2 GHz... all bets are off at 20 miles+...)
Not that it's a perfect test, since one repeater may be built better
than the other, but is there an analog FM repeater co-located where the
D-STAR repeater is? If you can consistently talk through the analog
repeater at the same site, you can sleep better knowing the problem is
at the OTHER end of the radio link...
Not that a problem like that will make you very happy if your heart's
set on talking on the D-STAR repeater... but you can go buy a couple of
grand worth of test gear and go help the D-STAR guys measure their
antenna system, including the duplexers, feedline, etc... if you really
want to fix that... (GRIN)... I recommend a recevier sensitivity test,
feedline loss test (return loss), and listening critically on the
repeater's input frequency with an ANALOG receiver for noise/mixes,
etc... if the problem is intermittent. (Or just off of the
discriminator tap described here before by the better repeater operators.)
Of course, to get to apples-to-apples on that troubleshooting, you'd
have to know if the analog FM system had a pre-amplifier too, and the
duplexers and filtering as well as the feedline and antenna would have
to be identical. Since they're probably not, practice up on calculating
the dB of loss/gain of the entire antenna system including filters
(after measuring all of it) from antenna down to the connector on the
back of the repeater's receiver itself. :-) Good math problem.
Generally though... the problem is TYPICALLY at the user end... so we'll
start there. Are you using full power? Have you measured that you're
putting out the full 5W or whatever your HT is rated at? Even though
they're 40 miles away and you're 20, do the other HT users have better
(downhill for example) line-of-sight to the system that you don't?
Have you asked the repeater operator about the antenna system installed
at the D-STAR site? Did they "favor" one direction or another with
antenna gain? (e.g. Pointed the antennas toward the more densely
populated area of town, away from your QTH, etc?)
I use the antenna that I put on my car but it does not seem to help at
all.
You're carrying around a mobile antenna with no ground-plane? I don't
understand. Want to be more specific? Typically the "best" antennas
for an HT are the 1/4 wave flexible whips. Maybe even with a "cat tail"
ground plane home-brewed hanging out from the bottom of the antenna, but
that looks dorky and even though it works, it's "hamsexy". The 1/4 whip
should be fine. Multiband whips for both VHF/UHF go on all of my HTs
and the factory rubber dummy loads come off almost as soon as I buy them.
I hear people (sometimes and sometimes they are R2D2). I can hear but
not talk. I just think the whole thing is weird plus I spent all this
money to talk on D-Star and the only time I can use it is when I am
not at home. Also I live in an apartment. (Oh.. and for those who are
not from the Kansas City area. The repeater sits on top of a very tall
building less than twenty miles from me.)
Different problems. For your RECEIVE problems, have you pushed the
button and listened on analog to see if you have local interference?
Many a digital user has thought the "repeater sounded bad" until they
listened with a critical ear and heard their favorite PC in the other
room throwing all kinds of RF hash. Heck, even I've been bitten by this
once when VHF systems in my area started sounding like crap at home
(compared to their usual decent signals, since I live on a hill... I
highly recommend hams look for houses on hills... heh heh... much
better...), until I found that a Linksys router was throwing RF crap
virtually from DC-to-Daylight, but mostly in the VHF spectrum. It got
smashed and THEN thrown in the trash can.
Oh Well.. Just venting.
No reason to vent. Understand doing it, but just fix it. :-)
Hope everyone else is having fun with it. I have just put my sites on
doing a lot more Echo Link. Would like to get involved in APRS but
can't figure that out yet either. My radio has the GPS built in the
mic but have not figured out if I need to do something else.. But
thats another group...
Actually as far as APRS/DPRS, if your radio is set correctly for your
local repeater, and has RPT2 set to the Gateway like it should whenever
running on a repeater that has one (until you figure out the rare
reasons you'd NOT want to do that...), and the repeater operator is
running all the proper Add-Ons at the Gateway server, your DPRS data
from the GPS mic should just get passed automatically to the APRS
servers... and show up on sites like aprs.fi (my favorite, but there's
lots of others)... "No Assembly Required".
I'm ASSUMING you're talking about an IC-92AD since you've said "HT" and
"GPS Mic". You might want to let us know on that one too.
Thanks for letting me vent.
James
KD0AJZ
Call it instead, "An opportunity to excel in radio technology
knowledge... instead of 'venting'"... LOL!
Just as a side-note... a building-top repeater 20 miles away blocked by
a bunch of ground clutter... is hard even on FM. Try it with some other
similar repeaters and ask if your signal is 100% FULL QUIETING, if the
locals even know what that means. (How many times have I heard someone
tell someone else they're FULL QUIETING on FM when there's a continuous
20-30% white noise in the background of their signal? A lot. They
MEANT to say the signal is COPYABLE, but they get caught up in the ham
radio phraseology horse-pucky and say "FULL QUIETING" instead. You can
usually spot people who tend to do this, by them saying they're
"Destinated" when they get out of the car, too... LOL! Find some old
dudes who actually know what the terms MEAN, and ask THEM instead... heh
heh.)
Nate WY0X
