Repeater Story
N9HUA REPEATER
145.490 -
offset w/pl 100hz
THE SYSTEM
This repeater
evolved over time from an idea, to a dual band/cross band repeater to the
repeater of today. Here is a breakdown
of the components used to come up with the final product.
The Receiver: Initially the receiver
started out as an Alinco DR-110.
The factors that lead to this decision are some of the same that lead to
changing it “CHEAP”!
This radio was plentiful and inexpensive and a solid performer except
the front-end was extremely susceptible to intermod. Alinco managed to make a radio that was
almost useless in an RF rich urban environment not to mention a repeater
environment, hence the availability of so many used ones.
After
some experimentation I settled on an Alinco DR-150. This radio had pl-tone encode and decode
(after optional board), dual band receive and an easily accessible spot on the
board to tap a COR signal.
Initially the dual band part was used however that portion of the
repeater was removed after having the repeater up for over a year and not
having anyone use the UHF side. As
for the intermod problem, it was still there and had to be corrected. DCI to the rescue with the DCI-145/435-DX-DB
Dual Band Filter.
The Transmitter: The transmitter started out
with an Alinco DR-135T & DR-435T pair.
Again the DR-435 was eliminated later into the project but the DR-135T
has performed flawlessly. This unit
has a DB9 connector on the back for control, an item I found very useful later
on. If you are to ever purchase
single band radios, the Alinco DR- 135,235,435 are the best performing I have
found in a mobile radio. The DR-135
and been running for 3 years at full output (50 watts) and has not skipped a
beat. Of course I was sure to add
cooling before putting the repeater on air but this model radio has it all and
is tuff.
The Controller: This was by far the most
complicated of the decisions.
Originally I started out with a bland controller with no bells and
whistles. As a matter of fact, it
didn’t even have the basics!
That unit has a COR detect, transmitter keying circuit and time out
timer! To this I added a
stand-alone ID’er and phone patch.
Needless to say after spending weeks trying to get these items to play
nice with each other, a friend asked it I ever played with EchoLink or
EchoStation. Off to the web and
EchoStation was downloaded for testing.
EchoStation testing began on
a Dell Dimension L__r, 666 MHz Processor, 256 MB Ram and SoundBlaster Live
(Dell version – more on that later) audio card. What made this the appropriate computer
was that it had two serial ports, which makes installation much easier. Just a note to those computer companies
that advertise a brand name “SoundBlaster Live Sound Card” may want
to ship their units without the small white lie! You see, Dell did not purchase the
consumer version of the SoundBlaster Live card, but a stripped down version
made especially for Dell that oh yah did I mention doesn’t work the
updated drivers needed for EchoStation.
Thank goodness for Google and someone else that found a work around for
that.
The First Beast: This is for posterity! An ORIGIONAL work of art! It amazes me how hard you work to come
up with a project that works and looks are thrown out. As you can see, this works and uses a
small space (save the computer) but I guess I didn’t put a lot of thought
into making it visually pleasing.
Now don’t panic, this has been corrected and you will see the
finished product at the end of the tale.
EchoLink: When I realize that the UHF side of
this was not being utilized, I decided to remove the UHF side and EchoLink to
the VHF side. To achieve
a true EchoStation & EchoLink repeater the two controllers had to be
paralleled to operate properly.
Initially after some research, I was under the impression that one
computer serve both purposes according to others on the web however after
attempting it with four different computers and a dozen different sound cards I
opted to run two separate computers and parallel the interconnect
hardware. That worked and the N9HUA
repeater was worldwide.
The Final
Product: As you can see, the final
product doesn’t look so bad.
The final change to complete the system will be to add a duplexer. Currently the repeater uses 2 separate
Diamond 5/8-wave co-liner antennas so the price of a duplexer will have to
wait.
Same Great
Repeater – New Look!
Update:
The repeater has been removed from service
November 2006. Due to the close
proximity of two hospitals (within 2 blocks), their paging and radio systems
created a unique intermod problem.
Already having spent over $400.00 on filtering it was not cost effective
to continue.