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Grex > Radio > #1: Welcome to the 2nd edition of Radio | |
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| Author |
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| 25 new of 123 responses total. |
omni
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response 32 of 123:
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Aug 11 13:52 UTC 1998 |
scratch that. Try http://www.hamradiooutlet.com
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goose
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response 33 of 123:
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Aug 11 15:47 UTC 1998 |
RE#29 You could, but you could end up with some not very musical
tunings.
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rcurl
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response 34 of 123:
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Aug 11 17:57 UTC 1998 |
Why? Tuning is just setting a frequency. You have to choose the right
frequencies, musically, of course.
Counters will not handle signals with several frequencies of significant
amplitude. They just count zero-crossings, so higher frequencies win.
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scott
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response 35 of 123:
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Aug 11 23:12 UTC 1998 |
Actually, I think I should restate the problem.
I've got some RF-based computer gear. It communicates over radio, and
sometimes it refuses to work, as if somebody else was crudding up the same
frequency.
I know what frequency my stuff uses (900Mhz, some items do 902MHz). How can
I test for somebody else using that frequency?
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rcurl
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response 36 of 123:
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Aug 12 02:50 UTC 1998 |
Turn off your stuff and turn on a radio that receives in the same band,
and scan. There may be a number of interfering signals. I just turned
on my counter and in the 10-1250 MHz range it likes signals fluctuating
around 838-842 MHz. Cellular? In the 10-500 MHz range, it likes 226-228 MHz.
Oh wait! If I hold the antenna closer to this computer it likes ca. 146 MHz.
Below 10 MHz, it finds 13KHz - near the monitor. This is all pretty
meaningless.
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goose
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response 37 of 123:
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Aug 12 19:15 UTC 1998 |
<slap on forehead> Please Ignore the idiot in the front row. Sorry Rane,
I was thinking of people who only view tuning as "mathmatical", of course
if you know the right frequencies......
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bmoran
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response 38 of 123:
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Aug 13 12:25 UTC 1998 |
Has anyone listened to 1630am? We listened from A2 to the zoo a few
mondays ago. Eastbound M14 just past Domino's we started to pick up the
signal from M14 and I275. North I 275 it started to fade and was replaced
by I-275 and I-696. East I-696 was replaced by I-696 and Telegraph, which
started to break up and fade badly in the concrete ditch. Just started to
get I-696 and I-75 as we got to the zoo. This is the traffic advisory
system, tho there were no warnings, just locations being broadcast.
'Finding" stuff like this still thrills me, even after years of listening.
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scott
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response 39 of 123:
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Aug 14 16:46 UTC 1998 |
Is there an affordable radio receiver that will listen to 900MHz and perhaps
also around 170MHz?
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omni
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response 40 of 123:
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Aug 15 05:08 UTC 1998 |
You might want to invest in an Icom R-1. It's handheld and recieves from
.5 to 1.5Ghz. I think they're around $300.
Or you can borrow my 2m handheld which recieves from 138-174Mhz.
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n8nxf
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response 41 of 123:
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Aug 17 19:19 UTC 1998 |
Or you can go to your local Radio Shack and check out there line of scanners.
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scott
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response 42 of 123:
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Aug 18 11:02 UTC 1998 |
Wow, that's the most useful suggestion yet. The RS line seems to cover all
the areas I care about, and with tuning to an appropriate number of decimals.
And since I don't need to transmit...
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goose
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response 43 of 123:
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Aug 18 22:30 UTC 1998 |
I have a RS scanner (I forget the model number, it's one of their trunking
scanners) the best thing to do is get an aftermarket antenna.. The little
rubber one they supply isn't so good. My scanning world opened right up when
I bought a better antenna (a RS one no less)
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n8nxf
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response 44 of 123:
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Aug 19 10:52 UTC 1998 |
The Radio Shack disc-cone is a nice all-band antenna. Hook it up with
decent coax if the coax is going to be longer that about 10 ft. 9913
is good stuff with low losses at the higher frequencies. Get that at
Purchase Radio since I doubt that Radio Shack sells it.
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goose
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response 45 of 123:
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Aug 19 17:34 UTC 1998 |
Disc-cone's are quite directional antennas, yes?
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danr
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response 46 of 123:
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Aug 19 21:41 UTC 1998 |
Why don't you give Ken a call at Communications Electronics? I'm sure
he's got what you need.
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eprom
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response 47 of 123:
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Aug 19 22:31 UTC 1998 |
disc-cone antenna's are omni-directional...there good generally for
VHF/UHF reception...and very good for listening to airplane's cuz
of the radials angled around 45 degrees
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goose
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response 48 of 123:
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Aug 20 02:33 UTC 1998 |
Okay, thanks. I haven't covered antennas in my Tech study guide..yet.
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omni
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response 49 of 123:
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Aug 20 05:54 UTC 1998 |
You could even make your own, that is if you know the dimensions, and
all that. All you would need is a SO-239, 5 coathangers, wire snips, a tape
measure, solder and patience. Discone's are nice but they are a zero gain
antenna.
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n8nxf
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response 50 of 123:
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Aug 20 10:28 UTC 1998 |
Disc-cones are omnidirectional. They have relativity low gain but make
up for that by having a wide bandwidth. Their gain is far better than
that of the rubber duckie that comes with the scanner. As with antennas
in general, operating frequency has all to do with length. The longer
you make the elements the lower in frequency it will go. HF disc-cones
are not uncommon, just large. The Radio Shack disc-cone is good for
100 MHz to 1.5 GHz or so. They are simple to build and any good antenna
book will show you how. Once you see one you will also understand where
the name comes from. As with all antennas, the higher you get it the
better it will work.
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gull
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response 51 of 123:
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Aug 21 19:36 UTC 1998 |
The ARRL Handbook has (or had) plans for one that worked on the 2 m and 70
cm bands made out of 1/4" hardware cloth.
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n8nxf
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response 52 of 123:
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Aug 26 10:46 UTC 1998 |
The one Radio Shack sells will also work on 2M through 70cm and beyond.
It is also nice since it is all stainless steel. A friend mounted one of
the RS disc-cones on the mast of his sailboat for 2M / 70cm and it worked
very well. W8BY made a disc-cone out of coat hanger wire that also worked
very well and was cheap to boot. Once again, antenna height is very
important. The higher the better in most cases.
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omni
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response 53 of 123:
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Aug 26 15:51 UTC 1998 |
I have W8BY's plans. I was going to make one, but you know how
procrastination is.
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scott
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response 54 of 123:
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Oct 8 21:52 UTC 1998 |
Status report:
I bought a Bearcat trunking scanner. It covers 450-470 and 900MHz bands, both
of which are what I'm working in. It works great in the 450-470MHz range
(older UHF based systems) and OK for 902-928MHz spread spectrum systems
(spread is hard to get a handle on anyway). So I've got what I need, a way
to see what else is out there at frequencies I'm trying to use.
Thanks to all, esp. to Klaus for suggesting the scanner. :)
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scott
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response 55 of 123:
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Oct 9 00:31 UTC 1998 |
(Shouldn't be a big suprise to find out thet the Radio Shack "Trunk Tracker"
scanner is nearly identical to the Bearcat "Trunk Tracker", only cosmetic
differences and a higher price)
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harish
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response 56 of 123:
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Oct 26 13:47 UTC 1998 |
Hello Everybody,I am merely a SWL and operate with a domestic type
sangean, telescopic antenna.I wonder if there are any like me here. As
far as I can see, this appears to be only for HAMs. Although it is
interesting to read,it would be nice to exchange SWL/DX news once in a
while.
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