HDTenEightyP/NetNews huggingface dataset:
Newsgroups: rec.radio.shortwave
Subject: Re: 16ch Cobra Scanner
From: ** Sender Unknown **
Date: 10 Apr 92 01:42:16 GMT
Keywords: scanner


        It probably isn't worth much since one can get a 200 channel scanner 
for about $250 bucks new.  16 channel scanners are pretty rare today.  Some 
companies still sell them, Uniden comes to mind, but with the low cost 
multiple channel scanners today, you probably would not get more than 40-50 
dollars for it.
From: philip@cetia.fr (Philip Peake)
Newsgroups: rec.radio.shortwave
Subject: Re: Detector != Diode, liquid "diodes"
Date: 15 Apr 92 19:23:24 GMT
Organization: CETIA, France

In article <SWL-L%92041323555973@CUVMA.COLUMBIA.EDU> "David L. Wilson" <dwilson@S850.MWC.EDU> writes:
>The oddest rectifier I remember is the 0Z4 tube that used to be used in
>most old tube car radios.  This tube did not require a "heater voltage"
>but somehow (I never found out how) rectified the AC coming from the
>transformer after the vibrator.  the 0Z4 as i recall had a bluish gow
>when it was working.

I *think* if memory serves me correctly, that an OZ4 was a voltage
stabiliser, which would have provided the HT supply for the oscillator
section of the radio.

Better quality radios had "synchronous vibrators", which had an extra
set of vibrating contacts which whipped back and forth across the
transformer secondary, "sampling" the output in phase with the chopped
input (from the other contacts). This "rectified" the
output for you, it was chopped DC, just needed smoothing.

Philip

PS it makes me feel *old* to remember such things ...
From: doa@med.unc.edu (David Carrozza)
Newsgroups: rec.radio.shortwave
Subject: RF-6300 Documentation Needed
Date: 11 Apr 92 04:23:36 GMT
Distribution: usa
Organization: UNC Office of Information Technology
Originator: doa@pelham


              Panasonic RF-6300 Documentation Needed

	      If anyone has a service manual for this
	      receiver and is willing to photocopy
	      it, please respond by e-mail.          


	      David Carrozza
	      doa@med.unc.edu
From: mcovingt@athena.cs.uga.edu (Michael A. Covington)
Newsgroups: rec.radio.shortwave
Subject: Re: Ramsey FM Kit & Radio Shack Antenna Kit...
Date: 17 Apr 92 18:50:40 GMT
Organization: University of Georgia, Athens

In article <SWL-L%92041714224089@OHSTVMA.IRCC.OHIO-STATE.EDU> "Joseph O. Nattey" <JNATTEY@KENTVM.BITNET> writes:

>2). I just bought the shortwave kit from radio shack
>    and before, I try to set it up, I would appreciate
>    some ideas from the pros.

Expect very low performance from the Radio Shack shortwave radio _kit_.
(I assume you mean the build-it-yourself radio.)  You will be lucky to
hear just a few international broadcasters.  But it will whet your
appetite...


-- 
==========================================================================
Michael A. Covington, Ph.D. |  mcovingt@uga.cc.uga.edu  |  ham radio N4TMI
Artificial Intelligence Programs | U of Georgia | Athens, GA 30602  U.S.A.
==========================================================================
From: rpo@trsvax.tandy.com
Date: 16 Apr 92 08:04 CDT
Newsgroups: rec.radio.shortwave
Subject: Re: DX-390 Specifications
Message-ID: <7400001@trsvax>
Nf-ID: #R:ux1.cso.uiuc.edu:21729:trsvax:7400001:000:1091
Nf-From: trsvax.tandy.com!rpo    Apr 16 08:04:00 1992


Sensitivity:
(for 20 dB Signal-to-Noise ratio):
AM    150  kHz  1990 uV/m
      300  kHz   700 uV/m
      600  kHz   400 uV/m
      1.4  MHz   400 uV/m
      3.1  MHz     4 uV
      7.1  MHz     4 uV
      15.1 MHz     4 uV
      28.1 MHz     4 uV

(for 20 dB Signal-to-Noise ratio):
SSB   150  kHz   140 uV/m
      300  kHz    45 uV/m
      600  kHz    28 uV/m
      1.4  MHz    28 uV/m
      3.1  MHz   0.4 uV
      7.1  MHz   0.4 uV
      15.1 MHz   0.4 uV
      28.1 MHz   0.4 uV

(for 30 dB S/N ratio):
FM   87.5 to 108 MHz   4 uV

Image Rejection Ratio:
AM/SSB   150  kHz     34 dB
	 300  kHz     36 dB
	 600  kHz     40 dB
	 1.4  MHz     40 dB
	 3.1  MHz     40 dB
	 7.1  MHz     40 dB
	 15.1 MHz     40 dB
	 28.1 MHz     40 dB
FM 87.5 to 108 MHz    40 dB

Selectivity:
AM/SSB              -6 dB       -50 dB
           wide    +/- 3 kHz   +/- 7 kHz
	   narrow  +/- 2 kHz   +/- 4 kHz
IF AM/SSB/CW   1st   55.845 MHz
	       2nd   450 kHz
   FM                10.7 MHz

Frequency Stability:
Within 1 kHz per hour after 60 minutes warm up.

Paul Opitz -- Radio Shack Publications
N5TPQ
From: jfw@ksr.com (John F. Woods)
Newsgroups: rec.radio.cb
Subject: Re: AM or SSB
Date: 8 Apr 92 11:38:10 EDT

ami9667@venus.tamu.edu (IACOVIDES, ANDREAS MICHAEL) writes:
>What's the "max" range you can talk with two AM CB's and what about
>SSB, when the one will be at the base and the other mobile?

Depends on propagation conditions.  When the ionosphere smiles on you,
either will carry all the way around the world.  In general, when the
proper receiver bandwidth is used, a single-sideband signal will show
an effective gain of up to 9 dB over an a-m signal of the same peak power.
A 5W-input AM rig should have a slightly higher PEP than a 12W PEP-output SSB
rig, but you're still talking about 8 dB of improvement, which is a ratio of
6.3, which (if I haven't made any silly math mistakes, and if range is
inversely proportional to the square root of the power) ought to represent
a factor of 2.5 in favor of SSB.

Take the numbers with a small grain of salt (I don't have time to check my
formulae or calculations), but there's a definite benefit to SSB.

John, WB7EEL
Newsgroups: rec.radio.cb
From: nomad@ecst.csuchico.edu (Michael Larish)
Subject: Re: Let's talk about skip (was Re: AM or SSB)
Organization: California State University, Chico
Distribution: na
Date: Thu, 09 Apr 1992 08:56:52 GMT

In article <1992Apr8.161538.20121@rti.rti.org> jbs@rti.rti.org writes:
>In article <c5eQ02U2c00200@amdahl.uts.amdahl.com> ikluft@uts.amdahl.com (Ian Kluft) writes:
>>Elevation can have an affect, too.  I've made crystal-clear mobile-to-mobile CB
>>contacts from over 15 miles away when I parked on top of a 2000-foot mountain.
>>However, small hills in between two units may make CB contact impossible.
>
>I once talked from my base (1/2 wave ground plane) in Clemmons, N.C. to a
>mobile unit atop Grandfather Mountain, N.C., which I would estimate is a
>seperation of roughly 90+ miles. Both radios were operating at 5 watts.
>Neither of us was using a receive preamp. This was about 6 a.m., and noise
>was VERY low at the time. Audio was good, but signal was weak.
>I find nighttime mobile-to base range to max out at about 15-20 miles (with
>no skip in the way). This is with a Shakespeare 4' continuously loaded (I
>believe 5/8 wave electrical length) fiberglas whip mounted on the hood.
>
>  -joe KD4LLV

	The farthest I've talked on CB was somewhere around 40 or so miles.
It was late one night.  I was just entering the town where I live at around
200 feet ASL and got in contact with a guy 40+ miles away up in the mountains
at around 4,000 feet ASL.  He came in decently well.  I was very surprised
when he told me his location... (for those who might know the area, it was
from Chico to Butte Meadows).

-- 
Michael G. Larish       | Amateur Radio Callsign:  KD6CTZ
aka Nomad the Wanderer  | Golden Empire Amateur Radio Society (GEARS) - W6RHC
nomad@ecst.csuchico.edu | Chico State Amateur Radio Society (CSARS)
CSU Chico, CA           | C&M Group: 27.215 MHz AM / SSB Club 31x1078 27.355 LSB
Newsgroups: rec.radio.cb
From: nomad@ecst.csuchico.edu (Michael Larish)
Subject: Re: AM or SSB
Organization: California State University, Chico
Distribution: na
Date: Thu, 09 Apr 1992 08:46:21 GMT

In article <c5eQ02U2c00200@amdahl.uts.amdahl.com> ikluft@uts.amdahl.com (Ian Kluft) writes:
>
>If you need more distant communications then a no-code amateur radio license
>may fit your needs better.  Using one repeater, I recently made contact from my
>handheld transceiver to a friend in a vehicle 75 miles away.  Using linked
>repeaters, I've covered distances over 200 miles.

	Actually Ian, at the time we talked (ie you at your apartment and I
in my car on I-505), we were approximately 150 miles apart and that was
without a linked repeater...  :-)

-- 
Michael G. Larish       | Amateur Radio Callsign:  KD6CTZ
aka Nomad the Wanderer  | Golden Empire Amateur Radio Society (GEARS) - W6RHC
nomad@ecst.csuchico.edu | Chico State Amateur Radio Society (CSARS)
CSU Chico, CA           | C&M Group: 27.215 MHz AM / SSB Club 31x1078 27.355 LSB
From: jfw@ksr.com (John F. Woods)
Newsgroups: rec.radio.cb
Subject: Re: Let's talk about skip (was Re: AM or SSB)
Date: 9 Apr 92 12:01:46 EDT
Distribution: na

jbs@rti.rti.org writes:
>This has been going on regularly for about two months, and is pretty well
>unprecedented in any of our experiences.
>Common conjecture is that the cause is ozone depletion; more ionization
>than usual is taking place in the F2 layer during the day, and at night
>when the UV isn't hitting the "night side" ionosphere anymore, ionization
>remains at a high level much later into the night than it used to, and
>somehow this is causing the F2 layer to remain active and relatively low
>at night rather than receding to a higher altitude and combining with F1
>(Have I got the names of my layers right? Probably not).

The ozone layer in in the stratosphere; the ionosphere is quite a bit above
it (60-200 miles).  Now, if the *Earth* were radiating UV, ozone depletion
would increase ionization...  ;-)

There are three ionosphere layers of interest in RF propagation, the E layer
(about 70 miles high), the D layer (about 60 miles), and the F layer (175
miles).  The D layer is responsible for absorption of low frequency HF signals
during the daytime.  The E layer is responsible for daylight propagation of
higher frequency signals (and of lower frequency signals that make it through
the D layer, which is pretty much limited to straight up and down trips).
The F layer is pretty much permanent, but reaches a minimum just before sunrise
(as you might think).  During the day, it splits into two layers, called F1 and
F2, which have average heights of about 140 and 200 miles respectively.

A quick check of the propagation prediction charts in last month's QST
indicates that between mid-March and mid-April,  the 50% prediction line for
MUF for East coast to South America circuits was predicted to be above 24MHz
between 0000Z and 0400Z, and the 10% prediction line doesn't dip below 27
until about 0600Z, which seems to agree pretty well with your observations.
I only have one QST handy (and I don't have several years worth), so it would
be really hard to figure out if this is terribly unusual, but note that the
current high-sunspot cycle is still on the high part of the peak (but
dropping).

> I have not yet upgraded from Nocode Tech yet, so I haven't been messing about
> in the 10-meter band, but I would suspect that they would be experiencing
> the same increased nighttime propagation as the CB band.

Well, good luck if you decide to go for it, and if not, the MUF for West Coast
to Australia links is predicted to get as high as 51MHz around 2300Z...  :-)

John, WB7EEL
Xref: sparky rec.radio.cb:472 news.answers:1047
From: jfw@ksr.com (John F. Woods)
Newsgroups: rec.radio.cb
Subject: Re: Dual Units and Dual Antennas
Keywords: Just an idea
Date: 8 Apr 92 15:02:23 EDT

bphdarcy@ubvmsb.cc.buffalo.edu (SJ Roc D'Arcy, MBP) writes:
>         --rig one ------------------ first antenna      
>         |  
>Mike------
>         |
>         --rig two ------------------ second antenna
>Second, would it help performance?

If you mean to have them on the same channel, it would certainly not help
performance, and probably hurt it.  To help performance, the two transmitters
would have to be phase-coherent, quite impossible unless they shared the same
master oscillator or had their oscillators phase-locked to a master source,
and unless the phase delay through each rig was constant (I think it would
not have to be the same, since you could make up for that with extra coax).
It would hurt because the two rigs would be unlikely to be at precisely the
same frequency, so the two AM carriers would heterodyne against each other.
(What's the tolerance on CB channels, 10ppm?  They could be as far apart as
540Hz.)  Sideband would certainly be hard to understand, and might just come
out as an unintelligable garble.
From: ikluft@uts.amdahl.com (Ian Kluft)
Newsgroups: rec.radio.cb
Subject: Re: AM or SSB
Date: 8 Apr 92 04:37:23 GMT
Distribution: na
Organization: Amdahl Corporation, Systems Software, Sunnyvale CA

[I've restricted this reply to North America since it doesn't apply to Europe
or Japan.]

In article <7APR199213413423@venus.tamu.edu> ami9667@venus.tamu.edu (IACOVIDES, ANDREAS MICHAEL) writes:
>What's the "max" range you can talk with two AM CB's and what about
>SSB, when the one will be at the base and the other mobile? What are
>some good antennas for base and for mobile?

You've got a lot of variables in there.  No one can precisely put a range on
the parameters you gave there, but I can help you sort through some of the
issues.

Legally, in the US, the maximum is 150 miles.  You probably won't get anywhere
near that number.

First, in the daytime when the Ionosphere is on causing "skip", the background
noise level will be high enough that your range between the 2 units will be
down to a few miles.

At night, the range between 2 mobile CB units with properly matched antennas
can be up to 6-8 miles without difficulty, assuming a low noise environment.
(i.e. the San Francisco Bay Area has a lot of RF noise so that cuts range a
lot.)  Subtract a few miles for cheap or poorly-tuned antennas.  Add a couple
miles, maybe, if one is a base station (as you asked).

For the mobile antenna, try for a top-loaded or whip antenna.  (The periodic
Frequently-Asked Questions articles have more information if you need it.)  At
a base station, any 1/4-wave dipole will be fine but elevation will probably
be the biggest factor.  Other users of this newsgroup have reported poor
results from imitation-cellular or AM/FM & CB combo antennas.

You can dramatically increase your range between your hypothetical mobile and
base stations by using a directional antenna at the base.

Elevation can have an affect, too.  I've made crystal-clear mobile-to-mobile CB
contacts from over 15 miles away when I parked on top of a 2000-foot mountain.
However, small hills in between two units may make CB contact impossible.

If you need more distant communications then a no-code amateur radio license
may fit your needs better.  Using one repeater, I recently made contact from my
handheld transceiver to a friend in a vehicle 75 miles away.  Using linked
repeaters, I've covered distances over 200 miles.
---
Ian Kluft    KD6EUI                    UTS Systems Software, Amdahl Corporation
ikluft@uts.amdahl.com                                             Sunnyvale, CA
From: ikluft@uts.amdahl.com (Ian Kluft)
Newsgroups: rec.radio.cb
Subject: Re: ground wave propagation (was: AM or SSB)
Date: 15 Apr 92 08:52:25 GMT
Organization: Amdahl Corporation, Systems Software, Sunnyvale CA

fisher2557@iscsvax.uni.edu writes:
>[...] Any two people 100+ miles away that do
>not have *high* antennaes or a valley between them are talking purely on .....
>I lack the proper term....  I wanna say "ground waves" but as you pointed out,
>that's not right...  UNDERground waves.  that's the word.  Beam antennaes also
>direct this signal. (I don't believe polarization matters underground,either)

I'm sorry to rain on your parade but there is no such thing as underground
waves.  Radio signals do not propagate very well through the ground.  Try
transmitting or receiving from your basement if you have any doubts.

Ground wave propagation follows the surface of the ground.  It does not go
through the ground.  It is also typically much weaker than a point-to-point
signal received from the same source.  It doesn't take a very big hill to
completely block a signal.

In your example of two CB units 100+ miles apart, they're going to need line-
of-sight or VERY near it because it's too far for surface propagation alone
and probably not far enough for a skip signal to return to the surface from
the Ionosphere.  Remember they refract off the Ionosphere so it's at a very
shallow angle.  See the FAQ - they call it "skip" because it skips over a
large area, often over 1000 miles and probably not less than several hundred,
before returning to the surface and being audible again.  Actually, at 100
miles, even if one of the units is on top of a mountain, at least one will
have to have a beam (directional) antenna if the two are actually going to make
reliable contact.  (So, you're right about the beam antennas being necessary to
extend the range where 2 CB units can communicate.)

Actually, in reality, 100 miles is way beyond where you should expect to have
reliable CB communications.  Sure, there's skip (as so many people like to
point out) but that doesn't become an option until way beyond the distances
where direct reception is possible and it varies depending on solar activity.
Ground wave reception is not something to count on either because it means
that you've got terrain in the way and not all of the signal is getting to you.
---
Ian Kluft    KD6EUI                    UTS Systems Software, Amdahl Corporation
ikluft@uts.amdahl.com                                             Sunnyvale, CA
Newsgroups: rec.radio.cb
From: comptec91006@camins.camosun.bc.ca (Michael Botten)
Subject: Re: Dual Units and Dual Antennas
Organization: Camosun College
Date: Fri, 10 Apr 1992 04:28:43 GMT

In article <1992Apr8.124424.1268@acsu.buffalo.edu>, bphdarcy@ubvmsb.cc.buffalo.edu (SJ Roc D'Arcy, MBP) writes:
> I was wondering if anyone had tried or could provide some feedback on the 
> following idea:
> 
> I have two spare mobile rigs.  I also have a spare base station antenna.
> What I was wondering, is what would be the results if I rigged up the 
> microphone so that it was connected to both rigs and transmitting from
> two attennas on top of the house (one on each end of the roof). 
> 
>          --rig one ------------------ first antenna      
>          |  
> Mike------
>          |
>          --rig two ------------------ second antenna
> 
> First, would it be legal?  I am still running under 4 watts, but on
> two different rigs.
> 
> Second, would it help performance?  This is like twin whips times two.
> I don't think the antenna would have to be matched (they are quite close
> though), since they come from different units. 
> 
> Let me know. 
> 
> SJRD
 
Ever heard what it sounds like when two people key up at the same time?
That's what would probably happen...
_______________________________________________________________________________
               __    __   __ ___ ___  __
 /\  /\  o |/ |_    |__/ |  | |   |  |_  |\ | (Well, isn't this special...)
/  \/  \ I |\ |__   |__\ |__| |   |  |__ | \| CompTec91006@Camins.Camosun.BC.CA
_______________________________________________________________________________
From: fisher2557@iscsvax.uni.edu
Newsgroups: rec.radio.cb
Subject: WANTED: FCC rules
Date: 6 Apr 92 14:36:16 -0500
Organization: University of Northern Iowa

Would anyone happen to have (or know of an ftp site with) a copy of the
FCC rules & regs reguarding CB and related communications?  I've been
hit with quite a few quotes of numbers and subparts and would like to
have something to reference when I hear these things.  Thanks.

(ohhhh YES!  the skip is dying down!)

later,
 Nathan
  FISHER2557@ISCSVAX.UNI.EDU      (this tag line is umop ap!sdn)
 --------------------------------- -------------------------------
| "I'd challenge him to a battle  |  University of Northern Iowa  |
|  of wits, but I don't fight     |    where men are men,         |
|  the unarmed...."               |       and sheep are nervous   |
 --------------------------------- -------------------------------
Hi! I am a .signature virus.  Copy me into your .signature to join in!
Newsgroups: rec.radio.cb

>          --rig one ------------------ first antenna      
>          |  
> Mike------
>          |
>          --rig two ------------------ second antenna
> 


Sorry; bad idea.  Unless you would have some way of keeping the two rigs
EXACTLY on the same frequency, you would in essence be "interfering with
yourself."  The audible effects on the other end would be similar to what 
happens when two people "double."  (If the rigs are far enough off in
frequency - something that's not all that unlikely - you might even hear a
whine due to the "heterodyning" effect of the two carriers.  (The situation
would be even worse in the case of SSB, but for slightly different reasons.)

Even given precise frequency control, the pattern resulting from the
two antennas would be unpredictable, given that the two outputs would have
an unknown phase relationship.  (Yes, there are ways around these objections,
but it certainly isn't as simple as the above drawing.)

As far as the legality of the set-up, I'm doubtful.  If Uncle Charlie
wanted to argue that such a rig constitues 8W instead of 4, I'm not certain
I'd disagree.  (For example, one way around the first objection would be
to run the two rigs from the same RF oscillator, in which case this could
be viewed as a case of a single tranmitters with parallel output devices.)


Bob Myers  KC0EW   Hewlett-Packard Co.      |Opinions expressed here are not
                   User Interface Tech. Div.|those of my employer or any other
myers@fc.hp.com    Fort Collins, Colorado   |sentient life-form on this planet.
From: ami9667@venus.tamu.edu (IACOVIDES, ANDREAS MICHAEL)
Newsgroups: rec.radio.cb
Subject: Wanted: Two CB radios
Date: 6 Apr 92 22:33:00 GMT
Organization: Texas A&M University, Academic Computing Services
News-Software: VAX/VMS VNEWS 1.41

I need two CB's SSB most preferable. Please contact by e-mail.
From: gary@ke4zv.uucp (Gary Coffman)
Newsgroups: rec.radio.cb
Subject: Re: AM or SSB
Date: 9 Apr 92 19:06:39 GMT
Reply-To: gary@ke4zv.UUCP (Gary Coffman)
Organization: Gannett Technologies Group

In article <7APR199213413423@venus.tamu.edu> ami9667@venus.tamu.edu (IACOVIDES, ANDREAS MICHAEL) writes:
>What's the "max" range you can talk with two AM CB's and what about
>SSB, when the one will be at the base and the other mobile? What are
>some good antennas for base and for mobile?
>
>Andreas 

The maximum range of two AM CB sets is 12,500 miles. On rare occasions
when long path is in, signal travel of 25,000 miles can be achieved, but 
the maximum separation of two stations remains 12.500 miles. SSB is the 
same. The maximum *legal* range remains 150 miles at all times of course.

Now the maximum *practical* *groundwave* range is a different, and much
more complex matter. Depending on antenna height above average terrain,
terrain roughness, and noise and interference on the channel, maximum
*groundwave* range can be as much as 30 to 50 miles, or as little as
.5 mile. Average is around 15 miles for typical base to base installations.
Less for base to mobile due to the lower antenna of the mobile.

SSB has a *theoretical* eightfold improvement over AM due to the fact
that more of the available power is in the intelligence carrying sideband
and not in a carrier or redundant sideband, and due to the twofold decrease
in effective receiver bandwidth. The full eightfold improvement is seldom
seen, however, due to the same limitations of height, terrain, and interference
that limit AM. SSB's main advantage in the real world is in it's improved
performance in the face of interference. This is primarily a *receiver*
issue and not a transmitter issue. Either mode puts out enough power to
have a usable signal out to the limits of propagation if no interference
is present.

Barring a yagi beam, the best antennas for groundwave use are 5/8
wave vertical antennas mounted as high and in the clear as possible.
Since a 5/8 is really big, mobiles usually are limited to 1/4 wave
whips. Depending on mounting constraints, any coil loaded short antenna
is going to perform worse than a full size antenna mounted at the same
location. Since a 9 foot whip is still large, and usually reduced to 
bumper mounting, some of the better shortened antennas, like the K40, 
mounted on the top or trunk, are used with good success in mobiles.

Gary KE4ZV