HDTenEightyP/NetNews huggingface dataset:
From: ming@enel.ucalgary.ca (Yang Ming)
Subject: Re: SWR Tuning and PLL
Date: Wed, 23 Dec 92 22:18:05 GMT
Organization: ECE Department, U. of Calgary, Calgary, Alberta, Canada

In article <1992Dec20.144424.1428@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes:
>In article <1992Dec18.213844.7701@hpcvaac.cv.hp.com> billn@hpcvaac.cv.hp.com (bill nelson) writes:
>>v054rtzw@ubvmsb.cc.buffalo.edu (RUFUS) writes:
>>: 
>>:  Jason,
>>:   An SWR meter measures the Standing Wave Ratio hence SWR. What SWR is is the
>>: amount of reflexed power recieved by your rig from a mistuned antenna. A 
>>
>>Close. It is the ratio between the power reaching the antenna and the power
>>reflected by the antenna.
>
>The SWR, properly the VSWR, is the ratio of the forward voltage on the
>line to the reverse voltage on the line at any point along the line.

This is conceptually incorrect. VSWR = Vmax/Vmin, not the ratio of
the 'forward' to the 'reverse' voltage. Your definition is the inverse
of the reflection coefficient.

>The "standing wave" is the vector sum of these two voltages. All the

Correct.

>power injected into the transmission line by the transmitter is dissipated 
>in either the antenna or the line losses, none is absorbed by the radio. A

The power reflected from the transmission line and the antenna due to 
mismatch CAN be absorbed by the radio, depending on the impedance 
when you look into the radio from the transmission line. If this impedance
is equal to the characteristic impedance of the line, all reflected power
will be absorbed by the radio. Thus, power injected into transmission line
can be reflected and absorbed by the radio. You have to look at the 
match conditions on the two ends of the line.

[deleted]

P.S.
The definitions of VSWR and reflection coefficient can be found in any
reference that touches transmission lines. For instance, one can look at
'Antennas' y Blake, P75-76.

Ming.
From: jxs18@po.CWRU.Edu (Jerry Sy)
Newsgroups: rec.radio.cb
Subject: no transmit when wet
Date: 31 Dec 1992 17:42:38 GMT
Organization: Case Western Reserve University, Cleveland, OH (USA)
Reply-To: jxs18@po.CWRU.Edu (Jerry Sy)
NNTP-Posting-Host: hela.ins.cwru.edu


I use a magnet mount cb antenna on my car mounted on the trunk.  on
normal days, tx and rx is fine.  however, when it is wet (rain, etc),
I can receive but I can't seem to transmit, that is, my other cb at home
cannot hear me.

any idea what is causing this problem and how to fix this ?

please email response if possible.

jerry
From: jbs@ee.egr.duke.edu
Newsgroups: rec.radio.cb
Subject: Re: Delta SSB Club seeks new members FREE!
Date: 22 Dec 92 15:46:34 GMT
Organization: Joe's Bar and Grill
Originator: jbs@ee.egr.duke.edu

In article <BzMoEE.wI@Interlan.com> powell@interlan.interlan.com (Glen D. Powell) writes:
>
>The World-Wide Delta Radio SSB Club is actively seeking new members.
>We have chapters in most of the USA states and most countries around the
>world. The Delta Club is NOT a skip club, per se. Our only rules are to
>promote proper legal operation,
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Then why are so many of your US members' "home frequencies", as listed in
your newsletter, outside the CB band allocation?  Misprints?

>-glen, 9 DELTA 1, NH USA Chapter President and Secretary

  -joe
-- 
                You spend the night
            Like you were spending a dime

                   - Lyle Lovett
From: myers@hpfcso.FC.HP.COM (Bob Myers)
Date: Mon, 21 Dec 1992 18:05:11 GMT
Subject: Re: SWR Tuning and PLL
Organization: Hewlett-Packard, Fort Collins, CO, USA
Newsgroups: rec.radio.cb

> The "standing wave" is the vector sum of these two voltages. All the
> power injected into the transmission line by the transmitter is dissipated 
> in either the antenna or the line losses, none is absorbed by the radio. A

Minor nit: SOME of the power most certainly WILL be "absorbed by the radio,"
unless we assume that the output stage of the transmitter represents either
a perfect open or a perfect short to the returning (reflected) signal.  Both
are unlikely.  The mismatch at the transmitter end is very rarely considered
in SWR examples, as things get really messy.

Given a decent matching network, though, I would agree that the biggest problem
resulting from a high SWR on the line is the line loss, which usually is a
don't care unless you've got a long line.  (It is also REMOTELY possible, in
high-power installations - but we don't got none o' them in CB, right? - that
excessive VSWR would cause voltage peaks which would exceed the coax's 
dielectric's rating, but this is pretty rare.)

As a really trivial aside, note that there is also a current standing wave,
a quarter-wave out of phase with its voltage counterpart.  As Gary said, VSWR
(or "CSWR", for that matter - same magnitude in either case) is NOT the
ratio of reflected to transmitted power, although you CAN figure the reflected
power, given the VSWR.  SWR *is*, among other things, the ratio of line to
load impedance (or vice-versa, whichever gives a number >= 1).


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: ming@enel.ucalgary.ca (Yang Ming)
Newsgroups: rec.radio.cb
Subject: Re: SWR Tuning and PLL
Date: 22 Dec 92 19:47:29 GMT
Organization: ECE Department, U. of Calgary, Calgary, Alberta, Canada

In article <1992Dec18.213844.7701@hpcvaac.cv.hp.com> billn@hpcvaac.cv.hp.com (bill nelson) writes:
>v054rtzw@ubvmsb.cc.buffalo.edu (RUFUS) writes:
>: 
>:  Jason,
>:   An SWR meter measures the Standing Wave Ratio hence SWR. What SWR is is the
>: amount of reflexed power recieved by your rig from a mistuned antenna. A 

>Close. It is the ratio between the power reaching the antenna and the power
>reflected by the antenna.
>
Wrong. According to this definition, a perfect match will have SWR of infinity,
because a perfect match gives 0 reflected power. Actually, SWR is defined as:

                  SWR = (1 + G)/(1 - G)

where G is the absolute value of the reflection coefficient. SWR should be
always between 1 and +infinity, with 1 the perfect match and +infinity the
total reflection.

Ming.
Newsgroups: rec.radio.cb
From: gary@ke4zv.uucp (Gary Coffman)
Subject: Re: SWR Tuning and PLL
Reply-To: gary@ke4zv.UUCP (Gary Coffman)
Organization: Gannett Technologies Group
Date: Thu, 24 Dec 1992 22:39:27 GMT

In article <103400061@hpfcso.FC.HP.COM> myers@hpfcso.FC.HP.COM (Bob Myers) writes:
>> The "standing wave" is the vector sum of these two voltages. All the
>> power injected into the transmission line by the transmitter is dissipated 
>> in either the antenna or the line losses, none is absorbed by the radio. A
>
>Minor nit: SOME of the power most certainly WILL be "absorbed by the radio,"
>unless we assume that the output stage of the transmitter represents either
>a perfect open or a perfect short to the returning (reflected) signal.  Both
>are unlikely.  The mismatch at the transmitter end is very rarely considered
>in SWR examples, as things get really messy.

Well of course a conjugate match at the transmitter forms a perfect reflector
for the reflecting wave and sends it right back toward the antenna. As you
note, most fixed tuned radios will not be a perfect conjugate match, though
they may be close. However, the reflected wave can't dissipate in the load
impedance of the radio PA since that is only a calculated intermediate
product of voltage and current in the PA and not a real dissipative  load
for the wave. What happens instead is that the voltage and current vectors
add to the dynamic values in the PA and shift the operating point. This can
lower the *efficiency* of the PA stage and *indirectly* increase the heat
dissipation of the PA stage. All the RF power in the stage, generated and
return wave, does go back out the port to the antenna, however, where it
eventually dissipates in a real dissipative load. That forward power will
be lower than expected, of course, due to the reduced efficiency of the
PA stage.

Gary
-- 
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | uunet!rsiatl!ke4zv!gary
534 Shannon Way             |    Guaranteed!      | emory!kd4nc!ke4zv!gary      
Lawrenceville, GA 30244     |                     | ke4zv!gary@gatech.edu
Newsgroups: rec.radio.cb
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: SWR Tuning and PLL
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
Date: Thu, 31 Dec 1992 11:21:59 GMT

gary@ke4zv.uucp (Gary Coffman) writes:
: In article <1992Dec25.084712.14174@hpcvaac.cv.hp.com> billn@hpcvaac.cv.hp.com (bill nelson) writes:
: >
: >It certainly will make the coupling of the transmitter to the mismatched
: >line/antenna system efficient.  If there is no radiation from the cable, 
: >then your statement would be correct. If the coax is radiating, due to the
: >mismatch, then the antenna efficiency could be very poor.
: 
: A mismatch won't make the feeder radiate, but an imbalance will. That's
: a separate issue. A perfectly matched antenna can still have lots of
: feeder radiation if antenna balance is not correct. That's where feeder
: routing and baluns come into play. A mismatch will only cause reflected
: waves *inside* a coax, feeder radiation requires RF currents on the
: *outside* of the coax.

Yeah - that's what I meant. I just wasn't using the right term. I meant
antenna imbalance. Thanks for clearing it up.

: >Although I never have done so myself, I knew a ham who ran better than a
: >5:1 SWR using an open-wire feeder. The loss was so low that he put out a
: >good signal.  He did say that there was a fair amount of radiation from
: >the feeder, however. I don't know if this was due to the feeder/antenna
: >mismatch or to too short an antenna.
: 
: Physical balance problems with the antenna. An open wire feeder is
: inherently balanced and won't radiate unless something unbalances
: it. That could be one end of the flattop near a conductive object,
: asymetric feedpoint, etc. A perfect feedpoint impedance match won't
: cure these types of problems.

Thanks for the info.

Bill
Newsgroups: rec.radio.cb
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: SWR Tuning and PLL
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
Date: Mon, 21 Dec 1992 18:03:56 GMT

gary@ke4zv.uucp (Gary Coffman) writes:
: >Close. It is the ratio between the power reaching the antenna and the power
: >reflected by the antenna.
: 
: The SWR, properly the VSWR, is the ratio of the forward voltage on the
: line to the reverse voltage on the line at any point along the line.
: The "standing wave" is the vector sum of these two voltages. All the
: power injected into the transmission line by the transmitter is dissipated 
: in either the antenna or the line losses, none is absorbed by the radio. A
: mismatch can affect the *efficiency* of the radio output stage, thus causing
: heat buildup, but this isn't power "reflected" into the radio from the
: line.
: 

Correct. Sorry if I mislead anyone. This is why, when using a high efficiency
transmission line (such as open wire), a high SWR can be tolerated. The loss
in the line is very low, so almost all the power is dissipated by the antenna.

Bill
Newsgroups: rec.radio.cb
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: SWR Tuning and PLL
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
Date: Fri, 25 Dec 1992 08:47:12 GMT

gary@ke4zv.uucp (Gary Coffman) writes:
: 
: Well education is rarely totally wasted. If one reader learns something,
: it's been worth it. One very practical bit of information that can be
: gleaned from this exchange is that a matchbox at the transmitter capable
: of matching the complex impedance formed by the reflected wave and the
: forward wave's vector addition will give nearly fully as effective a signal 
: as adjusting an antenna's matching network or length, with only an additional
: negligible cable loss, and that doing so won't damage your radio.

It certainly will make the coupling of the transmitter to the mismatched
line/antenna system efficient.  If there is no radiation from the cable, 
then your statement would be correct. If the coax is radiating, due to the
mismatch, then the antenna efficiency could be very poor.

Although I never have done so myself, I knew a ham who ran better than a
5:1 SWR using an open-wire feeder. The loss was so low that he put out a
good signal.  He did say that there was a fair amount of radiation from
the feeder, however. I don't know if this was due to the feeder/antenna
mismatch or to too short an antenna.

Bill
From: kauppila@sunburn.ec.usf.edu. (Jim Kauppila (DO))
Newsgroups: rec.radio.cb
Subject: Best mobile with SSB?
Date: 31 Dec 92 15:02:59 GMT
Organization: Univ. of South Florida, College of Engineering

What is the best mobile currently available with SSB?
--
Jim Kauppila                |  E-Mail: Internet: kauppila@sunburn.ec.usf.edu
College of Engineering      |             GEnie: j.kauppila
University of South Florida | Heartland Freenet: jkauppil@heartland.bradley.edu
Newsgroups: rec.radio.cb
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: SWR Tuning and PLL
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
Date: Tue, 22 Dec 1992 18:24:38 GMT

myers@hpfcso.FC.HP.COM (Bob Myers) writes:
: 
: As a really trivial aside, note that there is also a current standing wave,
: a quarter-wave out of phase with its voltage counterpart.  As Gary said, VSWR
: (or "CSWR", for that matter - same magnitude in either case) is NOT the
: ratio of reflected to transmitted power, although you CAN figure the reflected
: power, given the VSWR.  SWR *is*, among other things, the ratio of line to
: load impedance (or vice-versa, whichever gives a number >= 1).

If  you wish to be precise, this is all true. However, for run-of-the-mill
CB purposes, it is the ratio of transmitted to reflected power. Why confuse
people with all the possible types of standing wave, or methods of determining
the SWR?

The fine distinctions matter, if you are designing an antenna system or a
matching network for a transmitter. They do not matter at all to Oscar
Overmodulator - CB operator.

Bill
Newsgroups: rec.radio.cb
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: SWR Tuning and PLL
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
Date: Wed, 23 Dec 1992 00:09:47 GMT

ming@enel.ucalgary.ca (Yang Ming) writes:
: In article <1992Dec18.213844.7701@hpcvaac.cv.hp.com> billn@hpcvaac.cv.hp.com (bill nelson) writes:
: 
: >Close. It is the ratio between the power reaching the antenna and the power
: >reflected by the antenna.
: >
: Wrong. According to this definition, a perfect match will have SWR of infinity,
: because a perfect match gives 0 reflected power. Actually, SWR is defined as:
: 
:                   SWR = (1 + G)/(1 - G)
: 
: where G is the absolute value of the reflection coefficient. SWR should be
: always between 1 and +infinity, with 1 the perfect match and +infinity the
: total reflection.

So, how does this agree with what I said? I never stated that it was equal
to a simple division.  Matter of fact, I implied otherwise - either in the
post to which you are responding, or another. I stated that an SWR of 1.2:1
produces a power loss of about 4%.

Bill
From: klee2@uoft02.utoledo.edu
Newsgroups: rec.radio.cb
Subject: J C Whitney 3-function meter
Date: 24 Dec 92 16:28:18 EST
Organization: University of Toledo, Computer Services

I saw there is a 3 function meter in the J C Whitney (mail order Co. in
Chicago, Il), the price is good $17.00 or so,plus S&H $5.00.
Functions are VSWR, FSM and PM.
I would like to know if there is any one out there knows about this
meter. And some opinions.
The application will be CB.
Trying to build ants by myself (for curiousity only, hope it won't kill
my CB)

Thanks in advance.
Merry Christmas to all.

KLee
From: kauppila@sunburn.ec.usf.edu. (Jim Kauppila (DO))
Newsgroups: rec.radio.cb
Subject: GMRS?  Anyone use it?
Date: 30 Dec 92 15:00:59 GMT
Organization: Univ. of South Florida, College of Engineering

I was wondering if anyone here is licensed to operate a GMRS radio.
If so, what are your experiences with it in regards to the amount
of noise on the frequencies, broadcast range, equipment prices, etc..


Thanks!

--
Jim Kauppila                |  E-Mail: Internet: kauppila@sunburn.ec.usf.edu
College of Engineering      |             GEnie: j.kauppila
University of South Florida | Heartland Freenet: jkauppil@heartland.bradley.edu
From: myers@hpfcso.FC.HP.COM (Bob Myers)
Date: Mon, 21 Dec 1992 18:10:00 GMT
Subject: Re: 40 channels at onces?
Organization: Hewlett-Packard, Fort Collins, CO, USA
Newsgroups: rec.radio.cb


Sounds like an urban legend; a very unlikely one.

For one thing, even assuming that the FCC *could* do the "40 at once" trick,
why would they?

(In answer to the original question - this IS possible, with a rather
specialized set-up, but REALLY, REALLY unlikely to be in the FCC's standard
bag of tricks.)


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: twong@civil.ubc.ca (Thomas Wong)
Newsgroups: rec.autos
Subject: Re: LH test-drive results (by a buyer)
Date: 31 Dec 1992 09:23:42 GMT
Organization: Dept. of Civil Engineering, U.B.C., Vancouver, B.C., Canada
NNTP-Posting-Host: sam.civil.ubc.ca

In article <D2150040.me5vo3@destiny.howtek.UUCP> paul@howtek.UUCP (Paul Rothenberg) writes:
>
>....
>On an alternate note, a Honda dealer let me test drive a Prelude Si
>ALONE and as long as I needed. Hmmmm. 
>

That's nothing!
A friend of mine was looking at a Caravan a month ago. ANd the salesguy
let him take it home for a day of testing and bring it back tomorrow!

I had a similar expereince with a Nissan dealer which gave me the keys
to a 240sx and told me to drive around as long as I'd like. And yes,
there was a full tank of gas! So I think it's a matter of the luck of
the draw as to what kinda salesbeast you run into.

Thomas.
From: mdennie@beryllium.mc.xerox.com (Matt Dennie)
Newsgroups: rec.autos
Subject: Re: impact is dead
Date: 30 Dec 92 19:43:09 GMT
Reply-To: mdennie@beryllium.mc.xerox.com
Organization: Xerox Corporation

In article 17703@magnus.acs.ohio-state.edu, bqueiser@magnus.acs.ohio-state.edu (Brian J Queiser) writes:

>You and others may have differing opinions on these subjects, and you
>certainly have the right to have them.  You can also go out right now and
>buy a stripped out Fiero or Festiva that has been made into an electric
>car.  But before you force a manufacturer to sell 2% (or whatever) of their
>vehicles as zero emission (which right now, essentially means electric powered)
                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>you better make damn sure it's a good idea.
>
>I say it isn't.
>
>That's my humble, informed opinion, which is always open for revision.
>
>Regards,
>
>Brian
>
>bqueiser@magnus.acs.ohio-state.edu
>------------------------------------------------------------------------
>I am the engineer, I can choose K.
>------------------------------------------------------------------------
>Department of Engineering Mechanics
>Ohio State University
>Columbus, OH

What about bicycles?  Ferrari and Lotus are into them these days.  Can they
sell cars in CA?

---
--Matt Dennie                              Internet: mmd.wbst207v@xerox.com
Xerox Corporation, Rochester, NY (USA)
"Reaching consensus in a group often
 is confused with finding the right answer."  -- Norman Maier
Newsgroups: rec.autos
From: schludermann@sscvx1.ssc.gov
Subject: RFI:Is radar accurate in rain/drizzel/fog?
Organization: Superconducting Super Collider Laboratory
Date: Wed, 30 Dec 1992 19:29:11 GMT

 Can anyone inform me of the reliability/accuracy of RADAR when it is used
in high humidity situations rain/drizzel/fog? I recall that the validity
of radar in those situations is not reliable. But That was some years ago that
I heard of this. 

thanxs in advance

kris
 
Newsgroups: rec.autos
From: nau@ssesco.com (William Nau)
Subject: Re: Car bras
Organization: SSESCO
Date: Tue, 22 Dec 1992 22:02:11 GMT

In article <92357.110207SROWELL@ESOC.BITNET>, <SROWELL@ESOC.BITNET> writes:
|> The US seems to be the only country in the world that uses these 'Car
|> Bras' (correct me if I'm wrong). Whenever I see a car with one of these
|> vinyl sheets strapped to the bonnet, it's often one of those cars that
|> have those parking sensor probes sticking out of it, the hifi blaring out
|> through heavily tinted windows and driving conspicuously slowly so everyone
|> can notice 'the wheels'.The owner probably still has the polythene wrappers
|> on the front car seats!

That sounds like an inaccurate stereotype to me.  Sure it's fun to make up
such a streeotyp, but I hardly thingk it's true.

|> No, Car Bras are very silly and if you don't tailgate (as has already been
|> pointed out by some sensible gentleman)you are very unlikely to need one.

Let's see, I try not to tailgate.  I must not be because people are always
cutting in front of me.  Yet I still seem to get hit by flying rocks (and 
other stuff) from cars that are 60ft in front of me.  I also get hit by
rocks being throwin off of (by other cars) overpasses.  Drive your car
daily (to work) in a climate where they sand the roads (probably other places
as well) and you will get hit by lots of pebbles.  It will damage a car
with a low profile front end.

|> Save your money and buy a small pot of touch-up paint...

Yea, my sloppy touch up work will look real pretty on the front end of
my probe.
|> Simon

BTW:  I'm not saying that you should use a bra.  I don't use one, but
      often wonder if I should.  All those nicks and dings, make me
      wonder.
-- 
William R. Nau
Supercomputer Systems Engineering and Services Company (SSESCO)
511 11th Avenue South, Suite 216
Minneapolis, Minnesota 55415-1536
(612) 342-0003

nau@SSESCO.com
From: hhtra@usho21.hou281.chevron.com (T.M.Haddock)
Newsgroups: rec.autos
Subject: Re: RFI:Is radar accurate in rain/drizzel/fog?
Date: 30 Dec 92 21:43:39 GMT
Organization: Chevron

In article <1992Dec30.132911.1@sscvx1.ssc.gov>, schludermann@sscvx1.ssc.gov writes:
|> 
|>  Can anyone inform me of the reliability/accuracy of RADAR when it is used
|> in high humidity situations rain/drizzel/fog? I recall that the validity
|> of radar in those situations is not reliable. But That was some years ago that
|> I heard of this. 

 Well... I've never seen any cops using radar while its raining or foggy, 
 so this may have some validity ...
 
 or maybe they just wanted to stay warm and dry.


 TRAVIS
Newsgroups: rec.autos