HDTenEightyP/NetNews huggingface dataset:
Newsgroups: rec.radio.cb

> > connector. Each S unit below S9 represents a *halving* of the
> > signal strength at the antenna. Note that since these are *voltage*
> > dBs and not *power* dBs, it takes 6 to represent a halving of the
> > signal. 
> > 
> > dBV=20*log(V1/V2) and dBP=10*log(P1/P2)
> > 
> 
> 6 dB always means halving of the signal strength in voltage. Note that the
> 2 equations you wrote down for dBV and dBP (I'm not sure if there really is
> a dBP) are actually equal since P =V^2/R.
> 
>    dBP=10*log(V1)^2/(V1)^2 = 20*log(V1/V2) = dBV.

Well, if you want to be precise, both of you have it exactly backwards - there
aren't "power dBs" and "voltage dBs."  The decibel is ALWAYS a unit of *power
ratio*, and THAT is what produces the "10" and "20" in the above equations.

The decibel is one-tenth of a Bel, which is the log of the power ratio.  
Therefore, to get to dB from a straight ratio of two power measurements, you
take the log and multiply by 10.  But, as is mentioned above, power is 
proportional to the square of voltage (or current), and so you have to do an
additional "multiply by 2" step when you start with a ratio of voltages.
(I.e., doubling the voltage across a given resistance *quadruples* the power,
so it's twice as many dB as doubling the power!)  Of course, there is the
inherent assumption that you're talking about voltages across the same 
impedance (as otherwise, the voltage ratio cannot be made into a meaningful
power ratio this simply).


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: darrellm@pogo.wv.tek.com (Darrell McGinnis)
Newsgroups: rec.radio.cb
Subject: microphone woes...
Date: 12 Oct 92 19:02:16 GMT
Article-I.D.: pogo.13747
Distribution: usa
Organization: Tektronix Inc., Beaverton, Or.



	The mike on my radio is flakey & I want
	to build my own.
	
	
	I want to use an electret mike (have one)
	 & eventually put in a band-pass filter 
	 centered around 2-3Khz. 
	
	Given the current thing is a dynamic mike,
	what kind of voltage levels does the radio
	expect from the mike ?

	(I know a pot would allow for vaiable gain, but 
	I'd like to be in the ballpark when I key up.)
	
	Anyone have a quick schematic of a electret
	mike used with a CB ?
	
	Other alternatives, (don't want to fix the current one as
	I want to end up with a desk mike) ?
From: vbreault@rinhp750.gmr.com (Val Breault)
Newsgroups: rec.radio.cb
Subject: Re: CB Tips
Date: 7 Oct 92 20:55:02 GMT
	<1992Oct7.181704.20015@hpcvaac.cv.hp.com>
Organization: General Motors Research Labs
In-reply-to: billn@hpcvaac.cv.hp.com's message of 7 Oct 92 18:17:04 GMT

In article <1992Oct7.181704.20015@hpcvaac.cv.hp.com> billn@hpcvaac.cv.hp.com (bill nelson) writes:
   taber@ultnix.mro1.dec.com (Patrick St. Joseph Teahan Taber) writes:

   : |>Contrary to what you believe - possession of a linear amp is not illegal. The
   : |>use of one, by a CBer, is.
   : 
   : It *is* illegal to posess a CB amp.

Sorry Bill, I agree with Pat.  Here are a few answers to your questions.

   It is? Then why have hams modified them for use on the 10M band?

Some of them were originally designed for operation on the amateur bands.
Perhaps those hams were restoring the amplifier to it's original condition.

   Why, when the FCC was enforcing 11M regs better, did they not confiscate
   linears that were not connected to the transceiver and antenna?

Beats me.  I don't (can't) speak for the FCC.  Perhaps the law that
prohibits posession was not written at that time. 

   I think you will find that it is illegal to sell them to the general public
   but that simple possession is not illegal.

I'm going to look through my references tonight and see if I can find
the specific law that prohibits the ownership by an unlicensed person
of an amplifier capable of transmitting in the citizens band.  Hopefully,
facts will sway this discussion more than mere opinions.

   Bill

-val-

--

Val Breault - vbreault@gmr.com - N8OEF
General Motors Research and Environmental Staff.
The opinions expressed by the author do not necessarily reflect 
those of the GMRES or the General Motors Corporation.
From: john.denison@yob.sccsi.com (John Denison) 
Newsgroups: rec.radio.cb
Subject: MICROPHONE WOES...
Date: 13 Oct 92 13:36:00 GMT
Distribution: world
Organization: Ye Olde Bailey BBS - Houston, TX - 713-520-1569
Reply-To: john.denison@yob.sccsi.com (John Denison) 

-> & eventually put in a band-pass filter centered around 2-3Khz.

I guess you could use a small capacitor (don't know which value to use
for a 600 ohm mic) and that would filter out the audio below a specified
frequency. At least it does work for tweeters in a car stereo speaker. I
don't see why you would want to filter the mic anyway when CB's don't
have a very good audio respone anyway. I long for 20-20000 Hz response
in Stereo in CB. :)
                                                                   
Newsgroups: rec.radio.cb
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: CB antenna inside a roof?
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
Date: Tue, 13 Oct 1992 04:47:48 GMT

bernardo@erevax.bitnet (Marcelino Bernardo) writes:
: I live in a development where it is forbidden to put up any external
: antenna.  I'm considering installing a CB antenna (a dipole or a vertical
: with radials) inside my attic.  I've done this before in another house and
: I know that it works.  
: 
: The questions are: 
:    How much of a loss would the roof cause me? 

If it is not metal sheathed, little or none. A dipole is fairly directional.
That could be either an advantage or a disadvantage. I would install both 
and use an antenna switch.

:    WouId I be able to communicate with a car 12 miles away (AM or SSB if
:     necessary)?

Probably, if you can do so with an external antenna mounted at the same
height.

Bill
From: billn@hpcvaac.cv.hp.com (bill nelson)
Newsgroups: rec.radio.cb
Subject: Re: Antenna Mounting...
Date: 13 Oct 92 19:18:02 GMT
Article-I.D.: hpcvaac.1992Oct13.191802.1990
Organization: Hewlett-Packard Company, Corvallis, Oregon USA

elesatz@diana.cair.du.edu (Eric LeSatz) writes:
: In article <1992Oct13.045316.24516@hpcvaac.cv.hp.com> billn@hpcvaac.cv.hp.com (bill nelson) writes:
: >system@gravebbs.UUCP (SYSTEM 0PERATOR) writes:
: >
: >Whips are not designed for roof mounting. They are designed for use with
: >a ground plane. You would be far better off getting a base station antenna.
: >If you are going to put in all that effort, do it right.
: 
: A few years ago I bought a 1/4 wave whip, the hardware to mount it
: with and 4 non-insulated wires. That antenna worked great on the roof
: (with just the four wires as the ground plane) and didn't cost me
: nearly as much as a prepacked base antenna. Plus, the white fiberglass
: blended extremely well with the sky..the antenna wasn't noticible at
: all unless you were specifically looking for it. Most base antennas I
: see are the ugly (and obvious) silver color.

Note that you are just emphasizing what I said.  I still do not think
that it is the best way to go - the whips are too flexible. A 5/8 wave
vertical would also have more gain that a 1/4 wave whip.

: I recommend building your own. Much cheaper, equal performance (I had
: an SWR of 1.2 on mine) and you will learn a little about radio theory
: doing it.

I agree. At least, you may learn a little about antenna and transmission
line theory.

Bill
From: stever@pro-haven.cts.com (Steve Rodgers)
Newsgroups: rec.radio.cb
Subject: IsoLoop 10-30
Date: 16 Oct 92 16:29:40 GMT
Organization: ProLine [pro-haven] - Pariahs' Haven BBS, 409/693-8262, 9600-300

I am looking for any comments on the AEA IsoLoop 10-30 antenna.  There is a
good review of it in the current 73 Review, and it sounds like it might be
just the trick for those of us with very restrictive covenants.  Any infor
at all appreciated.  73, Steve
---
Internet: stever@pro-haven.cts.com
UUCP:     crash!pro-haven!stever
Newsgroups: rec.radio.cb
From: jbs@rti.rti.org
Subject: Re: RE: CB TIPS
Organization: Joe's Bar and Grill
Date: Thu, 8 Oct 92 14:48:39 GMT

In article <5qNBsB9w165w@bluemoon.rn.com> johnw@bluemoon.rn.com (John L. Wilkerson Jr.) writes:
>edwardl@freddyk.uucp (Edward Langenback) writes:
>
>> phantom@pro-haven.cts.com (Tiffany Keller) writes:
>> 
>> > In <1992Oct05.145246.2876336@locus.com> dana@locus.com (Dana H. Myers) writ
>> > 

...

>> sheesh! enough already!  how about redirecting anything further on this 
>> thread to /dev/null?
>> 
>> 
>       I agree.  the whole damn subject has been run into the ground and 
>has deviated from the whole topic of this newsgroup.   I see 10 messages 
>about all this Bs and ONE pertaining to radio.    Get off it people!

I gotta agree with John. Enough has been said on this subject. Anything
else said is a useless waste of bandwidth. There are far too many followups
to this thread saying nothing of substance. Everybody should just let it
go and not run it into the ground. Anybody out there agree with me?

;->

  -joe
From: billn@hpcvaac.cv.hp.com (bill nelson)
Newsgroups: rec.radio.cb
Subject: Re: CB Problems....
Date: 16 Oct 92 20:22:13 GMT
Organization: Hewlett-Packard Company, Corvallis, Oregon USA

lcj0@ns1.cc.lehigh.edu (Lutz C. Jacob) writes:
: 
: >This kind of antenna works fine for cellular phones because cellular phones
: >operate at ~800 MHz, where the wavelength is 3.75cm rather than 11m, and
: >where the admittance of the capacitor (inverse of impedance) is ~30 times
: >higher.
: 
: Thanks for the reply, so is there another way around the normal large 
: cb antennae?  That is basically what I don't want, but I want the cb....
: (Picky aren't I)  This may seem to much to ask, I don't know too much about 
: the various antennaes that are around.  The antennae mentioned above was 
: advertised as a CB antennae, but right now is isn't worth a dead bug....

There are magnetic "rooftop" mount antennas for CB that are only about
1 meter long. They work fairly well - sometimes better than a full length
whip mounted on the bumper of the car.

Bill
From: gary@ke4zv.uucp (Gary Coffman)
Newsgroups: rec.radio.cb
Subject: Re: Antenna Mounting...
Date: 13 Oct 92 12:54:47 GMT
Reply-To: gary@ke4zv.UUCP (Gary Coffman)
Organization: Gannett Technologies Group

In article <V3JJsB1w165w@gravebbs.UUCP> system@gravebbs.UUCP (SYSTEM 0PERATOR) writes:
>Just to briefly get off the topic of LINEAR AMPS..  I bought a 108" steel 
>whip and I was planning to mount it onto my roof.  But:
>1. Where's the best place to mount it?  (Chinmey, Edge, Gutter?)
>2. Is it necessary that I ground it?
>3. Does the cable really matter?  (Does it HAVE to be RG-58 or RG-8?)

A *mobile* whip, even a full size one, is not a good base antenna. Unless
your house has a *metal* roof to work against, the antenna will not perform
properly. You need a *groundplane* base antenna. This style of antenna uses
*radials* to replace the missing metallic RF mirror that the car body supplies
in a mobile installation. 

You can "make do" with three copper wires, each 108" running out from 
the base of the whip in a horizontal, or slightly drooped, configuration.
Connect the coax center to the whip and the shield to the radial wires.
How you support the wires is up to you. Laying them on the roof may work,
but won't be as efficient as if they were in free space. 

The National Electrical Code, and common sense, says you must ground the
antenna. However, with the makeshift antenna described above, or a bare
whip, that's not possible. Number 8 wire direct to an 8 foot ground rod
is the NEC requirement. You'll be better off if you put that whip on the
bumper of your car and get a proper base station antenna of the "plumber's
delight" design that will allow proper safety grounding.

As to where to mount a base antenna, the simple rule is to mount it as
high and as in the clear as possible. Often that's a mast fastened to
a chimney, or use of a roof tripod, or an honest to God *tower* in the
yard.

On the subject of cable, if you want low VSWR, you'll use 50 ohm cable
like RG-58 or RG-213. RG-8 is no longer a military specification and the
cables you get *labeled* RG-8 can be of any construction or quality, especially
junky Radio Shack cable. The military number that supercedes RG-8 is RG-213. 
A very good "house brand" RG-8 *type* cable is Belden 9913. It's usable way 
up into the UHF range and is likely overkill for CB. If your radio doesn't
care about VSWR, or you have a *tuner*, then CATV cable like RG-6 will work
fine. The loss due to VSWR is trivial as long as you can load the transmitter
into the impedance presented.

Gary KE4ZV
Newsgroups: rec.radio.cb
From: billn@hpcvaac.cv.hp.com (bill nelson)
Subject: Re: CB Tips
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
Date: Thu, 8 Oct 1992 18:39:26 GMT

johnw@bluemoon.rn.com (John L. Wilkerson Jr.) writes:
:  
: OK.   I'll quote the CB reg here.  This may clear it up....
:  
:  95.411  ( CB rule 11 )
:  
:      par. c   "The FCC will presume you have used a linear or other 
: external RF amplifier if--"
:  
:  (1) It is in your possession or on your premises (there it is, BUT...)
:       AND
:  (2) There is other evidence that you have operated your CB station with 
: more power than allowed by CB rule 10.  ( 4 watts AM Carrier power, 12 
: Watts PEP SSB)
:  
:    Sooo.... in my interpretation, posession IS illegal IF say, other 
: evidence, such as MASSIVE bleedover and such exists that the FCC thinks 
: someone is using that linear on CB.

Nope. What you have quoted on says that the FCC will presume that you have
used the linear - if you fit the above description. I don't see anything
there that says such possession is illegal. On the contrary, because of (2),
it seems to imply otherwise.

Thanks for the input John. 

Bill
From: jbs@ee.egr.duke.edu (Joe B. Simpson)
Newsgroups: rec.radio.cb
Subject: bb19s20@instem.uucp: mail bounced
Date: 14 Oct 92 21:19:11 GMT
Distribution: usa
Organization: Joe's Bar and Grill


   ----- Transcript of session follows -----
421 instem.uucp.smtp... Deferred: Invalid argument
550 bb19s20@instem.uucp... Host unknown: Invalid argument

   ----- Unsent message follows -----
Received: by ee.egr.duke.edu (AIX 3.2/UCB 5.64/DUKE-EE/1.8)
	id AA83155; Wed, 14 Oct 1992 17:16:01 -0400
Date: Wed, 14 Oct 1992 17:16:01 -0400
From: Joe B. Simpson <jbs>
Message-Id: <9210142116.AA83155@ee.egr.duke.edu>
To: bb19s20@instem.uucp
Subject: Re: Antenna Mounting...


>Regarding the Antron-99...I know you can use it with the ground plane kit or 
>without. Does this ground plane kit effect recieve only or does it affect 
>transmit also?...Curious.

Neither, as far as the people I know who've added the kit say. If it affected
either, though, it should affect both. The antenna's either more efficient
at the resonant frequency or it isn't, so any improvement in receive should
have a commensurate improvement in transmit.

Mine works absolutely great without the ground-plane radials. I don't plan
to buy any.

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

                   - Lyle Lovett

X-Spook-Fodder: CIA NSA FBI SBI Bush overthrow uprise assasinate anarchy
From: john.denison@yob.sccsi.com (John Denison) 
Newsgroups: rec.radio.cb
Subject: MICROPHONE WOES...
Date: 13 Oct 92 13:33:00 GMT
Distribution: world
Organization: Ye Olde Bailey BBS - Houston, TX - 713-520-1569
Reply-To: john.denison@yob.sccsi.com (John Denison) 

-> The mike on my radio is flakey & I want
-> to build my own.

I just recently build my own speaker/mic out of an old Midland
microphone. I removed the mic and put a small 8 ohm speaker in its
place, with a little mod of the mic case, and connected the speaker to
the external speaker output. I found a small microphone element which
works but I don't know if it is the right impedance (600 ohms) or not,
but it does pick up my voice with no problem.
As far as a schematic all I can tell you is that out of three mics that
I have, President, G.E., and Midland, all are wired similar inside the
mic shell. A negative wire coming from the CB is connected to the
negative side of the mic, and is also connected to the switch. The
switch allows one output wire to be negative when RX and the other to be
negative when TX. Plus the Switch connects the positive of the mic when
Tx and disconnects the mic positive when RX. The switch should have six
prongs. It should be a DPDT switch, with three prongs on the bottom and
three on the top. One set is for the switching of the negative
connection and the other set is for switching the mic element on and
off. The positive wire from the CB to the switch should have a shield
around it which is connected to ground.
As far as the other end of the mic is concerned, where it plugs into the
CB, the pin configuration varies from one CB to the next. If you see
where the wires connect inside the mic shell then you can trace the same
color wire to the plug. I plugged a President mic into a G.E. cb and it
TX when the button was not pressed, but when I pressed the button, it RX
but sent the audio to the mic element. Pretty Strange. I did find out
that the Midland and G.E. mics were wired the same from on end to the
other.
From: johnw@bluemoon.rn.com (John L. Wilkerson Jr.)
Newsgroups: rec.radio.cb
Subject: Re: Linear Amps..
Date: 8 Oct 92 10:52:02 GMT
Organization: Blue Moon BBS ((614) 868-998[024])

randall@informix.com (Randall Rhea) writes:

> 
> 60 watts on AM will also do you little or no good.  This will increase
> your range slightly for local communication.  To "talk skip" on AM,
> you will need a lot more than 60 watts.  Conditions on CB are usually
> very bad, with lots of interference from other stations.  If you wish to 
> "talk skip", you are better off either: 1) Investing in an SSB radio, 
> or 2) Investing in a directional antenna, such as a quad or yagi.  
> Chances are, the linear is poorly designed and constructed, and it
> will only mess up your signal.  Spend your money on a good antenna instead.
> 
   
   ANY watts on AM, (In my opinion) other than the legal amt does no good 
or at the most very little.   This is both for loacl comms. and skip 
shooting.   Band Conditions determine if a signal will "skip", not power.  
Four Watts, or MUCH lower power can easily skip.
 
    I hear of hams making DX contacts running MILLIwatts, then hear some 
Idiot CBer running 1 KILOwatt and /only/ making it to the next state.   
Makes me laugh.
     Of course, CB band is crowded, which makes a big difference, but the 
principle is what matters.    
 
     I'd figure you know all this, but added in my comments to reinforce 
the uselessness of Linears on CB to those who may be ignorant.
 

--
  ___                      _       _     __  _
 (   >      /            _//      ' )   /   // /
  __/______/_  ____      /         / / / o // /_  _  __  _   ________
 / /  (_) / /_/ / <_    /___ o    (_(_/ <_</_/ <_</_/ (_/_)_(_) / / <_
<_/     johnw@bluemoon.use.com     jwilkerson@delphi.com
        71140.77@compuserve.com
From: cse0947@desire.wright.edu
Newsgroups: rec.radio.cb
Subject: Scanning the Citizen's Band
Date: 13 Oct 92 22:15:46 GMT
Organization: Wright State University

Is there such a thing as scanner for a CB radio? Something that will allow
me to scan a selected number of channels? I would assume it to be built
into a radio?
From: jbs@ee.egr.duke.edu (Joe B. Simpson)
Newsgroups: rec.radio.cb
Subject: Re: Antron 99
Date: 16 Oct 92 14:25:25 GMT
Distribution: usa
Organization: Joe's Bar and Grill

In article <yBHosB1w165w@bluemoon.rn.com> johnw@bluemoon.rn.com (John L. Wilkerson Jr.) writes:
>jbs@ee.egr.duke.edu (Joe B. Simpson) writes:
>
>> multe-wave antennas.  I have to put in another plug here for the A-99, former
>> sold as the Antron 99.
> 
>    Hasn't Antron stopped makinh the 99 though?  I heard the designer quit 
>or something, and took all rights with him.   Something in that antenna 
>was patented, and they have to design a different antenna.   

They're not sold with the Antron name on the box or the antenna anymore, if
that's what you mean. The name changed to A-99 when the new manufacturer bought
production rights. The one I bought wasn't marked "Antron", but I can't recall
the name of the manufacturer.

>     I also heard, the A-99 is a "dirty" antenna.   Eats phone 
>conversations for breakfast

I've never had any problems with mine. If you've heard this from people who're
running illegal power (the antenna's rated for 2000 watts, I think), then
their phone conversations probably *are* being trashed.

I don't really know how an antenna that is properly tuned could cause (or
allow) more harmonic radiation than another antenna, but then I just got
the ARRL antenna book in the mail this week and after reading a bit confirmed
my suspicion that I've got a heckuva lot to learn...

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

                   - Lyle Lovett

X-Spook-Fodder: CIA NSA FBI SBI Bush overthrow uprise assasinate anarchy
Newsgroups: rec.radio.cb
From: johnw@bluemoon.rn.com (John L. Wilkerson Jr.)
Subject: Antron 99
Organization: Blue Moon BBS ((614) 868-998[024])
Distribution: usa
Date: Thu, 15 Oct 92 04:55:57 EDT

jbs@ee.egr.duke.edu (Joe B. Simpson) writes:

> 
> multe-wave antennas.  I have to put in another plug here for the A-99, former
> sold as the Antron 99.  I've been through quite a few base station antennas
> over the years (including homemade dipoles), and nothing's come close for
> omnidirectional performance.  The A-99 cost me $45 new, and will tune down to
> absolutely rock-bottom SWR.  It has no radials (unless you want it to), so it
> 
 
 
    Hasn't Antron stopped makinh the 99 though?  I heard the designer quit 
or something, and took all rights with him.   Something in that antenna 
was patented, and they have to design a different antenna.   
 
     I also heard, the A-99 is a "dirty" antenna.   Eats phone 
conversations for breakfast

--
  ___                      _       _     __  _
 (   >      /            _//      ' )   /   // /
  __/______/_  ____      /         / / / o // /_  _  __  _   ________
 / /  (_) / /_/ / <_    /___ o    (_(_/ <_</_/ <_</_/ (_/_)_(_) / / <_
<_/     johnw@bluemoon.use.com     jwilkerson@delphi.com
        71140.77@compuserve.com
From: lcj0@ns1.cc.lehigh.edu (Lutz C. Jacob)
Newsgroups: rec.radio.cb
Subject: Re: CB Problems....
Date: 16 Oct 92 17:26:08 GMT
Article-I.D.: ns1.1992Oct16.172608.13979
Organization: Lehigh University

In article <16927@ksr.com>, jfw@ksr.com (John F. Woods) writes:
>lcj0@ns1.cc.lehigh.edu (Lutz C. Jacob) writes:
>>Greetings....
>>(Here it comes....)  JC Whitney.  It is a small antennae, with a loaded coil,
>>and the cellular spiral looking thing in the middle as well.  It is about two 
>>feet high.  I bought this antennae because I hate the looks of normal cb 
>>antennae's.  Unfortunately, the transmission and receive capabilities are 
>>atrocious.  I don't know anything about SWR meters and such.  Has anyone ever
>>used an antennae like that?  It is constructed much like a cellular phone 
>>antennae, even goes through the glass.  Since these seem to work really well 
>>with cellular phones, I thought I would try it.... any ideas/suggestions?  

>This kind of antenna works fine for cellular phones because cellular phones
>operate at ~800 MHz, where the wavelength is 3.75cm rather than 11m, and
>where the admittance of the capacitor (inverse of impedance) is ~30 times
>higher.

Thanks for the reply, so is there another way around the normal large 
cb antennae?  That is basically what I don't want, but I want the cb....
(Picky aren't I)  This may seem to much to ask, I don't know too much about 
the various antennaes that are around.  The antennae mentioned above was 
advertised as a CB antennae, but right now is isn't worth a dead bug....
-- 


------------------------------------------------------------------------------
lutzer@plasma.physics.lehigh.edu
lutzer@biff.cc.lehigh.edu                       Lutzer (R)
lcj0@Lehigh.edu                                 LUCC Student Konsultant