home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
QRZ! Ham Radio 4
/
QRZ Ham Radio Callsign Database - Volume 4.iso
/
digests
/
antenna
/
940129.txt
< prev
next >
Wrap
Internet Message Format
|
1994-11-13
|
6KB
Date: Mon, 2 May 94 04:30:12 PDT
From: Ham-Ant Mailing List and Newsgroup <ham-ant@ucsd.edu>
Errors-To: Ham-Ant-Errors@UCSD.Edu
Reply-To: Ham-Ant@UCSD.Edu
Precedence: Bulk
Subject: Ham-Ant Digest V94 #129
To: Ham-Ant
Ham-Ant Digest Mon, 2 May 94 Volume 94 : Issue 129
Today's Topics:
Transmitting 160m w/ a looptick? (2 msgs)
Y'all are a shy bunch, aintcha'? (3 msgs)
Send Replies or notes for publication to: <Ham-Ant@UCSD.Edu>
Send subscription requests to: <Ham-Ant-REQUEST@UCSD.Edu>
Problems you can't solve otherwise to brian@ucsd.edu.
Archives of past issues of the Ham-Ant Digest are available
(by FTP only) from UCSD.Edu in directory "mailarchives/ham-ant".
We trust that readers are intelligent enough to realize that all text
herein consists of personal comments and does not represent the official
policies or positions of any party. Your mileage may vary. So there.
----------------------------------------------------------------------
Date: 01 May 1994 20:16:19 GMT
From: ihnp4.ucsd.edu!agate!darkstar.UCSC.EDU!news.hal.COM!olivea!grapevine.lcs.mit.edu!chaos.dac.neu.edu!chaos.dac!dean@network.ucsd.edu
Subject: Transmitting 160m w/ a looptick?
To: ham-ant@ucsd.edu
Hi:
Loopstick antennas are great for small AM radios, so why can't they
be used for transmitting? Are they inefficient or something?
-Dean
------------------------------
Date: Mon, 2 May 1994 03:01:17 GMT
From: ihnp4.ucsd.edu!swrinde!cs.utexas.edu!asuvax!pitstop.mcd.mot.com!mcdphx!schbbs!fl08ara014.comm.mot.com!user@network.ucsd.edu
Subject: Transmitting 160m w/ a looptick?
To: ham-ant@ucsd.edu
In article <DEAN.94May1161619@splinter.coe.neu.edu>,
dean@splinter.coe.neu.edu (Dean Gelabert) wrote:
> Hi:
> Loopstick antennas are great for small AM radios, so why can't they
> be used for transmitting? Are they inefficient or something?
Small loop antennas with or without ferrite cores are extremely inefficient
(albeit highly directional). In the case of receiving applications where we
are dealing with field strengths in the range of microvolts per meter thus
very tiny induced currents, these inefficiencies cause the dissipation of
very small amounts of power. But at typical transmitted power levels, well
... you guessed it, the antenna is going to get just a bit warm :-(
--
Don Burns
Plantation, Florida
epur01@email.mot.com
------------------------------
Date: 1 May 1994 13:53:46 GMT
From: ihnp4.ucsd.edu!usc!howland.reston.ans.net!usenet.ins.cwru.edu!po.cwru.edu!sct@network.ucsd.edu
Subject: Y'all are a shy bunch, aintcha'?
To: ham-ant@ucsd.edu
In article <2pslcp$24he@whale.st.usm.edu>,
William Matt Watkins <wwatkins@whale.st.usm.edu> wrote:
> So, let's try it again from scratch. How do I make an antenna
> for an AM or FM radio that is highly directional?
Part of the reason you didn't get an answer is because there are so many! :-)
You may want to borrow a copy of the ARRL Handbook from somewhere. It has
an introduction to radio direction-finding techniques that will be helpful.
My uneducated guess is that a shielded loop antenna, TDOA antenna-switching
gadget, or a portable beam may be helpful to you.
If you're going to count on this for navigation, there is nothing to beat
a GPS receiver. They are a couple hundred dollars these days, but they are
very good at telling one exactly where one is. In other words, I'd be
hesitant to trust my navigation in woods solely to getting bearings on
broadcast stations. What do you do when you're stuck in a valley, for
example? How do you know that the BC signal strengths will be right for
the equipment you are carrying?
Stephen
--
Stephen Trier "Never underestimate the power of a quarter note."
sct@po.cwru.edu -- Paul Ferguson
KB8PWA
------------------------------
Date: Sun, 1 May 1994 22:13:47 GMT
From: ihnp4.ucsd.edu!swrinde!cs.utexas.edu!asuvax!pitstop.mcd.mot.com!mcdphx!schbbs!fl08ara013.comm.mot.com!user@network.ucsd.edu
Subject: Y'all are a shy bunch, aintcha'?
To: ham-ant@ucsd.edu
In article <2pslcp$24he@whale.st.usm.edu>, wwatkins@whale.st.usm.edu
(William Matt Watkins) wrote:
> So, let's try it again from scratch. How do I make an antenna
> for an AM or FM radio that is highly directional?
AM or FM has nothing to do with the kind of antenna you want. FREQUENCY
does. What range of frequencies are you talking about?
--
Don Burns K4GHD
Plantation, Florida
epur01@email.mot.com
------------------------------
Date: Sun, 1 May 1994 20:58:45 GMT
From: ihnp4.ucsd.edu!usc!howland.reston.ans.net!pipex!uknet!EU.net!Germany.EU.net!netmbx.de!zrz.TU-Berlin.DE!math.fu-berlin.de!fub!chamber.in-berlin.de!klaus@network.ucsd.edu
Subject: Y'all are a shy bunch, aintcha'?
To: ham-ant@ucsd.edu
wwatkins@whale.st.usm.edu (William Matt Watkins) writes:
[...]
>So, let's try it again from scratch. How do I make an antenna
>for an AM or FM radio that is highly directional?
How about beeing a bit more precise than 'I'd like to buy a cheap and fast
car, could you help ?'...
What I'm trying to say, is, that 'AM or FM' doesn't say anything about the
wavelength or other specs of the antenna, you are looking for.
What do you mean by 'highly directional' ?!
Klaus.
________________________________________________________________________________
klaus@netmbx.netmbx.de, Klaus Tiedemann on the air : DL4EBY, DK0TU
klaus@chamber.in-berlin.de AX25: DL4EBY @ DB0GR.EU
------------------------------
End of Ham-Ant Digest V94 #129
******************************