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Hello All,
I am located on a city lot with one tower (Rohn 45G @ 65')
The lot is small, made smaller by the pool and a separate 500 square foot
separate building which serves as radio room and a "He Man, All Women
Stay Out without Permission" sanctuary for N5RP.
Yard and tower space are utilized to the maximum available.
The load on the tower for antennas can be better understood by going to
my WEB page and seeing the list of radiators on this lonely tower. It is
a very loaded tower; crammed with a lot of stuff that interacts, I am
sure.
The Question is, what to do about the need for a new wire on 80,
and I can do the old "put up and take down; try, try anew" sort of
research on the matter, but I am hoping for some insight from the
experiences of others.
I used to have an inverted vee, fed with coax, though a balun, with the
wires angled off opposite to each other, and with the inclusive angle
being adequate for impedance and resonance. It worked well even though
the wires were broadside to the NW and SE. (Wires "went" to the NE and
the SW)
The wire running off of the tower towards the SW has to be moved now. I
have side mounted another tri-bander which does not allow for it to
remain as it was before the tri-bander was installed.
I am down to, most likely, having to put up just a 1/4 wave sloper on 80,
running off of the top of the tower, sloping towards the NE, and fed with
coax, using an RF choke on the feed line. The wire can run off of the
tower at about a 60-70 degree angle from the tower.
The "shield connected wire" is the problem.
It must come down rather sharply (if it is to run off SW and opposite to
the "hot wire"), go off at a wield angle with respect to the "hot wire"
(out to a corner guy point in the WSW corner of the yard), or it can even
be bonded to the tower, run down the tower, inside the tower, etc., so as
to make sure I have a resonate counterpoise sort of affair.
What would the thoughts be out there?
I realize the question is pretty boring compared to stacking, feeding,
and all of the other esoterics of high priced spread installations,
but my real concern, given my puny lot size, and desire to radiate RF out
of my yard, is that there will be several combinations of installation
that will resonate properly for impedance and frequency.
These various combinations of seemingly "working antennas" can trick me
into thinking I have an antenna, when I actually have nothing more than a
resonant frustration device.
Which form of installation will act more as a radiator and less as a
dummy load?
Back to basics, Guys.
What say out there to one of those dumb type situations?
Now then, having asked the above.............................
Here is what I think might be best.
Please comment before I commit with sweat and soul.
AA)
Feed the "driven" wire with the coax passing through a ferrite bead RF
choke device. This puts me to feeding a NE running wire.
BB)
As for the coax shield; feed it to a (electrically and mechanically
isolated) resonate counterpoise wire and just run it away as best I can,
figuring that it serves only for resonance contribution and contributes
nothing to the pattern of radiation.
The radiation and takeoff patterns are already influenced by the location
of the tower relative to the "driven" wire, and all of the hardware
mounted on same.
Attached is HTML code of the existing tower installation, as is.
73,
Bob Perring
12715 Westmere
Houston, Texas 77077
tele: (281) 493-5780
fax: (281) 493-5780
Std e-mail: perring@texas.net
Int'l e-mail: N5RP@compuserve.com
<underline><color><param>0000,0000,ffff</param>http://lonestar.texas.net/~perring</color></underline>
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<HEAD>
<BODY BACKGROUND="images/tdxsback.gif" TEXT="#000000">
<EMBED TYPE="music/crescendo"
SONG="http://lonestar.texas.net/~perring/images/starwars.mid";
PLUGINSPAGE="http://www.liveupdate.com/dl.html"; WIDTH=200 HEIGHT=55>
<SCRIPT LANGUAGE="JavaScript">
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{
var m1 = " ----- MORSE CODE IS INTELLIGENT";
var m2 = " 'DOODLY DOODLY' SOUND ";
var m3 = " THAT EXCITES THE FEW WHO TRULY UNDERSTAND -----";
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<BODY
onLoad="timerONE=window.setTimeout('scrollit_r2l(100)',500);"><TITLE>Amateur
Radio Station N5RP</TITLE>
</HEAD>
<P>
<BR>
<font color="#ff0000">
<H1><STRONG><CENTER>The station at <a
href="http://www.lonestar.texas.net/~perring/images/qsl.jpg";>N5RP</a> consists
of the following
equipment:</CENTER></STRONG></H1></font> <center><IMG
SRC="images/rainbow.gif"></center>
<p>
<B><P>
<STRONG><H2>Transceiver(s) ..........</H2></STRONG> Kenwood TS-940S/AT (dual
radios) w/ SM-220 Monitor Scope, and IF interfaces to the station computer.<BR>
Heathkit HW-8 for QRP work.<BR>
Kenwood TS-440S/AT for mobile CW and DXpeditions.<P>
<STRONG><H2>Amplifiers ..........</H2></STRONG> Kenwood TL-922A.<BR>
Single 4-1000A w/ up to 6 KVDC.<BR>
Ten-Tec Titan amplifier.<P>
<STRONG><H2>Antennas .......... <font color="0000ff"><blink>The Single Tower
Nightmare !!!</blink></font></H2></STRONG><P>
Rohn 45G tower at 70 Ft. with DX Engineering Switch Box
for:<BR>
Inverted Vee for 75 / 80 Meters.<BR>
Inverted L for 160 Meters.<BR>
Homebrew 3 ele. on 40' boom for 40 Meters.<BR>
Stacked Mosely TA-36 tribanders (Over 30 years old)<BR>
Cushcraft Rotary Dipole for WARC Bands.<P>
4 Elements for 6 Meters.<BR>
14 Elements for 2 Meter SSB/CW.<BR>
Hustler 144/440 MHz Vertical for Packet.<BR>
2 X 10 (144 MHz) with 2 X 8 (432 MHz) Satellite array w/
Az-El Control.<BR>
Mast mounted pre-amp for 2 meter satellite reception.<P>
Heathkit Antenna Tuner Model SA-2060.<P><BR>
<STRONG><H2>Additional Equipment .......... </H2></STRONG> Kenwood 2 Meter
TR-7730 for Packet.<BR>
Yaesu FT-736R (computer controlled); 50 mHz, 144 mHz,
440 mHz, 1296 mHZ ...... all modes.<BR>
100 Watt solid state amp for 2 Meters.<BR>
150 Watt solid state amp for 6 Meters.<BR>
150 Watt solid state amp for 70 Centimeters.<BR>
<STRONG><H2>Digital Equipment ..........</H2></STRONG>486 CPU MSDOS Based
Computer.<BR>
Kantronics KAM w/ expansion board.<BR>
AEA CK-2 Keyer w/ Vibroplex iambic paddles.<BR>
Heathkit Ultra-Pro CW Keyboard.<P><BR>
<STRONG><H2>Software ..........</H2></STRONG> Hostmaster 2+ w/ PACTOR
capability.<BR>
SSTV software.<BR>
N6RJ 2nd Op for Data Base.<BR>
K1EA & K8CC Contest Software.<BR>
Various TNC software programs.<BR>
<STRONG><H2>Station is located in a 500 square foot "shack",<BR>with everything
compressed on to a rather small city lot.</H2> </STRONG>
</b><p>
<HR ALIGN=center SIZE=5>
<a href="index.html"><STRONG><H3><CENTER>__I wanna QSY back to the Perring's
Home Page!__</CENTER></H3></STRONG></a><P>
</b><p>
</BODY>
</HTML>
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