-Original Message-
From: Eugene Colton
Sent: Monday, September 03, 2018 12:25 PM
To: donov...@starpower.net
Cc: topband@contesting.com ; MU 4CX250B
Subject: Re: Topband: Air wound coil
Jim,
@ say, 1.83 MHz, the electrical length of your vertical is about 47.4 deg,
necessitating a top ha
Well Nick,
I’m not sure who has told you that but if they were any kind of men they would
stand up and be held accountable for their opinions and actions that cause good
people, that are the future of this hobby, to be dissuaded from participation.
Shame on you folks...and he’s rightyou don
Grant wrote:
>>> Or the inverse as I did, cut my T for the low end of the band. Then three
>>> series capacitors with PCB relays to short each individually (none, 1, 2,
>>> or 3) yielded nearly full band coverage <1.5:1 swr. My T is 85' to top and
>>> a 50:25 ohm TLT is a close match, then the
and that right there sums up why we have a problem.
Sorry to see you go. I am a 40+ ham and only 54 years old. This makes
me really sad and angry as I would like my hobby to be around in for the
next 40 years too...
Hope to hear you on the bands, Nick.
W0MU
On 9/2/2018 9:09 PM, Nick Masl
Hi all,
While I have enjoyed many of the technical topics of the list, I have
become rather annoyed by the blame that has repeatedly come across the
reflector. From the FT8 arguments in addition to the "millennials causing
the WWV shutdown" argument, it appears that the parts of the hobby that I
e
Jim,
@ say, 1.83 MHz, the electrical length of your vertical is about 47.4 deg,
necessitating a top hat of about 42.6 deg. I followed the prescription of
John, ON4UN and calculated out a surge impedance of 377 ohms based on an
average radiator diameter of 2.25 inches; the hat capacitance would be
Hi Jim,
If you base load a 68 vertical on 160 meters it will create very
high voltage at the base of the vertical which may damage the
base insulator. Much better to use top loading to avoid high
voltage at the base.
73
Frank
W3LPL
- Original Message -
From: "Jim Garland" <4cx
Jim,
I have that 80m quarter wave vertical by DXE and use a simple matching network
with it for 160m. As it stands, the vertical is basically an 1/8 monopole with
~12 ohms real Z on 160, so I use a 4:1 balun to bring the 50 ohm coax down to
12 ohms then add a 4 inch diameter coil in series to
Jim,
Just my 2-cents. Here goes...
First, NEC 4.2 160m "T" modeling shows very little advantage of having 4
top-hat wires instead of just two. The azimuth radiation pattern is almost a
circle in the horizontal plane with two wires since very little field strength
is radiated from symmetrical
I have often used an Omega match, in this situation.
Have a great day,
--... ...-- Dale - WC7S in Wy
"Actions speak louder than words"
1856 - Abraham Lincoln
_
Topband Reflector Archives - http://www.contesting.com/_topband
Jim,
Maybe a combo of the two methods, that way you can tap up from the bottom of
the loading inductor a few turns to get a perfect match for the coax
feedline. Plus have the convenience of adjusting to resonance by tapping
down from the top of the same coil.
73,Roy K6XK
On this
On this general topic, I'm erecting a 68 ft aluminum self-supporting
pole (DX Engineering) that is four inches OD at the bottom, tapering to
about 1/2 inch at the top. It is designed as a full size 1/4 wave 80m
vertical. I'd like to use it on 160m. If I add four capacity hat wires
at the top, w
If that antenna is resonant at 1900 kHz, and you have a suitably sized
inductor between the bottom of the vertical wire and ground, there will
likely be a tap-point on the inductor that will give you a low SWR. No need
for a transformer.
I think that is probably the simplest and most solid solu
Or better still, Shorten the L until it is self resonant at 1.9mhz, thereby
lowering the amount of horizontal polarisation. Then use a simple hairpin
coil across the feedline typically around 5microhenries. This will then when
chosen correctly match at your chosen ideal spot say 1825.
And provide
Bob W7RH - you don't need expensive hard-to-find vacuum capacitors to
match a quarter wave 'L' or 'T' on top band. I use cheap multilayer high
voltage disc ceramics and these have been working perfectly at QRO levels
with my inverted 'L' for years.
I use 1600pF made up from 1000pF + 470pF + 220pf
Per the following added comments.
Me too.
Or the inverse as I did, cut my T for the low end of the band. Then
three series capacitors with PCB relays to short each individually
(none, 1, 2, or 3) yielded nearly full band coverage <1.5:1 swr. My T
is 85' to top and a 50:25 ohm TLT is a close
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