I measured my 160m top hat antenna 4600uh plus. Took 600pf on series and 250pf
parallel to tune it.Jim K9TFSent from my T-Mobile 4G LTE Device
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Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
I measured my 160m top hat antenna 4600uh plus. Took 600pf on series and 250pf
parallel to tune it.Jim K9TFSent from my T-Mobile 4G LTE Device
_
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
On 1/1/2021 12:09 PM, Mike Waters wrote:
I am ONE of the people who claim that four elevated radials can have
approximately the same efficiency as 120 buried quarter wavelength radials.
N6LF's work on this showed that imbalance of the current in elevated
radials can significantly reduce field
Check out those links on my old ground radials page, especially the ones by
N6LF. See what you think. :-)
73, Mike
W0BTU
On Fri, Jan 1, 2021, 2:51 PM CUTTER DAVID wrote:
> Groundbreaking work for the BC industry.
>
> Is the short distance coverage required of BC stations always relevant to
>
This link at to top of that page is a must-read, too.
https://web.archive.org/web/20180923221943/http://lists.contesting.com/_topband/2007-11/msg00248.html.
Guess I might as well include the text...
I am ONE of the people who claim that four elevated radials can have
approximately the same
True indeed Charlie
It was such an observation by accident that clued me into the fact that
I needed a choke on a system with elevated radials the first time :)
Dave
NR1DX
On 1/1/2021 2:10 PM, n0...@juno.com wrote:
To offer another view.IMHO
Measure the impedance at the base of the
On Thu, Dec 31, 2020, 9:10 PM Artek Manuals
wrote:
> Elevated radial systems NEED a choke ..PERIOD. Been there , done that,
> got the RF burns to prove it...8^(
>
You bet they do! Otherwise, the coax feedline on the ground seriously
degrades the antenna's performance! I don't recall anyone
The logic is good, but most instruments are probably not sufficiently
sensitive to see the difference.
73, Jim K9YC
On 1/1/2021 11:10 AM, n0...@juno.com wrote:
To offer another view.IMHO
Measure the impedance at the base of the antenna without the feedline
attached in any way. While
To offer another view.IMHO
Measure the impedance at the base of the antenna without the feedline
attached in any way. While watching your instrument (259B, VNA, etc),
touch the feedline *shield* to the radials at the base of the antenna.
If your instrument shows
no change in the impedance,
Wes
That is an option you have and no one is making anything do anything. It
is 100% up to you.
Happy New Year
On Fri, Jan 1, 2021 at 1:21 AM Wes wrote:
> Hi Mike,
>
> I've read all of that stuff and more many times. Frankly, I'm not
> motivated to put a 10 pound lump of ferrite on every
Jim/ K9YC
I am with you 100% on your comments below
my 80/ 160 verticals all run "10 lbs of ferrite" at the feed points but
that is because I run elevated non resonant radials these days. 5lbs of
ferrites just got to warm to touch, but that is fodder for a whole
different thread.� My
On 12/31/2020 7:09 PM, Artek Manuals wrote:
Not hard to measure see
https://forums.qrz.com/index.php?threads/measuring-common-mode-current.623054/page-2.
you can make a simple common mode choke and do a before and after to see
the relative change..if any
I haven't read the link, but common
Hi Wes,
The chokes in my latest Cookbook weigh a LOT less than that. I won't
debate your engineering judgement about whether one is needed on your
antenna. You're as good an engineer as anyone on this reflector!
73, Jim
On 12/31/2020 10:21 PM, Wes wrote:
Frankly, I'm not motivated to put a
On 12/31/2020 5:01 PM, Michael Walker wrote:
Hi Ken
Chokes at both ends of the feed line are always a good idea.
At the base of the antenna, yes, so that the feedline doesn't become a
radial. More are probably wasted money. See my latest Cookbook at
k9yc.com/publish.htm
I have a similar
Hi Mike,
I've read all of that stuff and more many times. Frankly, I'm not motivated to
put a 10 pound lump of ferrite on every wire into or out of my shack. It
appears that common-mode chokes and articles about them, have become a cottage
industry. I will leave my opinion of the topic at
Hi Wes
The chokes do a few things. For transmitting, they keep the RF off the
feedline. It is critical for RX and TX.
Just as importantly, they keep RF and Noise off the feedline while
receiving, and this is what you want. The quieter you are, the more you
can hear.
Common Mode Currents
Kenny
My personal experience with radials on the ground is that with a fair
number (16 or more) that I end up with little if any common mode
currents on the coax . Smaller (numbers of)� ground mounted radial
counts could benefit somewhat from a choke, depends on other factors�
besides the
I have the same situation and no choke. IMHO the transmission line is just
another random length radial. I don't have chokes on any of the others either.
Wes N7WS
On 12/31/2020 5:15 PM, Kenneth Silverman wrote:
Hello, I have an inverted-L and the radials are laying on the ground AND
the
Thanks Mike. I wasn’t sure if one was needed where the coax exits the radial
field
Regards , Kenny K2KW
> On Dec 31, 2020, at 8:01 PM, Michael Walker wrote:
>
> Hi Ken
>
> Chokes at both ends of the feed line are always a good idea.
>
> I have a similar setup to you but with elevated
Hi Ken
Chokes at both ends of the feed line are always a good idea.
I have a similar setup to you but with elevated radials and I have Mix 31
chokes right at the base of the antenna with an UNUN since I am using 75 ohm
coax and then more chokes at the antenna switch.
You can’t use enough
Hello, I have an inverted-L and the radials are laying on the ground AND
the coax is on the ground too with radials right near the coax run. Do I
need a choke to stop any feedline coupling/radiation, and if so, where in
the feedline?
The antenna is in the woods so burying either the radials or
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