Before I reinvent the wheel, I thought I'd ask if this exists as a
commercial product or homebrew project. I've googled quite a bit
without success.
What I need is a screwdriver antenna controller that listens to CI-V and
commands a DC motor to a predetermined stored in memory rotation
I'm not sure why the bidirectional coaxial cable Beveridge doesn't get
more discussion. It is described in ON4UN's book, and seemed to work
fine when I built one at a prior QTH, although it does take two
feedlines from what would logically be the closest end to the shack.
Given the price of
It is often mentioned that very high RF voltages are present at ends
of dipoles, voltage nodes on loops, etc. but I haven't been able to find
any guidance in the form of numbers. How high is very high? Assuming
QRO power into a full size apex up delta loop, corner fed, vertically
polarized,
Thanks for the insight. I will try the EZNEC suggestion.
stub was a bad choice of words, I've got two approaches in
contemplation/analysis mode, both wire loading schemes:
1. Four relay switched vertical wires at the center bottom voltage
node. The antenna has about a 25 KHz 2:1 bandwidth
haven't thought through how to use (number??) Tornado coils in a delta
loop. Two would exceed the cost of the SteppIR 40m vertical.
Grant KZ1W
On 11/22/2012 11:45 AM, Richard (Rick) Karlquist wrote:
On 11/22/2012 9:13 AM, Grant Saviers wrote:
with the antenna. An MFJ screwdriver controller
A neat and cheap insulator for along a Beverage is the C shaped screw in
insulator for electric horse fences. The ends of the C overlap so a
half twist allows the wire to be inserted and then held with 90 degree
rotation. It is then free to slide in the insulator. Most any horse/ag
supply
Thanks for the comments and pointers. The land around the antenna is
mixed grass and forested islands so on the ground radials would be
partially buried and partially on the surface. Digging through the
trees and clearing the brush is not something I want to do. Also, based
on prior
I second this motion. Nearly every day brings some new insights.
Thanks,
Grant KZ1W
On 12/17/2012 11:30 AM, Lew Sayre wrote:
Yo,
Tom, et. al. please do keep taking this seriously! Most of us on this
reflector do not have
engineering degrees involving the physics of RF. However we do
A little different version of this question - is there any general
guidance about what to do with pickup on other antennas when
transmitting? Shunt the pickup to a dummy load? short? open?
something else?
I'm adding a vertically polarized pair of phased 80m delta loops (ON4UN
design) on
Can I incorporate reinforced concrete and a steel building into a radial
field?
About 20% of my 60 buried radials from a grounded tower will encounter
concrete pads/driveway before they get to the target length of about
90'. One reference I found quotes moist concrete as having a
The reversible single coax Beverage is described in ON4UN 's Low Band
DXing at least editions 4 5. I've built a couple elevated ones from
ebay RG58 and they work fine. I think RG6/RG59 would work as well with
small changes to the transformer ratios.
Grant KZ1W
On 1/11/2013 9:17 PM, Jim
My top loaded T top band vertical is up. 85' vertical, 43' each side
T and 3 elevated 123' radials at 10 to 12'. Resonance Z is currently
36 ohms and 90KHz 2:1 swr BW.EZNEC+ shows a resonance Z of 25 ohms
with 4 elevated radials, so I presume the delta is ground loss. The
antenna is
My first and maybe my last 160m SSB effort. It did motivate me to get a
160 antenna up. I would agree that participation is thin. Worked most
states but no !!! W1's (only weakly heard 2) VE's a few Caribbean,
. Propagation and the central/east coast US QRM and their QRN levels
require a
Tom,
Great stuff! Could you elaborate on a couple of points -
1. I would think that a system with elevated radials that slope upward
towards the far ends (e.g for 160m 10' at feedpoint and 30' at far ends)
should have less loss as the field is less near earth where the voltage
is high in the
Bought some, but what I received is so hard it is near impossible to
bend. The 9ga solid Al fencing wire seems like a better alternative,
although I've been using the 13ga for elevated radials. They claim a
30ksi yield strength so compared to soft steel at 38ksi it should stand
up. Relative
The book is a pdf so the OS shouldn't matter. The SW on the CD is one
DOS program, so the OS needs to run or emulate DOS.
Grant KZ1W
On 3/10/2013 2:20 PM, k2...@juno.com wrote:
Hello All,
I would like to buy the latest edition
on ON4UN's Low Band DXing with the CD ROM.
On the ARRL book
I have built several chokes on FT240-31 cores with RG142 double silver
shield TFE coax (ok for QRO anywhere at HF) and measured them with my
VNWA 2.6. For my 160m top loaded vertical I stacked three cores and
used 12 turns for 4k ohms resistive. My results generally agree with
G3TXQ's and
Posted on towertalk yesterday was the link to the free download of the
1952 text Radio Antenna Engineering
http://www.lulu.com/us/en/shop/edmund-laport/radio-antenna-engineering/ebook/product-17560294.html
Some fascinating stuff since much of the focus is high power
broadcasting LF/HF and
Here is a little data in a sea of complexity:
My 160m T is 10' up at the base with 6 x 125' radials elevated ten feet
(4 more planned), in a mixed hemlock/red cedar/alder forest/clear area.
The top is at 87' and the T arms are 42' each side at the same height.
The vertical wire (13ga
a briefly KDKA employee on the studio side
pre WWII and the two brothers roomed with Dave Garroway who started his
broadcasting career at KDKA.
Grant Saviers KZ1W
On 9/10/2013 12:32 PM, Herb Schoenbohm wrote:
There is an old story about KDKA's antenna system that was told to be
a long time ago
site KDKA/Westinghouse experimented with MW
400kw transmissions.
Grant Saviers KZ1W
On 9/10/2013 12:32 PM, Herb Schoenbohm wrote:
There is an old story about KDKA's antenna system that was told to be
a long time ago. During WWII KDKA along with a frew other stations was
allowed to operate
Try a large transformer shop. 5kw and up transformers often use it.
I've bought round magnet wire from temcoindustrialpower.com, but don't
see rectangular wire on the web site, so give them a call for a link.
Grant KZ1W
On 9/15/2013 9:04 PM, n0...@juno.com wrote:
I've just used strips of
There are plenty of Allen Bradley 1w real carbon composition resistors
on ebay at prices ranging from $0.25 ea to absurdium. Buy some that you
can series/parellel to get the value you want. If it doesn't say A-B on
the packaging, squash one in your vice. I've found wire-wounds inside
some
I had a 40m and 80m top loaded vertical on galvanized steel roofs. The
80m was outstanding for DX and the 40m so-so since the roof was not well
bonded electrically. IMO, unless you can insure electrical connectivity
along the panel seams there will be no advantage to the foil. You would
Or you could replace the open wire line with a bi-directional coax cable
Beverage. see ON4UN. I've built a couple from RG58 and they worked
ok. RG6 would be stronger, but might have a bit more loss with the
copperweld center conductor, but that usually isn't a concern.
The RG58 fit thru
How about a compass and declination map? A bit simpler good enough
+/- 2 degrees.
http://www.ngdc.noaa.gov/geomag/WMM/image.shtml
The standard for course plots on nautical charts is the letter T for
true or M for magnetic after the degrees number and then an arrow to
indicate for which
At my (former) CA ranch QTH, in the hills only 4 miles east of downtown
San Jose, our cats weigh 130#. Sorry I can't send the game camera pix
of the gorgeous mt. lion taken a couple of weeks ago near my spring.
He/she looks happy on the diet of cats, dogs, coyotes, lambs and rarely
a jogger.
And one more question -
ON4UN in V5 states that the Spitfire will lose a few db of gain due to
ground losses. How does one calculate near field ground losses? What
software is needed?
A related question is a general one for antennas with near ground
horizontal elements - e.g. Bruce delta
An interesting point from Tom re SSB modulation added problems.
A really informative website re plain old RTTY is
http://www.frontiernet.net/~aflowers/k3rtty/k3rtty.html
and is a good introduction to the technical complexity of digital
modulation systems and what to do to make better RTTY
Hoping for some help to be able to use some older Philly. The factory
tells me their grips won't work on parallel strand construction which
is what I have, epoxy potted sockets are required. However, they only
pot at the factory (liability etc etc) which means tossing 6 x 300' of
5/8 45klb
Thanks to all who provided info and suggestions.
I plan to run some tests, starting with a modification to my 20T H
frame press so I can tension test specimens up to 10k lbs or so and
measure force with a simple Dillon mechanical 5k# force gauge I have. A
lever arm will give me 2x and maybe
I'd like to understand how NEC 4 achieves this calibration for MW BC
ground systems.
Do others share this concern? What errors are introduced for other
analysis as a result?
Grant KZ1W
On 1/24/2014 1:58 PM, Guy Olinger K2AV wrote:
I have already stipulated many times that NEC
4 is
My VNWA V2.6 factory assembled Vector Network Analyzer, designed by
DG8SAQ is available for $400 incl shipping, USA only, as I upgraded to
the newer version V3.
1KHz to 1300MHz, 2 port, USB powered, no cables or standards included.
see www.sdr-kits.net for full specs
Radcom review at
I have made sweeps of my 160m T on many occasions as I tuned it, added
elevated radials, and then installed a remote series capacitor switch to
tune the entire band per a W8JI suggestion. There was no interference
from AMBC, I'd be glad to forward the sweeps. My current QTH does not
have a
Steady S7 here in Redmond, WA at 3:30 PDT on a T loaded vertical.
My receive 4 sq puts it strongly to my NW of 47.68N x 122.01W QTH
No loop to resolve it further.
Grant KZ1W
On 3/25/2014 12:48 PM, Lee K7TJR wrote:
OK, we now have a challenge for any hams interested in finding a stray
- N9LB [mailto:lloydb...@charter.net]
Sent: Monday, January 13, 2014 5:15 PM
To: Grant Saviers;topband@contesting.com
Subject: RE: Topband: Ends for older Phillystran
Hi Grant!
I worked at WDAE Radio in Tampa, FL back in the 80's and 90's. The engineer
before me decided to try the new technology
I use 9 gauge Al electric fencing wire for elevated radials among my
trees. It is pretty tough stuff, as 3 branches have fallen on it
without anything but a little stretch. it doesn't stretch much with
time either. Now 7.5 cents per foot on Amazon
--
From: Grant Saviers gran...@pacbell.net
Date: Wed, May 28, 2014 at 9:56 PM
Subject: cable clamps on old Phillystran
To: topband@contesting.com
Cc: t...@kkn.net
Per prior topband posts and discussions about this topic, I've
concluded a
round of testing of cable clamps on parallel strand (old
I recently concluded testing of wire rope clamps (clips) on old
parallel Phillystran (PS). The old PS does not work with the current PS
guy grip type of termination. These tests showed that clamps as a
termination system has risks that are not acceptable to me.
Since the factory no longer
re elevated radials:
For a thorough analysis of radials check out antennasbyn6lf.com for
Rudy's work. Assuming farming happens, perhaps you can get them high
enough to make the owner happy. Mine are at 10', but higher is better.
I use #12 or #14 aluminum electric fence wire elevated 10.
At TX5D, Raivavae, Australs FP, I could real time A/B a vertical at the
high tide line on 15m vs one 100' feet back and got 1 to 2 S units
better for the beach one on the USA path about 7000km.
Grant KZ1W
On 8/11/2014 1:16 AM, Guy Olinger K2AV wrote:
The riveting experience I draw on is one
In addition to my prior long term creep tests for loads to 11,000#, I've
concluded a tension test to failure of the Crosby Spelter socket
terminations for the older parallel strand Phillystran in 5/8 OD size
and using West Marine 105 epoxy as the potting compound. I was unable
to source the
Over the past 25 years, at 3 QTH's, I've used thousands of feet of the
synthetictextilesinc.com 1/4 and 5/16 and have been very happy with
it. Tough, strong, and lasts a very long time (MA winters, CA sun). I
do use 29/30mm ball bearing pulleys (blocks) from Harken HAR340,
RonstanRF20100
The smaller diameter (20 to 30mm) ball bearing sailboat blocks are $15
to $25 as I previously posted. Here is a slick block from REI for
rigging ropes up to 15mm.
http://www.rei.com/product/807414/camp-usa-large-mobile-pulley-ball-bearings
5600# break strength so WLL at 25% is 1400#.
the
Have you checked the design with EZNEC? A little more top hat and you
won't need a coil. I had an 80m top loaded 3 dia vertical 40' tall
which resonated at 3.8MHz. A tweak of that model to 70' showed the 8 x
8 ft spokes at the top would resonate at 1.8MHZ, 33 ohms. A perimeter
wire seems
I've had real Synthetic Textiles lines up 10 years and more. Some in CA
sun, without significant degradation. OTOH, some dacron bought on
ebay is likely a dacron-polypro blend and lasted only a few years.
Grant KZ1W
On 9/17/2014 2:37 PM, Tom W8JI wrote:
In about 7 years that Dacron stuff
The way to squeeze the most watt-hours out of panels and into batteries
is with MPPT regulators. Maximum power point regulators that adjust
rapidly to the real time insolation. A series regulator is throwing
away W-H.
See http://en.wikipedia.org/wiki/Maximum_power_point_tracking
some
Jim,
Would the type 75 material from Fair-Rite, be a better choice for 160
80 with 5 turns thru the 0.75 id clamp on?
http://www.fair-rite.com/newfair/LowFreqSuppression.html
your thoughts?
Grant KZ1W
On 9/29/2014 11:56 AM, Jim Brown wrote:
On Mon,9/29/2014 10:43 AM, wb6r...@mac.com
I have the DX Eng 4 sq rcv and am amazed at how directive it is, 70' on
a side, works well for 160 80, my Moxon beam is usually better on
40m. I bought 6' long (5/8, 1/2, 3/8 od) telescopic tubing from DXE
instead of SS whips, cheaper and slightly more gain. I made holders for
the tubing
Cool, never seen one. A nice tool but probably $25k+.
Another way I've used to install a 6000' long water line is to use a
single blade ripper to pull 200' lengths of 1 PVC using a Kellems grip
(Chinese finger grabber) as shown in the video. We dug a small hole at
the end of each pull for
The old portable marine RDF radios with a ferrite rod antenna would work
well. Besides tuning the marine LF beacons many also covered BC and
low MF bands. I tossed mine long ago, maybe there are some lurking in
attics or garages, they provided a very sharp null for DFing.
There are many on
I'm considering insulating elements on large yagis and would like to
understand pro's and con's of various boom to element plate insulating
materials - RF insulation, physical strength, creep, uv resistance,
etc. These raw material properties are easily found, but have some had
longer term in
A nice tutorial about the what and why of line connected capacitors at
http://www.justradios.com/safetytips.html
Grant KZ1W
On 2/4/2015 10:32 AM, Jim Brown wrote:
On Wed,2/4/2015 9:52 AM, Roger Graves wrote:
I would like to try bypassing the AC line.
There is a particular class of bypass
Adding on, 200Ksps to 1 Msps 8bit (and more) A/D convertors are good
enough and cheap if one can store the data stream for a few seconds or
so and the stations are time sync'd to record. Then correlate the
wavefront to accurately resolve the time. A bonus is the transmitter
signature is
I would suspect that a DC HV line operator will pay A LOT of attention
to any arcing from what I've seen of HV DC arcs. Once the ionization
gets established and metal ions vaporized from the terminals get flowing
it avalanches until the protection circuits act. Small AC arcs are much
At TX5D (FO-A), I was able to instant A/B a 15m vertical (two elevated
radials) at high tide line vs a crankIR tuned on 15m about 70' from high
tide. US stations (5k to 7k km) reported 1 to 2 S unit improvements
with the antenna nearer to the lagoon salt water. Received signals were
at least
I put my DX Eng 4 sq right at a corner of my lot. A 4' ground rod only
worked ok, but in a pretty wet area most of the year, so I added three
15 foot bare #14 Cu radials for drier times. Two along the 90 deg
baselines as keeping radials away from the feedline to the central
switch seemed a
With 1/3 of the worlds hams in Japan (1.2M) as one mult and many EU
countries with less 10k hams each as a mult the whole way most contests
are scored makes no sense. Of course there is no perfectly fair system
of scoring, but Stew Perry has some ideas that may work as a new HF
contest. It
Since non plenum rated cables no longer meet codes, there is an
opportunity to buy the NOS of it cheap on ebay. I've scored a couple of
ebay 1000' spools of tinned double braid rg59 Belden, 20 ga center for
around 10 cents a foot. I think it's the precision video cable Jim
mentions.
Here
in a suitcase and cover 80-10m.
My rule of thumb is get within 1/4wl of the salt water for best
results. Then v-o-b's rule.
Grant KZ1W
2/13/2015 1:11 PM, Jim Brown wrote:
On Fri,2/13/2015 12:29 PM, Grant Saviers wrote:
At TX5D (FO-A), I was able to instant A/B a 15m vertical (two
elevated radials
My 4 sq DXE exhibits similar no directivity at times. I think it is
high angle signals. I did add three 20 foot radials to each antenna, I
don't think it matters what the vertical element is, a little better
grounding is good. My soil is wet/swampy forest/grass mix and I don't
think they
Rock ledges probably mean directional drilling would be prohibitively
expensive. Even in soft soil it costs A LOT more than trenching. Same
for a Ditch Witch over ledge even with carbide teeth, but you might get
a lot of it underground.I put in 6000' of 1 water line (mostly PVC)
to a
Pretty hard to find a box with the volume you need and already cut for
outlets. What I do for large size line filters is use a plastic
junction box from Home Depot (Carlon or Thomas Betts). They come
4x4x2, 4x4x4, 6x6x4 and larger. Then a pigtail out to a standard outlet
box of any type
Since this thread continues, I thought I would share some EZNEC Pro/4
modeling results I have submitted for publication to QEX, with a focus
on verticals on the beach for DXpeditions. EZNEC Pro4 can segment
ground along a line into two arbitrary ground properties, in my modeling
4 S/m, 80 for
Per ARRL the K3LC NCJ work is unobtanium. (WHY?) A Google search
yielded nothing. If a member has pdf's of the articles or a link,
forwarding them to me would be much appreciated.
Grant KZ1W
On 4/2/2015 15:55 PM, Carl Luetzelschwab wrote:
Just an FYI with respect to verticals by the
The commercial grade protectors are quite a bit more sophisticated than
the few small MOV's network in the small residential units. A look
inside a Joslyn is instructive about what it probably *really* takes to
protect against serious surges. They have means to maintain protection
since MOVs
Have you surveyed the site for HF RFI? One mountain top property I was
considering had awesome 360d unlimited visibility but had so much power
supply hash, PIM, intermod, etc. from comm installations that any
amateur operation would be near impossible. My spectrum analyzer showed
huge
I found NOS Soviet block screw mount micas on ebay that looked like they
would handle QRO and have three pairs in series to cover the band with
shorting relays - all shorted = 1820 then each step (2 short, 1 short,
all open) adds 50KHz. 85' to top, 2x 30' hat and 8 10' elevated 125'
radials.
Recently I put up a big new tower and a ground system for it and learned
a few things.
The actual ground conductivity is a bit of a mystery and highly variable
over short distances, so I bought a clamp on ground resistance measuring
meter on ebay, a Chinese knockoff for $300. It was quite
I rented the smallest walk behind trencher from the local Home Depot, it
cuts about a 2" wide trench and will go down at least 12". By not
getting close to tree trunks to avoid any large roots and to minimize
any tree damage, I cut a 300' run through a forest for 1 1/4" conduit.
The cable
Yet another alternative is the coax cable bidirectional Beverage
described by ON4UN (see fig 7-118 in the 5th edition). I've built a
couple of them with ok results. Various small (cheap) coax can be used,
mine were ebay surplus Belden RG59. RG6 is also a good choice. With a
copperweld
Not having any particular axe to grind, I'll pile on a bit with some
comments.
1. The superhet/SDR vs direct sampling radio manufacturer and
technology competition is and will continue to be very good for the ham
community.
2. The early days of CD audio yielded, "I can't stand the sound"
see N6LF's work on 160m top hats
http://rudys.typepad.com/files/qex-short-verticals-for-160m.pdf
My guess is that informed the DXE design.
Grant KZ1W
On 1/1/2016 12:07 PM, Richard (Rick) Karlquist wrote:
On 1/1/2016 8:16 AM, K4OWR wrote:
Does anyone recall that I originally asked about
Rudy N6LF has covered the top loading issues pretty thoroughly, see
http://rudys.typepad.com/files/qex-short-verticals-for-160m.pdf
Bottom line IMO: install as many top loading wires as you can as
horizontal as possible and then consider a loading coil.
I had eight 6' spokes of 3/8 Al tubing
I did some modeling of radials with elevated radials after 3 "on the
beach" DXpeditions. QST said they will publish it this year, sometime.
Rudy N6LF has done a lot of modeling of elevated radials see
antennasbyn6lf.com and his QEX articles.
From my modeling: There is quite a bit of
I was a participant in this years CQ-160-SSB. Maybe some data helps the
discussion.
I was a bit surprised to hear others using frequencies below 1820 as a
run freq. My recollection from very limited prior participation is that
it was a bit unusual. For all the reasons cited, the band is
I cut my top loaded "T" (85' at top, 10' high feed, elevated 8x 125'
radials) for 1825. Then 3 equal value series capacitors are shorted by
PCB relays (10a, 5Kv coil insulation) to switch in C, C/2, and C/3
(C=4000pf for this antenna). That yields 4 by 40KHz spaced segments
with > 50KHz 2:1
My 2c, having owned MFJ269, AIM4170, VNWA2.3 & 3, AA54, SARK110, old
noise bridges, and used a friends FG-01 on a DXpedition.
The MFJ is old, not all that accurate and really useless in the presence
of other strong RF, eg BCB. Sold it. I'd call it obsolete vs current
competition.
AIM4170
Great presentation! It inspires a question about detuning a vertical:
The goal is to reduce noise and any pattern distortion in my receive 4
sq (DXEng) which is about 200' from my transmit vertical.
My 160m transmit antenna is a 75' vertical T with 8x 125' radials 8-10'
above ground. I've
I've had two verticals on galvanized metal roofs. An 80m top loaded 40'
3" irrigation pipe on a two pitch steep barn roof about 30 x 60' and a
full size 1/4wl 40m on a essentially flat roof shed 26 x 26'. The 80m
worked super even though the roof was in bad shape. I did add a number
of sheet
I have one from Heros Technology in UK, bought 12 years ago, they are
still in business and have some interesting products. I checked the
filter yesterday with my VNWA and it is exactly as advertised.
Array Solutions also has a W3NQN design with better specs at the high
end of the BCB.
Good recommendations. I did a couple of things differently for my 160 T
hung to 3 trees,
I use Lewmar or Ronstan or Harken small swivel blocks, cheaper, more
durable in tough environments and the swivel helps keep lines from
tangling or twist from messing things up. Don't use 3 strand rope.
I have a Bliss MatchMaster remote tuner I can part with and about 150'
of control cable with mil-spec connectors. At the time this was the
best remote tuner in the market, custom made for each customer. see
http://www.eham.net/reviews/detail/1582
Grant KZ1W
On 7/14/2016 7:24 AM, Gary Marks
I've been using PB Blaster penetrating oil with good success. Since you
know there are Penetrox particles (it is zinc dust plus castor oil per
the MSDS) between the tubes, I'd try to wick some PB in there, let it
sit for a while and then work it back and forth to loosen up the dried
up
Check out the Ohmite non-inductive 100w series
http://www.ohmite.com/cat/acl_ap101.pdf
Digikey stocks some values.
Grant KZ1W
On 1/25/2017 15:31 PM, jcjacob...@q.com wrote:
How do,
Where can you obtain, at a reasonable price, a high wattage, non-inductive,
resistor for a terminated
One thing that W8JI clarified for me in winding binocular cores is what
is a "turn". Normally, a wire thru a toroid hole is a "turn". A
binocular core is two toroids in a single piece of ferrite. Tom
proposed calling a wire in one side of a binocular core a "pass" and
thru both sides a
Agree. I use three fixed serial caps with shorting relays to tune my
160m T, 8 elevated 125' radials, across the full band in 45KHz
segments. The antenna is cut for 1820 and fed with a 50::25 TLT.
The voltages across each cap (3 all the same value) is well below 400v
at QRO so I used
My experience with a 600' regular Bev 6' over a 5 wire barb wire fence
was not good. Modeling also showed it had little directivity. A
solution in the modeling was to insulate all wires every 150',
segmenting it into 4 x 150' fences. Wires beyond the Bev ends could be
continuous any length.
From a coil loaded 80m 2L yagi (bought JKantennas) and 80m rotatable
dipole I built and reading here are some thoughts.
My rotatable 80m Tornado loaded 86' dipole at 100' doesn't have much of
a pattern, height is everything and at about 130' or so they really
start to play. The beam is at
As you were disconnecting the radials the ground losses were increasing
until it got to enough ohms and you had a good match at 50ohms.
My 160 T matches 25 ohms 1.12:1 at 1812Khz and is fed with a 50:25
transmission line transformer. With 8x 125' elevated radials the N6LF
research shows I
The larger the diameter of the antenna, the broader the bandwidth. So an
aluminum self supporting vertical that starts with 3" diameter tubing
(the HD DXE starts with 4") can have twice the intrinsic bandwidth of
16ga wire. It also gets a bit shorter for same resonance frequency. I
had a
With 75' of vertical you have 56% of a 1/4wl which is about the net
vertical dimension of my T with elevated radials. My 2 top wires are
about 36' long, ultimately they were cut to get a 25 ohm resonance
around 1810KHz. The antenna has about 70 KHz of 2:1 swr bandwidth. I
use a commercial
I was asked by a DXpedition leader if it was practical to bandpass
filter the input (antenna side) of the DX Engineering 4 sq's they plan
to use (I have one). Given the few acres of the island and 5 feet ASL
there isn't space to get adequate antenna separation and of course both
transmit
My WSTJ waterfall shows about 50Hz bandwidth for ft8 signals. In "band
plan" theory the ft8 segment is 1840 to 1842.5. However, many rigs
won't pass audio much below 300Hz and may not above 2.5KHz. I run "wide
open" DSP on my Pro3 so see to 3Khz. Above 2.6Khz there are few ft8
signals to
Hi Jim,
Well, yes on the 5 acres, but still suburban. But, I do notice that FT8
on the vertical 160 T often decodes as well as my DXE 4 sq receive which
has directivity and thus less noise. Same comment from another op here
locally. I don't see any advantage to subsegment filtering, and in
10/25/2017 20:15 PM, JC wrote:
there is no human intervention on FT8 after the
first click.
Not in my experience with FT8. Crowded bands, DX with poor ears,
callers on the DX frequency all make it a challenge for other than the
casual CQ response. The GUI is hard to use when the list
On a couple of DXpeditions we damaged the front end of a couple of
analyzers by transmitting on a nearby antenna on a different band so
this is another hazard to be aware of.
Grant KZ1W
On 6/11/2018 10:14 AM, terry burge wrote:
Jim,
There is room that the 0.01-0.02uF cap could go in. Due to
For simulating a solid conducting plate in NEC with wires, Roy Lewallen
(EZNEC author) advises 0.1 wavelength on a side squares of wires. That
would be 16m for topband. Since adding the mesh is a search for tenths
more db's, be conservative and use half his recommendation, 8m or 25'.
If a
It is well known by DXpeditioners and an EZNEC analysis demonstrates
that verticals within 1 wavelength of the sea have greatly enhanced gain
at low elevation angles in the seaward direction. There is no need for
the antenna to be over water for that benefit. In the opposite
direction the
JC,
Have you read the papers I cited? Looked at numerous reports from
DXpeditions and several antenna experts re the performance of verticals
NEAR salt water?
google "vertical antenna near salt water" for a longer list of
references re a well proven fact.
Grant KZ1W
On 6/5/2018 4:34
1 - 100 of 201 matches
Mail list logo
