---> QUAD BAND END FED HALF
WAVE WIRE ANTENNA. -- VE3AB
Earl Andrews - NEW REVISED
ARTICLE: (OCT 2- 2014).
I previously had two wires attached
to the matchbox in effort to try and
get multiband version. Basically
..that attempt late Sept-- FAILED --
the old article..with my ideas is still
available at this link if you wish to
refer to it for information.
|Hamelectronicsmagazine.com / earlandrews.com
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FREE ON-LINE MAGAZINE and mail order parts as well !
|Oct 2 -2014 - rainy day up here in Northeastern Ontario. A good day to do some
antenna work! -- Antennas always work better when installed or modified in
miserable weather - or so..the saying goes.
My previous attempt to install the Quad band LNR matchbox with dual
radiating elements was a failure. THE ORIGINAL ARTICLE (NOW TITLED LNR
FAILURE IS STILL AVAILABLE AS A REFERENCE PAGE (link here old article).
There is too much interaction between the two elements. So..I lowered the
matchbox portion and feed with my rope and pulley system and cut off the 17
meter (18 mhz) element and then I trimmed the remaining element and tied it
off to my fence post.
NOW..it exhibits very good SWR readings on 20 meters and not bad on 10
meters. SEE ALL THE PHOTOS OF THE SWR ANALYSER READINGS BELOW.
|The TV tower and mast. TV tower is self supporting up to about 27 ft and then there is about 10 feet of 1.5 inch mast above the tower. A
couple of rope and pulley arrangements are used. 1 is for the QUAD band LNR precision antenna. The other rope and pulley I will use later
on. - I have an LNR Precision 20 meter 200 watt matchbox I could put up as a second antenna but..I already have 20 meters covered with the
QUAD matchbox antenna. I only had about 40 foot or so for a straight run of wire off the tower sloping to Europe (more or less) so I modified
the LNR 40-20-10 (25 watt antenna) using the coil and the dimensions to build a 40-20-10 with the old loading/isolation coil but using the new
LNR QUAD matchbox. What I have now is a short antenna that works well.
Lately (December) I have been working stations on 40 meters close to me ie Sudbury ON. (about 100 miles east of me) and Ottawa and
getting very good reports on 40 m ssb on the Transprovincial net 7.055. Good strong reports of S-7 from Ottawa and 10 over 9 from Sudbury.
This new (modified) end fed antenna has been working well. I was using my Ten Tec Argonaut 515 on ssb with about 5 to 6 watts output for
those reports. I want to do some more contesting with qrp with this new antenna.
|ABOVE: UGLY DUCKLING end fed half wave matchbox. It seemed
to work fine and SWR curves around 28 mhz were quite good. The
full 2 page article is available at this link here. A single band
matchbox is not all that hard to build. The multiband matchbox is a
mystery though. I did not break the seal to peep under the hood
of the new QUAD BAND MATCHBOX. I do plan (however) to saw
into the old 40-20-10 matchbox and take a look at the arrangment.
I want to try and build one for fun.
Actually, there is experimentation (see you tube videos) and
some images on the web where one fellow cut open the
|Above: at the far end of the wooden fence at the east end of my yard. You can see a vertical antenna stored on hooks on the fence. My yard is a
pretty nice yard for a city lot. It is about 60 ft wide and about 125 ft deep. One of the bigger and flatter yards in Elliot Lake.
|This coil is about 80 uh or so. I could (and maybe will) make a coil for my LNR Quad
band antenna but this commercial version is rugged and light weight and I prefer it
for that reason.
The coil is sufficiently high inductance and impedance that it seems to divorce
itself from 20 and 10 meters (for the most part) so that the 32 foot main radiator still
works well on 20 and 10 but with inductor allows 40 meter resonance-- and it
seems to work (as an antenna) quite well through my eperiences with the LNR
(PAR) 40-20-10 ef 25 WATT version.
December 2014 update: I am very well pleased with it on 40 meters. Getting good
reports. Id say it might be about as good as a full size dipole or fairly close to that.
I have no other comparison antenna however and this is just a practical guess.
|SWR readings of the "new" 40-20-10 (and maybe some other bands) antenna!
|LOOKS LIKE THE LOADING COIL is working good now
on 40 meters! -- I have checked in on Thursday
night 7.117 to the Great Lakes Slow CW net on 40
meters at 9 pm. Got decent reports of 579 or
something along those lines. I was using about 20
watts with my IC-718. I lowered power from 100 watts
because the check ins are mainly qrp operators.
I could use my tuner and try 60 meters as well. Looks
like it might work there too with a bit of persuasion.
|Some persuasion and I might have an antenna that will get me on the other amateur bands like 10 mhz. The 40 meter SWR curve is
better..more broadbanded than I would have thought.
THE REASON I MODIFIED THE ORIGINAL LNR PRECISION QUAD BAND ANTENNA - I did not use the full 66 foot or so radiator with the
tuning stubs is because of the layout of my backyard and the space I had to work with. I only have one tall support (my tower and mast)
and the antenna would have to be a SLOPER OFF THE TOWER. The LNR quad band tuning stubs would not work all that well because
of the stubs not being able to hang down perpendicular to the antenna element.
So I modified the LNR quad bander with parts from the LNR 40-20-10. On 10 meters.. the SWR curves are not all that good. I will just
use a tuner for 10 meters.
|THE SWR CURVES are better than I
had anticipated. 20 meters looks
like a real winner.
SWR is flat with a dummy load as
well! - The real test of the pudding
is in the eating! - I will be on the air
with this antenna during the month
of October and November.
I may make some tweaks
depending on performance OR.. I
may leave it alone if it peforms
well. Even if I have to use a tuner
to tune the thing.. it might be a
good all round general purpose
|The antenna requires only one tall support and slopes off the tower. It is broadside to Europe in one direction and the other direction
..I guess it is broadside to Russia or maybe Alaska. I have another antenna I can put up the tower with a pulley and rope..but for now.. I
have only the one wire antenna up.
You can also see my 33 foot vertical in the right of the picture. Because it is vertical and off to the side.. it should not interfere with
the LNR quad end fed wire. -- I have a QST article handy in my shack right now.. that shows how to use a small amount of inducatance
at the base of a vertical..to get two bands from the vertical..either 40 and 17 meters OR.. 12 meters and 30 meters. -- Perhaps..I will go
with the 12 and 30 meter vertical. I will have to modify the current vertical a bit by shortening it to around 23 ft or so. That way ..I will
have quite a few bands covered with my wire and vertical antenna system.
MY main rig is an IC-718 I bought used. I also have older Ten Tec Argonauts and FT301s I play around with. I also have a plan (right
now in the back of my head) to add a top loading coil onto the 23 foot vertical which will give me a short vertical on 80 and the loading
coil should not upset the 17 and 30 meter operation of the vertical. --- STAY TUNED and I will be doing some more antenna work in the
spring and will write it up in this magazine.
JUST A BIT OF ADVERTISING NOW -- MY NEW WEB SITE IS www.nettyelectronics.com (NETTY ELECTRONICS) is the company name. I just
started this tiny mail order parts company. It is run out my home in Elliot Lake. You can visit this new site by clicking this LINK HERE.
I sell toroid cores and other radio parts and it helps pay for the hobby. It is a "hobby business"of sorts. Just got the Ontario Business
licence here 2 December 2014.
This magazine "hamelectronicsmagazine.com" will continue on but as a separate entity from the business side of the house.
73 and thanks for reading. Earl VE3AB
|NEW -- I have uploaded 4 movies that are antenna related
including these End Fed Wire antennas and the Small
Transmitting Loop I am currently experimenting with in
Here is a link to the LNR Quad band antenna clip -- see my
other short clips on You Tube as well including the one
"loopvswire" which illustrates the low noise reception
using a small loop. I"m in a noisy radio environment here.
|This is the coil from my previous antenna - The LNR Precision
40-20-10 antenna. The 40-20-10 can only take about 25 watts of applied
power. The weak link is the capacitor inside the matchbox. I would
think that the 150 pf cap in the matchbox would crack if 100 watts
were applied to the matchbox on a regular basis.
The loading coil (however) looks like it could take 100 watts no
problem. So.. I transplanted this coil into the new LNR QUAD antenna
and created the best features of both antennas.
|THIS IS A SHOT OF THE LNR PRECISION (MODIFIED) QUAD BANDER. IT now is a 40-20-10 (41 ft) loaded wire. Works great on 40. I can run
100watts into this antenna but (lately) I have been using it on the low end of 40 with my ARgonaut 515 barefoot at only 5 or 6 watts
|This is the antenna I now am using. The LNR QUAD bander with the shorter dimensions (modified) and with the LNR loading coil
about 33 ft from the matchbox. The coil is not visible in this picture. The antenna is sloping in the direction of Europe. The antenna
works fairly well on 20 meters to the west as well. I will be doing more testing this winter.
|Below a picture from below the antenna going up towards the feed
point. The coil and the tag end of the antenna are visible. The
matchbox can be made out next to the antenna mast.
Its on a pulley system and can be lowered in a minute or so.
There is a second pulley up the tower and I planned to get
another LNR precision antenna up and sloping in the opposite
direction but that will have to wait till spring now.
|Below: the 20 meter curves are very good. This antenna is quite broadbanded on 20 with good low SWR. Up on 18 mhz the
SWR is up around 3 to 1. It could be pressed into service for 18 mhz with a tuner..but I might keep the power down to around
50 watts out so as not to burn out the coil or perhaps even a component in the QUAD matchbox.
|Below: the far end of the antenna. You can see quite clearly (if you look hard enough) the
40 meter coil towards the end of the antenna. Also visible ..the blue weed whacker line I
use to tie off the far end of my wire antennas.
|NAVIGATION LINK BACK TO HOME
click here for home page
|NOTE: I have been in correspondence with Dale
Parfait .. the developer of the PAR end Fed (in
conjunction with LNR Precision) and I have made a
suggestion that they offer the type of modified
version of this antenna (for single support small city
lot or portable use). 73 earl ve3ab
|THIS ARTICLE and these End Fed
antennas are currently being worked on
August 13th 2015. I took the coil out of the
antenna and am going to try multiple
radiators (again) and some other tricks.
Stay tuned for more updates as I
experiment with antennas this summer.