PA3CLQ's Leuke Linken Nr. 438
T1 tuner. Random wire lengths?
Just received my T1.
Used a 35 foot 26 gauge stranded wire and tuned from 40 to 10 meters, no problem!
Any suggestions on other lengths I can use and counter poise lengths?
I didn't use a contest poise.
Just
the KX2 and a male bnc to binding posts.
Perhaps someone has something in excel with wire / counter poise lengths to
bands?
73 de Joe kn2a
REM :
Joe
Counterpoise wire length in feet should be slightly longer than 234/F in MHz, for a single band antenna.
CW is Real Radio 73, John...K8JD
REM :
Can
you be more specific on "slightly"? Is there a range in inches or
feet?
George Sims
REM :
"Slightly" should have been 5%
CW is Real Radio 73, John...K8JD
REM :
If you use insulated wire, the velocity factor of the insulation will make them slightly longer, electrically.
It
is really cut & try and those length are ball park numbers.
Joe V31JP
REM :
Joe,
is it velocity factory or capacitive loading, making the wire electrically longer?
Also, generally counterpoises are approx 5% shorter than the 234/fmhz formula,
but I guess if you start out "slightly" longer you will get to the
same place...
73 all Dean , K2WW
REM :
With
insulated wire, it is the velocity factor that makes the wire electrically
longer.
Laying on the ground , there is the capacity loading.
If the counter poise was in free space (in the air), we would be dealing with the LC of just the wire.
Laying
on the ground, you will have added capacitance.
I don't mean to confuse anyone.
In
free space, we can deal with exact formulas.
But we are not in free space.
So,
you build it by the formulas and loose your hair like me trying to figure out
what caused the measured variances in actual use.
With these current analyzers to measure the results with, it is a little
easier.
If we would have had them 50 years ago when I was designing antennas, I might
have had some hair remaining today.
I thank God for guys like John Kraus, W8JK, and his book.
Hmm!
I see it on the shelf right now.
Joe V32JP
REM :
Joe,
Here is a page I made awhile back.
The red bands are difficult ranges (high voltage at wire end) that typical tuners can't handle.
But
they're also the best areas, closer to resonant, for more capable impedance
matchers.
http://udel.edu/~mm/ham/randomWire/
73, Mike ab3ap
REM :
Mike,
Thank you for making this page.
I consulted your graphs a few years ago when I was trying to figure out how to do antennas for 30 m and 80 m in the space I had to work with.
I used your info to settle on 70 feet of end-fed wire (70 feet from screw terminal on tuner to the end of the wire).
It tunes up very nicely on both 30 m and 80 m, just like your graph says it will.
About the first 6 feet are in the house, so I probably do have a little RF floating around the room, but since I only run QRP I don't worry about it.
Steve AI9IN
REM :
All I did was write code that solves the little 468/f equation, though for band combinations rather than single freqs.
So
I can't take credit for doing much!
73, Mike ab3ap
REM :
Ti? Sorry, I must have missed what a T1 is, but guess ir is a antenna tuner.
Here
is a neat article about using a counter poise with a mobile.
http://www.qsl.net/wr9a/counterpoise.htm
Here is a little table that is in it with recommend lengths:
|
BAND |
LENGTH |
WIRE SEGMENTS |
|
|
6 m |
43" |
Orange + Yellow |
|
|
10 m |
77" |
Green |
|
|
12 m |
87" |
Orange + Green |
|
|
15 m |
103" |
Orange + Blue |
|
|
17 m |
120" |
Purple |
|
|
20 m |
153" |
Purple + Yellow |
|
|
30 m |
213" |
Purple + Blue |
|
|
40 m Phone |
296" |
White |
|
|
40 m CW |
306" |
White + Orange |
|
|
75 m Gen Phone |
552" |
All except Green |
|
|
75 m A/E Phone |
586" |
All except Yellow + Orange |
|
|
80 m Data |
596" |
All except Yellow |
|
|
80 m CW |
619" |
All except Orange |
Perhaps
someone has something in excel with wire / counter poise lengths to bands?
73 de Joe
REM :
Hi there Joe.
The T1 is a small Automatic Antenna Tuner made by Elecraft.
I recently purchased the Kx2 (elecraft newest QRP radio) .
The radio has the option of a internal ATU however I chose not to have that option because I am a big fan of the Alexloop antenna ( magnetic loop antenna ).
I bought the T1 so that I can use it with other QRP radios and small transmitters I like to build.
Thank you for the information and I thank everyone for all the help.
73 de Joe KN2A
REM :
MFJ sells a counterpoise "tuner".
Don't know how well it works.
I
was thinking of giving it a try but don't really want to have an additional
tuner to mess with.
I use a couple of counterpoise wires with my endfed wire, for 40 and 80 meters.
They are just cut to formula length and strung out on the flat roof adjacent to my shack location.
Their main purpose is to help keep the RF out of the computer, keyboard & mouse.
That
can be a problem with non-resonant antennas...
73, Drew AF2Z
REM :
Since some QRP operators seem to be willing to pack along extra wire for a counterpoise and extra equipment in the form of a tuner, then how about simply using a balanced feed and a balanced antenna?
Get a better signal on transmit, a quieter signal on receive, zero r.f. around the little station and...into the bargain...retain your hair!
John at radio station VE7AOV
REM :
John:
That likely calls for a center-fed dipole of some sort.
When you are out in the field doing QRP it is unlikely you are going to find two properly spaced trees to hang your antenna from.
Sometimes its tough enough to get one end of an antenna up a tree, why double the hassle?
Dick.
k2rfp
REM :
I don't do QRP or portable operating but I like my endfed wire because I can use it on any band, 160 thru 10.
It's
not the best antenna of course but I'm more interested in being able to work
whatever band is open right now, rather than waiting for propagation to favor
the few bands on which I might have a "proper" antenna.
I also have a resonant antenna in the attic, a five band
'cobweb', for 10 thru 20.
It does do better on those bands than the endfed wire, but if I had to choose only one it would be the endfed wire.
I would just prefer to have mediocre performance on 10 bands vs better performance on only 5 bands.
I figure propagation is everything; antenna and output power are distant seconds.
The
more bands, the more propagation opportunities.
The RF out doesn't care if the antenna is resonant or not,
assuming I can tune it efficiently and the rig is happy.
I've
been thinking about installing a dedicated receiving antenna to perhaps
minimize noise, but haven't tried anything along those lines yet...
BTW, regarding the endfed wire charts that Mike AB3AP posted
earlier: my EFW length happens to fall into one of the "windows" on
his chart so it tunes easily on most bands.
I have a homebrew T-match that will tune it on all bands with good efficiency (output capacitance at max).
The
auto tuners in the Elecraft rigs (K2 and K3) have no problem with it either,
except for 160: the K3 ATU algorithm doesn't like it so the tuning elements
have to be set manually.
73, Drew AF2Z
REM :
The reasons are several, Dick.
For those who are interested:
the two wires can be about any length as long as they are the same length.
So...whatever wire there is can be fed in the middle rather than at one end and so needing a "ground" connection of some kind, something not easy to find out in the woods.
The
two wires are their own antenna, no muss, no fuss, no ground.
Elevating an antenna into trees is not really necessary.
If only one end can be put up, as suggested, then simply use the antenna as a sloper.
Depending on the nature of the ground, a wire laid out along the ground can do a pretty good job for the purpose discussed, too.
If there are no trees around, probably the ground is dry.
Please...try
it.
Light test fishing line on a spinning reel not only makes a great
"end insulator" but it is a fine halyard, too.
A rock tossed through a tree anywhere along the line of the antenna, even quite far away, can be used to put the light test halyard up into the tree.
Whatever distance remains from the end of antenna leg to the tree is taken up by the fishing line.
That's done here at both ends with a permanent installation.
The four pound test fishing line is nearly invisible at a bit of a distance; if you have fellow campers, they won't be grumping!
Today's monofilament line stands up to sunlight for years. "Sureline" No. P14-4 is in use here.
Deterioration of the line in the sunlight has not occurred.
Cost is not an issue, either. 1,125 yards cost all of C$3.99.
A spinning reel is $5.00 at a flea market.
John Nigtingale
REM :
Not only that, but lots of national park campgrounds won't let you nail or hang anything from a tree.
I've been busted at two of my favorite campsites.
I
now carry a Jackite, but that isn't possible for QRP hams who hike in
somewhere.
I met a ham at Joshua Tree NP who had set up in the group camping area to run
NPOTA contacts.
He strung a wire antenna to a nearby Joshua tree.
He just threw the wire over the arm.
He didn't nail it, tie it, or bungee it.
The rangers made him take it down--and they were hams!
Turns out many rangers are now very familiar with ham radio because of NPOTA and as a result they got interested in ham radio themselves.
That means they have antenna radar too.
Most
hams can spot an antenna anywhere.
Eric KE6US
REM :
Joe
Very clever radial design.
It looks to me like small crimp bullet connectors at:
would be lighter, less bulky, and cheaper than the PowerPole connectors. Color coding - if desired - could be done with colored vinyl tape, but simple masking tape tabs with A, B, C coding would suffice.
Gary, K9ZMD
REM : see:
http://www.qrp-shop.biz/T1fert
https://sites.google.com/site/impulsenoise/making/elecraft-t1-atu-kit
Editor
73, your Editor Jan Pieter Oelp PA3CLQ
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