Hi Jim,


While most rigs these days are at least "pretty good", I would put out a
shameless plug for a rig like the Kennwood TS-830.

I had the chance to go over one of those old beauties recently, and
found it a sweet radio indeed. It has tube finals, and a very nice
receiver. It has the Kenwood sound to boot. Lots of knobs if you are a
tweaker. These can be found in the 3-400 dollar range.

Other radios I've had the chance to evaluate are the:

IC-761. A high quality radio. It is a big one though. But I like large
radios.

IC-745. Second Generation synthesized Rig. Pretty good one. Smaller
radio for the day. You could go mobile with this one.

IC-756 Pro - A fair radio. The Pro II is better, but probably priced
outside your range.

I might suggest picking up a tuner such as one of the MFJ 300 watt ones.
Then get ladder line, and throw a general purpose dipole in your trees.
That for my money is the best starter antenna going, and can service you
long after you're a newbie. Some do not like to have to tune the
antenna, but I can say that It is possible to contest with such a setup.

Finally, look around and be patient, better deals come to the patient.

From 5.5 years ago......

My first setup was:

IC-745 - $250.00 used

MFJ 949 Tuner - $129.00 new

Ladder line - $30.00 new

Antenna wire - $12.00 for a 500 foot reel of #12 THNN

There is $421 dollars and on the air. I don't remember the costs of the
nylon rope and misc stuff like end insulaters, but it wasn't much extra.

And of course, you won't find copper at that price, but you can expect
to pay 60 or so for 100 feet of ladder line, and whatever outrageoous
price for wire these days.

- 73 de Mike KB3EIA -

"Michael Coslo" wrote

I might suggest picking up a tuner such as one of the MFJ 300 watt ones.
Then get ladder line, and throw a general purpose dipole in your trees.
That for my money is the best starter antenna going, and can service you
long after you're a newbie. Some do not like to have to tune the antenna,
but I can say that It is possible to contest with such a setup.

I think it's even more than a "starter" antenna -- it's great, loads on just
about any frequency, and if decently in the clear will work quite well. When
I move to a place with the room for a hundred footer up in the trees, it
will be the only antenna I'd really ever need for HF. However, I think a
ladder-line fed antenna needs a tuner (i.e., transmatch) that has a pretty
beefy balun. I had the MFJ-948 that gave me lots of trouble using a 55' long
dipole with ladder line. I learned how to make a bigger and better 4:1
toroid balun to replace the dinky one that came with it... then it worked
really well. Right, Cecil? ;-)

Howard N7SO

Howard Lester wrote:
"Michael Coslo" wrote

I might suggest picking up a tuner such as one of the MFJ 300 watt ones.
Then get ladder line, and throw a general purpose dipole in your trees.
That for my money is the best starter antenna going, and can service you
long after you're a newbie. Some do not like to have to tune the antenna,
but I can say that It is possible to contest with such a setup.

I think it's even more than a "starter" antenna -- it's great, loads on just
about any frequency, and if decently in the clear will work quite well. When
I move to a place with the room for a hundred footer up in the trees, it
will be the only antenna I'd really ever need for HF. However, I think a
ladder-line fed antenna needs a tuner (i.e., transmatch) that has a pretty
beefy balun. I had the MFJ-948 that gave me lots of trouble using a 55' long
dipole with ladder line. I learned how to make a bigger and better 4:1
toroid balun to replace the dinky one that came with it... then it worked
really well. Right, Cecil? ;-)

I agree that a random length dipole fed with ladder line makes a great
antenna. I've used one for years with a traditional tuner. My
question: If I put a balun between the ladder line and the tuner, can I
use one of the automatic tuners built into modern rigs? If this works,
it provides the advantages of one simple antenna for multiple bands
without the hassle of having to retune when changing bands/frequencies.

73, Steve KB9X

"Steve Bonine" wrote

I agree that a random length dipole fed with ladder line makes a great
antenna. I've used one for years with a traditional tuner. My question:
If I put a balun between the ladder line and the tuner, can I use one of
the automatic tuners built into modern rigs? If this works, it provides
the advantages of one simple antenna for multiple bands without the hassle
of having to retune when changing bands/frequencies.

Steve, if the auto tuner can handle very high SWR's.. then sure. ;-)
Seriously, I don't think it'd work. I had one of those in-line baluns
designed for the purpose of being able to run RG8 coax through the wall to
the transmatch. The coax length was maybe 8 feet. My antenna was about 50'
long, fed with 450 window line, and I used it on all bands from 10 - 40m.
The balun was from RadioWorks and was rated at maybe, I forget.... 4KW? I
was running 100 watts and that balun got HOT. After a while, it seemed that
the balun broke down from the excessive heat and was no longer useable. (Can
that really happen?) That should give you an idea about the auto tuner idea
for this kind of setup.

It's really not that hard to re-tune a transmatch. Find the right settings
for each band [segment] and write down the numbers. There are typically just
three transmatch knobs to re-set, and it can be done in five seconds. OK,
maybe seven seconds. ;-)

Howard N7SO

I agree that a random length dipole fed with ladder line makes a great
antenna. I've used one for years with a traditional tuner. My
question: If I put a balun between the ladder line and the tuner, can I
use one of the automatic tuners built into modern rigs? If this works,
it provides the advantages of one simple antenna for multiple bands
without the hassle of having to retune when changing bands/frequencies.

Depends a lot on the radio and on your individual installation.

The ATUs built into a lot of modern rigs are of the "line flattener"
persuasion. They're intended to be used with an antenna which isn't
too awfully far from a resonant 50-ohm load. As a rule of thumb, I'd
say that most of them can match a 3:1 load, some of them will cope
with most loads of up to 5:1, and few of them can handle 10:1 loads
at all well.

For what it's worth, the ATU in my Kenwood TS-2000 won't even attempt
to match anything above 10:1. It'll struggle with a lot of loads
between 5:1 and 10:1, depending on whether they're low-Z, high-Z,
and/or substantially reactive. I suspect that this ATU is probably
fairly typical of modern rigs.

External tuners often have a substantially wider matching range than
an internal line-matcher, and probably have significantly lower losses
when handling difficult loads.

An unbalanced tuner plus a robust balun is probably going to work
better than a rig's ATU plus a balun. The balun can be a problem in
either case, with difficult (high-Z) loads - it's not easy to build a
balun which has a high enough choking reactance to really balance out
the line currents well if it has to work into, say, 5000 ohms or so.
Link-coupled tuners seem to be a better technical choice for such
difficult loads, although (as per your comment) they aren't the most
convenient beasts in the world.

If your doublet length and feedline length leave you with reasonably
tolerable in-the-shack feedpoint impedances on the bands that you care
about, then you might want to consider a sort of hybrid approach. Use
a robust balun to connect to the feedline, and feed the unbalanced
side of the balun to a (bandswitched) set of L networks. You'd want
one L-network per band, selected to bring the impedance down to
somewhere in the 3:1 SWR range (or so) in the band center. The output
of the L networks would go to the transceiver.

With this approach, the L networks would perform the "gross" tuning of
the antenna feedpoint Z, and bring it down to the point at which the
transceiver's internal ATU could do the rest of the matching across
the full width of the band.

Since the L networks wouldn't need to provide an exact match for a 1:1
SWR, selecting the component values and tuning the networks would be
simplified.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

"Steve Bonine" wrote in message
...

I agree that a random length dipole fed with ladder line makes a great
antenna. I've used one for years with a traditional tuner. My

I would strongly suggest against a random length doublet. A non-resonant
doublet will have impedances all over the place. At some freuencies it
cannot be matched at all, at others the losses in the tuner make you wish
you hadn't been able to tune it. The trick is keeping those nasty spots out
of the ham bands.

There are a number of G5RV type antennas that are doublets whose length has
been chosen to keep those nasty spots out of the ham bands. Spend a few
minutes looking up the right lengths for your doublet and avoid potentially
a lot of grief.

Random length, of course, is random. you COULD get lucky. Or not ....

...

xpyttl wrote:

Random length, of course, is random. you COULD get lucky. Or not ....

I guess I'm lucky. I've never had a problem matching a random-length
dipole on any frequency I've tried. That does not imply, of course,
that any random length can be successfully used on any arbitrary frequency.

And of course, "random length" should have read "as long as possible,
given the placement of the trees."

Thanks to everyone who chimed in on using an external balum and an
automatic tuner. My gut told me that the consensus ("it won't work")
was correct, but it was nice to get some more factual backup for that.

Steve Bonine posted on Wed, 26 Sep 2007 10:12:27 EDT

xpyttl wrote:
Random length, of course, is random. you COULD get lucky. Or not ....

I guess I'm lucky. I've never had a problem matching a random-length
dipole on any frequency I've tried. That does not imply, of course,
that any random length can be successfully used on any arbitrary frequency.

And of course, "random length" should have read "as long as possible,
given the placement of the trees."

Thanks to everyone who chimed in on using an external balum and an
automatic tuner. My gut told me that the consensus ("it won't work")
was correct, but it was nice to get some more factual backup for that.

Steve, the factual backup on antenna matching has abounded
in texts, mostly the 'pro' kind, for years. It's been used for years
to impedance-match all kinds of things within a radio box...as well
as outside it. As to amateur equipment, the subject gets colored
(and both glamorized and defamed) by the lack of comparisons
to other matching equipment and the affinity that some have for
certain brands from certain manufacturers.

If you wish, I can send you a copy of the L-section matching math
that I've previously sent to Mike Coslo in e-mail. It isn't "formal"
but it is accurate, but it does involve simple algebra. The L-
sections are used in most of the automatic antenna tuners
because it is simple (and therefore low-cost) and adapts to the
measure-and-change L- or C- component algorithms that fit into
small microprocessor programs.

The heart of all of them is the Bruene RF voltage and current
detector that senses the phases of each at the load end. [or
variations on that 1955-beginning detector] The micro then
determines which parts of the L- or C-components are to be
switched in or out to get close to the ideal in-phase E & I of
RF for most power transfer.

Now the designer-manufacturers don't make auto-tuners that
will match ANYTHING...even though it CAN be done. To reduce
manufacturing costs they limit the number of internal inductors
and capacitors and THAT will reduce the ability to auto-match
anything. They are trying to be competitive on price. The newer
transceivers have SOME internal auto-tuning capability but they
clearly state the limits of their equipment. Not all separate auto-
tuners specify that. [I have both just as a backup]

"Baluns" aren't all perfect, either. They are good but just not
perfect. Some are better than others but it would take ALL of
them and some good lab test equipment to do a good
comparison. However, MOST work well enough for amateur
radio purposes and do allow for balanced-to-unbalanced line
conversion at HF.

Now ANY impedance-matching tuner will let one load up just
about anything. All that serves is to transfer the most RF power
into a load. What is NOT known is WHERE all that RF is going.
Unless some ham has a balloon-borne sensor and data transfer
gizmo, NOBODY can know just where the pattern is going to be.
Big trees WILL affect the pattern, especially changing it between
dry and wet climate times and between different kinds of trees.
So will structures and assorted conductive things (aluminum
patio covers, small garden sheds, power, phone, and TV cables)
all within the near-field (within five or so wavelengths). Even
some houses which have had aluminum siding added on
compared to similar houses with just wood or stucco or brick
siding.

One can take an example of the U.S. Army's little AN/PRC-104
backpack transceiver. It covers the whole of HF using a whip
antenna. It has had an auto-tuner built-in since it went
operational in 1986. A human bean is a poor counterpoise for
any antenna with HF wavelengths and soldiers aren't all "built
to spec" for that purpose. Further, the transceiver and whip must
operate from unknown field environments, in trees or well away
from them, in swampy soil or dry desert. The transceiver can't
get any higher than the soldier carrying it. But, the little built-
in antenna tuner assures him that the whip antenna is going to
get as much RF power into/out-of it as possible. The rest of it
is trying to keep the whip as vertical as possible while in-use.

Now a PRC-104 won't win any DX awards or enable contacts
with Antarctica or Yurp, but it is a case-in-point where an auto-
tuner certainly helps maximize signals in a 1:10 frequency
range with a practical-minimal fixed antenna, allowing for a
highly-variaable counterpoise/ground-plane environment. The
vertical whip will probably maximize its pattern between 10
and 40 degrees above horizontal, give-or-take. It works in
practice (for the equivalent of QRP amateur-style). Works
well enough, that is. The auto-tuner built-in certainly helps
it.

Everyone's residential location varies greatly and only a very
few are "perfect" (as to the antenna analyzer programs). One
can load up practically anything with a tuner but only the shape
and arrangement of conductive elements is going to determine
where most of the RF goes to (or comes from). No tuner can
help that.

73, Len AF6AY

"AF6AY" wrote

Lots of good stuff snipped....

Now ANY impedance-matching tuner will let one load up just
about anything. All that serves is to transfer the most RF power
into a load. What is NOT known is WHERE all that RF is going.
Unless some ham has a balloon-borne sensor and data transfer
gizmo, NOBODY can know just where the pattern is going to be.
Big trees WILL affect the pattern, especially changing it between
dry and wet climate times and between different kinds of trees.
So will structures and assorted conductive things (aluminum
patio covers, small garden sheds, power, phone, and TV cables)
all within the near-field (within five or so wavelengths). Even
some houses which have had aluminum siding added on
compared to similar houses with just wood or stucco or brick
siding.


Everyone's residential location varies greatly and only a very
few are "perfect" (as to the antenna analyzer programs). One
can load up practically anything with a tuner but only the shape
and arrangement of conductive elements is going to determine
where most of the RF goes to (or comes from). No tuner can
help that.

I had to leave the important stuff... sorry to make everyone scroll down....
Len, I'm confused as to just what you're specifically referring to. Do you
mean a doublet fed with balanced line (300 or 450 ohm window line) to a
transmatch in the shack is something you don't recommend? Or are you
referring to this system fed with coax to an autotuner? It'd seem to me
that, as long as the system (fed with window line to keep the serious losses
down to negligible) is in the clear, the transmission line is 90 degrees to
the doublet for the "required" distance... all should be fine and the
radiation pattern should emanate properly from the antenna itself, not so
much the transmission line. ?

Howard N7SO

On Sep 25, 11:03?pm, "xpyttl" wrote:

I would strongly suggest against a random length doublet.
A non-resonant
doublet will have impedances all over the place.

That's true, but it's not a reason to reject the 'random length'
doublet.

Spend a few
minutes looking up the right lengths for your doublet
and avoid potentially
a lot of grief.

It's not just the doublet length that matters but also the length,
impedance and loss of the transmission line. Antennas like the
G5RV choose a combination of dipole and transmission line
length that present reasonable impedances on several bands.

A very useful tool is modeling software such as EZNEC or G4FGQ's
DIPOLE3. They will give useful predictions of shack-end impedance, so
you can judge if it's in matching range or not. So even if the antenna
is 'random' length, you can have a good idea if it will match and how
efficient it will be before you put it up.

With regard to transmatches, also called antenna tuners, for balanced
loads, the two typical amateur approaches are the unbalanced-tuner-
followed-by-a-balun method, and the link-coupled method. The
unbalanced-tuner-with-balun method assumes the balun does its job over
a wide range of impedances, which isn't always a good assumption,
while the link-coupled method can be complex to bandswitch.

A third method, described by AG6K, consists of a balun followed by an
L network - the balun is on the rig side of the transmatch rather than
the antenna side. Thus the balun only has to deal with 50 ohms
nonreactive once the L network is adjusted. Google AG6K to see a
description of his method. Although his tuner uses ganged roller
coils, fixed coils with taps could be used in a homebrew version for
simplicity and lower cost.

Random length, of course, is random. you COULD get lucky.
Or not ....

Modeling software can be a big help in removing the randomness.

73 es GL de Jim, N2EY