I'm quite active in CAP and MARS and so I need to be able to operate on a
fairly long list of frequencies between about 2.2 MHz and about 27 MHz
(actually up to 24 MHz would probably be OK, not much goes on above there).

I'm looking for the best compromise antenna that will get me most of those
frequencies with reasonable receive performance without a tuner, and SWRs
under about 3:1 that my FT-1000's internal tuner can handle.

The plan is to program the frequencies of interest into my rig's memories
and then scan across them, hence the need for reasonable receive
performance with the tuner out of the circuit.

I'm aware of the B&W "radiating dummy load" (TTFD) antennas but I'm not
quite ready to give up that much efficiency and I'm DEFINITELY not ready
to blow $300 on one.

I don't mind putting up a multi-legged dipole array but I don't want to go
overboard, and from my calculations (such as they are), I'd need a total
of SIX (6!!!) dipoles all fed with a common feedline and operating on
their fundamentals and third or fifth harmonics in order to stand any
chance at all of covering it all.

I was thinking of maybe something like some variation of the G5RV, or the
W5GI "Mystery Antenna" (http://www.w5gi.com), cut to an appropriate center
frequency above or below the 20 meter band as needed, then maybe (MAYbe) I
could get away with three of them.

Any thoughts?

Rick (W-A-one-R-K-T) wrote:
I'm quite active in CAP and MARS and so I need to be able to operate on a
fairly long list of frequencies between about 2.2 MHz and about 27 MHz
(actually up to 24 MHz would probably be OK, not much goes on above there).

I'm looking for the best compromise antenna that will get me most of those
frequencies with reasonable receive performance without a tuner, and SWRs
under about 3:1 that my FT-1000's internal tuner can handle.

The plan is to program the frequencies of interest into my rig's memories
and then scan across them, hence the need for reasonable receive
performance with the tuner out of the circuit.

I'm aware of the B&W "radiating dummy load" (TTFD) antennas but I'm not
quite ready to give up that much efficiency and I'm DEFINITELY not ready
to blow $300 on one.

I don't mind putting up a multi-legged dipole array but I don't want to go
overboard, and from my calculations (such as they are), I'd need a total
of SIX (6!!!) dipoles all fed with a common feedline and operating on
their fundamentals and third or fifth harmonics in order to stand any
chance at all of covering it all.

I was thinking of maybe something like some variation of the G5RV, or the
W5GI "Mystery Antenna" (http://www.w5gi.com), cut to an appropriate center
frequency above or below the 20 meter band as needed, then maybe (MAYbe) I
could get away with three of them.

Any thoughts?


Rick;

Don't sell the B&W antenna short. It is more than sufficient for most
CAP/MARS/Amateur communications. When configured as a NVIS antenna you
can reach almost everyone in your region. I have worked a distance
sufficient to cover the upper portion of the US east of the Mississippi.
Yes the efficiency of the B&W is not on a par with a tuned dipole
antenna but it offers the flexibility to cover all the CAP/MARS/Amateur
frequencies with out having to resort to an antenna tuner. Even then the
relative efficiency of the B&W when compared to an out of resonate
dipole is more than enough to compensate. This is why CAP/MARS/DOD use
the B&W for ALE communications.
If you insist in not using the B&W then a fan array of dipoles cut for
your frequencies of choice can be used. There is some interaction
between bands using this type of antenna which complicates the tuning of
the various dipoles. Be ready for a lot of ups and downs during tuning.
There is no best antenna for anything. The standard to which the
relative efficiency virtually all antenna are compared to is the dipole.
What ever you do it isn't wrong,just different.

Dave Nagel
RF 143
WD9BDZ

BTW: I believe the current cost for a B&W 160-6 non stainless steel
antenna is about $225US from most sources.

David G. Nagel wrote:
Rick (W-A-one-R-K-T) wrote:

I'm quite active in CAP and MARS and so I need to be able to operate on a
fairly long list of frequencies between about 2.2 MHz and about 27 MHz
(actually up to 24 MHz would probably be OK, not much goes on above
there).

I'm looking for the best compromise antenna that will get me most of
those
frequencies with reasonable receive performance without a tuner, and SWRs
under about 3:1 that my FT-1000's internal tuner can handle.

The plan is to program the frequencies of interest into my rig's memories
and then scan across them, hence the need for reasonable receive
performance with the tuner out of the circuit.

I'm aware of the B&W "radiating dummy load" (TTFD) antennas but I'm not
quite ready to give up that much efficiency and I'm DEFINITELY not ready
to blow $300 on one.

I don't mind putting up a multi-legged dipole array but I don't want
to go
overboard, and from my calculations (such as they are), I'd need a total
of SIX (6!!!) dipoles all fed with a common feedline and operating on
their fundamentals and third or fifth harmonics in order to stand any
chance at all of covering it all.

I was thinking of maybe something like some variation of the G5RV, or the
W5GI "Mystery Antenna" (http://www.w5gi.com), cut to an appropriate
center
frequency above or below the 20 meter band as needed, then maybe
(MAYbe) I
could get away with three of them.

Any thoughts?


Rick;

Don't sell the B&W antenna short. It is more than sufficient for most
CAP/MARS/Amateur communications. When configured as a NVIS antenna you
can reach almost everyone in your region. I have worked a distance
sufficient to cover the upper portion of the US east of the Mississippi.
Yes the efficiency of the B&W is not on a par with a tuned dipole
antenna but it offers the flexibility to cover all the CAP/MARS/Amateur
frequencies with out having to resort to an antenna tuner. Even then the
relative efficiency of the B&W when compared to an out of resonate
dipole is more than enough to compensate. This is why CAP/MARS/DOD use
the B&W for ALE communications.

Can't beat instanteous good enough match.. and the loss is on the order
of 6dB (see Cebik's webpage on T2FDs). pretty darn simple and screwup
proof.

If you insist in not using the B&W then a fan array of dipoles cut for
your frequencies of choice can be used. There is some interaction

some interaction? You're going to go insane trying to tune this,
particularly in a field installation if there's any wind blowing to
change the relative positions of the wires and any surrounding stuff. 3
wires works ok to cover 10,15,20,40 and can be tuned reasonably well in
10-15 minutes if you have some sort of antenna analyzer that lets you
sweep it to find the resonances.


between bands using this type of antenna which complicates the tuning of
the various dipoles. Be ready for a lot of ups and downs during tuning.

That's for sure.



There is no best antenna for anything. The standard to which the
relative efficiency virtually all antenna are compared to is the dipole.
What ever you do it isn't wrong,just different.


BTW: I believe the current cost for a B&W 160-6 non stainless steel
antenna is about $225US from most sources.

And, it would be quite straightforward to build one yourself, if you
have time and materials available. Look up B&W's patent at
http://www.uspto.gov/ for complete construction details. (I think the
patent number is on the B&W website) The patent is expired, by the way,
so you're not infringing to build one. Probably the only hard thing to
come by might be the big resistor, but that can be improvised in many,
many ways. (blocks of charcoal, pipes with salt water, etc.)

Rick (W-A-one-R-K-T) wrote:



I'm aware of the B&W "radiating dummy load" (TTFD) antennas but I'm not
quite ready to give up that much efficiency and I'm DEFINITELY not ready
to blow $300 on one.

I used one for a few years with great success on all bands 80 thru 10.
Don't let the old 'dummy load' stories throw you. You can build one
easily -- there are lots of plans -- just google it as T2FD.

Irv VE6BP

On Aug 6, 11:52 am, "Rick (W-A-one-R-K-T)"
wrote:


I'm aware of the B&W "radiating dummy load" (TTFD) antennas but I'm not
quite ready to give up that much efficiency and I'm DEFINITELY not ready
to blow $300 on one.

If I were to spend $300 , I'd rather put it into a decent tuner,
rather than antenna.
Then you could run a single ladder line fed dipole, if a one
wire solution was better.. Also use it with any other antennas
you might mess with.
I'd never pay $300 for one of those antennas, but heck, I wouldn't
pay $300 for any antenna... It's against my religion.
Actually I was too cheap to even pay $300 for a tuner. I got a coil
form
damaged 989c free, and repaired it. :/
I don't use it much, but it's handy to have around.. Can feed about
anything, including ladder line.. It uses a balun, but I haven't
really
had any real trouble with it as far as noticable balance problems.
Some other tuners might be a bit better though if balance is critical.


I don't mind putting up a multi-legged dipole array but I don't want to go
overboard, and from my calculations (such as they are), I'd need a total
of SIX (6!!!) dipoles all fed with a common feedline and operating on
their fundamentals and third or fifth harmonics in order to stand any
chance at all of covering it all.

Knowing me, thats probably what I would run. Tuning wouldn't be that
big a deal if all the legs are spread out as far apart as possible.
But if you closely stack them, tuning can be a hassle..
But the attraction of this system is that is not really much of a
compromise as far as efficiency is concerned. And instant
QSY too. I'd only bother with the bands I'd know I'd use.
When I was in AF mars back in a previous life, we only used
two freq's for the most part.. Sure they had others listed, but
rarely
used. BTW, yes you can make use of a few other resonant points
that will pop up.. Many will be able to be matched with the radio
tuner. IE: 7mhz can do 21mhz, etc.. Your radio tuner will be pretty
much acting as a line flattener, so the tuning could be off a bit and
still
work ok.
MK

Rick (W-A-one-R-K-T) wrote:

I'm aware of the B&W "radiating dummy load" (TTFD) antennas but I'm not
quite ready to give up that much efficiency and I'm DEFINITELY not ready
to blow $300 on one.

I think you need to rethink this. A T2FD antenna is a radiating dummy load
on frequencies that it is not really cut for. A squashed rombic is more
accurate. On frequencies near resonance it is mostly antenna, as the
resonance drops it becomes an oddly shaped feedline with a dummy load
on the end.

The T2FD was developed by the U.S. Navy and is a popular millitary and
government antenna. The B&W one is designed for that market, you can make
one very easily from copper wire, strips of insulating material and some
resistors. The requirement for the resistor is that it be around 600 ohms
and non resonant, so depending upon exactly what you transmit with,
and how you transmit, the power requirment may be less than you think.

The resisitor must be able to withstand the peak power and the average
power. Carbon resistors tend to withstand much higher peaks for very
short times than they are rated. Average power is often far less than
peak, for example while AM and RTTY will heat the resistors far more
than other modes, CW and SSB will not. One figure I read was 12%.

One book, I have is Practical Wire Antennas, by John Heys, which discusses
it in simple, easy to make terms. The book seems to out of print,
replaced by Practical Wire Antennas 2 ISBN 1-905086-04-0.

I think it came from his book, but I remember a high power resistor
made from a combination of low power resistors in a series parallel
form.

I'm sure you could build one for far less than $300, most of the
money going to the resistor and if you decided to buy one, a
9:1 balun.

Geoff.


--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 U.S. Voice: 1-215-821-1838
Visit my 'blog at http://geoffstechno.livejournal.com/

On Tue, 07 Aug 2007 05:10:10 +0000, Irv Finkleman wrote:

I used one for a few years with great success on all bands 80 thru 10.
Don't let the old 'dummy load' stories throw you.

All I can say is, I was on a CAP HF net a while ago with another station
about 10 miles away from here, and we were both working another station
about 125 miles north. I was running 5 watts to a cut dipole at 17 feet,
and the 10-mile-away station was running 100 watts to a B&W at 25 feet.
The faraway station reported that my signal was stronger than his by a
comfortable margin.

This morning I was on the same net with the same 10-mile-away station,
working another station about 90 miles away. He reported the faraway
station as weak but readable, and I was receiving it loud and clear, about
10 over S9.

I realize there are MANY other variables that could account for this and
the only real proof will be if I set a T2FD up here and compare them side
by side... still, the difference in signal reports is impressive and more
than I expected.

wrote:
On Aug 6, 11:52 am, "Rick (W-A-one-R-K-T)"
wrote:


I'm aware of the B&W "radiating dummy load" (TTFD) antennas but I'm not
quite ready to give up that much efficiency and I'm DEFINITELY not ready
to blow $300 on one.


If I were to spend $300 , I'd rather put it into a decent tuner,
rather than antenna.

It would be tough to find a tuner that can handle hundreds of watts,
tune in milliseconds, and cost less than $300..

The original poster was talking about *automatic* link establishment,
which implies hands-off operation. The T2FD antennas do that quite
nicely. You're not looking to dig out faint DX from a pileup here, but
establish a link on a designated channel. If the 6-10 dB hit is too
much, you look for a channel where propagation is better.

Geoffrey S. Mendelson wrote:
Rick (W-A-one-R-K-T) wrote:


I'm aware of the B&W "radiating dummy load" (TTFD) antennas but I'm not
quite ready to give up that much efficiency and I'm DEFINITELY not ready
to blow $300 on one.


I think you need to rethink this. A T2FD antenna is a radiating dummy load
on frequencies that it is not really cut for.

But so what... in ham terms, an antenna that radiates 25% of its
feedline power would be considered egregiously inefficient, but hey,
that's only a 6dB hit. Easy to make it up with an amplifier on Tx, and
on Rx, you're usually external noise limited anyway, so, from a system
standpoint, the T2FD isn't a bad approach.

On Tue, 07 Aug 2007 09:49:45 -0400, "Rick (W-A-one-R-K-T)"
wrote:

He reported the faraway
station as weak but readable, and I was receiving it loud and clear, about
10 over S9.

Hi Rick,

The difference is called propagation, and you have the advantage of
being in line-of-sight. Even a Christmas tree bulb can communicate
that far at those antenna heights.

73's
Richard Clark, KB7QHC