Hustler mobile antenna
Neil Gibson
Although it was designed as a mobile I want to use it as a portable, can
anybody tell me the length of the counterpoise needed for this model? or can
I just use an earth wire>
JGBOYLES
anybody tell me the length of the counterpoise needed for this model?
A 1/4 wave counterpoise would be about 65 feet or 20 meters. Mobile antennas
use the vehicle body as a counterpoise. Your 65' wire or a vehicle used as a
counterpoise will not produce very good results, because the efficiency of the
short radiator is only a couple of percent.
As an option, a really good performing portable 80m antenna that I have used
many times is an inverted vee supported by one of those 33' fiberglass poles.
It is fed with 450 ohm line and a tuner. The vee is 50' (15 meters) per leg.
You will need about 80'-90' to spread the vee. That's a lot of space, but you
will need 65' for the counterpoise for the Hustler. It will beat the
Hustler-counterpoise idea significantly, and you can QSY all over the band.
With a Hustler you have a narrow bandwidth.
Good luck and DX.
73 Gary N4AST
Mark Keith
> I have a Hustler amateur mobile antenna model RM-80 for 80 Meter 25-30 KHz.
> Although it was designed as a mobile I want to use it as a portable,
You may think you do, but you really don't..:( Well, maybe if you like
radio torture sessions where 100w out works like 5w...:( Only if you
were at the beach on salt water, or had 60 or more radials under it
for a normal ground mount, would I give it an estimate of doing a half
decent job.
can
> anybody tell me the length of the counterpoise needed for this model? or can
> I just use an earth wire>
As noted, a 1/4 wave is appx 60 ft, but one radial is nearly useless
at reducing ground losses on a ground mount vertical. And being the
vertical is short, and fairly inefficient, the need of a *good* radial
or ground system is extra critical.
On a car, you just take the ground losses and deal with them, as there
is no real choice. But the hustler antenna in itself, is not the best
in the west. The coil is fairly lossy. But on the other hand, with one
radial, ground losses would likely overshadow coil losses, and it
wouldn't matter. :/ What is "portable" going to be? When I run
portable, I just string up a quicky dipole, or use my mobile antenna
thats on the truck. But my mobile antenna is a good bit better than
the hustler...Less coil loss. It's a fairly usable system even on 80m.
But I string a dipole in some trees if I want a *real* signal. I also
have two of those "drive on" mast holders that you park a wheel on. So
I can actually put up masts quite easily portable if no trees are
around.
I use those cheap 10 ft fence rail sections as mast. Two gives 20 ft,
and can be put up easily by one person. Three is too top heavy unless
you use extra guying precautions..I've tried lifting three together
once, 30 ft" and it was kind hairy...So I just stick with 20 ft
worth. It's good enough for the average NVIS stuff I usually work on
80m. MK
Mark Keith
> Although it was designed as a mobile I want to use it as a portable,
You may think you do, but you really don't..:( Well, maybe if you like
radio torture sessions where 100w out works like 5w...:( Only if you
were at the beach on salt water, or had 60 or more radials under it
for a normal ground mount, would I give it an estimate of doing a half
decent job.
can
> anybody tell me the length of the counterpoise needed for this model? or can
> I just use an earth wire>
As noted, a 1/4 wave is appx 60 ft, but one radial is nearly useless
'Doc
Neil,
By now, you have probably figured out that the 'Hustler'
antenna as a portable isn't exactly the best idea without
a very good ground system. But, it will work with a
counterpoise. Not well, but it will work. Something in
the near 'neighborhood' of a 1/4 wave for the counterpoise's
length should make the transmitter 'see' a load it can work
into (depending on how that counterpoise is 'laid out').
There are other options for a portable antenna that may
work better than an extremely shortened mobile antenna...
'Doc
Crazy George
counterpoise? Coax center to a quarter wave piece of wire, shield to a
(ugh! I had one once) Hustler not too near the ground. Nothing different
probably, but you never know.
--
Crazy George
Remove N O and S P A M imbedded in return address
"'Doc" <w5...@cwis.net> wrote in message news:409B81EE...@cwis.net...
Jim
And, one other idea !! (found on the bay of "e"), and available elsewhere-
a mount for 2 of these (or the hustler, and an Iron Horse, ect) "1/4" wave
antenna -- first antenna goes to center of coax, second goes to shield!!
makes a dipole, about 15 foot long, and can be mounted to mast (conductive,
or plastic, same diff! tho the impedence will be quite low (because of
these loaded
whips), and the effeciency will be also not the best, at least would be an
effective counterpoise!! and, to boot, parts available to build adaptor at
rip-off shack!! got whole thing off epay for about 50 bux, + shipping!!
Jim NN7K
"Crazy George" <muNn...@attSglPobaAl.nMet> wrote in message
news:409c3...@news1.prserv.net...
Jim
need only one ant, and the adaptor.
"Jim" <NN...@Reno.Rmci.Net> wrote in message
news:109onmd...@corp.supernews.com...
'Doc
George,
It does that every half cycle...
'Doc
Ron
Use another RM-80 as the counterpoise.
Ron
Cecil Moore
> And, one other idea !! (found on the bay of "e"), and available elsewhere-
> a mount for 2 of these (or the hustler, and an Iron Horse, ect) "1/4" wave
> antenna -- first antenna goes to center of coax, second goes to shield!!
> makes a dipole, about 15 foot long, and can be mounted to mast (conductive,
> or plastic, same diff! tho the impedence will be quite low (because of
> these loaded
> whips), and the effeciency will be also not the best, at least would be an
> effective counterpoise!! and, to boot, parts available to build adaptor at
> rip-off shack!! got whole thing off epay for about 50 bux, + shipping!!
> Jim NN7K
What do you consider to be the purpose(s) of a counterpoise?
--
73, Cecil http://www.qsl.net/w5dxp
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Cecil Moore
> BTW that is Both Antennas, and the adaptor- not too expensive- cheaper when
> need only one ant, and the adaptor.
It works well enough above 14 MHz, but such an antenna for
75m is a real dog.
Cecil Moore
>>I have a Hustler amateur mobile antenna model RM-80 for 80 Meter 25-30 KHz.
>>Although it was designed as a mobile I want to use it as a portable, can
>>anybody tell me the length of the counterpoise needed for this model? or can
>>I just use an earth wire>
>
> Use another RM-80 as the counterpoise.
Hmmmmm, a 2% efficient antenna with a 2% efficient counterpoise. :-)
'Doc
in efficiency!
(I agree with you anyway...)
'Doc
Cecil Moore
A 2% efficient radiator and a 2% efficient counterpoise
doesn't add up to 4% total efficiency. :-)
Anyone who wants a portable rotatable dipole on 75m can
do much, much better than two Hustlers. Two SD-20 poles
with high-Q loading coils in the middle of each comes to
mind. And that's not much more trouble than two Hustlers.
The SD-20 approach is available at http://www.wr6w6.com
Jim
you ever tried to load a 1/4 wave whip (without one)? Makes great dummy
load! Dont radiate worth a darn! Needs the full "1/2 wave" to radiate
effectively say that as can be done with loading coils, ect to shorten the
effective length, or a ground media for the 1/4 part to work against (tho,
at vhf there are SOME 1/2 wave , base coupled antennas that need no counter
poise-- but then talking 75 meters- 125 foot tower to do that!!
Jim
be easier to pack, and set up, then packing a roll of wire , aprox. 67 feet
long, and haveing to retrieve it later!! and, would be willing to bet,
even as lousey is this is, would beat that one manufactured by a certain
outfit that is about 3 foot high, and LOADS up your coax (ISO-T) to avoid
lawsuits, like they involved 73 in years ago . Ron-er Jim NN7K
Ron
<Cecil....@ieee.org> wrote:
>Ron wrote:
>>>I have a Hustler amateur mobile antenna model RM-80 for 80 Meter 25-30 KHz.
>>>Although it was designed as a mobile I want to use it as a portable, can
>>>anybody tell me the length of the counterpoise needed for this model? or can
>>>I just use an earth wire>
>>
>> Use another RM-80 as the counterpoise.
>
>Hmmmmm, a 2% efficient antenna with a 2% efficient counterpoise. :-)
Hmmmm, I wonder what 2% efficient means. 2% radiated power with 98%
reflected back into the radio? Ability to contact only 2% of the
stations that you can receive? What?
Ron, W1WBV
Ron
<Cecil....@ieee.org> wrote:
>'Doc wrote:
>> Hey Cecil, 4% is better than 2%, and a 'hunerd'% increase
>> in efficiency!
>> (I agree with you anyway...)
>
>A 2% efficient radiator and a 2% efficient counterpoise
>doesn't add up to 4% total efficiency. :-)
>
>Anyone who wants a portable rotatable dipole on 75m can
>do much, much better than two Hustlers. Two SD-20 poles
>with high-Q loading coils in the middle of each comes to
>mind. And that's not much more trouble than two Hustlers.
>The SD-20 approach is available at http://www.wr6w6.com
The question was the length of a counterpoise, not a rotatable dipole.
I figured another Hustler sure beats running radials out in a portable
situation.
If someone was to ask you how to make their Chevy run better would you
tell him to get a Ford? ;-)
Ron
Cecil Moore
> <Cecil....@ieee.org> wrote:
>>Hmmmmm, a 2% efficient antenna with a 2% efficient counterpoise. :-)
>
> Hmmmm, I wonder what 2% efficient means. 2% radiated power with 98%
> reflected back into the radio? Ability to contact only 2% of the
> stations that you can receive? What?
It's a ballpark estimate and means for every 100 watts going
into the antenna, two watts are radiated. If the feedpoint
impedance is 50 ohms, 98 watts are dissipated as heat in
the antenna, primarily in the coil(s). (Try transmitting 100w
into a 75m hamstick for one minute and then grabbing the coil.)
Cecil Moore
> I figured another Hustler sure beats running radials out in a portable
> situation.
Maybe so, and I figured a slightly different approach would
triple the radiated power. Anyone who uses a mobile antenna
for portable operation on 75m is simply wasting power since
portable antennas invariably can be longer/higher.
> If someone was to ask you how to make their Chevy run better would you
> tell him to get a Ford? ;-)
No, but if someone asks me how to make their Ford run better,
I would tell him to get a Chevy. :-)
Dave Shrader
an 8 foot antenna at 3.9 MHz is in the range of 1 to 2 ohms depending
upon coil location. The antenna losses, I^2*R, can be in the range of 10
to 20 ohms [Ra], and the ground losses can be in the range of 10 to 20
ohms {Rg]. So, your nominal '50 ohm load' is comprised of Rr + Ra + Rg = RL.
Efficiency is (Rr/RL)*100%. So, 2/50 = 4% or 1/50 = 2%. Take your pick!
The energy is NOT reflected back. It is wasted as heat in the antenna
and ground losses!
Deacon Dave, W1MCE
+ + +
Ron
<Cecil....@ieee.org> wrote:
>Ron wrote:
>> I figured another Hustler sure beats running radials out in a portable
>> situation.
>
>Maybe so, and I figured a slightly different approach would
>triple the radiated power. Anyone who uses a mobile antenna
>for portable operation on 75m is simply wasting power since
>portable antennas invariably can be longer/higher.
>
>> If someone was to ask you how to make their Chevy run better would you
>> tell him to get a Ford? ;-)
>
>No, but if someone asks me how to make their Ford run better,
>I would tell him to get a Chevy. :-)
Well, now, that's more like it :-)
Ron
Ron
<david....@comcast.net> wrote:
>Taking Cecil's example a step further. The radiation resistance [Rr] of
>an 8 foot antenna at 3.9 MHz is in the range of 1 to 2 ohms depending
>upon coil location. The antenna losses, I^2*R, can be in the range of 10
>to 20 ohms [Ra], and the ground losses can be in the range of 10 to 20
>ohms {Rg]. So, your nominal '50 ohm load' is comprised of Rr + Ra + Rg = RL.
So you can use the formula I^2*R (which is for finding P) without
knowing the variable "I" to find the resistance (Ra)?
I don't think so. Unless you have a magic wand, Harry Potter :-)
Ron
Dave Shrader
> On Sun, 09 May 2004 17:26:05 GMT, Dave Shrader
> <david....@comcast.net> wrote:
>
SNIP
>
> So you can use the formula I^2*R (which is for finding P) without
> knowing the variable "I" to find the resistance (Ra)?
>
> I don't think so. Unless you have a magic wand, Harry Potter :-)
>
> Ron
You certainly can!!
Total power to the antenna SYSTEM = I^2*(Rr + Ra + Rg).
Total power radiated = I^2*(Rr).
When you divide the two terms to get efficiency the I^2 term cancels.
This leaves Rr/(Rr + Ra + Rg). The current terms drops right out!!
DD
Ron
I didn't come here to fence with you guys. I know nothing about the
relative efficiency of antenna systems.
You could be right and the effiency of a tuned dipole "may" be 2%,
which in my mind means if it were replaced with a regular dipole, the
signal strength at a remote location would increase 50 times, but that
certainly cannot be determined that with that brand of math.
Sorry,
Ron
On Mon, 10 May 2004 00:20:55 GMT, Dave Shrader
Dave Shrader
Ron
<david....@comcast.net> wrote:
>Yes it can! Gain improvement = 10*Log{50) = +16 dB or about 3 S-units.
I already gave up. You know more about the subject than me.
Just a question, is W1MCE your original call?
Ron W1WBV (1952)