HF Mobile - Grounding Antenna when stationary
 

Korbin,
I have just done a heap of experimenting on 80m using a Terlin Outbacker
"Outreach" mobile whip.
I found that it made none or little difference when using 4 x 1/4 wavelength
radials.
I then used a 33 ft fibreglass extendable pole with a dipole attached,
certainly and naturally it outperformed the mobile whip.
I made up a full wave loop on 80m, slung it vertically between 2 large
trees, and found it out performed the dipole, mainly because of the noise
level was lower than either the mobile whip or the dipole.
On receive the full wave loop was the best, followed by the inverted vee and
lagging way behind was the mobile whip.
my 2 cents worth.
John

"Korbin Dallas" wrote in message
news:Uem7g.54594$Eh4.50096@trnddc01...
: On Sun, 07 May 2006 10:33:51 +0930, OZUser wrote:
:
: As an avid 4WD SUV owner I do a lot of outback travelling (Austrlian
: Deserts, Cape York, Kimberly Coast) and as such have a Barrett 950
HFradio
: &Barrett 910 Autotune antenna installed for comms.
:
: Would it be preferable when camped / stationary to earth the vehile to a
: "ground" ground = what I am looking for is a better receive signal ?????
:
: Switching to a Dipole antenna suspended from the trees would be a Major
: step upward in performance.
:
: Mobile antennas have very low efficiency, grounding them will not improve
: that significantly relative to the dipole.
:
: KD

HF Mobile - Grounding Antenna when stationary
 

VK2KCE wrote:

:
: Would it be preferable when camped / stationary to earth the vehile to a
: "ground" ground = what I am looking for is a better receive signal ?????
:
: Switching to a Dipole antenna suspended from the trees would be a Major
: step upward in performance.
:
: Mobile antennas have very low efficiency, grounding them will not improve
: that significantly relative to the dipole.
:
: KD

Efficiency doesn't even come into play in his case, being he is only
worried about receiving. As far as voltage to his radio, he already
has
more than enough with the mobile whip as is. As one mentioned, the
s/n ratio is what matters. And going to a larger vertical is likely not
to
help at all. Even switching to a dipole would not be an improvement
unless the signals are coming from higher angles, etc. IE: 75m NVIS..
There are cases where my mobile antenna outperforms my home dipoles.
But these will be cases where the distance, etc favors using a
vertical.
So anyway, the short of it is adding radials to the mobile will not
help receiving at all. And switching to a larger antenna is not likely
to
help either unless there is a reason such as a horizontal dipole
favoring
NVIS. All but the puniest mistuned receiving antennas have enough
voltage
to get an acceptable s/n ratio from any decent radio. It's like adding
a tuner,
etc to a random wire. Unless there is a specific reason for it, it's a
waste
of time in most all cases.
MK

HF Mobile - Grounding Antenna when stationary
 

VK2KCE wrote:
Korbin,
I have just done a heap of experimenting on 80m using a Terlin Outbacker
"Outreach" mobile whip.
I found that it made none or little difference when using 4 x 1/4 wavelength
radials.
I then used a 33 ft fibreglass extendable pole with a dipole attached,
certainly and naturally it outperformed the mobile whip.
I made up a full wave loop on 80m, slung it vertically between 2 large
trees, and found it out performed the dipole, mainly because of the noise
level was lower than either the mobile whip or the dipole.
On receive the full wave loop was the best, followed by the inverted vee and
lagging way behind was the mobile whip.
my 2 cents worth.
John

"Korbin Dallas" wrote in message
news:Uem7g.54594$Eh4.50096@trnddc01...
: On Sun, 07 May 2006 10:33:51 +0930, OZUser wrote:
:
: As an avid 4WD SUV owner I do a lot of outback travelling (Austrlian
: Deserts, Cape York, Kimberly Coast) and as such have a Barrett 950
HFradio
: &Barrett 910 Autotune antenna installed for comms.
:
: Would it be preferable when camped / stationary to earth the vehile to a
: "ground" ground = what I am looking for is a better receive signal ?????
:
: Switching to a Dipole antenna suspended from the trees would be a Major
: step upward in performance.
:
: Mobile antennas have very low efficiency, grounding them will not improve
: that significantly relative to the dipole.
:
: KD


Throw the terlin away and you will gain 6db by using a decent mobile
antenna, no joke. The thing is dummy load for dx.

You would not say that about vertical mobile antennas if you screwed a
1/4 wave whip on your vehicle using the same ground

Considering that people claim terlins to work when they tuner them to a
1:1 vswr is laughable really, with something like 40 ohms ground loss
resistance!


You could try a inverted L with a autotuner at the base if you wanted
better efficiency. A 6 meter fishing pole with 6 meters of wire
horizontal is a cracker antenna.

Worst mobile antennas are those base loaded auto tuning antennas from
codan and barret, they have a honest 12 db loss compared to a good
monoband 20 meter centre loaded whip.


When you antenna is short you better off using multiple very small
radials than a few long ones.

Just forget all the nonses and make a good centre fed doublet with open
wire feedline and use it on all bands. No Better or cheaper antenna around.

Yeah and forget those joke Dummy Load Antennas sold by Barret Codan and
Bushcomm. They a heap of crap.


Greg