Smith Family Meeting

Smith Family Meeting
WA4DXP
Mobile Antennas
♦ Mounts, Antennas, Tuners
(or not) & grounding
♦ Presented by M.D. Smith
Mobile Antennas WA4DXP
♦ Mounts
Bolt on antenna mount. . .
Same as used on heavy truck mirror mount
Sheet metal plate for mag mount & ground
Available at Radio Shack
Mobile Antennas WA4DXP
♦ Mounts - 2” Hitch Insert mounts
Mobile Antennas WA4DXP
Note: Right Angle Co-Ax
connector used here, but with
hole in bottom, it could be
mounted that way.
Mounts: 2” Hitch Insert mounts & anti-rock bolt on plate
Mobile Antennas WA4DXP
Not ideal for pickup when tail gate comes down.
♦ Mounts to bolt on existing trailer hitch under ball
♦ Mounts – cheap
ball, stainless
steel or all brass
& stainless $100
Breedlove?
Mobile Antennas WA4DXP
♦ Mounts
Trunk,
hood or
hatchback
lip mount
Mobile Antennas WA4DXP
Bumper mount, tailgate, rain gutter
and bolt to side with adjustment ball
types of mounts.
♦ Mounts
Mobile Antennas WA4DXP
♦ Magnet Mounts
Come in ALL sizes
and mounting pins
from SMA & BNC
to co-ax and 3/8”
threaded. The triple
mag mount is very
difficult to remove.
It’s strong.
♦ Other Mounts
Mobile Antennas WA4DXP
♦ Mounts
Mobile Antennas
WA4DXP
So as not to cover license
plate an offset hitch mount is
made, and various truck bed
mounts are available. Also the
1 ¼” inserts as well as 2”.
♦ Tarheel Mounts
Mobile Antennas
WA4DXP
♦ Tarheel Mounts
Mobile Antennas WA4DXP
♦ Antennas
Mobile Antennas WA4DXP
♦ ¼ wave antennas
Mobile Antennas WA4DXP (Best to ROOF mount
this one since it’s a base loaded coil at lower freq.)
♦ Antennas – Opek all bands for $65
Mobile Antennas WA4DXP
Do it yourself, just have a
base, coil with a clip wire to
tap in different spots and a
whip and you are set for most
bands. You mark your spots
for each band as you tune
them and you can usually go
back to the center of the band
of choice as you change taps.
This looks like the MFJ
antenna I have brought
tonight.
♦ Home Made Antennas
Mobile Antennas WA4DXP
Hustler base sections 54” can
fold at 27” or 15” from base.
Either works on 6 meters with
no coil or with coil attached.
Solid base available. Coils are
between $17 and $25 good for
400 watts and $22 to $48 for
1,000 watt coils. Quick
Disconnect only for light
antennas (20 & up).
♦ Antennas: Hustler base and coils
Mobile Antennas WA4DXP
♦ Hamsticks in all
bands $19.00 each
Bulk of coil is near the top
of the base section making it
nearly a center loaded
antenna. They work very
well.
Mobile Antennas WA4DXP
Scorpion Antennas
Mobile Antennas WA4DXP
Antenna, Screwdriver, 3.5-30 MHz, 3/824 in. mount, 200W PEP, 73 in. max.
height, Motor Switch Included,
Kit - - $390.00
SD330-3-8
♦ Diamond Antennas
Mobile Antennas WA4DXP
MFJ HF Portable/Mobile Manual
Screwdriver Antennas MFJ-1664
80-6M (10' Whip), 40-6M (4.5'Whip)
Manual Screwdriver Antenna
Price:$169.95
♦ MFJ Antennas
Mobile Antennas WA4DXP
♦ Tuners: best located close to antenna
Mobile Antennas WA4DXP
♦ Antennas
♦ No matching network needed when tuned proper
Mobile Antennas WA4DXP
♦ This is using the Hustler 20 meter coil antenna
♦ Antennas
Mobile Antennas WA4DXP
If you only have a SWR meter to tune your mobile antennas,
that is fine. Dual meters are greatly preferred over the old single
meter with switch for forward & reverse power. Sweep band
in a tune or AM position to see if your antenna needs to be
shortened or lengthened to center on your favorite frequency.
20 M and up are quite broad, but 40 M and down are sharp
before SWR gets high.
Using a MFJ antenna analyzer is the best of all worlds. You can
connect AT the antenna base and tune the antenna perfectly.
Also works OK at the end of a 2 meter-mag mount with cable
attached inside your car. You will use the Antenna Analyzer
many times over the years.
♦ Tuning
Mobile Antennas WA4DXP
MFJ-259C Antenna
Analyzer.
SWR and Complex
Impedance
530 KHz to 230 MHz
$269 at GigaParts.
♦ Tuning
Coil can be
expanded to
vary
inductance
You can tune your
antenna directly to
make a 25 ohm into
a 50 ohm match with
a “L” network or use
a 2 to 1 toroid balun
to couple antenna to
feedline. Mostly
needed on 80 meters.
Cactus says this small enameled wire
inductor is about 2 micro henries and
variable by expanding or compressing.
“L” network of Cactus
K4YMB for 80 meters.
This coil is the
inductor part and the
antenna has some
capacitance to make
the network that brings
the plain antenna from
what might be 25 ohms
up to a perfect match
of 50 ohms. You DO
have to retune if you
change bands. On 40
you expand the coil
somewhat for a match
and it’s not needed on
20 and up.
Cactus now uses a 2 to
1 RF transformer
built by K4POZ,
changing his raw 25
ohm resistance at the
antenna base to 50
ohms at the coax feed.
Inside the plastic box
is a toroid 2 to 1 RF
transformer. (next)
Note the toroid chokes on the control
line and the handy quick disconnect for
the cable.
However, as you saw, I
get a 1:1 match with
my hustler and no
matching devices at all
at center frequency. I
only have a very small
mismatch at 80 meters.
Inside the K4POZ box
is about #14 or #16
enameled wire. Both
windings are
interleaved around the
core. Coax feed is
input and the output
cable connects to the
antenna.
Mobile Antennas WA4DXP
♦ Grounding, very important
♦ Radio located under front
passenger seat, grounded to seat
bolt that holds extension for head.
♦ Antennas
Mobile Antennas WA4DXP
♦
Grounding,
very
important
♦ Antennas
Mobile Antennas WA4DXP
♦ Chokes on control cables and feedlines
are good idea.
Mobile Antennas WA4DXP
The summary is that whether you are looking for HF,
VHF, UHF or ALL of them together, which I do, you
can be set. The Yaesu FT-857D and the Icom-7000
both cover HF through 440, and have individual coax
outputs for HF and VHF/UHF. I use a dual band
mag-mount on the roof for 2M/70cm and the Hustler
for all other bands. I use either Hustler or Hamsticks
on my bike.
Mounts are everywhere and every type from the
heaviest for giant screwdriver antennas to light
mounts on cars, trucks, motor homes and yes, even a
bicycle. TUNE that antenna for best performance.
Ground rig and antenna base well. Happy mobile
hamming.
♦ Antennas
Mobile Antennas WA4DXP
♦ Trivia – what year did this stamp come out?
Mobile Antennas WA4DXP
♦ Trivia – 1964 on 50th Anniversary of ARRL
Mobile Antennas WA4DXP
♦ Trivia – 1964 on 50th Anniversary of ARRL
Mobile Antennas WA4DXP
♦ Trivia – 1964 on 50th Anniversary of ARRL
WA4DXP
Mobile Antennas
The End
♦ Mounts, Antennas, Tuners (or not) &
grounding
♦ Presented by M.D. Smith
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