Mobile Antenna Installation
 

Hi, i am a new ham and i just purchased an old VP commodore station wagon. I
was wondering what the best method would be mounting antennas on this
vehicle. It has a non metallic roof rack so i was thinking of getting a
metal plate across the roof rack and mounting the antennas on that. So i was
thinking:

1. How to electrically connect the plate to the vehicle
2. What order/sizes to have the antennas in. (Largest at back, smallest at
front? It shouldn't really matter, depending on directionality
requirements.)
3. The best method of routing the coax from inside car to roof plate, i
don't want to cut holes in the roof if not needed but probably will have to.

Please feel free to suggest any methods used or ideas. I will probably have
antennas for the following but not sure what the "best" antennas are for
each radio, once again, feel free to suggest antennas to use...

UHF CB
2 Metres
70cms
Scanner

I could use a dual band for the 2/70 antenna but i want a good one. I am in
VK land so anything not sold in VK i won't buy.

Thanks for looking...

Gary
VK3LCD

Mobile Antenna Installation
 

Gary Smith wrote:
Please feel free to suggest any methods used or ideas. I will
probably have
antennas for the following but not sure what the "best" antennas are for
each radio, once again, feel free to suggest antennas to use...

UHF CB
2 Metres
70cms
Scanner
Gary
VK3LCD

Andy writes:
If you get a large set of longhorns and mount them on the
front hood as a hood ornament. and wrap them in tin foil, you can
make a fine 2 Meter dipole...

Oops.... two Metre !!!!

Andy W4OAH in Eureka, Texas


:))))))))))))

Mobile Antenna Installation
 

On Sun, 4 Mar 2007 00:23:25 +1100, "Gary Smith"
wrote:

I
was wondering what the best method would be mounting antennas on this
vehicle.

Hi Gary,

Consult vendors such as:
http://www.cometantenna.com/index.php
for mounting components.

73's
Richard Clark, KB7QHC

Mobile Antenna Installation
 

Hi, i am a new ham and i just purchased an old VP commodore station
wagon. I was wondering what the best method would be mounting antennas
on this vehicle. It has a non metallic roof rack so i was thinking of
getting a metal plate across the roof rack and mounting the antennas
on that. So i was thinking:

1. How to electrically connect the plate to the vehicle
2. What order/sizes to have the antennas in. (Largest at back,
smallest at front? It shouldn't really matter, depending on
directionality requirements.)


Gary,

Since the large metal plate you are thinking of putting on your roof
is only acting as a ground-plane for VHF/UHF antennas, I see no need to
have it electrically connected to the roof... though you may end up doing
so simply from whatever mounting techniques you decide to use.

Also, one consideration might be to use half-wave type base loaded
antennas, which technically do not require a ground plane.

Thirdly, there are vendors, such as Antenna Specialists, who make a
metal foil tape for installing on the underside of non-metallic roofs at
antenna mounting holes so as to provide a ground plane for the antenna.
They're used a lot in ambulances here that have fiber-glass tops.

Food for thought.


Ed K7AAT

Mobile Antenna Installation
 

On Mar 3, 5:23 am, "Gary Smith" wrote:
Hi, i am a new ham and i just purchased an old VP commodore station wagon. I
was wondering what the best method would be mounting antennas on this
vehicle. It has a non metallic roof rack so i was thinking of getting a
metal plate across the roof rack and mounting the antennas on that. So i was
thinking:

1. How to electrically connect the plate to the vehicle
2. What order/sizes to have the antennas in. (Largest at back, smallest at
front? It shouldn't really matter, depending on directionality
requirements.)
3. The best method of routing the coax from inside car to roof plate, i
don't want to cut holes in the roof if not needed but probably will have to.


I did something like this for my VW Passat. The way I wound up
connecting it was two fold. First, the ends of the rack rails had a
plastic cover over where the bolts holding the rack onto the car body
were. Popped the cover off, removed the nut, put wire with lug under
the nut. Cut small notch in edge of beauty cover to run wire through
and popped it back on.

As far as coax went, I just ran through the rear hatch gasket. Cut a
small slit in the gasket, and carve out a hole big enough for the
coax, install coax, then use gasket glue (or superglue) to repair the
slit.
use small coax, at least for the gasket traversing part. RG-174 is
pretty small (2mm?) and a 10-15cm doesn't have all that much loss.

A friend went to quite a bit more trouble and went through the
existing radio antenna hole. he built a little "collar" that matched
the base of the antenna. There's a fairly large hole through the body
there, but to route the wires you have to pull the headliner off.



BTW, A good body shop or car stereo installation place can remove and
replace interior trim quickly, cheaply, and efficiently. They have
all the right weird shaped tools and the judgement about just how much
you can pry or pull without breaking things.

Especially if you have Sirius or XM radio in VK land, there's probably
folks around who have gotten pretty good at inconspicuously routing
coax from outside the car to inside.

Mobile Antenna Installation
 

"Gary Smith" wrote in
:

Hi, i am a new ham and i just purchased an old VP commodore station
wagon. I was wondering what the best method would be mounting antennas
on this vehicle. It has a non metallic roof rack so i was thinking of
getting a metal plate across the roof rack and mounting the antennas
on that. So i was thinking:

The VP commodore is about 15 years old now.

You haven't stated why you don't want to put holes in the roof. Most
people with a car of that age, if it of average value for its age, would
put holes in the roof without hesitation.

It is a little difficult to comment on your plate proposal, how big is
it, how will you prevent wind noise, vibration, failure etc.

If the plate is not large enough, you really have one antenna with four
feedpoints. One could argue that the entire roof of the wagon is only
just large enough to accomodate all the antennas you propose.

You could feed coax in between the door and door seals, but it is
inconvenient and fraught with problems (cable damage, water ingress etc).

Unless the car is of some special value, I would place holes in the roof,
spaced out down the centreline. Get someone experienced to help you find
where to cut the holes so that they have room underneath, so you can
route the cables down the windscreen pillar, and without dropping a hot
piece of metal (eg the donut after holesawing the roof) through the
headlining.

There are commercial dual band antennas sold here, but I would skip the
MobileOne product. Look at the Diamonds and the like, but they require a
proprietary base. Your other antennas will probably go on a vanilla
5/16" brass thread stud base.

If you don't want to put too many holes in the roof, you could place one
good 2m/70cm antenna with the base just behing the interior light, and
put the other two on Z brackets on the front mudguards.

I was wondering why you need the chook band when you have 2m and 70cm, 2m
and 70cm seem like they are half way to CB here, certainly the lingo is
strongly CB.

73 or 1004, or whatever they say on air these days.
Owen

Mobile Antenna Installation
 

I was wondering why you need the chook band when you have 2m and 70cm,
2m and 70cm seem like they are half way to CB here, certainly the
lingo is strongly CB.



I don't know about your location, but the need for CB can be quite valid,
even for a ham, in many places. My location, as numerous others, has a lot
of logging activity, and if one is driving on some of our back roads, it is
quite helpful to hear where the logging trucks are.... they commonly
announce their presence on dangerous parts of these roads. There are many
other instances in rural areas where CB can be helpful, too.


Ed K7AAT

Mobile Antenna Installation
 

Yes, i am in rural Southwest Victoria. I am currently running a discone on 2
Metres which is about 5 Metres above ground.
The closest 2 Metre repeater is approx 100Km line of site and has big
problems with RX, as such i cannot access it with my current antenna. I have
a 20 element yagi on UHF CB with a repeater to the Southeast and us locals
use that repeater to communicate as we have for years, and its our local
link, still, at this stage. So, we're not all surrounded by repeaters in our
back yards in this corner of this state and the terrain isn't all flat
either, our town is built on the Glenelg river and fortunantly i live a
little higher than the centre of town. We still have non amateur friends on
UHF CB and like to keep in touch with them. I pitty those that use UHF CB
repeaters in or near cities, usually it's a waste of time talking on them
but there are SOME good operators there as well. "in the sticks" we use them
for proper conversations instead of kids trying to overpower each other.
Maybe thats why you are wondering why i still want UHF CB

Gary


"Ed" wrote in message
. 192.196...

I was wondering why you need the chook band when you have 2m and 70cm,
2m and 70cm seem like they are half way to CB here, certainly the
lingo is strongly CB.



I don't know about your location, but the need for CB can be quite valid,
even for a ham, in many places. My location, as numerous others, has a
lot
of logging activity, and if one is driving on some of our back roads, it
is
quite helpful to hear where the logging trucks are.... they commonly
announce their presence on dangerous parts of these roads. There are many
other instances in rural areas where CB can be helpful, too.


Ed K7AAT

Mobile Antenna Installation
 

"Gary Smith" wrote in
:

Yes, i am in rural Southwest Victoria. I am currently running a
discone on 2 Metres which is about 5 Metres above ground.
The closest 2 Metre repeater is approx 100Km line of site and has big
problems with RX, as such i cannot access it with my current antenna.

Gary, 100km is a long path to a repeater, so you have to make sure you
are doing some things right.

I don't want to be negative about your discone, but they, being very
broadband, accentuate IMD problems (so called pager interference) with
receivers. If you are in the sticks, that won't be as noticeable as in
the city, and it will affect ham gear more than commercial LMR which tend
to have better front end selectivity. The other thing about the discone,
is it is relatively low gain on tx.

I note that your main problem with the 2m repeater is it hearing you, so
you should be trying initially to boost your transmit signal. Perhaps you
should look around at one of the commerical high gain 2m or dual band
antennas that will give you 3 - 6dB lift depending on the model (in other
words to double to quadruple your effective radiated power). Review your
feedline situation to see you are not chucking signal away there as well.
Another alternative is to build or buy a small yagi, 4 to 6 elements,
vertically polarised and fixed on the repeater, but of course it is a bit
restrictive for other contacts.

I have a 20 element yagi on UHF CB with a repeater to the Southeast
and us locals use that repeater to communicate as we have for years,
and its our local link, still, at this stage. So, we're not all
surrounded by repeaters in our back yards in this corner of this state

Repeaters aren't everything, I think there are 9 or so here for a
relatively low ham population, I don't use them, and they aren't very
busy except for drive time when they sound a bit like CB.

and the terrain isn't all flat either, our town is built on the
Glenelg river and fortunantly i live a little higher than the centre
of town. We still have non amateur friends on UHF CB and like to keep
in touch with them. I pitty those that use UHF CB repeaters in or near
cities, usually it's a waste of time talking on them but there are
SOME good operators there as well. "in the sticks" we use them for
proper conversations instead of kids trying to overpower each other.
Maybe thats why you are wondering why i still want UHF CB

Have fun, try experimenting with some different antennas, reserve your
discone for a radiating dummy load.

Re the Commodore, when I was younger, the deal was that the car owner
purchased a slab, invited some competent mates around and after a certain
anaesthetic threshold was reached, the holesaw came out and the antenna
was installed... just watch that the guy with the holesaw isn't as
anaesthetised as a newt!

Owen

Mobile Antenna Installation
 

Thanks Owen, Yes, i know the discone is low gain, and i have (Shock, Horror)
approx 60 ft of rg58 connected to it :
I have been playing with radio for about 20 years but only just aquired my
Ham ticket. I have read the ARRL handbook around 5 times now i would say,
cover to cover.

I am modifying an ex CFA "Polar" 163.2 MHz vertical at the moment, there are
plans on the net to modify this antenna to 146 meg. For those wanting to
view this pdf, google vk3cmc cfa. I am also going to price tubing for a 17
element 2 Metre Yagi and later on one for 70cm. Combined with some RG-213 i
think that will be quite fine, another station further away than i am is
getting into the repeater with a 6 element. My tower will be going up soon,
got a 50ft and 75ft so debating which one to use. 75ft is narrower inner
section (3 stage tilt over crank up) so would not hold as much weight and
wont take my KR400 inside the top section (too narrow).

I have the discone as a way to get up and running, can use the Mount Gambier
repeater with it all the time and that one is around the same distance AND a
large hill between it and me.. Most repeaters for us are around 60-100k +.
we have members all over the corner of the state and would be stuffed
without repeaters, fantastic things!!

Anyway, back to my ex CFA antenna...


Gary
VK3LCD




"Owen Duffy" wrote in message
...
"Gary Smith" wrote in
:

Yes, i am in rural Southwest Victoria. I am currently running a
discone on 2 Metres which is about 5 Metres above ground.
The closest 2 Metre repeater is approx 100Km line of site and has big
problems with RX, as such i cannot access it with my current antenna.

Gary, 100km is a long path to a repeater, so you have to make sure you
are doing some things right.

I don't want to be negative about your discone, but they, being very
broadband, accentuate IMD problems (so called pager interference) with
receivers. If you are in the sticks, that won't be as noticeable as in
the city, and it will affect ham gear more than commercial LMR which tend
to have better front end selectivity. The other thing about the discone,
is it is relatively low gain on tx.

I note that your main problem with the 2m repeater is it hearing you, so
you should be trying initially to boost your transmit signal. Perhaps you
should look around at one of the commerical high gain 2m or dual band
antennas that will give you 3 - 6dB lift depending on the model (in other
words to double to quadruple your effective radiated power). Review your
feedline situation to see you are not chucking signal away there as well.
Another alternative is to build or buy a small yagi, 4 to 6 elements,
vertically polarised and fixed on the repeater, but of course it is a bit
restrictive for other contacts.

I have a 20 element yagi on UHF CB with a repeater to the Southeast
and us locals use that repeater to communicate as we have for years,
and its our local link, still, at this stage. So, we're not all
surrounded by repeaters in our back yards in this corner of this state

Repeaters aren't everything, I think there are 9 or so here for a
relatively low ham population, I don't use them, and they aren't very
busy except for drive time when they sound a bit like CB.

and the terrain isn't all flat either, our town is built on the
Glenelg river and fortunantly i live a little higher than the centre
of town. We still have non amateur friends on UHF CB and like to keep
in touch with them. I pitty those that use UHF CB repeaters in or near
cities, usually it's a waste of time talking on them but there are
SOME good operators there as well. "in the sticks" we use them for
proper conversations instead of kids trying to overpower each other.
Maybe thats why you are wondering why i still want UHF CB

Have fun, try experimenting with some different antennas, reserve your
discone for a radiating dummy load.

Re the Commodore, when I was younger, the deal was that the car owner
purchased a slab, invited some competent mates around and after a certain
anaesthetic threshold was reached, the holesaw came out and the antenna
was installed... just watch that the guy with the holesaw isn't as
anaesthetised as a newt!

Owen