On Wed, 28 Nov 2018 07:02:16 -0500, "Mr. Luddite"
wrote:

On 11/27/2018 11:15 PM, wrote:
On Wed, 28 Nov 2018 03:06:28 -0000 (UTC), Bill
wrote:

Mr. Luddite wrote:
On 11/27/2018 7:36 PM, wrote:
On Tue, 27 Nov 2018 17:47:44 -0500, "Mr. Luddite"
wrote:

On 11/27/2018 5:22 PM, wrote:

I have a uniden CB radio (new) and have an existing larsen wb vhf
radio already on my truck. Will this antenna work with my new radio.
Derek


Can't determine without knowing what freq range the truck antenna is
"cut" for. There are two VHF bands, low-band VHF (49-108 MHz),
high-band VHF (169-216 MHz). Marine radios operate in the high band.

Generally it will receive ok but transmit range may be limited due to
high standing wave ratio (SWR).

Even a marine VHF antenna should be tweaked in terms of length to
minimize SWR in the middle of the radio's freq range.


He is talking about CB (27mz) so that is over twice the wavelength of
the lowest frequency VHF.
SWR is really going to be ugly but since they are capped at 5w,
(usually more like 4.5) I doubt the magic smoke comes out but he won't
be "getting out" far either.

If his "truck" is a real one (breaker good buddy size) and he has 8-9'
from mirror to mirror the best antenna is the co phasers you see on
big rigs. Otherwise it is hard to beat a bottom coil loaded ~48"
antenna right in the center of the roof. That is what I had on my van
but you had to remember to take off the vertical when you went into a
parking garage. ;-)



I completely missed that it was a CB radio he was talking about.
Thought he was talking about a new VHF Marine radio. But the antenna
issues remain the same. For max range whatever antenna he uses needs to
be of the proper length. At 27 MHz a full wavelength is about 103
inches. A half wave antenna would be about 51.5 inches long and
aquarter wave length antenna would therefore be about 25.75
inches.

If really anal about these things, an SWR meter should then used to trim
the antenna length to the lowest SWR on channel 20 (mid-range).

I have an old SWR meter from the CB craze years that I never use anymore
but for some reason it's one of those things I just can't throw away.






I have one for my marine VHF. Have not used it in years. Actually I am
looking at a new radio for the boat. One with AIS. Maybe Santa Clause.

My wife has her phone. That is all we need ;-)
Worst case I call a tow pirate but I have plenty of neighbors who owe
me a tow.
Sinking is not an issue, we will just wade ashore, I will plot a
course through the mangroves with my aerial photos and boy scout
compass and we will walk home.
I do have loppers on the boat ;-)


Back in the CB craze (late 70's) Radio Shack sold a base unit that
could easily be modified if you knew what you were doing. I bought
one along and acquired a list of the required modifications.

The modifications added an additional 40 channels (unauthorized) and
increased the carrier power from 5 watts to 15 watts.
It also increased the effective single sideband mode power to
over 30 watts depending on how much you modulated it which was
also another "tweak". At the time we lived in a rented house
near the shore and on Sunday mornings I could communicate via "skip"
with people in much of eastern Europe, as far away as Italy. In the
evening I could easily talk to people west of the Mississippi using
skip as far away as California, depending on the time as the sun set.

Ended up doing the same mods for a couple of people who also
bought the same Radio Shack radio.

Don't know whatever happened to that radio. I lost interest in CB
after a while.

CB was pretty big down in Southern Maryland because a decent base
station with an illegal antenna (too tall) could reach 15-20 miles
down the bay. If you had a decent marine antenna they could hear your
answer.
Most of my time was talking to truckers tho. I did make some pretty
good friends over the years.