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Bill[_12_]

wrote:
On Thu, 29 Nov 2018 01:02:42 -0000 (UTC), Bill
wrote:

wrote:
On Wed, 28 Nov 2018 17:40:39 -0000 (UTC), Bill
wrote:

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 ;-)

We get fog, and lots of ship traffic in SF Bay and slightly offshore.
Would be nice to know what is coming.

That is RADAR, a little overkill on a 20' pontoon don't you think?
I doubt I will see that much ship traffic in the Estero Bay anyway,
unless they can run in 2-3' of water.
We have been socked in with fog tho. My wife thought it was so cool. I
was navigating with aerial photos, a compass and the shapes of the
edges of the mangroves.
We did fine.

I can run in a foot of water. But a 21’ boat is not really a radar
platform. As to radar, I screwed up about 50 years ago, not getting a
license with radar endorsement. Friend took care of the police radars,
great side business. I spent 3 years fixing airborne transport radars.

I get the idea that police RADARs are like Bic lighters. Other than
calibrating them I imagine they get thrown away if they break.
Electronics these days doesn't really break that much ... why I
retired.

This was when we still fixed boards. Would have made a nice pile of money
as a side job.