RadioBanter - View Single Post

July 20th 04, 03:21 PM

On 19 Jul 2004 05:01:36 GMT, (ROCH USMC) wrote in
: *Hi
*Here is what I just got, Cobra 29 LTD Classic that was bumped up a bit,
a new Palomar Elite 300 amp (ebay) , Diesel (?) noise canceling mic and
a Wilsom 5000 mag mount ant.
I cant get the SWR down below 2.5. I ran a new 18' cable and a ground
wire to the frame of the truck but ever time i key up the ANT light
lights up on the radio.
My questions a
1. How can I get the SWR down?

Just three words: Grounding, grounding, and

grounding. You need to ground the radio AND

the amp AND the antenna.

The antenna is already grounded. A Wilson mag mount needs no additional
ground.

By "grounding" I

mean an "RF ground". At 27MHz, this means

mounting the radio and amp directly to the

chassis and/or using grounding straps that are
no more than a few inches long. Only after

your system is properly grounded can you

address any other issues.

Nonsense. One can mount the radio in a slide mount and to make it
temporary or it can be mounted in a permanent manner. It can be mounted
to the dash and a myriad of other places. The radio does not need
directly mounted to the chassis in order to provide proper grounding. In
fact, this is less practical and not the manner of which the majority of
cb installs are complete.

And those other issues can be many.

Almost as many as there are ways in which to mount the radio other than
mounted directly to
the chassis.

For example, your 'bumped' Cobra may have

been 'bumped' by a moron; your Palomar may
have a detuned input or output, a bad power

transistor, or even worse it might be

self-oscillating; you might be using cheap coax
(never use foam!); you might have a bad

antenna; etc. But regardless of the problem,

it's always easier to troubleshoot if the system

is properly grounded.

*2. Is this a good combo?

Not really.

Sure it is. Palomar amps work quite well.

The makers of these cheap linears

(that usually aren't very linear at all) don't tell

you that the power rating is for -peak- power.

LOL,,umm,,that's how amps are rated.
You used the term linear, he called it an amp.
One that is familiar enough to add new coax to a Wilson is more than
likely already aware of this.

IOW, a 300-watt amp will do 300 watts PEP,

which translates to a maximum of 75 watts

RMS (AM carrier power). Push it any harder

and you will get a bigger carrier, but you start

clipping well below 100% modulation,

splattering your signal across the spectrum.

Watts are watts, regardless of how they are measured. Refer to them as
RMS, PEP, or BIRD, as you have in the past...watts are watts. With many
radios, the blue faced palomar 250 are will sing 100 watts all day long
without bleeding and they are very cheap.
You also appear to be incorrect pertaining to modulation, as there are
many instances pertaining to cb, when one wishes to achieve loudest
optimum modulation, a power mic is required. Many times, this can cause
the bleed over to begin. Remove the power mic in many applications, and
the bleed can often be removed. I don't expect you to follow, Frank,
you're still smarting after having your head handed to you after making
the stupid comment that fiberglass antennas can have nothing to do with
bleed issues.

You should have had your Cobra 'dumped'

instead of 'bumped'.

That's a personal opinion coming from one who doesn't know any better
and bases his technical advice on nothing but personal emotion. Slight
peaking and tuning is perfectly acceptable when done by a competent
technician. In fact, Many cb radios can use a tune-up alignment after
being shipped.

As for a mag-mount, personally, I wouldn't

waste my money.

Again, you don't know any better. Many of us have talked around the
world on mag mounts, barefoot, on a regular basis. Mag-mounts are great
solutions for temporary mounts, rental cars, quick disconnects, etc.
Money spent on a Wilson is not wasted.

But you have,

Again, a perjorative personal opinion of yours. Lockheed Martin proved
the efficiency of the Wilson in independent tests. You should check
their test data and you may grasp why they are so popular and have
legions of loyal customers,,,they make a tight product that delivers
what they claim.

so you should know that 18' of

coax isn't a reliable substitute for the terrible

grounding characteristics of mag-mount

antennas. If you want real power you need a

real antenna, not a glorified refrigerator

magnet.

"Real" is a relevant term. The Wilson will have no problem with the
amplifier he is using.
_

*3. on my amp it has a ON/OFF , HIGH, MED, LOW and a PRE-AMP on and off.
=A0 What is with the PRE- AMP.

The pre-amp is used to amplify the received

signal. They are mostly worthless because the
usually much better than the S/N ratio of the

pre-amps. IOW, they will just make the noise

louder. However, they work great for older and
low-end transceivers, and simple homebrew

receivers.

The pre-amps are worthless by no means. They work absolute wonders when
the needle is flat with no noise for those extreme fringe stations. I've
used a cheap pre-amp on a regular basis to talk to the east coast of Fl
late at night,,,BAREFOOT.

*Ok I know I will take a beating from some of you and that is part of
the game but any help or any suggestions would be great.

Here's your beating: If you want to play

'hammie', get a license.

Running an amp isn't "playing hammie" to all, just to those anal
retentive status starved individuals.

If you can't afford a license (about the price of

a happy-meal), or if the test is too difficult

(even when you are allowed to memorize the

questions and answers before the test), then

at least get yourself a book on the subject and
learn what you are doing.

Seeing as he can solder and change out a coax on a Wilson, it appears he
is learing what he is doing quite fine. If one wanted a hammie license,
I am certain one would find that information if that is what they were
seeking.
With all the bull**** you have given this dude, he may run like hell
from anything hammie related, merely because someone like yourself is
advocating it, and he wouldn't be blamed for doing so. It's just the
manner in which you come across to all those you can't understand.
-
*Thanks
Rock