Can somebody please help with providing some advice of how to tune a CB whip antenna to 88 MHz.
The whip antenna has a magnetic mount. At the base of the whip there are 5 turns of wire with a turn diameter of about 2.6 cm (1.0 inch). The length of the whip – excluding the turns at the base – is about 136 cm (53.5 inches).
Ideally, I would like to reduce the dimensions (number of turns and/or whip length) rather than increase them for the purposes of tunning the antenna to 88 MHz. Further, I would prefer to avoid the use of radials.
Thanks in advance for your advice, in terms of values for physical dimensions and/or formulae to calculate the same.
NikosE
How to tune a whip antenna?
Moderators: Sir Nigel, Nina, pcs, 5r, phpBB2 - Administrators
Date: Sat Jul 20, 2002 7:27 am
Subject: Educate U' Selves_________"THE MUST HAVE'S"
Please allow me to share my views with those of us,who are very
active D.I.Y kinda person.Even if your are a "dipstick",you still
need to comprehend certain terminologies and get a "basic first
principle"understanding.
A)A wattmeter/vswr combination preferably.This should be left in
Line,to be able to have a constant view of your VSWR especially.That
one parameter can provide you with some very good clues as to the
state of affairs.
The DAIWA Crossmetered readings of power&vswr simultaneously,seems to
be pretty popular and accurate,compared against the Bird standard.If
you are useing the Bird 4304 or Bird 43,Then go for a reflected
reading of about 10% OF FORWARD POWER...This is a safe, general
industry standard figure of merit.
Make a mental notation of what your final resonated antenna VSWR
IS....It is quite normal to observe a slight increase or decrease,in
your vswr reading whenever it is raining,snowing,or if a bird(s)
decide to perch on your "Hailleys Comet"....One may observe that in
the wee hours of the morn, that your swr will change a slight
degree,the change should not be too drastic...if it is it would
indicate that you may quite possible have a moisture infiltration
problem...The base matching coil in the Comet is an area where one
may want to ensure that no moisture can enter,thereby detuning the
coil to any large degree.Also attention needs to be paid to the
sealing and proper termination of the end of the PL259
connection,,both cable and Antenna insert end...Seal it up properly!
If you find that your vswr figure changes drastically in the presence
of early morning dew,then one can assume that in a heavy down-
pour,things can only get worse.
Norm B
Subject: Educate U' Selves_________"THE MUST HAVE'S"
Please allow me to share my views with those of us,who are very
active D.I.Y kinda person.Even if your are a "dipstick",you still
need to comprehend certain terminologies and get a "basic first
principle"understanding.
A)A wattmeter/vswr combination preferably.This should be left in
Line,to be able to have a constant view of your VSWR especially.That
one parameter can provide you with some very good clues as to the
state of affairs.
The DAIWA Crossmetered readings of power&vswr simultaneously,seems to
be pretty popular and accurate,compared against the Bird standard.If
you are useing the Bird 4304 or Bird 43,Then go for a reflected
reading of about 10% OF FORWARD POWER...This is a safe, general
industry standard figure of merit.
Make a mental notation of what your final resonated antenna VSWR
IS....It is quite normal to observe a slight increase or decrease,in
your vswr reading whenever it is raining,snowing,or if a bird(s)
decide to perch on your "Hailleys Comet"....One may observe that in
the wee hours of the morn, that your swr will change a slight
degree,the change should not be too drastic...if it is it would
indicate that you may quite possible have a moisture infiltration
problem...The base matching coil in the Comet is an area where one
may want to ensure that no moisture can enter,thereby detuning the
coil to any large degree.Also attention needs to be paid to the
sealing and proper termination of the end of the PL259
connection,,both cable and Antenna insert end...Seal it up properly!
If you find that your vswr figure changes drastically in the presence
of early morning dew,then one can assume that in a heavy down-
pour,things can only get worse.
Norm B