The excellent web site for calculating matching network values should have
been:
http://home.sandiego.edu/~ekim/e194rfs01/jwmatcher/matcher2.html
not the one I posted yesterday.
73,
Tom G3OLB
_
Topband Reflector
: Topband: 'Hairpin' matching
The excellent web site for calculating matching network values should have
been:
http://home.sandiego.edu/~ekim/e194rfs01/jwmatcher/matcher2.html
not the one I posted yesterday.
73,
Tom G3OLB
_
Topband Reflector
_
Topband Reflector
Just measured the 'hairpin' coil for my 160m 38 foot top loaded - coil
and 2 x 18 foot wires - antenna.
Feedpoint impedance without match is 12 ohms.
Placing shunt coil to ground of 1.7microH and tx sees 50 ohm 1:1.
Only problem with the vertical being so short the bandwidth is only 12
khz
!)
73,
Charlie, K4OTV
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom
Boucher
Sent: Friday, September 20, 2013 2:25 AM
To: 160 reflector
Subject: Topband: 'Hairpin' matching
The excellent web site for calculating matching network values should
the theory said it
would be.
I was very impressed.
Tim N3QE
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Charlie
Cunningham
Sent: Friday, September 20, 2013 8:16 AM
To: 'Tom Boucher'; '160 reflector'
Subject: Re: Topband: 'Hairpin' matching
Very
Thankyou Charlie.
I got those Q numbers from
http://www.m0ukd.com/Calculators/air_core_inductor_calculator/
Maybe a decimal point was left out.
Thanks Tom
--
Jim K9TF
_
Topband Reflector
Just to add a comment on this thread:
I do not use an inductor to match my inverted 'L', just a capacitor from coax
centre/bottom of wire to the radial point. Further I do not use big wide space
'toast-rack' Cs, but tiny ceramic ones rated at 6.3KV which will handle very
decent amounts of
The thing works, I mean the shunt match works.
what would be a good Q for just the coil? 300, 600, 900
Operating Q, what is the desired value? Whats your formula for that?
Q of the operating antenna, cannot be expressed as band width equation I
see so many others use. there is another quick
than I have time for at the moment.
73,
Charlie, K4OTV
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim GM
Sent: Wednesday, September 18, 2013 1:05 PM
To: Tom W8JI
Cc: topband
Subject: Re: Topband: Hairpin Matching Coil Questions
The thing works, I
: Wednesday, September 18, 2013 2:44 PM
To: 'Jim GM'; 'Tom W8JI'
Cc: 'topband'
Subject: Re: Topband: Hairpin Matching Coil Questions
Hello, Jim
You seem to be lost!
First of all, the thing that you originally called a hairpin match is
NOT a shunt match. The coil, or hairpin is in SERIES
: topband
Subject: Re: Topband: Hairpin Matching Coil Questions
The thing works, I mean the shunt match works.
what would be a good Q for just the coil? 300, 600, 900
Operating Q, what is the desired value? Whats your formula for that?
Q of the operating antenna, cannot be expressed as band width
tunes rather nicely!
73,
Charlie, K4OTV
-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Mike
Waters
Sent: Tuesday, September 17, 2013 5:51 PM
To: W2RU - Bud Hippisley; topband
Subject: Re: Topband: Hairpin Matching Coil Questions
Ok, I found the photos
A hairpin or a parallel matching inductor should be adjusted this way:
1. select inductance (hairpin length);
2. adjust wire length for the desired resonant frequency.
Repeat 1 and 2 until you get SWR = 1 at the desired resonant frequency.
Do not attempt to adjust resonance via hairpin
To amplify a little on some other comments - For an Inv L, and a decent
radial system, with a coil shorted across (shunt) the vertical wire
input to the braid/radials, the otherwise low impedance can be
transformed to 50 ohms. One way to do it is to use an antenna analyzer
to measure the
I have an inverted L and using a hairpin coil to match in on 160M.
One coil is 6 inches OD the other is 2 inches OD. I have been thinking
about making another hairpin with wire wrapped around a toroid donut,
I have noticed with the 6 inch coil I have a higher noise level on 160M and
hear BCI
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