[600MRG] The best way to transfer power from TX to loading coil

[Edward R Cole]

Andy,

Exactly my method:  Base coil is sandwiched between bottom 
of  vertical wire and ground rod/radials.  Coil 10-diameter 11-inch 
long wrapped with stripped No. 12 THHN 1/4 inch spacing per turn (45 
turns).  Antenna connects about 3/4 of length from grounded end and 
coax tap is about 2-1/2 turns from ground.  Maybe you suggested 
it?  Some one from the group in 2012.

Finding the antenna end tap point on the coil was done using a 
modified MFJ-269B (added a toroid coil in series with lowest freq 
range inductor for the internal signal generator).  Wrapped 
wirearound the 3/8-inch toroid until oscillator worked from 800 to 
1200 Hz.  Inserted meter between ground an coil and located the tap 
where the complex impedance was nearly zero.  R=18 ohms at that point 
and was used un formula to calculate ERP.

May not work if you are near a BC station on lower end of BC 
band.  Meter has no selectivity to reject BC stations signal and will 
lead to erroneous results in finding resonance.  My nearest station 
is 920 KHz about 15 miles away.  My inverted-L picks up BC stations 
out thousands of miles away.  I've copied NDB's 1100 miles remote 
from me and copied Rudy's CW FB.

Not QRV but only need to tune the antenna down to 473

73, Ed
Today I shoveled snow.

At 11:53 AM 3/17/2018, Andy - KU4XR via 600MRG wrote:
>Hi all:
>
>I back, with a question now on the best way to transfer power from 
>the transmitter into the loading coil..
>I see several posts referring to auto-transformers, tappable torroid 
>step-up / step-down transformers, etc.
>I have a single coil, doing both jobs; TX Matching, And, Antenna 
>Tuning .. Below is a dropbox link to a
>picture of my Matching / Loading coil setup - to see what I am working with :
>
>https://www.dropbox.com/s/3b59n1djmoamm7i/KU4XR%20Matching%20-%20Loading%20Coil%203-17-18.jpg?dl=0
>
>The picture shows the bottom is grounded, and I tap - UP - from the 
>bottom to match the TX for 50 ohms..
>Is there a Better / More Efficient way to transfer the power from 
>the TX to the Coil ? Or, is what I am doing
>perfectly acceptable ? Any mismatch that I have is due to Unknown 
>Reactance in the antenna that I am
>unable to measure, and wash out at the moment..
>
>Thanks for comments, and suggestions, and 73 to all:
>
>Andy - KU4XR
>______________________________________________________________
>600MRG mailing list
>Home: http://mailman.qth.net/mailman/listinfo/600mrg
>Help: http://mailman.qth.net/mmfaq.htm
>Post: mailto:600MRG at mailman.qth.net
>
>This list hosted by: http://www.qsl.net
>Please help support this email list: http://www.qsl.net/donate.html

73, Ed - KL7UW
   http://www.kl7uw.com
Dubus-NA Business mail:
   dubususa at gmail.com