[ARC5] AN/ARC-5 on MF 630 Meters

[Richard Knoppow]

    Look for "Radio
Antenna Engineering" Edmund A. Laport. This classic is available 
in a reprint. Laport worked for RCA International division. The 
book covers LF and VLF antennas, few other books do. While its 
aimed at high power antennas the basic principles are the same 
regardless.

On 3/18/2022 12:53 PM, Hubert Miller wrote:
> This assumes the station is the traditional setup where there is 
> a radio shack or radio room and the antenna leadin drops right to 
> that location.
> 
> I would guess that this is no longer the predominant situation. 
> If the antenna is a vertical or mostly vertical and the base is 
> for example out in the
> 
> backyard, you will have to use coax to there and dispense with 
> antenna loading inductance in the transmitter and also correct 
> for the low impedance
> 
> output system of the transmitter to its load coil.
> 
> The only thing I have read about LF antennas in the last few 
> years that really piqued my interest was an article in QST, where 
> the writer found that
> 
> connecting the load coil right to the ground system, and feeding 
> the antenna between this top of the load coil and the antenna. 
> Instead of the traditional
> 
> connection where the coax goes to ground and the bottom of the 
> load coil. The article reported this resulted in a noteworthy 
> increase in radiated signal.
> 
> As I write this I am now wondering if maybe the feedline had to 
> be balanced, open wire or twinlead, but I don't want to look up 
> that article right now.
> 
> I'll remind myself to look at that article again.
> 
> -Hue Miller
> 
>>Something to bear in mind as one works on transmitting gear for 
> 630 meters:
> 
> Much surplus and vintage gear was not intended for a 50-ohm 
> load.  They originally worked into short-for-the-wavelength 
> antennas, and most of us will be using just that sort of antenna 
> for our ham operations.  So there may not be any good reason to 
> convert the transmitter's output to drive 50 ohm loads, just to 
> then have to build a matching network to raise the antenna 
> resistance to 50 ohms.
> 
> You can read and see some of my experiences on my website at
> 
> http://www.wd8das.net/630m.html <http://www.wd8das.net/630m.html>
> 
> I also wrote an article for QST, which can be read here...
> 
> http://www.wd8das.net/630mPractical.pdf 
> <http://www.wd8das.net/630mPractical.pdf>
> 
> And I have a video presentation posted here...
> 
> http://www.wd8das.net/HamExpo/630mPractical.mp4 
> <http://www.wd8das.net/HamExpo/630mPractical.mp4>
> 
> Steve WD8DAS
> 
> 
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-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL