[Elecraft] Matching resonant antennas

[Wes]

I wrote about some of this in my paper ARRL Antenna Compendium paper on ladder 
line 20 years ago. https://sadxa.org/n7ws/Ladder_Line.pdf

I've seen pictures of those SW transmitting plants and always assumed that they 
must have been very efficient.  Upon reflection---no pun intended---now I'm not 
so sure.  If losses mounted up, (which they most certainly did at 14:1 SWR) they 
had the option of just turning up the wick.

Furthermore, as I said in closing: "Contrary to the conventional wisdom, ladder 
line is not a panacea for every transmission line problem."  In the ensuing 20 
years, I've become even more convinced of this.  When tuner and balun losses are 
factored into this picture I don't know why anyone would want to use this 
stuff.  I sure don't.

I have a KAT500 and use it to tune some way-off resonant antennas (fed with 7/8" 
Heliax) but I don't delude myself into thinking "I've contained system losses."

Wes  N7WS
https://www.qrz.com/db/N7WS


On 7/17/2020 2:32 PM, Barry LaZar wrote:
> Resonance is over rated. The problem of believing you must have a resonant 
> antenna arose with the use of coax cable began. High SWRs causes high system 
> losses.
>
> Prior to the widespread use of coax, open wire was used and few antenna 
> systems were really resonant, and nor were they reflecting a 1:1 SWR. Back 
> then, no one cared as tubes were used and pi-net or swinging links were used 
> to match to whatever was connected to the transmitter. In fact, I once visited 
> a site that used rhombic antennas and Sterba curtains being fed by high power 
> transmitters. The feed line were copper pipes about 1/4" in diameter and 
> spaced about 4". The SWR, I was told, was 14:1. I asked if that was a problem 
> of transferring energy to the system. The answer was no as the final output 
> stage could match it and the system losses were low due to the type of feed 
> line used. This was a lesson I learned 60 years ago and haven't forgotten it. 
> The site was the RCA site the once stood on Montauck Point on Long Island, New 
> York.
>
> One point that keeps getting forgotten is the conservation of energy concept. 
> What that means is energy can only be changed and not lost. Typically that 
> means transmitter energy would be changed to heat, but not lost. What is not 
> changed to heat on the coax will make it to the antenna where it MUST be 
> radiated and not lost.  Yhe practical application of this is use really good 
> coax if you can't get to a 1:1-2:1 SWR, ot there about. Alternatively, use 
> ladder line and a current balun. Elecraft tuners easily tune 10:1 SWR which 
> contains system losses nicely. I have been doing this for a very long time and 
> have achieved WAS, DXCC phone, DXCC CW, and DXCC digital, and, I'm 13 short on 
> 80 of making 5BDXCC.
>
> 73,
>
> Barry
>
> K3NDM