http://elecraft.85.s1.nabble.com/Horizontal-Delta-Loop-Questions-tp7154769p7155116.html
well served by posting this question. I was aware that doublets needed to
regarding loops. Looking at the current system on my spreadsheet, there
advice seems to have some objective truth evident. Last weekend I trimmed
to achieve a decent match on 10 and 6 meters. I'll take your advice and
> In an antenna design where one is already committed to a broadband
> feedline and a tuner, particularly one that is working, making the antenna
> "resonant" may actually WORSEN your results. Efficiency is not hide bound
> to "resonance". What most people mean by resonance is a low Z feedpoint
> that has no reactive component, and also want to feed it with 50 ohm coax
> with no further devices. In other words what they want is SIMPLICITY. I'm
> not knocking that at all, but it is NOT the only way to fly. The doublet
> with the most gain is something called a double extended zepp, is NOT
> resonant, needs a low loss balanced feedline and a tuner to feed it.
>
> Working wire solutions for most gain, best efficiency in a given space is
> a tricky science that involves modeling, and RARELY produces resonant
> solutions that feed with nothing except 50 ohm coax. In critiquing one
> person's work, he had defeated himself by forcing the wires to produce a
> no-tuning-device 50 ohm feed. When he dropped that requirement and got
> used to the idea of designing for results and matching it to coax
> afterward, he very quickly designed something that fit his back yard and
> worked well.
>
> In your case what screams at me is "If it ain't broke, don't fix it!" and
> "Model it, and see what is going on."
>
> "Resonance" is way, way over-rated.
>
> 73, Guy K2AV
>
> On Thu, Jan 5, 2012 at 10:13 AM, Rick McClelland, AA5S <
>
[hidden email]> wrote:
>
>> Hi,
>>
>> I'm a CW operator who dwells in the lower end of the HF bands. My current
>> antenna is a 200' horizontal delta loop 40' high, fed with 87' of 450 ohm
>> ladder line. This connects to a 4 to 1 balun (common mode choke?) which
>> is
>> attached to my Dentron Jr. Monitor tuner via 5' of RG213. Looking at a
>> spreadsheet, I see that a full wave loop for 80 meters is 287' and 143.57'
>> for 40 meters.
>>
>> A hypothetical question to the wise ones on this list is would I expect
>> any
>> practical improvement in performance of my antenna system (on 40 meters
>> and
>> above) by reducing my 200' delta loop to 143.57' and feeding it with
>> 71.78'
>> of ladder line so that the sum of the antenna length plus twice the ladder
>> line length is 287'? This seems to make theoretical sense since the
>> entire system would be resonant at 7mhz and integral multiples thereof.
>> However, the performance of my current 200' loop appears to be quite good
>> from 80 to 6 meters and my small tuner matches whatever impedance this
>> system is presenting to it so I'm hesitant to take a pair of snippers to
>> my
>> antenna.
>>
>> I would like to increase the length of the loop to 287' feet and feed it
>> with 71.78' of ladderline but that is another story. Also, would I expect
>> to be able to tune any of the these three antennas on 160 meters if I were
>> to purchase either a KXAT100 or KAT500 tuner which presumably have a wider
>> tuning ranges than the Dentron Jr. Monitor tuner?
>>
>> Rick McClelland, AA5S
>> Fort Collins, CO
>> ______________________________________________________________
>> Elecraft mailing list
>> Home:
http://mailman.qth.net/mailman/listinfo/elecraft>> Help:
http://mailman.qth.net/mmfaq.htm>> Post: mailto:
[hidden email]
>>
>> This list hosted by:
http://www.qsl.net>> Please help support this email list:
http://www.qsl.net/donate.html>>
>
>