Fw: Fw: Re: [Antennas] 450 Ohm Ladder Line

2002年12月11日 11:39:35 -0800

At 12:35 PM 12/11/2002 -0600, you wrote:
>On the other hand...........
>>* Ladder line tests were performed at 50MHz to 150Mhz (instrumentation
> limitation) where losses are greater .....not at HF, 160m - 10m

Knowing those values it is easy to calculate the losses at lower 
frequencies. The formula is given in the article.
>* Many of the tests were performed with Wireman Type 554 ....should
> also use the larger AWG.

Not so. He measured Wireman's numbers 551, 552, 553 & 554 the results are 
shown in Table 1.
>* The premise is that you are trying to load random length dipoles due to
> space limitations .....the antennas I feed are "tuned dipoles".

I believe he was cautioning that substantial losses can and will take place 
feeding short (less 3/8-wavelength) dipoles with window line.
>* Wet measurements are made by wetting the line, including an open wire
> "reference line" which had NO change (indicates that a high moisture
> "mist" dielectric was not considered) .....this also implies that the
>change
> in impedance and attenuation shown is due to a wet ladder web only.
> Making the web smaller should help this.

Mist? Really? And how are you going to qualify that one and make it 
repeatable?
Both wet and dry measurement are shown. (Again Table 1)
>I'd also like to know, for a HF antenna system, do you get more power
>radiated by the resonant antenna if 1) you have an impedance mismatch
>of 9:1 (with it's resultant SWR) between 200ft of 450ohm transmission
>line and the 50ohm antenna .....or 2) if you use a toroidial 9:1
>transformer
>(with it's loss) between the balanced transmission line and the balanced
>antenna ?
>
The article addresses the window line losses only. For comparisons with 
other systems you're going to have to dig deeper elsewhere.
Danny
>Fun stuff.
>>73 Kees K5BCQ
>>--------- Forwarded message ----------
>From: Sandy and Kees Talen <[email protected]>
>To: [email protected]
>Date: 2002年12月11日 11:06:33 -0600
>Subject: Fw: Re: [Antennas] 450 Ohm Ladder Line
>>Great article, thanks Dan. It's always good to see real data, determined
>using a controlled experiment, and excellent test equipment.
>>73 Kees K5BCQ
>>>------- Forwarded message ----------
>From: Dan Richardson <[email protected]>
>To: [email protected]
>Date: 2002年12月11日 08:24:01 -0800
>Subject: Re: [Antennas] 450 Ohm Ladder Line
>Message-ID: <[email protected]>
>>For those interested here is URL which provides a very through analysis
>on
>this subject.
>>http://users.triconet.org/wesandlinda/ladder_line.pdf
>>Danny, K6MHE
>>>No trees were destroyed in the sending of this message.
>However, a large number of electrons were terribly inconvenienced.
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Danny
K6MHE
No trees were destroyed in the sending of this message.
However, a large number of electrons were terribly inconvenienced.