[TowerTalk] K6STI Receiving loop question

[Pete Smith]

Well, as a 'frinstance, if he's using RG-6 75-ohm cable, say 100 feet long, 
and the antenna is presenting 240 ohms to the cable, on 1.8 MHz the 
additional loss in the cable due to the mismatch is about .4 dB out of a 
total of .8db, according to TLW.

73, Pete N4ZR

   At 03:16 PM 11/18/2004, Joe - WDØM wrote:

>Good point - how close is "close enough" - but if you're doing it the 
>first time, why not 'do it right" instead of having to do it over?  :-)
>73,
>Joe
>WDØM
>
>At 01:11 PM 11/18/2004, Pete Smith wrote:
>>On the other hand, if it is a receiving antenna, do you care?  The 
>>additional loss in the feedline due to SWR *may* be trivial in this 
>>application.
>>
>>73, Pete N4ZR
>>
>>At 02:51 PM 11/18/2004, Joe - WDØM wrote:
>>
>>>Hi Dave,
>>>
>>>Perhaps the easiest way (if you have an antenna analyzer or access to 
>>>one) is to check the impedance at the antenna using an antenna 
>>>analyzer.  That will tell you which way to go in modifying the turns 
>>>ratio.  I just put a beverage antenna together, and the analyzer was 
>>>very helpful in assembling the transformer.  I used my Autek analyzer - 
>>>and it's probably the best investment I've made to be sure every watt I 
>>>own gets to the antenna and then on to the other guy's radio.  ;-)
>>>
>>>73,
>>>Joe
>>>WDØM
>>>
>>>
>>>At 11:47 AM 11/18/2004, Dave Quick wrote:
>>>>I recently put up a K6STI loop for 80m. It's about 8 feet off the ground
>>>>and built according to the plans in the Sep. 95 issue of QST. It's 21
>>>>feet on each side and I used 450 ladder (window) line and a 77 mix
>>>>ferrite bead for the transformer.
>>>>
>>>>My problem is that I can't get the SWR below about 3:1 or so. I do get a
>>>>dip as I adjust the cap, but never below 3:1. I'm guessing that I need
>>>>to adjust the turns ratio of the transformer, which is 4 turns to 10
>>>>turns as the QST article specifies, but I'm not sure which way to go
>>>>with the turns ratio.
>>>>
>>>>Does anyone have an advise for me?
>>>>
>>>>Thanks.
>>>>
>>>>Dave Quick K0EKL
>>>
>>>
>>>_______________________________________________
>>>
>>>See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless 
>>>Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with 
>>>any questions and ask for Sherman, W2FLA.
>>>
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>>
>
>