K8RI wrote: 6.5 sounds pretty high.
Well it is. Seems there was a minor problem with the decimal point. It
should have been 0.65 dB for 20 meters, not 6.5. I did notice that I
used a 125 ft dipole instead of the 135 ft he stated.
Those numbers were for no balun in the system since one wasn't stated.
Before actually putting this up it would probably be worth while
rerunning the numbers for different lengths of 450 ohm line, with and
without a balun. Might save a few dBs. The SWR as seen by the RG213
varies from about 1.4 to 60. The 60 was on 20 meters. It definitely
needs some juggling to fix 20 and 15 meters.
It's amazing how many replies I got from people thinking that coax loss
isn't a function of SWR.
Since I missed the length, here it is again for a 135 ft dipole, 90 ft
of 450 ohm line, 30 ft of RG213, antenna at 40 ft.
3.5 MHz 1.48 dB
7 MHz 0.94 dB
10.1 MHz 1.51 dB
14 MHz 3.12 dB
18.1 MHz 2.72 dB
21 MHz 3.89 dB
24.9 MHz 1.1 dB
28 MHz 0.59 dB
Roger (K8RI) wrote:
>>A quick check with EZNEC shows the following loss in the 30 feet of
>>RG213. The antenna was placed at 40 feet.
>>3.5 MHz 2.17 dB
>>7 MHz 1.95 dB
>>10.1 MHz 4.42 dB
>>14 MHz 6.5 dB
>6.5 sounds pretty high. What kind of match/mismatch are you giving him?
>With or without a balun.
>>18.1 MHz 2.28 dB
>>21 MHz 3.1 dB
>>24.9 MHz 4.35 dB
>>28 MHz 3.12 dB
>Roger (K8RI - ARRL Life Member)
>N833R (World's oldest Debonair)
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