trimmerj
KD3DID
Run is close to 100'. Doing a tri-band (20 40 80) fan dipole.Think the loss at 20 meters is noticeable with 8x?
Thanks
Thanks
Rgx8 vs Rg213
- Thread starter trimmerj
- Start date
mmckenna
I ♥ Ø
At 14 MHz, 100 feet:
RG-8X = 1.087dB loss. Of the 100 watts, 77.8 reach the antenna.
RG-213 = 0.741dB loss. 84.3 watts reach the antenna.
0.346dB difference between the two. That isn't zero, but it may be very hard to notice. For the purist, it's an easy answer, but RG-213 isn't the ceiling. Consider the cost of 100 feet of RG-213 and then look at LMR-400 (0.454dB loss/90 watts to the antenna) or LMR-600 (0.287dB loss/93 watts reach the antenna).
If the RG-8X is already installed and working, I'd have to convince myself pretty hard to put the effort into changing that out. A few more watts getting to the antenna is not likely to make/break anything, but for some, it's worth every penny.
RG-8X = 1.087dB loss. Of the 100 watts, 77.8 reach the antenna.
RG-213 = 0.741dB loss. 84.3 watts reach the antenna.
0.346dB difference between the two. That isn't zero, but it may be very hard to notice. For the purist, it's an easy answer, but RG-213 isn't the ceiling. Consider the cost of 100 feet of RG-213 and then look at LMR-400 (0.454dB loss/90 watts to the antenna) or LMR-600 (0.287dB loss/93 watts reach the antenna).
If the RG-8X is already installed and working, I'd have to convince myself pretty hard to put the effort into changing that out. A few more watts getting to the antenna is not likely to make/break anything, but for some, it's worth every penny.
At 14 MHz the difference isn’t that great and generally would not be noticeable, especially on SSB.
Would you ever change the antenna to work up to 10 Meters?
Here is a good site for calculating loss:
K6GBW
Off Grid Kid
The weight difference between RG8X and the heavier coaxes is pretty significant. Something to consider if you have a center fed fan dipole.
Something not mentioned is that coax expects to be terminated with its characteristic impedance.
SO, with a decent match, the loss calulators are awful close.
More than 2:1 mismatch, now you have heating to contend with in the form of additional loss.
Best place to learn feed lines is ARRLs Antenna book.
SO, with a decent match, the loss calulators are awful close.
More than 2:1 mismatch, now you have heating to contend with in the form of additional loss.
Best place to learn feed lines is ARRLs Antenna book.
Yes that's true, but at 100 feet, I'll take RG-213 all day, any day for HF work. If it's from a quality maker, then it should last a long time too.
trimmerj
KD3DID
I'm kinda worried about the weight of the rg8x. Long run without much suspension. Ladder line would be a better choice. Still fabricating the antenna.
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