Or we can assume that 79/50 = SWR 1.58, which adds an additional 0.13 dB of
loss... Hardly worth cutting coax for...
Now, given that the impedence measurement was made at the generator end of the
coax, the impedence at the load end will not be the same 79 + 0j...
What we will need to know is your coax loss figure and the total length of the
coax used for this antenna, then we can calculate matching sections more
accurately...
However, my suggestion is that given quality coax the additional loss per
hundred feet for all SWR under 3:1 is so low that you stick to a convenient
matchbox at the transmitter end of the coax... A simple L match - a series
coil with a variable cap across the antenna terminal of the coil to the braid -
will do the job nicely - and you can qsy all over the band, and other bands...
Does not need to be in a fancy enclosure and will keep the transmitter happy...
You can wind the coil on thin wall, septic drain, 4" dia. PVC from Home Depot,
or equal... Probably 3 to 5 turns (didn't do the calculations for that,
perhaps Gerald or others will chime in)
denny ... k8do
---------------------------------
Stay in the know. Pulse on the new Yahoo.com. Check it out.
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|