Yesterday I went to the VFW 3115 and procured in our equipment box a hank of 100 feet of RG8X coax.. Our Cushcraft X-7 beam I had to research, as MFJ is out of business but I did find, that because it is semi-log rhythmic design; It uses a balun impedance transformer at the input and has a coax connector. So I am prepping that cable with a PL259 on it today..
BTW- MFJ has only 1 X7 in leftover stock and it is selling for $1599. Closeout..
Now before anyone poo-poo's using RG8X -
#1 that is what we have used on the beam since it was installed
#2. We have working hundreds of countries with that set up,
#3. it will handle a Kilowatt.. We have 600 watts.
#4. The antenna has 13dB gain. 94 feet of RG8X looses 2dB at 10 meters, leaving 11dB gain to work with.
#5 combination of 600 watts, and 11 dB overall gain gives us an Effected Radiated Power (ERP) of over 6500W
We will not use the entire 100 feet so we can cut the opposite length to our needs.
A concern I have is that there are multiple coax runs that need to be removed from the tower.. Some unused..
The new coax will not travel through water puddles like the old stuff.. but along the outside wall of the building, under the eve for weather protection. The rotor cable currently follows the bad coax.. However the rotor cable just needs to be re-routed.
Given time and manpower, as long as we get the tower done because we will only have the truck Saturday, The rest of the cable run can be done later or on another date..
Eventually we need to remove the coax runs from above the kitchen ceiling. The coax remaining on the ground is water contaminated from 3-4 years ago.. and needs to be scrapped but there will be some good. pieces we can have a program one meeting night to demonstrate how to test and certify coax using a VNA.
Larry W8LM
Larry Macionski