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Hi again Bob. Like I said before, coax is hanging down, about 16 feet without touching the mast, about 40 feet of coax is laying on the roof and about 10 feet from edge of roof running inside tower to the coax relay box .

Bob, I would like to know your answer to my question.

Today I taped the coax cable at 6 feet high to see what happened. About half inch of coax was taped to the mast. Before that, coax cable was hanging down not touching the mast. Antenna height and conditions remained the same. See post 619 for you to compare. Resonant frequency shifted up and...

No, I did not noticed the attenuation I had before. Maybe it was the line isolator, the jumper I used to connect it to the Vector, I don’t really know. Even when I had higher SWR, I didn’t have attenuation without line isolator installed. For short, adding the isolator gives me some kind of...

Hi Bob. Do those number look right ?

Today I made some final adjustments and could achieve this with LMR-400 cable, 45.56’ of coax from RCS-4 control switch to remote coax relay box in the tower, and 60.74’ from relay box to Vector 4000 @ 16 feet above roof. SWR reading taken with a SWR/Watt meter at the station. SWR———FREQUENCY...

Since I had some attenuation on RX, I decided to take the isolator off and leave it installed with RSC- antenna switch. It’s working fine like that, with SWR of 1.2 on channel 28 and a bandwidth of 1,850 KHz Specs says SWR @ resonant frequency should be equal or less than 1.2 on resonant...

Here is the picture of the isolator installed

Bob, right now it is 16 feet above roof. I’ ll take a picture of the isolator installed. I am thinking about insertion loss caused by both a 3” jumper connecting isolator to antenna and the isolator itself. I, ll take it out and I’ll try again.

It was a good thing to have it tuned on channel 8 because I know that as soon as I raise the mast up, SWR and resonance frequency tend to raise as a whole. Check this out. I hooked the analyzer with the 1/4 wave , 14’ feet tuned jumper I made out of LMR-400, 6 feet above roof. SWR——-Frequency...

Which one ?

Yesterday I could finally use the analyzer with the 7.25’ feet long of LMR-400. Hi Bob. What do you mean that the 1/4 wavelength jumper I made ( by the way it’ s LMR-400 ) will invert impedance , while the 1/2 wavelength will not ? Dr._DX These last days, I was playing with the...

Hi Bob. I used two type of line isolators, a Radio Works T-4 and a CMC-330-1K. Using good coaxial. As well. Antenna grounded. Then, What else can I do ?

Thanks Marconi for this video. I followed this video and could calculate 1/4 wave resonant jumper. I set the analyzer in Impedance R & X on 27,205 KHz. ( Channel 20 ). In order to use this method, one must cut the coax longer like Dr_DX said, to cut coax 20% longer ( I recommend to use formula...

Thanks Bob. I forgot to mention, SWR does not change if I disconnect the ground strap, not even a little. And of course, roof has rebar all over the place. It is a concrete roof reinforced with rebars. I think I tested with the line isolator, with no difference but, I’ll try tomorrow again and...

At last I could tune the Vector. I had to shorten L3 to 23 5/8 inches and L2 adjusted to 24 3/4 inches. Here are the numbers from the MFJ analyzer measured with a 1 foot of LMR-240 jumper on 6 feet mast on top of my roof. SWR———-Frequency———-R———X 2.0 ———— 27,805—————42——-3 1.5————-27...

Are you talking about the Vector ? Those are the frequencies I am interested in, the Vector ones

Hi Dorado. I’be bought two spools of RG-8X from DX-Engineering. It is good stuff. Why so many ? Because I resell it. to cbers around here. It is the only RG-8X with Type II jacket on the market. In theory it won’t get green (contaminated) with time like the regular RG-8X. Jacket is more...