Fan dipole question

[KC2UGV]

Ok, people, got a zinger for you to help me out with.

Just got done putting my fan dipole for 40-20-10 up. MFJ Analyzer (Not the digital one, with the Z meter, just SWR), everything tuned down to 1.5 or better; fed with RG8(?) Rat shack cable (I know, crap cable and all). No balun.

40 Meters - I can get full 100 W output.
20 Meters - Max 20 W Output
10 Meters - Full output

My first thought? Something blown in the 20 meter band portion of the radio, or similar reasons. So, I grab the dummy load, plunk it down to 14.275 (In case of RF leakage), and voila! I get full 100W output.

Now, why, oh why do I only get 20W when connected to the antenna. In fact, on the frequency I use most on 20 (14.070) SWR is 1.2:1.

If there's not enough data, what else do I need to check? And what tools do I need to get my hands on? Or, what texts are out there I can read up to get a feel for where I need to look?

[w3bny]

Some stupid questions if I may.

1. What freq did you use on 20m?

2. Did you cut/prune the antenna for that frequency?

3. What is the resonant frequency of the antenna as it stands now?

4. Did you hook up your analyzer and see what its telling you about swr/Z at the operating frequency of question?

It sounds like the transmitter may have folded back. Just check and see what the antenna is telling you. Others should chime in shortly

[W5RB]

Let's get some details . How high's the antenna , and how close to the TX ? What kind of radio ? How long's the feedline ? What mode are you in when testing , and is there an external meter , or how are you measuring power ? If there's a jumper involved , how long is it ?

[N9FE]

Need some lengths. whats your spacing between the elements. lastly. you got to get a dip meter. Or a MFJ that shows impedence

[KC2UGV]

Some stupid questions if I may.

1. What freq did you use on 20m?

14.070 MHz

2. Did you cut/prune the antenna for that frequency?

Yep. Got a 1.2:1 at that frequency. 1.5:1 at 14.275 (Test frequency).

3. What is the resonant frequency of the antenna as it stands now?

7.035MHz, 14.070MHz, and 28.120MHz (Three element fan dipole).

4. Did you hook up your analyzer and see what its telling you about swr/Z at the operating frequency of question?

Analyzer only shows SWR, and at the operating frequency in question(14.070), it is 1.2:1

It sounds like the transmitter may have folded back. Just check and see what the antenna is telling you. Others should chime in shortly

That's what it sounds like to me as well. But why it does, I have no idea.

Let's get some details . How high's the antenna , and how close to the TX ? What kind of radio ? How long's the feedline ? What mode are you in when testing , and is there an external meter , or how are you measuring power ? If there's a jumper involved , how long is it ?

Antenna is about 30 ft high at the feedpoint, and the ends are about 26ft up. Distance (Straightline) from the TX, 10 ft. Feedline, 30ft (a 10ft cable + Union + 20 ft cable). Mode is PSK31 during operation and testing. Power measured by the power meter built into the rig. And no jumper, just fed through a hole in the wall.

[KC2UGV]

Need some lengths. whats your spacing between the elements. lastly. you got to get a dip meter. Or a MFJ that shows impedence

Spacing between elements, well, at the feedpoint, obviously none. At the ends, 10 ft or so. I droop subsequent legs down a little, by about 10 deg or so from the feedpoint.

Do you need lengths of the actual elements? That could take some time, as I would have to physically measure them.

[N9FE]

You got the legs one on top of each other. That will work. But thats not a true fan. Fans look like spokes of a wheel. Allways tune your highest band first. Which is 10. Don't cut nothin. Just fold back on itself and wrap around the end.

[KJ3N]

I'm leaning towards RF in the shack on 20m.

What additional grounding did you add?

What's the grounding system like?

[N9FE]

I don't like the splice in the coax either.

[KC2UGV]

You got the legs one on top of each other. That will work. But thats not a true fan. Fans look like spokes of a wheel. Allways tune your highest band first. Which is 10. Don't cut nothin. Just fold back on itself and wrap around the end.

I'll have to keep that in mind next time. I got all of them pruned and tuned already, but I did 40 first, then 20, then 10; then back to 40, 20, 10; until they were all where I needed them.

I'm leaning towards RF in the shack on 20m.

What additional grounding did you add?

What's the grounding system like?

RF ground? None. How would I RF ground on the second floor of a building? I figured I would just be inviting more issues trying to make an RF ground in my situation.

Electrical ground? House ground system.