Moxon for 11 meters

[vkrules]

Hi again Bow.First of all your own measurements show that the moxon is resonate just above 28.00 mhz ,don't confuse SWR with resonance.
Second unless that roof contains a lot of metal thats not the problem with the match. Yes it is an issue but I don't think it's the problem. Interesting that the frequency has gone high and the impedance low. looking at your figures I would have thought the frequency would be low if height above the roof was the problem Check that the spacing between the element ends are correct and make sure that the dark grey conduit is in fact a good insulator . Many dark coloured conduits are high in mineral content.
You have tried the moxon facing up on the tiles ,but you should have tried with the reflector raised off the tiles in case there is foil sarking used under the tiles. Every one whats to hear you got it fixed

 

[Bow]

Thanks VK...

I have not given up on it... I have been working 12-16 hour days last week, so I didn't have any time to play with it further.

I agree with your possibility the the Grey Conduit may be conductive, it is used for running electrical cabling, so that does make it possible to be conductive.

I will try to get some white PVC and swap the end spacers out as soon as I get some time to play with it.

 

[vkrules]

Quick test put a scrap in the microwave and see if gets hot.

 

[Bow]

Quick test put a scrap in the microwave and see if gets hot.

That could be an interesting light show as well...LOL

 

[222DBFL]

What is the electrical conductivity of PVC?
Answer
Very low.
It's used as an insulator.

 

[northern35s]

What is the electrical conductivity of PVC?
Answer
Very low.
It's used as an insulator.

All PVC? no! All PVC were not created equal and carbon is added to some types of PVC, that's why it is suggested to stick a small amount in the microwave and look for a change in temperature, any heat increase and you know it's electrical insulation properties are suspect

 

[222DBFL]

Sorry forgot to add that for for the grey conduit for electrical use. And yes the best way to tell is to stick them in the microwave in cups of water.

 

[vkrules]

Very funny. But the truth is some conduit will get hot in the microwave and are not suitable for rf insulators .You can use a high resistance ohm meter to check if you have one.The microwave tests works ( without the fireworks ) I don't know what the commercial use is for these conduits(maybe someone here can tell us) but I know they are coloured differently than the usual light grey used for house hold electrical use. Thats why I commented on the dark grey insulators on Bows element ends.

 

[POBILLY]

Manufacturers will add carbon black to plastics to make them conductive to reduce static electricity.

 

[91IR109]

Dear moxon masta,
I'd really like to build this kinda antenna on aluminium tube for elements & 1.25" PVC pipe for the boom. But :
1. I have the problem about bending the corner. How about if I just bolt the corner down together instead of using elbow/bent corner?
2. I'd like to use 9mm diameter aluminium tube, what shud I put the number on MoxGen?
3. Shud I use the air-choke?
4. Which one better, PVC or aluminium boom?
Thank you very much.

Salam,
Wing

 

[HomerBB]

Dear moxon masta,
I'd really like to build this kinda antenna on aluminium tube for elements & 1.25" PVC pipe for the boom. But :
1. I have the problem about bending the corner. How about if I just bolt the corner down together instead of using elbow/bent corner?

Yes. Try it to see if it works well. I once made one with very close corners. Wire Moxons have very abrupt corners.

2. I'd like to use 9mm diameter aluminium tube, what shud I put the number on MoxGen?

Worldwide Wholesale Distribution of Valves, Fittings, Tubing & Flanges: World Wide Metric
has a converter you can use, but I believe the Mox-Gen will use either metric or decimal inch entries.

3. Shud I use the air-choke?

If you wish. I usually do.

4. Which one better, PVC or aluminium boom?

Whatever you have available. PVC sags when the antenna gets too large.

Thank you very much.

Salam,
Wing

 

[91IR109]

Thank u a bunch, HomerBB,

has a converter you can use, but I believe the Mox-Gen will use either metric or decimal inch entries.

I meant, what should I put on the "wire size" on the generator? Since there only for "wire", not tubing.
Pls info.
Thanks

Wing
91 IR109
+628129088435

 

[vkrules]

Have another look. You can set the drop down box to mm or inch and put in whatever size tube you have.

 

[91IR109]

Finally, I bought a pipe bender.
Hahaa...
But still confused to put the number of diameter since I used 3 diff tubing diameter. 17mm, 12mm & 9mm (for corner) and ended with 12mm one.
Which diamater do I have to calculate?

Terima kasih.

 

[HomerBB]

Add them together, divide by 3, use that number and adjust the tune when you put it together.
gotta have some kind of starting point.