MC Maco V 5/8 insulator upgrade.....

[smalltiredart]

MC,

When you upgrade a V 5/8 to V5000 specs, what material do you use for the insulator ??? Delrin ???? Teflon ???

 

[Master Chief]

Teflon.

McMaster-Carr Part Number = 8547K17

(just copy/paste that part number into the "FIND" box on the left)

You may need someone with a 1" mill to machine the ID and a lathe to turn down the OD. It is VERY easy to machine, so they make it a bit fat on purpose. If I choose to sell kits, I will have all the machine work done.

Resists extreme heat, cold, and UV light. Absorbs less than 0.01% water. Virgin Electrical Grade Bars, Sheets, and Rods Made with Teflon® PTFE
• Color: Varies from translucent
white to opaque white depending
on thickness and shape
• Temp. Range: -350° to +500° F
• Softening Temp.: Not rated
• Tensile Strength: Poor
• Impact Strength: Good
• Very low friction
• Excellent electrical insulator
• Use indoors and outdoors
• Machine with standard tooling
• Hardness: Rockwell R55-R58, unless noted

Made with virgin Teflon® PTFE resins, this material surpasses most plastics when it comes to electrical insulation properties, low friction, chemical resistance, and performance in extreme temperatures. FDA compliant for food contact. All meet UL 94V0 for flammability.

 

[smalltiredart]

Thanks for the info... I have a friend that works in the aero space industry, and he brought home some 2'' solid teflon rod for me.... I have access to a mill, but have to pay to use the lathe....

 

[Master Chief]

I'd start with a 1.400" OD. I didn't mic the Maco base tube, but if it is like the rest of the antenna, it may be .049 wall which means 1.375" will be loose. You can always take more away if it is too thick, but you can't add it back!

You should have NO problems with the .500' ID of the Teflon.

The antenna calls for a 6" length (1" exposed out the top), but you can always make it longer if you wish.

The amount of the main radiator INSIDE the Teflon that overlaps the base section is approx 4". I have not done any serious tests yet, but I believe this overlap may interact with the matching network causing loss. The Hy-Gain Penetrator suffered (IMO) from the same type of arrangement.

I have THEORIZED that the elevated feed system of the Avanti Sigma 5/8 provided LESS LOSS in the feedpoint. We have seen other "elevated feed" systems that work better than mounting it close to or on the ground (or ground plane in this case).

I told Jay about the elevated feed system of the Sigma 5/8 WAY back in 1997 or 1998. I'd have to dig out the e-mail to be sure. I also sent him a Sigma 5/8 for testing against the Mastadon 5000. Later, the Mastadon was scraped and the I-10K came out with an elevated feed system like the Sigma 5/8.

A test I'd like to do some day is elevate the main radiator out of the base tube and see what it does. The problem is TEFLON is not strong enough to properly support the main radiator (which is probably why Avanti used thick wall fiberglass tube......and the I-10K uses a SOLID fiberglass rod).

Antennas are fun!