I am rebuilding a used Cushcraft A3S yagi. Can I sweep the traps to determine resonant frequencies?
@Michael_Remboldt
Yes, the Rig Expert Match, antenna analyzer, is designed to measure and tune antenna traps. It can determine the resonant frequency of traps, as well as measure other passive RF components like inductors, capacitors, and transformers within its frequency range. Here are just some of the things this wonderful analyzer can be used for:
Checking and adjusting antennas;
Сable length and velocity factor measurements;
1/4-λ, 1/2-λ coaxial stubs setup;
Finding cable fault;
Measurement of parameters of other RF elements - capacitors and inductors.
Transformers;
Traps.
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Michael, Yes you will have to build a small loop as described in the user manual from Rig Expert. I also rebuilt a A3 last fall. I threw away all the rusted bolts and replaced everything with Stainless hardware. I polished all aluminum parts, elements, traps, etc.
One thing you will need to do is first find the parasitic (front) element and using a sharpie marker, label the front element 15m traps(x2) as TB. They are the traps closest to the element end. All other 15m traps label TC. All 10m traps can be labeled TA if you like.
You need to do this before you take all the traps off so you know which are 10m traps and which are 15m traps. The two 15m traps you marked TB MUST be put back on the front element. 2nd thing is the traps are probably filled with mud, grass, pieces of leaves, etc from insects entering the traps through their weep holes. You have to take the traps apart to clean them, one at a time so not to mix them up. I believe there is a you tube video on how to take the junk insects put in the traps out. You can’t find anything , let me know and I will try to send instructions and my experiences cleaning the traps. I’m good on qrz. I have the assembly manual and other help files if you want them. Just email me.
73 Jim NJ3T
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