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| Base Connector |
Here I try to explain how to construct it step by step :
Prepare all the material :
- 2 meter Larson antenna ( set )
- PVC Pipe 1-1/4 inch 30 cm long ( Incl. the cap )
- Resin
- Copper Wire 1.5 mm dia.
Take 2 m antenna connector and whip holder .
Make a hole just fit to the connector diameter at the PVC cap, and smaller hole just fit to whip holder size at the other PVC cap.
Solder outer and inner connector with cable about 10 cm long. Now fix it to the hole and put thin glue around the connector to avoid of resin leakage.
Don't forget to prepare of another cap, otherwise you will do mixing of resin twice, and double works of pouring. One thing I forget to tell you, make inside cap surface rough enough, if neccessary you can add something like anchor mounted at the connector body by soldering some cm of copper wire.
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| Base Connector |
After preparation this job is OK, you can start pouring resin on it.
If you are not familiar with resin work, ask chemical store to guide you how to do, especially for mixing. Don't repeat my bad experience , the resin never dry and leakage somewhere around base connector. It is because of poor mixing and less activator.
Now you can see the connector from bottom side.
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| Whip Holder |
It's the whip holder. You can see the whip going through the holder, I think it will be easy to adjust the whip up and down freely, to get wide range of resonance, but is a big mistake, I found it after some weeks I used it. The rain water come into inside and make SWR very high. So, now I change its style , I close the whip holder with strong solder, yes, the whip almost can't be adjusted, but it can make me relax.
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| Winding Style |
Now, it's very easy job to do. Make a hole for starting of winding of 44 turns ( but you can make more turns for easy adjustment). You can start it 2 cm from top ( for cap insertion space ), wind the wire closely, tape strongly for holding it then make another 5 or 6 turns up to matching coil end.
The matching coil is 8 turns with one wire space and tapping point is 3 turns from ground side.
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| Ready to adjust |
Now is ready for adjustment.
If you don't have antenna analyzer, you may use Grid Dip Meter and SWR meter, because it is very easy job.
Place this antenna to where the antenna will be installed. Make sure all the grounding system is already installed perfectly. First, bracket itself must be grounded ( with lead wire ), the doors must be connected to the car body. Don't do adjustment in garage , go to an open area for easy to get good result. If everything is OK, you can check with GDO by making loop wire at end fed to get frequency resonance. Keep all winding and whip just like that posistion. The adjustment is only at top winding
by adding or lessen the turn. If you are sure with frequency you choose, now connect to TRX and try with small power to check SWR. Slight tapping point slowly until you get the lowest SWR. Yes, now wrap it with heat shrink rubber and seal in some places like whip holder and edge of heat shrink. Good Luck.
