I bought the SPT-500 Super Penetrator new back in Aug of 2017. And put it up in Sept that year. I had tuned it for 27.025 MHz The middle of the 11-meter band. I have it up about 40 feet from the base. Also ran a drake 2k tuner and Henry 2KD5 AMP. I replaced the main wire coming out of the back of the antenna connector on the antenna so it would handle more wattages going thew the antenna. Everything was working well. So yesterday I had decided to take it down because my SWR had gone up to 3.2.1. After taking it down I had seen were the main bracket with the two u-bolts going thew had twitched and the shorting rod part number 170775 had snapped into two pieces. I know we get a lot of wind at our house why I don't know. The wind can be blowing here but go anywhere else close by and there is none. The same thing had happened to my Imax 2000 same house. Snapped that antenna into two pieces. So my question is could I use a piece of solid copper wire 14 ga and put it in place of the shorting rod? Or use some Gorilla 2 part Epoxy to glue it back together. Will, that work? Up until now, I thought the SPT-500 was a good strong made antenna. I think I just found the weakest part of the antenna. Does anyone make a good ground plane antenna anymore?
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MFJ- SPT-500 Super Penetrator help.
- Thread starter cbkidd1
- Start date
CB, I bet that part on this antenna gets a real working-over with the wind 24-7 whipping back and forth...plus the ground wire is attached securely at both top and bottom.
Do you think your Hooten-Nater might have fried this part? I don't know how much it matters...that this part be to specs. But, I wouldn't change it much. Copper is probably OK.
Do you think your Hooten-Nater might have fried this part? I don't know how much it matters...that this part be to specs. But, I wouldn't change it much. Copper is probably OK.
This failure may have less to do with wind and more to do with RF heating being fed with that Henry. At this power level there is enough current flowing through that DC shunt to cause heating. Expansion and contraction occur each time the mic is keyed at that power level and will cause the poor aluminum conductor to crack over time. Sometimes the bolt coming out of the connector housing will get hot and make the plastic melt around the bolt.
This wire can be replaced with copper but it should match the same diameter or gauge as the original part otherwise some adjustment in matching will probably be required. The same size in copper will increase power handling but don't reduce the gauge or the problem could get worse. Bend the new wire exactly the same shape and length as the old one or tuning will be required again.
This wire can be replaced with copper but it should match the same diameter or gauge as the original part otherwise some adjustment in matching will probably be required. The same size in copper will increase power handling but don't reduce the gauge or the problem could get worse. Bend the new wire exactly the same shape and length as the old one or tuning will be required again.
Thank's for the advice. The shorting rod is made of aluminum looks to be around 14ga. So I will try and see if the 2 part Epoxy will hold it. If not will get some 14 ga. solid copper wire and bend it to the same shape and length as the rod. Is the rod used for grounding? I will get a picture uploaded soon of the base plate and rod. It looks like the wind just twisted the base plate and when that happened it snapped the rod. There are two standoff insulators the one on the top has a crack in it. I don't know for sure maybe it was a combination of both wind and cold that cause the antenna to fail? That makes two in three years. The wind snapped the Imax in two. 73,
Don't waste your time trying to epoxy this part. You'll need to replace the wire to make a reliable repair. RF connections do not glue together well.
So your saying just get a length of solid copper wire not sure what gauge and same length? Should I just bend the ends around the screws or crimp a connector on the ends. I am asking because of not knowing if the connectors will interfere with the SWR. Here are a few pictures showing that the wind bent the Bracket and snapped the shorting rod or Beta Rod? from another thread here on the forum. 73,
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Skip the crimp connector because that's just adding another weak link. This is part of the matching network. It's primary job is to remove static buildup by shunting it to ground. It's also useful to reduce lightning damage but a direct strike would open that wire right up.
