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Good day,
Now that my introduction is complete. I now have questions for the experienced members of the club.
Sunday night, 29 March, the lightning storm that rolled through Hollis released its anger directly over my QTH striking one of the tall pines that my 80-meter OCFD was supported from. Now the sad story. The discharge did no physical damage to the home but did damage a significant amount of electronics including my, new to me, ham radio system (in service 2 weeks). The discharge vaporized the antenna, coax and flashed the power supply and transceiver rendering them inoperative.
For the experienced my questions:
Is it feasible to send the FT450D back to Yaesu for evaluation and repair cost estimate, or is the cost-benefit not effective? I purchased the radio used in excellent shape though the model may be nearing production end of life.
Are their other alternatives for cost-effective repair?
My installation and grounding setup:
The OCFD antenna was hanging 60’ high with the coax drop from the balun to the exterior of my garage connected to a PolyPhaser lightning protector 4’ off ground. The body of the PolyPhaser was connected to an 8’ ground rod with #6 copper, and 125’ of #6 copper wire ran around the house to the common utility ground rod for bonding. The power supply and radio were not bonded to the common system. The power supply was off but still plugged into a duplex outlet. This most certainly completed a path for current to flow from antenna to radio to house wiring system. I was fortunate we had no fire but plenty of smoke and ozone.What should I do differently if I choose to go with an elevated horizontal dipole again?
What would be the best method of using trees for support and still provide some means of lightning protection?The upside is I now have more time to practice my code! I have attached a photo of the tree and my balun/antenna remains.
Thanks,
Scott KC1MDH
Hi Scott,
It sounds like you were pretty lucky that this did not get inside. It’s really tough to build a ground system that can stand a near-direct hit like this. The best thing to do is to disconnect your coax and lay it back away from the house when you are not using your antenna. I’m guessing that you might have done this but we don’t expect to have a lightning storm as we had on Sunday in March!
I’d suggest you open the cover of your radio and see how much obvious damage there is inside. If there is not visible or only minor visible damage, it might we worth trying to get it repaired. You might also be able to get your homeowner’s insurance to cover the damage as well.
Sorry to hear about your bad luck.
Hello Scott,
My first HF radio was a FT-450D. It was a eBay “for repair – it worked when I turned it off and never came back on.” I thought “how bad can that be” and bought it.
It was clearly a lightning strike. Nearly every device on the DC circuit was dead, ICs had cracks, and tiny devices like diodes and small MOSFEET switches were missing replaced by a pile of black charcoal. There were over a dozen parts that needed replacing. The Digikey parts order came to $26. The 450D lives.
I have since repaired a number of lightning struck rigs. Many require $10 in parts. A few have needed a new processor board ($168) and new finals ($175). Only one was beyond repair. A service center will add labor and there is also shipping costs which can push the cost beyond the value of the radio.
If you are interested I can take a look at it. You’ll need to leave it on the door step, we can have a zoom session to go through it and also talk about grounding.
Hamilton,
I’ll accept your offer, though I sent it off to Yaesu for a repair estimate as my insurer assessed significant depreciation on the item. I don’t anticipate Yaesu will be a cost effective repair option but it provides me an additional cost price for further discussion with the insurer.
A discussion on grounding improvement will be great as I thought I had all areas covered. Then again hanging a ~130′ wire between 2 trees seems like it would be a lightning magnet.
Thanks,
Scott KC1MDH
The FT-450D lives again.
Many radios have a internal GDT (gas discharge tube) right at the RF connector, this radio has it located after two relays, the bias tee inductor, a parallel pair of series capacitors and connected with using a via hole.
The first relay had significant melting and char marks, a PCB trace was missing to the bias tee inductor, one of the series caps was 1/4 gone and the other cap’s metal end terminations were all that were left on the board.
The image is the PA board with the SO-239, relays, and L5403 inductor removed. The PCB trace no longer extends to the hole used to mount the inductor and there is some board charing left after a thorough cleaning. The white GDT (D5409) is still on the board.
[attachment file=”85484″]
I wonder about the engineering process that lead to a GDT rated for 2000 amps being placed after a string of components rated for 1 or 2 amps and connected through a small via hole.
There were a few penny parts (diodes, transistors, regulator) that were damaged and replaced. Most of these were on the bias tee line after the inductor.
Unfortunately the blown regulator took the MCU IC with it. The radio is using a processor board from a 450AT that was upgraded to a 450D while we attempt to locate a replacement MCU IC.
The RF/IF deck, DSP, synthesizers, RF drivers and Final MOSFETS, and the front panel and its processor, all survived without a mark and perform perfectly.
I have seen several radios that took an antenna strike. Those, like this one, with a ground rod and a Polyphaser or other quality surge protection had similar damage and were easily repairable even when the antenna, balun, and coax were reduced to charcoal bits in the garden.
The radios without similar protection were damaged beyond repair….
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