Lightning protection/preamp question
I'm installing a pair of M2 circularly polarized yagis. I have a long coax run, so I'm going to use SSB Electronics preamps mounted on the 8' tower.
I have a ground rod by the base of the tower with a couple of lightning arrestors that the two coax runs go through, but I was curious what to do about protecting the inputs to the preamps? Do I use a second pair of lightning arrestors between the antennas and the preamps? Or just mount the preamps on the shack-side of the existing lightning arrestors?
Rich, KD2CQ
Hi Rich,
Wow, your antenna arrangement sounds great!
I bet most of the guys and gals here will recommend to consider each antenna and preamp pair as a single unit in this particular case! …
That is, the preamps are as close to the antennas as practical, and your arrester/polyphasors mounted near the grounding connection through a nice tin-coated copper braid and connects the RF to your feedline to the shack. Except that you must make sure your arrester does not block any DC needed by your preamps. In which case you may need to power the preamps *not* through the cables.
Food for thought. Or to let the technical arguments fly!
Cheers,
Pat N8PK-FM19 Maryland USA
https://www.dxengineering.com/search/department/grounding-and-lightning-prot...
On Thu, Oct 20, 2022 at 10:19 AM Rich Gopstein [email protected] wrote:
I'm installing a pair of M2 circularly polarized yagis. I have a long coax run, so I'm going to use SSB Electronics preamps mounted on the 8' tower.
I have a ground rod by the base of the tower with a couple of lightning arrestors that the two coax runs go through, but I was curious what to do about protecting the inputs to the preamps? Do I use a second pair of lightning arrestors between the antennas and the preamps? Or just mount the preamps on the shack-side of the existing lightning arrestors?
Rich, KD2CQ
Pat,
Having sat through a number of arguments on this subject, I recall one such adventure. A friend of mine, a very well respected and long term ham who lives under an aluminum cloud listened and listened and finally spoke up. "Good insurance!" Do what you can afford but nothing will protect you completely. I always feed my preamp for 70cm over the coax so the point about no DC block is important. Before putting up a 2m preamp you might want to check local ambient noise. If high it might not buy you much on receive and is just one more thing to worry about.
John K7SYS
On Thu, Oct 20, 2022, 08:23 Pat Kilroy [email protected] wrote:
Hi Rich,
Wow, your antenna arrangement sounds great!
I bet most of the guys and gals here will recommend to consider each antenna and preamp pair as a single unit in this particular case! …
That is, the preamps are as close to the antennas as practical, and your arrester/polyphasors mounted near the grounding connection through a nice tin-coated copper braid and connects the RF to your feedline to the shack. Except that you must make sure your arrester does not block any DC needed by your preamps. In which case you may need to power the preamps *not* through the cables.
Food for thought. Or to let the technical arguments fly!
Cheers,
Pat N8PK-FM19 Maryland USA
https://www.dxengineering.com/search/department/grounding-and-lightning-prot...
On Thu, Oct 20, 2022 at 10:19 AM Rich Gopstein [email protected] wrote:
I'm installing a pair of M2 circularly polarized yagis. I have a long coax run, so I'm going to use SSB Electronics preamps mounted on the 8' tower.
I have a ground rod by the base of the tower with a couple of lightning arrestors that the two coax runs go through, but I was curious what to do about protecting the inputs to the preamps? Do I use a second pair of lightning arrestors between the antennas and the preamps? Or just mount the preamps on the shack-side of the existing lightning arrestors?
Rich, KD2CQ
--
Pat Kilroy 1
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I do as K7SYS does....feed the preamps via the coax. All three antenna coaxes (2M, 70cm, 23cm) are protected where they enter the shack with lightning protectors.
On Thu, Oct 20, 2022 at 9:18 AM John Kludt [email protected] wrote:
Pat,
Having sat through a number of arguments on this subject, I recall one such adventure. A friend of mine, a very well respected and long term ham who lives under an aluminum cloud listened and listened and finally spoke up. "Good insurance!" Do what you can afford but nothing will protect you completely. I always feed my preamp for 70cm over the coax so the point about no DC block is important. Before putting up a 2m preamp you might want to check local ambient noise. If high it might not buy you much on receive and is just one more thing to worry about.
John K7SYS
On Thu, Oct 20, 2022, 08:23 Pat Kilroy [email protected] wrote:
Hi Rich,
Wow, your antenna arrangement sounds great!
I bet most of the guys and gals here will recommend to consider each antenna and preamp pair as a single unit in this particular case! …
That is, the preamps are as close to the antennas as practical, and your arrester/polyphasors mounted near the grounding connection through a nice tin-coated copper braid and connects the RF to your feedline to the shack. Except that you must make sure your arrester does not block any DC needed by your preamps. In which case you may need to power the preamps *not* through the cables.
Food for thought. Or to let the technical arguments fly!
Cheers,
Pat N8PK-FM19 Maryland USA
https://www.dxengineering.com/search/department/grounding-and-lightning-prot...
On Thu, Oct 20, 2022 at 10:19 AM Rich Gopstein [email protected] wrote:
I'm installing a pair of M2 circularly polarized yagis. I have a long coax run, so I'm going to use SSB Electronics preamps mounted on the 8' tower.
I have a ground rod by the base of the tower with a couple of lightning arrestors that the two coax runs go through, but I was curious what to do about protecting the inputs to the preamps? Do I use a second pair of lightning arrestors between the antennas and the preamps? Or just mount the preamps on the shack-side of the existing lightning arrestors?
Rich, KD2CQ
--
Pat Kilroy 1
Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/
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Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/
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On 10/20/22 11:15, John Kludt wrote:
"Good insurance!" Do what you can afford but nothing will protect you completely.
Agreed. Having witnessed a strike to our house which hit the gutters only a few dozen feet away (and survived it -- inside), I can say that your best protection is _unplugging_ everything when not in use.
A direct strike arced over GDTs and still fried some of the equipment attached to the coax. This included the the cable modem, whose coax happened to run right beside the HF coax.
--- Zach N0ZGO
I have my surge protectors at the entrance to the house. I realize that a) this is only for surges, not a direct strike and b) this is not protecting the preamps at the antenna or the coax run, but I'll take that risk. I had to use a separate power line, and that also goes through a surge protector.
o73,
Burns WB1FJ
On Thu, Oct 20, 2022 at 10:50 PM Zach Metzinger [email protected] wrote:
On 10/20/22 11:15, John Kludt wrote:
"Good insurance!" Do what you can afford but nothing will protect you completely.
Agreed. Having witnessed a strike to our house which hit the gutters only a few dozen feet away (and survived it -- inside), I can say that your best protection is _unplugging_ everything when not in use.
A direct strike arced over GDTs and still fried some of the equipment attached to the coax. This included the the cable modem, whose coax happened to run right beside the HF coax.
--- Zach N0ZGO
Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/
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Keep in mind also that the ground for these surge protectors MUST be the same ground as everything (electricity, phone, cable, etc) otherwise you’ll have a different potential across the two grounds and set up a voltage across those two and wipe out a lot of stuff in your house… Ask me how I know this…
Herb
Please excuse any typo's as this was sent from my iPhone.
On Oct 21, 2022, at 7:16 AM, Burns Fisher [email protected] wrote:
I have my surge protectors at the entrance to the house. I realize that a) this is only for surges, not a direct strike and b) this is not protecting the preamps at the antenna or the coax run, but I'll take that risk. I had to use a separate power line, and that also goes through a surge protector.
o73,
Burns WB1FJ
On Thu, Oct 20, 2022 at 10:50 PM Zach Metzinger [email protected] wrote: On 10/20/22 11:15, John Kludt wrote:
"Good insurance!" Do what you can afford but nothing will protect you completely.
Agreed. Having witnessed a strike to our house which hit the gutters only a few dozen feet away (and survived it -- inside), I can say that your best protection is _unplugging_ everything when not in use.
A direct strike arced over GDTs and still fried some of the equipment attached to the coax. This included the the cable modem, whose coax happened to run right beside the HF coax.
--- Zach N0ZGO
Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/
View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/[email protected] To unsubscribe send an email to amsat-bb-leave(a)amsat.org Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org
Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/
View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/[email protected] To unsubscribe send an email to amsat-bb-leave(a)amsat.org Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org
participants (7)
-
Bob Hammond -
Burns Fisher -
Herb Sims -
John Kludt -
Pat Kilroy -
Rich Gopstein -
Zach Metzinger