T2FD on metal roof

[otobmark]

I’ve put up 2 of these on county EOC buildings for SHARES, including ALE. So far they seem to work. I have done things wrong in the past and somehow gotten away with it so now that we are putting up some more I figured I should investigate best practices. The roofs are metal decking covered with insulation board and fibertite membrane outer weather proofing. There is some equipment on the roofs (HVAC), and installation of lightening rod system. The 2 antennas already installed are about 15’ above the roof crossing above clear (no HVAC) surface. Environmental noise has been pretty low, probably due to roof shielding antenna from interior of the buildings and all of the backup 911 center gear contained within. Most used frequencies are 4, 5, 8, and 9 mhz range with some ham 20m/40m/80m. Using SHARES Winlink hitting RMS nodes at 500 plus miles has been seemingly good (nothing to compare to). My state is 560 miles wide which would be the longest throw possibly needed with a more usual throw to nearby counties or our capital which is fairly central.
Going up much higher would require more elaborate, fragile and expensive mounting hardware and I suspect make system more susceptible to environmental noise as receive angle opens up. Hope this is enough information. In a perfect world I would remote all HF operations and link by microwave or MESH.

 

[mmckenna]

I've got two of those setups, but they are flypacks with rollatube masts. When I set them up in the field, the tube mast puts the feed point about 15 or so feet up with the ends sloping down to about 5 or 6 feet off the ground. Works well for NVIS and in-state use.

I think if you can mimic that over the metal decking, it should work similarly. I've had no problem reach out a couple of hundred miles that way.

I need to convert one of my flypack to a base at our EOC, so looking at doing something similar, unfortunately no flat roof to work off of.

 

[otobmark]

I think if you can mimic that over the metal decking, it should work similarly. I've had no problem reach out a couple of hundred miles that way.

OK— I will keep doing what I’ve been doing. While I do operate HF on government and amateur frequencies, I cannot imagine it moving the needle during disaster for larger entities (cities, counties, states etc) but could be a lifeline for individuals or small communities of isolated people. Maybe a Mad Max situation.

 

[mmckenna]

While I do operate HF on government and amateur frequencies, I cannot imagine it moving the needle during disaster for larger entities (cities, counties, states etc) but could be a lifeline for individuals or small communities of isolated people. Maybe a Mad Max situation.

Just another layer in the P.A.C.E. protocol.
We received state grant funding for 2 HF packages. We have access to state and federal frequencies. The radio also has the "Free Tune" feature which lets me TX/RX on anything between 1.8 and 30MHz.

We have satellite capability, both radio and phone, so unlikely this would ever see real usage, but having two of them opens up some possibilities for us if we ever need to restore a communications path between our main site and some of the very remote sites we have.

 

[otobmark]

My goto for HF communications is Australia. Even rental cars sometimes have HF radios in them. The vast majority of the country is sparsely populated and depends on HF for phone, email and emergency services. The shear amount of trial and error alone would render workable solutions. Everything is Selcall with maybe a little ALE thrown in. If in my state we were serious about Emcomm we would have a working HF station in every County EOC with at least Selcall or my favorite ALE (and email). During activation station could run 24/7 and operate largely unattended on statewide net. The civilian/amateur side of HF is pretty much the wild west. Maybe some established HF amateur calling frequencies for emergencies would work— akin to the old days of Ch 9 CB. Civil Air Patrol used to run HF nets and that could be a model. COTHERN would probably be the best model.
My last experience with Helene and Amateur radio was mostly fail with just a few bright spots. Of the affected counties maybe 1 had a working “E” part of PACE. A 2 man team (1 paid other volunteer) went into Mitchell Co. and found some HF gear that they had to assemble to try to get comms to RCC prior to Starlinks arriving. Radio was not open banded and could not operate SHARES. As far as I know the remaining Co EOC’s had no HF or line of sight amateur up and running. Amateur repeater sites had no or limited backup power with none lasting more than 72hrs with exception of Mt. Mitchell. Only place amateur radio was close to being a game changer was in relief efforts and coordinating volunteer groups. This time our statewide trunk system mostly survived, hindered by fuel resupply and some site trunking. If we had experienced a more catastrophic TRS failure there would have been no quick backup. We could all talk about emcomm strategy and weaknesses for days on end. Starlink was our game changer this time around although it took a week or more to deploy. Next time our phones will be satellite direct. If satellites are ever turned off either deliberately or accidentally I fear no one will be ready. Satellites should not be considered E part of plan.
Our paid consultant for hotwash was what we always hear with focus on MORE trunksites/bandwidth. Well as a taxpayer I cannot see building out infrastructure for a once in a hundred years event Statewide online. The ability to deploy resources as needed to the areas of need would make more sense to me. I’m so glad I’m not making these decisions because there is probably is no right answer.

Thanks again for antenna comments, I now have more confidence in what we are doing.

 

[EAFrizzle]

Well as a taxpayer I cannot see building out infrastructure for a once in a hundred years event Statewide online.

It won't be a hundred years til the next 100-year event.

Signed,
Someone who's been through FOUR 500-year flood events since '96 and countless 100-year events since about '73.