HF Antenna For EMA Tower

[krokus]

Roger, I was thinking about getting a HF/VHF/UHF rig. I would like to have situational awareness during hurricanes, for our area, with the state EOC, for teams deployed and as a back up comm set up.

The mobile teams are not likely to utilize HF. The bands you want for regional coverage, mainly 40m & 80m, are more problematic with a mobile setup. If the USAR uses a transportable shelter, that might be able to have a 40m deployable NVIS antenna, without being too cumbersome. Using low-band VHF could be useful, with similar benefits to what 6m has.

Also, there is the matter of licenses. Your agency would benefit from getting licenses for the desired freqs, so anyone authorized by the agency may use the radios, and not be reliant on ARES/RACES operators. There is a lot to consider.

Lastly, I would caution to not get one radio with all the bands. That gives you a single point of failure, and limits options for having more than one radio operator, when traffic starts flying.

 

[K6GBW]

Something to consider in an antenna set up like this is that you want to be put up and STAY up with no issues for extended periods of time. The performance of an antenna like this is usually compromised to get the NVIS and broadband performance you want. A good antenna for something like this might be this:

Bushcomm SWE-100 Bushcomm SWE Series Broadband End-Fed Antennas | DX Engineering

Free Shipping - Bushcomm SWE Series Broadband End-Fed Antennas with qualifying orders of $99. Shop Wire Antennas at DX Engineering.

www.dxengineering.com

Hung at about 35 for 40 feet and sloping down to the other side of the buildings roof it should do what you want. It's super rugged and will stay up for years and years with no issues. Tuning it shouldn't be a problem either.

 

[WB9YBM]

I need some advice for an antenna to be placed on the tower that has very high wind resistance. The communications company that is designing the tower needs to know what type of HF antenna we will be placing on the tower so they can get the specs on the tower to us.

The commercial companies I've dealt with on similar topics have requirements that anything they'll install has to be commercially made (no homebrew--and in some cases broadcast quality instead of ham radio/hobbyist quality) so you might want to check the web sites of antenna manufacturers to see what's available; they usually provide mechanical spec's, too...

 

[W5lz]

I think the simplest way of going about it is to just put up maybe a fan dipole somewhere around 50 feet or so. That would give you typical range for most HF bands. Best way of doing it? Nope, but about average for most EMS. If your EMS uses specific HF frequencies, make a fan for them. Most towers have guy points that can be used for those dipoles/doublets. May need a few insulators and lots of guy cable though. Sort of "shade-tree it", you know?

 

[prcguy]

A fan dipole is not that simple compared to recommended EFHW and OCFDs and 50ft is too high for needed 40m NVIS.

I think the simplest way of going about it is to just put up maybe a fan dipole somewhere around 50 feet or so. That would give you typical range for most HF bands. Best way of doing it? Nope, but about average for most EMS. If your EMS uses specific HF frequencies, make a fan for them. Most towers have guy points that can be used for those dipoles/doublets. May need a few insulators and lots of guy cable though. Sort of "shade-tree it", you know?

 

[W5lz]

Sorry, but a fan dipole is really about as simple as it gets. You might notice that I didn't say 'easiest'. Depending on how it's made they don't have to have several tie-off point, just two and one on that tower.
Height is variable. 50 feet is a nice round number so why not? Do what's -practical- for you. You really aren't looking for a range of the whole world...

 

[prcguy]

Their is not much easier than an end fed with only two attachment points. Antenna heights have already been discussed here and 50ft will not provide good NVIS on 40m. 35ft is about the highest you would want to go and 32ft is probably ideal giving the most gain upwards for NVIS on 40m plus a low angle takeoff on 20m and still reasonable NVIS on 80 and 60m.

A preamade fan dipole from someone like AlphaDelta is all tied together from the factory but a home made fan dipole is a project. For the end fed, you just pay some $$ to Danny at MyAntennas, take the antenna out of the box, hang it up and it works perfect with no tuning or fiddeling and with essentially the same performance as a fan dipole.

Sorry, but a fan dipole is really about as simple as it gets. You might notice that I didn't say 'easiest'. Depending on how it's made they don't have to have several tie-off point, just two and one on that tower.
Height is variable. 50 feet is a nice round number so why not? Do what's -practical- for you. You really aren't looking for a range of the whole world...

 

[N4GIX]

Lastly, I would caution to not get one radio with all the bands. That gives you a single point of failure, and limits options for having more than one radio operator, when traffic starts flying.

I was just fixing to say the same thing. While my FT-857D is just fine for my car on HF the 2m and 70cm bands are redundant (but sometimes handy), I would not have an "all in one box" such as that in the EOC radio room. It's too restrictive and you will almost certainly want the ability to monitor multiple bands simultaneously.

 

[popnokick]

If you want flexibility and redundancy in the EOC (and most do)..... get TWO (or more) multi-band, multi-mode radios. No more "SPF" (Single Point of Failure).

 

[mmckenna]

A band specific dipole, or multiband fan dipole, may not be the best choice for an emergency management agency. If the agency decides to join the SHARES system, having something more broad banded would be a good plan.

Flexibility would be key.

 

[wa8pyr]

If you want flexibility and redundancy in the EOC (and most do)..... get TWO (or more) multi-band, multi-mode radios. No more "SPF" (Single Point of Failure).

Very true, but most EOCs I've experienced in my life don't have that kind of money, and are often space-limited as well. Unfortunately, the EMA/EOC is generally pretty far down the totem pole when it comes to funding.

For our EOC, I went with an off-center-fed dipole good down to 80m and up to 600 watts. We had limited funding, so I went with the best general choice for all-band coverage. It's about 25-30 feet off the ground and works reasonably well for NVIS.

 

[K6GBW]

Curious if the OP ever settled on a particular antenna, and if so, how did it work?

 

[csimpson911]

@k6bw I decided on going with a dipole antenna. The tower has not been constructed for the new building yet, but after talking with folks on here and looking at my needs, that will be the direction I will be going

 

[K6GBW]

Outstanding! I hope it all works as expected!