Commercial HF Antenna Options

[DisasterGuy]

Placing this in this sub as the most likely relevant… I’m doing a new HF install (Icom F8101) for Pactor 4 outside of the ham bands in NTIA spectrum. Coverage range is 2.5-27MHz. Install will be going at a public safety tower site. Siting for the antenna will be just outside of the compound and I have about 150’ to work with. Plan is to sink two utility poles for antenna support at about 30’ AGL. I’m leaning toward either an End-Fed wire with buried counterpoise using the AT-140 tuner (already on-hand) or a B&W BWDS-90N folded dipole (already on-hand) that shouldn’t require a tuner.

Antenna feed point will be about 200’ from the station and feed line will need to be buried. Planning LDF4 in conduit from antenna to shelter bulkhead and then 1/2” super flex for the 25’ inside the shelter.

Looking for thoughts / feedback between the end fed and folded dipole in this application.

 

[KevinC]

I moved this to the Professional forums.

 

[otobmark]

The folded dipole will give you simplified ALE capabilities. Look to solutions used in Australia since they use HF widely on a daily basis as a basic utility. If only by trial and error they have determined what works. The 2 EOC’s I work with use the folded dipole no tuner solution. Our footprint is 400-800 mile radius so somewhat of a moderate nvis pattern and some help with environmental noise. The big resistor eats power but the power that does radiate goes straight up where we want it. It’s also listening straight up. System really shines when all stations use nvis.
If you really want longwire look into inverted L.

 

[mmckenna]

I received some grant funded HF gear and it came with folded dipoles specifically for ALE/Bandwidth reasons as well as NVIS Not having to have a tuner in the mix makes it a good solution. Two poles if you don't need NVIS would be a nice setup, maybe a third for center support of the coax.

 

[techsender]

How far out are the out stations you are communicating with ? That will make a difference on going the NVIS route or not. If hanging the folded dipole plan on the middle support for the feedline / center insulator.

 

[DisasterGuy]

Thanks all. Without going into too much detail (for those familiar with WinLink) it will be a non-Amateur RMS node with a few other RMS Hybrid stations within a few hundred miles so NVIS isn’t critical as much as just contributing to CONUS coverage and being able to get propagation to a few other RMS nodes within the CONUS for offline / hybrid operation.

 

[techsender]

If you do decide to go the antenna tuner route make sure it is disabled or bypassed on receive otherwise you will find your receiver gets a little deaf above the last used transmit frequency.

 

[prcguy]

Sounds like your looking at mostly NVIS and that is usually below 10MHz, like the 2 to 8MHz range depending on time of day. A horizontal antenna is best and it will be the most efficient if its no higher than about 1/4 wavelength on your highest NVIS frequency. It can be lower but efficiency will go down requiring more power.

I've used a few B&W 90ft folded dipoles and despite their lossy nature they work surprisingly well. At 30ft high and on lower freqs like 2-4MHz they are mostly omnidirectional and on higher bands you will have gain lobes and nulls, so if you might run higher frequencies and longer distances you might map out the lobes on your frequencies of interest and try to mount the antenna so the gain lobes favor your needed direction.

Will you be running ALE? If so the B&W is a good choice for that because it doesn't need a tuner which can have problems in scan mode clacking away as your radio scans different channels.

 

[Thunderknight]

Second the B&W antennas.

 

[DisasterGuy]

Second the B&W antennas.

Yeah, it is feeling like a better option to ditch the tuner. Radio will be frequency hopping every few seconds. Price isn’t too big of an issue. I have a few B&W antennas on hand and in the scheme of things they are cheaper than any of my other station antennas.

 

[TampaTyron]

Terminated folded dipole as a main antenna with either a second t2fd or random wire with a tuner as a backup. Getting an ALE capable tuner with older gear is noisy/pain in butt. I have worked on several Micom, Icom, and Codan solutions....mostly SHARES, but some domestic HF networks for Caribbean/North African countries. TT

 

[K6GBW]

The folded dipole is pretty much the standard. The expensive standard!

 

[merlin]

If you have the real estate, a half wave T3FD is dynamite from 2 to 30 Mhz.
The next best thing to a half wave Rhombic.

 

[merlin]

Terminated folded dipole as a main antenna with either a second t2fd or random wire with a tuner as a backup. Getting an ALE capable tuner with older gear is noisy/pain in butt. I have worked on several Micom, Icom, and Codan solutions....mostly SHARES, but some domestic HF networks for Caribbean/North African countries. TT

Using a 140 foot EFHW and tuner works well but not as good as the T3FD
Pricy albeit, but what are you after.