Why Won’t My 80-Meter Dipole Cover the Whole Band?


Interesting and well done video covering one of the challenges of working with larger(er) antennas.
Need a simple antenna reference? Check out John Hill’s classic on wire antennas. How’s that commo coming along on the practical / tactical end? Got a class for that.

Spread the love
                

Share This Story, Choose Your Platform!

About the Author: NC Scout

NC Scout is the nom de guerre of a former Infantry Scout and Sergeant in one of the Army’s best Reconnaissance Units. He has combat tours in both Iraq and Afghanistan. He teaches a series of courses focusing on small unit skills rarely if ever taught anywhere else in the prepping and survival field, including his RTO Course which focuses on small unit communications. In his free time he is an avid hunter, bushcrafter, writer, long range shooter, prepper, amateur radio operator and Libertarian activist. He can be contacted at [email protected] or via his blog at brushbeater.wordpress.com .

9 Comments

  1. Hank March 31, 2021 at 19:59

    OT, a note on the DM 1701: the menu items are different for VFO and Channel mode. In fact in channel mode you can set from menu to show freq. or name, however if you set to show name you cannot switch back to VFO mode with the red button until you use the menu to show freq. again. Spent a lot of time reloading programming from software until I figured that out. Tried to post on Capt Atillas article, looks like comments are closed on that article. Thanks.

  2. DirlNasty March 31, 2021 at 21:06

    Good timing posting this as I am waiting for my Hf transceiver to get in. So after watching this I am thinking of a way to be able to either use something like a double fisherman knot to be able to quickly change the length of the wire or for base setup a 2:1 or 3:1 switch with different length antennas to select from?
    So question is how far apart would these antennas (if using NVIS) need to be for the not to interfere with one another? Or does it not matter? Am I overthinking this? I mean you burned the PACE plan into my head even though it was applied in practice to UHF and VHF, so is it reasonable to apply the pace plan to HF regional communications using NVIS? Because if so then it looks like I got to finagle my setup. Features and options for this capitalist I want all the frequencies……ya

    • NC Scout March 31, 2021 at 21:24

      At least one wavelength- so whatever one wavelength is for that band (80m is 128ft) that’s how far apart they should be at a minimum.

      • DirtNasty March 31, 2021 at 22:39

        Yes thank you! I will start there.

      • Jefferson Thomas April 1, 2021 at 10:28

        Need to double that – full wavelength is approx. 260 ft. Other things to do: orient dipoles 90 degrees from each other. This can help a little, but as you will be operating NVIS (unless you have big towers) this will reduce the effect. You can use a vertical for one which puts the two antennae at different polarizations in the near field. Lastly, distance between needs to be increased as true transmitting power used goes up.

        • NC Scout April 1, 2021 at 10:38

          Yeah, you’re right. I was pretty well-worn when I typed that last night.

  3. DirtNasty March 31, 2021 at 23:20

    Something I want to say that goes slightly off topic. On this site I see the least comments on the nerdy shit. I was born a Hy-bride model of 50% nerd/ 50% redneck. This Hy-tech stuff, all of us better start figuring out. Just like physical training books and technical knowledge is pain full. It sucks to do……….
    Point being when Scout posts this stuff, my opinion is there needs to be questions and responses on the nerdy shit? Truth be told “electronic warfare” is harder then shooting a rifle? Better learn fool~ if you love freedom!
    DirtyNasty out

  4. FlyBy March 31, 2021 at 23:24

    That is the best explanation I’ve heard on this topic!! Thanks for sharing.

  5. kc April 10, 2021 at 22:04

    For D.Nasty – I understand your goal is an antenna setup for NVIS (GREAT goal btw!). That means DON’T use a vertical; only horizontal polarized antennas, like a dipole. You want the radiation pattern straight up, NOT down on the horizon (which a vertical provides).
    Yes, you can combine multiple dipoles to cover the NVIS bands (typically 80m, 60m, 40m – the weak ionosphere for the next few years won’t support anything higher for any usable timespan). The neat thing is you don’t have to separate these dipoles – they can all be wired ‘in parallel’ right at the feed point, and fanned out ~60 degrees from each other. Just a single coax, and no switch is needed!
    For NVIS, a single support for the inverted-vee form of dipole is preferred, only 15-25′ tall. Cut the 80m dipole for best VSWR on your desired freq first, then the 60m, then the 40m. The 80m VSWR will cover a broader part of the band than shown in the video, because it is so close to the ground – which is needed to get the high angle radiation pattern. There are several good articles on the i-net that describe the inverted-vee, and single-feed multi-dipole antennas.
    Also, the plural of antenna is antennas – unless you’re talking about insects. Best of Luck on this – kc

Comments are closed.

GUNS N GEAR

Categories

Archives

Spread the love