Arborist throw lines: Ideal lengths, weights, and packs for field radio

Many thanks to Barry (WD4MSM) who writes:

Thomas,

I thoroughly enjoy the website and movies!

Could you answer one question?

How much arborist throw line do you take into the field? 150’ – 100’ – less?

Thanks for taking the time to answer.

Barry WD4MSM

Great question, Barry!

I basically have four variations of throw line kits.

You’ve asked about line lengths, but I’m also asked frequently about the throw weight sizes and throw line bags as well.

First, let’s take a look at my kit variations, then I’ll share my thoughts on throw line lengths, weights, and bags. Note that many of these products are Amazon so there are affiliate links:

Throw Line with folding cube

One is my original Weaver throw line kit made up of two parts:

The line length is 150 feet (45.72 meters).

I tend to use this throw line when I’m doing a POTA activation very close to my vehicle. It’s lightweight, but a bit bulky to take on a long hike.

Compact Arborist Throw Line Kit

This kit is identical to my large folding cube kit above, but the throw weight is 12 oz and I store it in a small Weaver stuff sack.

Here are the components:

This compact throw line kit is much easier to throw in a backpack and take on a hike. It takes longer to pack up because you’ll need to wind the line on your hand and stuff it in the sack so that it deploys without tangling. I made a video showing how to do this–it’s super easy to do and works a charm:

Click here to view on YouTube.

Mini Arborist Throw Line Kit

This kit is designed around portability and is even smaller and lighter weight than my Compact Throw Line Kit above.

Here are the components:

Since discovering the Marlow 2mm line last year, I almost exclusively use the Mini Arborist Throw line kit–you’ve likely noticed this if reading my field reports or watching my activation videos.

The kit is so incredibly compact even though it contains a full 50 meters of line. I simply pack it in the Tom Bihn bag the same way I do with the Compact Throw Line Kit (figure 8 winding on my hand).

The 2mm line is more prone to pick up small sticks and leaves on the ground as you pack it up and as it slides along the forest floor. The thicker Weaver poly line is much less likely to do this. That said, the convenience of having such an incredibly compact package is work it in my book!

25 Meter Throw Line Kits

Early this year, I started experimenting with arborist throw line lengths. I wanted to sort out what the shortest useful length would be for field radio. The idea was to make the throw line so compact I could use it without a bag, or stick it in the pocket of one of my Tom Bihn HLT2 field kits (this one for the MTR-3B was my first).

I wanted the length to be short enough that each time I use it, I could deploy the entire length of line and it wouldn’t take too long to reel it back in.

Here are the components:

I found that 25 meters or 82 feet–which is conveniently half of the 50M Marlow throw line reel–is ideal.

It’s short, yet long enough to deploy 95% of my field antennas in almost any situation.

So far, I’ve never found it “too short” for field work. I would find 25 meter restrictive if I’m installing a permanent antenna at home and want to launch the line as high as possible (say, with an arborist sling shot). In the field? Never an issue.

Suggestions for throw line lengths

I believe that if you’re planning to only have one throw line kit, go ahead and pack a full 150 feet of 1/8″ Weaver poly line or 50 meters of 2mm Marlow throw line. It’s more than you’ll ever need, but it also gives you room to cut off the end of the line when it eventually shows a bit of wear.

If you plan to use your throw line kit for SOTA, I would suggest buying a 50 meter reel of 2mm Marlow throw line and two Weaver throw weights to make two 25 meter throw line kits. Although I only typically carry one line, if you carry both it could come in handy on a summit or at a park when you want to launch a fully horizontal doublet, dipole or even a delta loop antenna.

Suggestion for throw weights

As you can tell from the kit descriptions above, I use 16, 12, and 8 oz weights.

Over the years, I’ve discovered that 16oz weights are a wee bit too heavy for my liking. I initially bought the 16oz weight with the understanding that it would give my throw lines some gravity assist when descending through the tree branches after a throw. I thought this might help keep the line from getting caught in a tree.

It was an unfounded fear, though, because not even my lightest throw line weights have ever had an issue pulling the line through tree branches even after hundreds of deployments.  I also don’t feel like I get as much height when I’m using the 16oz weight as I do with the lighter weights.

If you can’t decide on a throw line weight, you can’t go wrong with a 12 or 10 oz weight. They still have quite a bit of heft, yet are light enough that you can control them easily when throwing and retrieving.

If you’re backpacking, go for the lightest of this bunch: the 8oz weight. I’ve noticed that it’s nearly impossible to find a throw line weight less than 8oz and I assume this is because 8oz is truly the lightest workable weight. It’s super easy to throw and control, yet is heavy enough to pull a 2mm line though the trees (note I haven’t used it yet with the thicker 1/8″ yellow poly line).

It might require a few quick pulls of the cord when you deploy this in a tree with really rough bark or thick foliage. The quick pulls help it to glide back down to the ground. Most of the time, though, it works for me on the first go. That said, the heavier weights have enough inertia and build enough momentum that they rarely need an assist at all.

In short: go for a 12oz weight if uncertain, and go for an 8oz weight if you want to keep your gear as light as possible.

Throw weight folding cube versus compact throw bags

If you’re planning to do field activations close to your vehicle or on short enough hikes that you don’t mind carrying this bulkier package, go straight for the folding throw line cube I describe above.

It is the quickest to deploy and pack up.

If you want to keep your throw line kit in your backpack at all times (I highly suggest this for avid activators that are fully portable), then build a kit similar to my Compact or Mini Throw Line Kit as described above.

For more on throw line kits…

Check out this previous post where I discuss the virtues of the arborist throw line and dispel a few fears.

Also check out my first post about the larger Weaver throw line kit, and this one where I describe packing compact throw line bags.

Keep in mind these are all my personal preferences when it comes to throw line kits. Please feel free to comment with your experience and advice!

Thank you!

Thank you for reading this article! I’d also like to send a special thanks to those of you who have been supporting the site and channel through Patreon and the Coffee Fund. While certainly not a requirement as my content will always be free, I really appreciate the support.

19 thoughts on “Arborist throw lines: Ideal lengths, weights, and packs for field radio”

  1. Thank you for releasing this information on throwlines. I’m a recent convert and I must say it has proved better than a line with a water bottle on the end. Dedicated throw lines versus string and a weight are worlds apart.

    73

    de M0AZE Mike

  2. I pulled my throw line out and it is 60′ long with an 8oz weight. I have never felt wanting for more. I don’t use a sack, I coil my line and hold it and the weight together with a velcro strap.

  3. I use a throw line for nearly all of my activations, and I thoroughly endorse Thomas’s advice on the light-weight kit. By chance, I started with 50m of Marlow Excel in a weaver compact bag. Thomas’s video on figure-8 packing of line is a must-see. I moved from 14 oz to 8 oz weight with excellent results. In making a couple of additional kits, I also started carrying 25m of line instead of the full 50m roll. For other thoughts there is a discussion topic over on QRPer.net.

  4. Great article on throw lines. I have the Weaver rope and now needs to get the Weaver bag. Presently using a small Rubbermaid container which does not fit well in the backpack.

  5. I got a 50m roll of the Marlow Excel. I haven’t had a chance to use it, or even unwind it to take out the “memory”, but it looks like great stuff! Thanks!

  6. My thanks for the post and especially the links. Have been using sells Corn Hole kits). for years for my camping/portable use. Discovered the Arborist bags on Amazon and they tend to snag in the trees far less frequently than bean bags.

    I find a simple whip like the CBers use and a random length of wire attached to the end works really well for QRP CW on 40 and 20 mtrs. Does require a transmatch unless you get really lucks with the wire length. My KX3 and before that G90 always seemed to work really well with the built in transmatch, but they both handle 10:1 with ease.

    73 de Gil K4JST

  7. Thank you again for your experience.
    I bought the heavier set when I first read about it in your blog.
    However. One of these days soon, I’ll get the Mini setup to carry, which I see will have its advantages while hiking and carrying all.
    So again thanks & 73
    Wb8yxf

  8. I would like to know more about arborist throw lines. In what ways is the rope different from ordinary hard braid nylon cord? What is special about the weights? I note that the weights mentioned are a lot heavier than I use. Where are
    these kits sold?
    For my SOTA activations my antenna is a 32+ foot wire, with two 16′ counterpoise wires close to the ground. I usually aim for support on a branch 20 to 30 feet up. This works well for me on 40, 30, 20, or 15m. For a throwing kit I use a golf ball with a hole drilled through it, approximately 3 oz weight, and about 60′ of 1 mm diameter hard braid nylon cord. This has been adequate, but I’m open to suggestions for better methods.

  9. I recommend the larger cube for my picnic table style of operation. Easy to deploy the weaver throwline and 8 oz weight. Packing up is a easy to stuff instead of winding. Watch Thomas’s first Throwline video showing the cube and knots used.

  10. i use approximately 30′ to 40′ of 1/16″ line with a 12 oz throw weight. I regularly achieve a height of 40′ or so into the tree. This is always mated with a 40 meter length of antenna wire for the Spark Plug EFHW. Normally the weight will come through the tree to the ground. I will then deploy the entire length of antenna wire and 25′ of coax pulling the wire such that the throw weight ends up somewhere between the ground and the apex wire height in the tree. I will then give a one or two wind of the coax around the support structure (tree, shelter post) and the weight will counterbalance the wire, keeping it nice and taught yet still pliable to wind induced tree movement. No extra bag or ungodly amounts of rope to deal with. The whole shebang winds up on my little winder. It works a dream. To retrieve everything, I just walk the wire back so that the throw weight comes back down to the ground. The weight is removed and I figure-8 wind everything back up to the winder. Done.

  11. I’ve used 180’ of Zing-It with a weighted tennis ball pitched over limbs with a dog ball chucker. No throwline receptacle. Low rent and works just fine. (It helps that I inherited my mother’s good throwing arm.)

    73,
    Susan, WB2UQP

  12. Thank you! I’ve followed all your articles and videos about arborists’ lines and I appreciate this succinct summary. One suggestion I’d like to pass along as a middle ground between the box and the small bag — the Weaver medium bag isn’t all that large if you’re not hiking with it and it will hold 150 feet of Weaver line with room to spare, and you can just stuff the line into it without pre-winding.

  13. I use one of these reels for my
    Arborist line with my 12oz weight attached, very compact and works well from Amazon below

    STRINGLINER Company 25006 Stringliner PRO Twisted FL. Orange 135′, Multi

  14. Keep up the good work, the vids are enjoyable and I get a kick out of your comments at times. What bags do you use for the KX2 and KX3. I’ve looked here but not finding it.

    Do you have a pattern of operation. I watch the u tubes but they are always 3-4 weeks behind. How can I find you on the air and listen. Doubt we could work right away as I’m in Oregon!
    Thanks

    1. Hi, Paul,

      There isn’t much of a pattern to my activations because I often squeeze them into my busy family life and schedule. Some people use the Ham Alert application to get notified when I’m on the air.

      The KX2 pack I have is the one that you can purchase from Elecraft. I got the larger of their two packs. Back then, they could be ordered from Lowepro. It’s their CS60 pack: https://amzn.to/3AyU0a8

      Elecraft actually has them produced for them now since they fit the KX2 so well. You can order directly through Elecraft.

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