Two days ago, I activated Parc national des Grands-Jardins (VE-0499)–a stunning national park here in the Charlevoix region of Québec, Canada.

As soon as we drove up to the activation site I had researched in advance, I surveyed the picnic area and mentally noted the best spot to deploy an end-fed half-wave using my trusty arborist throw line.

With the throw line’s assistance, I had an antenna deployed within a couple of minutes max.

It hit me then just how invaluable a tool the arborist throw line has become for the types of park and summit activations I do.

Pre-Throw Line Activations

During NPOTA (National Parks On The Air) in 2016, I wasn’t aware of arborist throw lines and had been using some high test monofilament fishing line attached to a weight.

The fishing line was strong enough to support my QRP antennas and I could typically reuse the same length of line for 2-3 activations. Eventually, the line stretches and weakens thus it must be cut off and discarded.

Never again

I’m a big Leave No Trace kind of guy, so am embarrassed to admit that during one activation, my fishing line snagged high up in a tree and left a bundle of broken monofilament in a spot where I could not retrieve it. This was deep in a forest and although I doubt anyone will ever see it, I know it’s there. It bugs me to this day and if I ever sort out a way to remove it, I certainly will.

This occurrence was one of the catalysts for purchasing my first arborist throw line kit.

That throw line kit absolutely revolutionized my antenna deployments by:

• increasing the speed deployment,
• increasing accuracy,
• allowing me to re-use the same line hundreds of times,
• and being orders of magnitude more reliable and stronger than fishing line.

It changed everything and I’ve never looked back.

Since that first throw line kit (which I’ve lent to a newly-minted active ham), I’ve built four more throw line kits.

Compact Weaver Throw Bag

In early 2021, I purchased a second throw line and 12oz weight (identical to my first) for backpacking along with this compact Weaver Leather throw line storage bag (affiliate links).

I was searching for a more SOTA-friendly/backpack-able solution than the arborist throw line cube.

I was very skeptical about how easily this bag would work in the field. One of the reasons my throw line storage cube works so well is because the opening is large allowing the line to deploy without tangling. Packing up is fast because the line can be flaked back into the cube in a matter of seconds.

After taking delivery, I did a full break-in of the new throw line (attaching it to a tree, stretching it to full length, then pulling it for enough tension that some of the bend “memory” was removed). Then I attempted to simply stuff the line in my throw bag–it took ages, because the whole idea of a throw line is that it doesn’t easily tangle. The line wanted to “spring” from the bag as I tried stuffing it in. (I believe it was Scott KN3A described it as “trying to stuff a snakes in a bag”–!).

Then Mark (NW3S) gave me a simple tip: when stuffing the line back in the bag, wind it on your hand using the figure 8 method. 

In short, this works beautifully. Not only can I re-stuff the bag in very short order, but the line never tangles when I deploy it during my next activation.

I made a short video showing how to use the figure 8 method:

This small throw bag worked so well, I started using it for nearly all of my activations.

Then I learned about an even thinner, more compact throw line.

Ultra-Compact Marlow/Tom Bihn Throw Line Kit

In November 2021, Mike (W4MAF), suggested I check out  Marlow KF1050 Excel 2mm marine/arborist line. He’d mentioned that he’d had excellent experiences using it in the field. It’s much thinner than the yellow Weaver poly line I’d been using.

Marlow KF1050 Excel 2mm marine line is sold in 50 meter reels; I purchase mine from WesSpur (an excellent arborist product retailer).  I quickly realized that a Weaver throw bag was way too large for this line, but fortunately I had a spareTom Bihn Small Travel Tray which works perfectly.

Although the Marlow line is slightly more prone to tangle out of the bag because it’s not as “springy” as the bulkier Weaver line, and it can pick up little twigs and leaves off the forest floor when packing it up, it works beautifully.

In fact, it has become my default throw line since I first started using it in November 2021.

It’s so darn compact, you don’t even notice it in your backpack.

When I purchase a reel of 50 meters, I cut it in half to produce two 25 meter sections.

I find that 25 meters is more than enough line for all of my SOTA activations and the majority of my park activations. It’s so compact, I can actually store it on my MTR-3B Field Radio Kit:

Twenty five meters of 2mm line is so easy to wind on your hand, it’s not even necessary to keep a throw line bag to store it. Simply deploy the entire length each time, wind it back up in one go on your hand, and use a Velcro strap to hold it together.

Watch the first portion of this activation video for an in-depth look at my 2mm throw line kit:

Throw line fears

Over the past two years, I’ve heard from fellow friends, activators, subscribers, and readers who are reluctant to use an arborist throw line. Typically, they cite the following concerns:

• A line, throw weight, and bag will typically set you back $45-55 USD.
• Fear it will permanently snag in a tree
• Concerns that it’s too conspicuous when deployed

It’s true that proper arborist line and throw weights are pricier than fishing line, string, etc. That said, I believe it’s an investment that will last for years.

Some have told me they’re willing to pay for the line, but the throw line weights are too expensive.  Trust me: buy the highest quality throw line weights you can afford. The cheap ones are known to eventually bust when they hit the ground too hard.

And trying to use (as I used to) a heavy steel nut or rock? Think about what you’d rather have ricochet and hit your head or a nearby car: a heavy yet soft throw line weight, or a steel nut? Trust me: it’s worth the investment.

Side note: speaking of throw weights, I primarily use 8 and 10 oz weights with the 2mm line. With the thicker yellow Weaver line, I use 10 or 12 oz weights. I feel 16 oz weights are a bit too heavy if you want to launch a line high in a tree.

In the hundreds of deployments I’ve done with arborist throw lines, I’ve never had one come close to snagging in a tree. If this worries you, just avoid areas that are super dense with tree branches. Those are the spots most likely to snag a line.

In terms of throw lines being conspicuous, I actually think that’s not a bad thing. If operating alone in a park, you need to make your wire antenna deployment conspicuous if there’s any possibility of someone unknowingly walking through the middle of it. I bring flagging tape for those rare circumstances. You may also see that I use my high visibility throw line to encircle any trip points.

Of course, arborist lines can be stealthy as I learned only recently.

Paracord ≠ Arborist Throw Line

I’ve received a couple of messages from readers who’ve complained that their throw line is useless because of how difficult it is to deploy, how easily it tangles, and how it gets stuck in trees.

In both cases, I discovered that these ops were actually using paracord instead of arborist throw line.

Throw line is specifically designed for arborists and has a jacket that doesn’t easily tangle in trees. It reliably glides through branches despite rough tree barks you might encounter.

While I love paracord for supporting my permanent wire antennas or heavy field antennas–it’s super durable and useful–it is a poor choice as a throw line. Paracord’s jacket may feel smooth to the touch, but it actually grabs tree bark and creates fiction. Arborist line doesn’t do this.

Always use throw line that’s available from an arborist supplier/retailer and you’ll never be disappointed.

Summary

If you live in a part of the world with lots of trees and you’re a devoted park and/or summit activator who uses wire antennas, you really need to consider adding an arborist throw line to your field radio kit.

All of the throw lines I’ve mentioned above work well: choose one that fits your style of field radio work. If you’re not into backpacking, then consider the full folding cube option. If you’re into SOTA, go with one of the compact options.

I promise: you’ll consider a throw line kit one of the best purchases you’ve ever made to support your field radio addiction!