Tag Archives: Cheap Antennas

GW4OKT’s “Cheap & Cheerful Telescopic SPOTA Antenna”

Many thanks to Keith (GW4OKT) who shares the following guest post:


Cheap & Cheerful Telescopic SPOTA Antenna

Available on eBay for around £45, this 5m whip with a ground spike and counterpoise/radial.

Sold as a QRP antenna, yet in the specs, quote it as ‘able to withstand 300W’, I think I will stay at 5-10W to be honest!

Well, I used it on two POTA activations on the 11th of November, coupled to my KX2 and internal ATU. You can obviously adjust the whip for best match, but I was lazy and left it at full height.

Most QSOs where on 20m and 17m.  The seller quotes that it will tune 20m to 10m and I found this to be correct.  It will also ‘tune’ on 30/40m, but don’t expect decent performance.

This is truly a cheap compromise antenna, but I was surprised how reasonable the build quality was!   As you can see, it doesn’t take up much space, the aluminium ground spike is 10” long including the threaded portion.

The closed up whip is 20.25 “ including the threaded portion.

The ribbon counterpoise is also 5m long and is terminated with an eyelet that attaches to the ground spike threads.  I did consider splitting the ribbon to make a fan pattern, but thought it would be pretty messy to deploy an store, I kept it simple and still achieved good results!

This is a handy standby antenna, or for holiday activations, but bring your tuner along!

72 de GW4OKT

eBay Links:

“What battery, antenna, and ATU should I pair with the Discovery TX-500?”

Many thanks to Vitor Morais who asked the following question in the comments section of my YouTube video:

Hi,

Greetings from UK.
I recently learned that POTA [is now in the] UK so I am really looking forward to it.

I also recently put an order for [the Discovery TX-500] so I am really excited as well.

I would like to create a very compact setup pouch for field use to pair with this radio; one that I could take to summits or parks and also travel abroad.

What battery and antenna would recommend?

Would you recommend an ATU?

Or would you compromise to fewer bands or pack a secondary antenna?

I love to know your opinion.
Thanks

Great questions, Vitor! In truth, these sorts of questions are easy to ask but quite complicated to answer due of the insane number of options and possibilities available. It’s impossible to cover them all so I’ll try to give you some suggestions based on what I tend to use in the field. Continue reading “What battery, antenna, and ATU should I pair with the Discovery TX-500?”

Field Report: Let’s build a super simple antenna on-site and activate this park!

Until 2016, I had never purchased a commercial field antenna; I built all the ones I had ever used.

These days, I take a number of commercial antennas to the field and use them in my real-time videos and I really enjoy deploying and using them. My buddy Eric (WD8RIF) reminded me, though, that I hadn’t actually used a homebrew antenna in ages. He was right!

You see, while I believe commercial field antennas can be incredibly durable and compact, it’s important to note that antennas are one of the easiest components of an amateur radio system to build yourself. They require only the most simple of tools and are very affordable. And the best part? They can perform as well as those that are available commercially.

I also get a great deal of pleasure out of building things.

A simple goal

I’ve mentioned in previous posts that I often set a little goal that runs in the back of my mind for each park or summit activation I make.

On Monday, June 14, 2021, I made a simple goal: buy my antenna wire en route to Lake James State Park, build the antenna on site, and complete a valid Parks On The Air (POTA) activation.

A very simple antenna

I also decided to employ my Xiegu X5105 since 1.) it’s one of the most affordable general coverage QRP transceivers I own and 2.) it has a built-in antenna tuner (ATU).

One of the cool things about having an ATU is that, if it has the matching range, you can allow it to do the “heavy lifting” in terms of matching impedance.

Although I’d never put the X5105 to the test, I suspected its internal ATU would have the matching range to forgo building a 4:1 or 9:1 transformer and simply pair it directly with a random wire.

All I would need was a 28.5 foot length of wire for a radiator, at least a 17 foot length for a counterpoise, and a BNC to binding post adapter.

The antenna would benefit from multiple 17′ counterpoises, but I really wanted to keep this setup dead simple to prove that anyone can build an effective field antenna with a very minimum amount of components.

Even though I have plenty of wire lying around the house to build this simple antenna, I wanted to pretend I had none to prove that any wire would work.

And to add just a wee bit more challenge, I also limited myself to shopping for antenna wire between my home and the park without making a serious detour from my route. That really limited my options because there isn’t much in terms of commercial areas between me and Lake James State Park.

The wire

As I left the QTH, I decided that the best spot to shop was a Walmart in Marion, NC. It would only be a four minute round-trip detour at most.  I had a hunch that Walmart would even have speaker wire which would be ideal for this application.

In my head, I imagined I would have at least three or four choices in speaker wire (various gauges and lengths), but turns out I had a difficult time finding some at Walmart. We live in such a Bluetooth world, I suppose there isn’t much demand for it these days. A store associate helped me find the only speaker wire they had which was basically a 100 foot roll of the “premium” stuff for $17 US.

While I would like to have paid a fraction of that, in the end it’s not a bad price because once you separate the two conductors, you have double the amount of wire: 200 feet.

Although the frugal guy in me cringed, I bit the bullet and purchased their speaker wire. To be clear, though, I could have found another source of wire in that Walmart, but I preferred speaker wire for this application. And $17 to (hopefully!) prove a point? That’s a deal! 🙂

Lake James State Park (K-2739)

Once I arrived on site, I found a picnic site I’d used before with some tall trees around it.

Here’s how I prepared the antenna:

First, I cut 28.5 feet of the speaker wire from the roll and split the paired wires so that I’d have two full 28.5 foot lengths.

Next, I stripped the ends of the wire and attached banana jacks I found in my junk drawer. Although these aren’t necessary as the binding post adapter can pair directly with the wire, I though it might make for a cleaner install. In the end, though, I wasn’t pleased with the connection to the radiator, so dispensed with one of the banana jacks on site, and later dispensed with the other one as well. The connection is actually stronger without the banana jacks.

I then deployed the 28.5 radiator with my arborist throw line, and laid the other 28.5 half on the ground (the ground of this antenna would pair with the black binding post, the radiator with the red post).  I only needed 17 feet of counterpoise, but once it couples with the ground, I don’t think any extra length makes a difference (although less than 17 feet likely would).

The antenna was essentially set up as a vertical random wire with one counterpoise.

I then plugged the BNC binding post adapter into the rig, hit the ATU button, and was on the air.

It’s that simple!

My new speaker wire antenna in all its glory.

Gear:

On The Air

I’ll admit: I was a bit nervous putting this antenna on the air. Although I felt the X5105 ATU *should* match this antenna, I had no idea if it actually would.

Fortunately? It did.

At this point, if you don’t want any spoilers, I suggest you watch my real-time, real-life, no-edit, no-ad, video of the entire activation (including buying and building the antenna!).

Click here to watch the video.

Otherwise, scroll for my activation summary…

I was very pleased that the X5105 found a match on the 40 meter band.

I started calling CQ in CW and validated my activation by logging 10 stations in 13 minutes.

Honestly: it doesn’t get much better than this.

I logged three more stations on 40 meters CW, then moved up to the 30 meter band where the X5105 easily found a match.

I worked one station on 30 meters before heading back down to the 40 meter band to do a little SSB. I logged three SSB stations in five minutes.

Mission accomplished!

In the end, I logged a total of 17 stations including a P2P with K4NYM.

Not bad at all for speaker wire!

After the activation, I tested the X5105 ATU by trying to find matches on other bands–I was able to find great matches from 60 meters to 6 meters. Most impressive!

X5105 battery

You might recall that I attempted to deplete my X5105 internal battery at my last (rather long) activation of Lake Norman State Park.  I wasn’t able to deplete the battery at that activation, but I finally did at this one.

All I can say is that I’m incredibly impressed with the X5105 internal battery.  This was my fourth activation from one initial charge on May 16.  The battery lasted for 20 minutes, taking me well beyond the 10 contacts needed to validate this park. I’ll now consider taking the X5105 on a multiple SOTA summit run!

Short Hike

Even thought the heat was intense and the humidity even more intense, I decided to take in a 2 mile hike post-activation. I snapped a few shots along the way.

This is the Christmas Fern which derives its name from a few characteristics: its resilience to early season snows maintaining a dark green color beyond Christmas, and because folks believe its leaves are shaped like Santa’s boots or even Santa on his sleigh.

Improvements

I’ll plan to add more counterpoises to the speaker wire antenna as I know this will only help efficiency.

In addition, I’ll plan to build even more antennas with this roll of speaker wire. If you have some suggestions, feel free to comment!

Thank you for reading this field report!

Cheers,

Thomas (K4SWL)


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