When I do an antenna review on the channel, it’s never ‘one and done.’ I like to periodically revisit the product, put it on the air, and see if they continue to perform. Two antennas that have passed that test are Radioddity’s HF-009 and the improved HF-010. Both are portable vertical antennas with an adjustable coil near the center of the antenna. The HF-010 builds on the success of the HF-009 by including a freestanding base, longer whip, and easier to manage ground radials.
This week I take another look at the HF-010 and put it on the air. And that’s the subject of this week’s video: Is the Radioddity HF-010 Still Worth it? 6 month Field Test. https://youtu.be/no0Bp0pSbuE
Do you want a deeper dive on the HF-010. My original review video from last March still stands, and gives you more insights on tuning and using the antenna on multiple bands. Watch it here: https://youtu.be/UU45u9FDYqg
Ham Radio Campout Logo Merchandise: https://michael-martens-shop.fourthwall.com/
Use this link and get a $15 discount when you shop at Radioddity https://radioddity.refr.cc/default/u/KB9VBR
Purchase ELMER Brand Chokes and Save 10% Use link and discount code KB9VBR10 at checkout: https://elmerbrand.com/KB9VBR10
Rigexpert Stick 230 Analyzer: https://www.dxengineering.pxf.io/rEQxKD
Sandbags: https://amzn.to/4gFSOqt
Why Center Load Vertical Antennas?
In the video, I make mention of the HF-010 being center loaded, and how that can increase the efficiency of a vertical antenna. It all has to do with current.
Vertical antennas, both the full 1/4 wavelength and the shortened versions with a coil will have the highest electrical current at the feed point or base of the antenna. As you go up the antenna, current decreases and voltage rises. The greatest RF energy release is at the high current points. If you have a coil at the base, the current gets eaten by the internal resistance of the coil, turning that energy into heat. Moving the coil up towards the high voltage point reduces resistive losses, giving the RF energy more opportunity to release.
This high current at the base of the antenna is also why good ground networks are important in vertical antenna design. Lots of short ground radials are ideal in maximizing RF current distribution.
Elevated vertical antennas, like the KJ6ER PERformer, are similar in function. The high current point is still at the feed point. Raising the vertical antenna’s height and using a tuned counterpoise wire maximizes the current distribution in the antenna system. Elevating the feedpoint and using tuned counterpoise wires is why the PERformer can claim a structural efficiency of over 90%.
The Radioddity HF-010, a shortened HF vertical antenna, works as well as it does because the loading coil is out of the high current point of the antenna. Resistence is low when voltage is high, making the coil less prone to heat losses.
I put these two antennas, the elevated PERformer and the HF-010 head to head last spring. This is in no way a scientific test, but the results were a bit surprising. Even though I operated in two different locations on the same day, band conditions were similar. The HF-010 certainly held it’s own on that tough day.
How do we maximize our performance with a shortened vertical antenna? First, move the coil away from the feed point. This will help reduce the resistive losses in the system. Second, increase the ground radial system. The ground network is the ‘hidden’ half of the antenna system and a radial network like lots of shorter radials or a screen or Faraday Cloth will benefit the high current point near the base of the antenna.
If I wanted to supercharge my HF-010, I’d focus on the ground network. And that will be a topic for a future video.
Finishing Up
As seen in the video, my Wisconsin Ham Radio Campout merchandise is now available. T-Shirts, Hoodies, and a cool new zip-up all are in stock and ready for your autumn wardrobe. Even if you aren’t going to the campout, you can still rep the style.
Fall camping season has begun and we are hitting the road this weekend. Look for me to activate US-1439, Big Bay State Park, and US-4244 Big Bay Sand Spit and Bog, both on the shores of beautiful Lake Superior in the Chequamegon Bay. My time is a bit limited so look for a Saturday morning session on 40m and Saturday afternoon on 20 meters.
I hope to catch on the air
Michael
KB9VBR
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