Posted: 4/15/2026 11:28:27 AM EDT
[Last Edit: nikdfish][Edited]
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Got around to testing a printed "V" base for use with telescopic whips. In this sequence I am using two 102" whips (I think I got them on sale from wolf river, maybe 2 for 1 ?). This base was a test print that got modified (new part screwed in) to accommodate a vertical in addition to two angle whips. The latest version has that provision built-in. I used M10x1.5 inserts, so 3/8-24 to M10 adapters were needed to mount the 102" whips. I also have a couple of 220" whips that use M10x1.5. I plan to test one of those in the vertical position with the two 102" whips positioned at a downward 45 degrees as radials sometime later. In this test I only used the two angle mounts, positioned in an upward "V". Marks on the body allow for easy setting of roughly equal angles. The center tap lead is placed on the right side, ground on left. The second, unused, ground is left dangling. No transformers are used, just a straight run of cable from antenna base to the analyzer. Attached File Attached File Attached File Attached File With both whips fully extended, it covers 11m at 1.5 or better Attached File With the smallest section shortened to 10", it covers fully covers 10m @ < 2. Attached File EDIT TO ADD I put the files on printables https://www.printables.com/model/1690682-pole-topper-elevated-vvertical-antenna-base |
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I did a quick look at using the 220" whips as a "V", fully extended. Attached File This is a broad scan Attached File Now a closer look at the 20m neighborhood Attached File So a little shortening should do good with 20m I also took a look at using one 220" whip as vertical & two 102" whips as radials. Attached File Attached File The center is a bit higher. I shortened the vertical by one section (at bottom) and re-ran it. I don't have a wide scan pic, just one around 17m Attached File That's all I've gotten to so far. Eventually I will map out a chart of whip length/configuration against bands. It may take a bit as working with the 18' whips is a bit of a pain. |
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Working on another component for the pushup. Attached File Attached File This was a test print/build to see what needed tweaking on the design, but should be usable. Printed in ASA. Coil is done with 16awg tinned copper. Sliding contact is a keystone 5231 battery contact. M10 inserts on both ends, a M10 grub screw was threaded in at the bottom. M4 inserts for the screws & slider bridge screws. The inductance calculator says it should be ballpark 70 microhenries. 66 turns of a 1.4mm conductor on a 50mm form over 135mm span. I haven't yet done any sweeps with a vertical whip. Some minor ripples in the wire because it was recycled from an earlier test build. |
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Did a bit of testing with coil & 102" & 220" whips. Way too "twitchy" during adjustments with the wraps so close. Way more inductance than needed. Will probably re-do & try one with about half the overall inductance. With the 102" whip vertical, pole not extended, no ground/radials, full coil being applied. Attached File Attached File With the 220" whip vertical, pole not extended, no ground/radial Attached File Attached File With the 220" whip vertical, pole not extended, 102" whips horizontal, me touching ground @ analyzer. Center freq is 3.8 Mhz Attached File Attached File |
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Originally Posted By battlemidget: I like the extra ground tail, ground plane experimentation is always fun. I haven't tested it yet, but just finished a version of the pole topper base with a center vertical and three adjustable radial mounts. Attached File Attached File Attached File Attached File https://www.printables.com/model/1714142-elevated-vertical-with-3-elevated-radials Two more 220" whips coming, so will be able to populate all positions w/ 220" whips... |
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I also went ahead & put the current version coil files on printables. https://www.printables.com/model/1714158-loading-coil-for-vertical-antenna-with-sliding-con |
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Remembered I had a cheap LCR meter kicking around, found it & replaced the battery so I could see what it said about the coils I've been playing with. Here we have the coil with slider with the slider set for minium inductance. Meter calls it 0.7 micro Henries. Attached File Now the slider set at maximum inductance. Meter calls it 66 micro Henries. I had been ballparking it at 70. Attached File Slider in the middle area, meter calls it 26. Attached File This is a little shorty I wound with a target value of about 6.2 micro henries, meter calls it 7.1. I did this one to see if it would bump the 220" whip down to 40m when it was currently adjusted for 20m. Haven't tested that yet. Attached File |
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The shorty had some things I didn't like, so made a few changes on the body, re-printed & rebuilt it. This time it was pretty much on the mark. Measurement was taken at the M10 ring terminal. Attached File |
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Put the short coil files on printables. https://www.printables.com/model/1728284-65-microhenry-loading-coil |