Featured image of post 20250204 - Delta Loop failure and wins! Plus battery update.
HAM

20250204 - Delta Loop failure and wins! Plus battery update.

Small Delta at the park

taxonomy: tag: - ‘HAM Radio’ - ‘POTA Activation’ - SSB - 20M - 17M - FT-891 - LiFePO4 media_order: ‘2025-02-04 at 8.16.54 PM Large.jpeg,2025-02-04 at 8.19.07 PM Large.jpeg,2025-02-04 at 9.03.39 PM Large.jpeg’ weight: 250204

Last night I decided to try to build a new 15M Delta Loop antenna. I wanted to try a new design and a hammer out a new band for POTA. Just to be different.

I built the antenna figuring it would work on 15M and maybe 12M or 10M. Well during the POTA activation, I hoisted the antenna, Pointy side up, hoisted the delta up so the bottom was about 15’ in the air.

Check the SWR on 15M….. no good. Check it on 12M. Worse. 10M? Nope.

FAILED: Dang, how far off could it be… I measured spot on from the calculations.

Then I moved up to 20M and it tuned to 1:1.2! OK so it is long electrically I guess. Then I tune it on 17M and it was 1:1.1 SWR on the menu.

So I tune to 20m and find a few 20M parks and hunted them. Then I moved to 17M and spotted myself on the POTA.APP. Within 60 seconds, I had California calling. Four of the first six contacts on 17M were from California!

This antenna gave 55 through 59 reports most of the activation. It did seem to be pretty low on the noise, although I did not try an A-B test with another antenna to objectively find out if it is better at reception as deltas are known for.

WIN: This minority complex antenna worked. Now that I know more about them, I may build one for 10m. I am happy with how it did on 17m SSB. I need to try it with faint signal stuff like FT8!

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Can you spot the delta loop?

About the LiFePO4 23.4Ah battery. I am tracking my usage with it. It is taking about 50wH per hour of field usage to recharge at home. This makes sense, 50W is what I have been running my radio. So the battery says it is spaced for 300wH… thus I could expect maybe 4-5 hours of SSB use with 300aH and my measurements so far seems to say the battery is holding up to its label claims.

Here was the setup:

  • PARK: US-4451 - Tuskegee National Forest: Taska Recreation Area
  • GRID: EM72el
  • ELEVATION: Approx. 400+ feet
  • RIG: Yaesu FT-891 + ATU130 tuner. Set to 20M band and 50W power output, adjusted down to 20W as the day ran on.
  • ANTENNA: 15M Delta Loop) - tuned for 20M and 17M
  • BATTERY: 12v 23Ah LiFePO4 - used 63aH. Today.

MAP and STATS:

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