18 Apr 2013

Loopy results on 15m

WSPR results today with 2.5W to 80cm loop in the bedroom on 15m
Well never mind the theory - my loop WORKS well. On 15m, with the loop taped to the chair in the bedroom shack, I have already been spotted on WSPR in Japan when using just 2.5W from the FT817 at  9474km.  So, my first attempt with an indoor HF magnetic loop in the bedroom has left me very impressed.
Loop antenna in the bedroom (notice the grandchildren's toys!)
Current set-up is about 80cm diameter 6mm copper pipe inductor tuned with a small 365pF air spaced variable cap. Matched with a coupling loop 1/5 the size of the main loop made with RG58 coax. With the 365pF variable it tunes from 40m-10m, but the variable cap needs padding out as tuning is extremely sharp.

I should have tried magnetic HF loops long ago.

UPDATE 1600: Just QSYed to 14MHz with the loop in the bedroom and power reduced to 500mW and still getting plenty of WSPR reports out to 2600km or so so far.


Todd Dugdale said...

"I should have tried magnetic HF loops long ago."

Judging by the prices I've seen for them, you should have been selling them long ago, too.


Dick said...

PY1AHD makes a portable, low-power loop. Has very good reviews on e-ham. I am seriously considering one for balcony use when we are in the apartment down south for a month or so.

Congrats on your own fine results.

VE3WDM said...

I ordered the PY1AHD loop and it arrived the other day and depending on time this weekend I am going to give it a go. I will put it in my XYL's office on the second floor of our home. I will be interested to see how it preforms.

Dick said...

Which of them did you get Mike? The QRP version? I will be reading your blog for review.

Anonymous said...

"Judging by the prices I've seen for them, you should have been selling them long ago, too. "

Power handling and price go up exponentially. There aint no free lunch, and nobody is ripping people off selling loops.

If there was lots of money to be made, everyone and thier hippy uncle would be selling them. They are NOT, because they are hard to make well and expensive. The parts and labor to build an efficient small TX loop that handles any amount of power are VERY expensive. Its even expensive to build your own.

A 1kW 40-15 meter HOMEBREW loop can easily cost $400US.

A QRP loop for a couple higher bands can be built from scraps in your junk drawer.