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30 METER BEACON PHOTOS AND CAPTURES
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"pgdaulton"
I HAVE CREATED A PHOTO FILE "K5WMS" WITH PHOTOS OF MY BEACON CONSTRUCTION AND INSTALLATION.
ALSO INCLUDED ARE CAPTURES FROM KL1X/5 IN BARTLESVILLE,OK AND W4HBK FROM PENSACOLA FL. I AM IN CENTRAL ARKANSAS GRID SQUARE EM34WU. I ALSO HAVE BEEN COPIED BY MIKE WE0H IN ST FRANCIS MN BUT HAVE LOST THE CAPTURE. I EDITED THE CAPTURES AND ADDED THE TEXT. THANKS HANS AND STEVE FOR A FUN PROJECT. THREE DOWN AND 47 TO GO FOR WAS! PAUL DAULTON K5WMS |
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"hanssummers2000"
Hi Paul
I HAVE CREATED A PHOTO FILE "K5WMS" WITH PHOTOS OF MY BEACON CONSTRUCTION AND INSTALLATION.[Snip] Congratulations on the success, the screenshots, and I'm glad you're having so much fun! I hope you will look for your beacon on the worldwide grabbers too and soon see some DX reception when the conditions are right! One question I had... I see that you have mounted the PCB nicely in a box with hooks on the side, which look like they are designed so that the transmitter sits directly at the centre of the dipole... the dipole attaching to those two hooks. Then the coax brings power in at the "bottom" of the box (when it is hung on the tower). I'm no antenna expert at all, but I wondered about something... The LPF output is designed for 50 ohms output so putting it at the middle of the dipole should be Ok. However one arm of the antenna would also be connected directly to PCB ground, which is itself connected to the coax power feed cable. This means that the coax feed cable would form effectively part of the antenna "dipole", unbalancing it and probably no longer matching it to 50 ohms. I wonder if the results might be even better if this situation could be avoided. Perhaps a balun between the TX and the dipole? Or perhaps you could fit a couple of RF chokes at the two power connection inputs, to stop RF going back down the power feed cable? Feel free to ignore me if I'm talking giberish, as I say, I'm no expert on antennas (or anything else, for that matter). 73 Hans G0UPL |
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"Paul Daulton"
开云体育You are correct there is some rf on the coax. Note
the power box , the small one with metal plate. this has a type M coaxial power
socket and an F connector, a 7805 IC drops the voltage to 5v. I can use any
spare wall wart transformer with correct polarity and a plug that will
fit.
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I can touch the plate and see a slight bump in the
signal on my own receiver. I will put a choke in each leg of the? power
coax next time I take it down. Or maybe a bifilar wound choke.
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Note also I drilled two 1/8 inch holes in the
bottom of the tx box to drain any moisture out.
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I regularly check the grabbers on the digilander
site, so fara no DX. Our stateside forums dealing with the Lowfer beacons have
developed a very good reporting system. I have 19 states confirmed on my
185.3khz beacon. Thats all the states where active listeners reside. I encourage
all that listen to post screen captures, and where possible edit the captures in
Microsoft picture viewer by adding the text of the calls received.
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Check out our lowfer sites at and the
lowfer mailing list on? ?
click on side bar, email lists, and scroll down to "lowfer". I have been using
the Argo and Spectran software chasing weak signals? on 137khz, 160-190khz
and 13.555 to 13.565 mhz for about 9 years now. I've made lots of friends and
had lots of enjoyment. It is a two way partnership between those who beacon and
those who listen. A great learning experience.
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73 Paul
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"Newton"
Hi Hans,
You wrote: I wonder if the results might be even better if this situation could be >avoided. Perhaps a balun between the TX and the dipole?I remember you showed some pix at the FDIM where you rigged up your TX while on holday. I believe that you had fasioned a balun between your TX and the antenna. Can you describe how you made that balun? Thanks, Newt k0nwt |
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"hanssummers2000"
Hi Newt
Yes... for details of rhe holiday QRSS operations, seeI wonder if the results might be even better if this situation could be >avoided. Perhaps a balun between the TX and the dipole?I remember you showed some pix at the FDIM where you rigged up your TX while on holday. I believe that you had fasioned a balun between your TX and the antenna. and Can you describe how you made that balun?Yes... the TX has 5m of RG-58 coax directly from the LPF output to the balun. I used the same balun design I had used a few years ago in my junkbox beacon project, see this page: . The actual design is from this page: by N1HFX. For my QRSS transmitter, I used exactly the same design except with a FT37-43 toroidal core, with 6 bifilar turns. 73 Hans G0UPL |