Post by HighMountainRadio on Jan 13, 2018 14:54:50 GMT -6
Greetings To All !
As promised to a few of you, here is the easy, simple, CHEAP to FREE way to fabricate a very effective FM broadcast antenna balun, a very crucial part of your radio broadcasting facility.
You may fabricate this balun as a 'component' that can be retrofitted into your antenna feedline at the antenna termination point or you may integrate this balun right into your feedline when building or upgrading your FM broadcast facility.
Start by using good quality 50 ohm coaxial cable of your choice. Wind 6 loops of the coaxial cable into a 6 inch circumference, placing each loop of coax adjacent to the previous loop. The completed balun can be effectively held together by using either plastic or wooden 'spacers' to hold the balun into the desired shape. I used standard electrical tape to hold the wooden spacers in place. I used a chunk of RG-58/U coaxial cable from my junk box.
Prior to utilizing this balun, RF was radiating along the length of my antenna feedline causing very undesirable reflected power back to my transmitter which if permitted long enough can very easily cause your final output MOSFET or transistor to fail prematurely. Before the balun was fabricated and placed into service I had 10 watts output from my transmitter going up to the antenna, 3 watts of which were wasted by being radiated along the length of my antenna feedline and right back into my transmitter.
After incorporating this balun into my existing feedline I have a perfectly 'flat' VSWR (Voltage Standing Wave Ratio), the entire 10 watts going up to my ground plane antenna with absolutely NO reflected power, an ideal transmitter to antenna match ! Taking your time, you can easily fabricate this balun in 20 minutes.
The pictures included here show how the balun is constructed. I also included a picture of my homebrew Ground Plane antenna, it's a modified CB radio ground plane antenna simply cut down to my desired frequency of operation. It's a terrific way to save BIG $$$ on one of those pricey ground plane antennas on Ebay ! Ask your buddies or CB radio enthusiasts, very likely you can probably get one for free or dirt cheap ! Also, I would like to note that never overlook your local scrap or salvage yard for excellent aluminum tubing which can be easily used to fabricate many different types of FM broadcast antennas. The material will most likely only cost you whatever the going 'spot price' happens to be at the time, for scrap aluminum, mere pennies ! That is what I pay, and the supply is virtually endless ! Don't waste your hard earned money on pricey EBay antennas, you CAN build a very effective antenna yourself and have the satisfaction of having done it yourself ! You HAVE the capability and the resources ! Be creative ! Additionally you WILL learn a lot about antennas by fabricating your own and experimenting ! See included pictures of my setup included here.
Enjoy, Have Fun and Learn ! It's what it is all about !
73 To All !
Spooky... "Broadcasting From Somewhere High In The Remote Appalachian Mountains"
Attachments:
"Knowledge Is Always Made More Valuable By Sharing It With Others !" Always Remember To Be Kind ! True Greatness Often Has Very Humble Beginnings ! Help A Kid Out Today ! *** High Mountain Radio *** "Broadcasting From Somewhere High In The Remote Appalachian Mountains"
