HFU HF Underground
Technical Topics => Equipment => Topic started by: OgreVorbis on August 04, 2020, 1441 UTC
-
So at some point in the not too distant future, I'm going to purchase a new property with more space. I want to put up an antenna system with two antennas. One for shortwave and one for mediumwave (both for TXing and RXing). I want the minimum number of towers/supports for cost and size. The shortwave will be an inverted V and the mediumwave, inverted L. I want to insulate the base of the tower and drive it for mediumwave and for shortwave, I want to attach an inverted V to the top of the driven tower. Will this work or do I need another tower to support the V so I don't get interference or other problems? I won't TX on both at the same time if that helps.
Maybe you have a better idea?
(Note that the inverted V is not parallel with the L; it is perpendicular. It just looks like that cause I can't draw 3D.)
Here is a diagram:
(https://i.imgur.com/nHLP6M2.png)
-
That will be fine on SW but on MW (Txing), the SW feedline running close to the tower may cause an issue with tuning.
-
That pretty much worked for me back in 2007. The difference there was that I only used the tower itself for 160M, 75-80M, 60M, and 40M. I did not make an Inverted "L" though, and by then, my 40M dipole ripped down, so doing a home-brew Tower Shunt feed was cheap and very attractive. My tower was only a 50ft one. On RX it was great on MW to about 10Mhz. However, on TX, I only have four 100ft GND Radials spread out, so a 100W PEP SSB signal was usable, I was told by several 160M ops that, "We hear you, but you are weak." The MFJ-941D tuner tuned up everything from 160M to 10M. It was, however, one of the best MW RX antennas that I ever had. I could RX the three main NYC stations, (660, 770, and 880kHz.), with an S9 in the middle of the day from over 300 miles away and very little QRM / QRN! It also did well upon RX'ing 6925kHz pirates. At that time, the rig was a Yaesu FT-857D, so not that great of an RX capable transceiver. (In my view, anyway.) So, all that I can say, from my Tower Shunt experience, is to try it. Especially RX'ing from LF to 6M. You'll hopefully get a pleasant surprise. On TX??? You may want to use like 20 GND radials, so I've been advised. Good luck!!!!