Antenna plans, Antenna analysis and desig. Review of tested antennas and online projects
This week I’ve started investigating on Inverted L antennas for low bands (160 to 40). Expecially for restricted space scenarios, like mine. I found some interesting articles on the net, and a couple of PDF that I’ve embedded in an article dedicated to Inverted L Antenna for Low Bands
Surfing Youtube, I just discovered this amazing video that demonstrate in a very uncommon but efficient way how yagi antenna works.
Tuning GAP Titan DX
I had to remove the antenna last week-end due to maintenance works into the roof, so I took the occasion to play a little bit with the Titan tuing rods.
I Found this schema on the net originally made by CT1EFV based on the GAP picture.
I made some minor changes, expecially to the 10 meter part that based on what I read on manual and on the net, was wrong.
I’m sure this picture can help on tuning your antenna.
This is a project of an easy to build dual band (UHF and VHF) j-pole antenna done with a common TV twin lead and some coax cable.
Original PDF document can be downloaded here
ECO Antenne Closed
World-wide famous antenna manufacturer has closed it’s business on 1st decembrer 2010.
This is what I’ve learned by some hams, that have been in touch with Mr. Sergio Berutti formerly Eco Antenne owner.
Causes are not public domain, but everyone suspect has been due to economic factors.
Eco Antenne, has affirmed in the market for it’s economic product line, and for a wide range of antenna product line, allowing many hams to buy HF VHF UHF antennas at affordable prices.
Many dealers have still lot’s of antennas in stock, but will be the last ones. Website is down since a couple of weeks.
I’ve never owned an Eco Antenna, but at least here in Italy, Eco Antennas are very popular.
Good Bye Eco Antenne.
Mobile Antenna Farm
After evaluating HF vertical antennas I’ve finally choosen and ordered my new vertical hf antenna.
Gap Titan DX is the choosen one.
According to characteristics and price the Titan resulted the one with the best price / performance ratio.
I ordered at Wimo (german ham radio dealer) and it arrived in 3 days via UPS.
Best price and fast delivery, thanks folks at wimo.
More posts will come about antenna setup
After a long research on antenna makers websites I’ve produced a quick reference chart to compare most popular HF multiband vertical antennas.
This table will help me on choosing my next vertical antenna.
Populatrity of antennas has been decided by visiting eham reviews, qrz.com forums, and other local ham radio communities.
Price comparison has been done by quering eruopean dealers, and asking for better quotations without considering delivery costs but including VAT where needed.
Attached to this post you will find a PDF file with the full technical comparison.
Links to official web sites:
Download my Vertical Antenna Comparison Chart
As published in antennex Dec. 2001
The 40 Meters band stealth vertical antenna by K7ZB
“You’re 30dB over 9 here…” So goes the consistently fine signal reports received from around the USA and beyond – on 40 meters at the peak of Sun Spot Cycle 23. The most common antenna used in ham radio mounted over poor desert soil conductivity still performs beautifully!
Original article by K7ZB
Results
The simple 15′ vertical antenna shown mounted on the railing of our second floor deck has produced almost 200 countries worked around the world… VQ9′s in Chagos and 3B8′s on Mauritius in the Indian Ocean, TX0DX on Chesterfield Reef, VK0MM on Macquarie Island in the Antarctic region, BQ9P on Pratas Island off Taiwan, ZM7ZB on Chatham Island in the South Pacific along with FO0AAA on Clipperton, 9M0OO on Spratly Island in the South China Sea, JT1CO in Mongolia and on and on. What I hear, I can usually work with this little wonder and the small size and profile make it feasible for use in deed restricted neighborhoods.
A radio amateur friend and antenna designer came up with a simple design for a 10 meter vertical, which another friend and I modified to make work for the 14, 18, 21, 24 and 28 MHz ham bands. Its performance surpised us, and I’ll share it with you, in case you too are looking for a simple, inexpensive DX antenna that really performs well.
Main Antenna Concept
The basic concept is to put up a piece of aluminum tubing with a telescopic section held by a small hose clamp to adjust the height. By attaching the center conductor of a coax feedline to the tubing, and the shield of the coax to a couple of radials from the base of the tubing you can load the vertical across quite a broad range of frequencies.
Of course, with a vertical element of approximately 15′ this is a non-resonant antenna for the 10, 12, 15, 17 and 20 meter bands. I chose this length on purpose to allow the system to be tuned to resonance with an antenna runer.
Tuning
Since the SWR in an antenna system of this type will be relatively high, an antenna tuner unit will definitely be required. You may need an external ATU if the one in your transceiver can’t handle the impedance mismatches involved. Here at K7ZB, I drive my TS570 (which has a built-in ATU) thru the amplifier, which then drives a high power ATU to the antenna. I put the SWR/Power meter between the amplifier and ATU to ensure a good match for the amp, and in cases where I run barefoot without the amp, I can still use the ATU to assist the transceiver’s ATU in ensuring a good match.
In this way, everything is matched for maximum power output: from the transceiver to the amp, and amp to the antenna. And, even though the SWR’s are high at the feedline and the antenna, it doesn’t matter because the system is matched with the ATU.