The RSGB Newark Hamfest in just a few weeks from now will see the launch (through InnovAntennas) of the next step forward in G0KSC Yagi development. Enter the LFA-R.
The 4R5 - 5 element 70MHz LFA-R on a 3.45m boom providing over 11.4dBi gain
The LFA-R started form as an HF antenna, one of the many new antennas in the force 12 range. With a single flat, driven loop and one director, I was surprised just how much F/B was achieved along with excellent levels of gain too. Many element versions where not practical for HF so the experiments shifted to VHF and this is where the LFA-R really came into it's own.
The LFA-R uses a compact LFA loop at the back of the boom and has no reflector element at all. The arrangement of phase presents itself in much the same way as it does within an HB9CV. However, this loop is completely joined (or course) all the way around. Only director element follow the driven so on a 5 element version (such as the above shown example) you have 4 directors rather than the traditional 3 directors a typical Yagi would have. This, along with the driven element being moved further back on the boom that the traditional Yagi means more gain can be achieved.
Once corrected, the LFA-R still produces aroudn 11.4dBi forward gain from this compact boom
This extra performance does not come for free, the antenna has a much narrower bandwidth than you might be used to seeing with my designs. However, I have spent time on establishing non-conventional stability with the use of electrically connected elements and 'thicker' elements. Time had to be spent on establishing correction in order to replicate model but as you can see from the below software prediction and final analyser results, this has been achieved with near perfection.
The EZNEC V5 Pro/4 output prediction for SWR on the 4m band with the 4R5
The AIM analyser results show lead-in and lead-out curves tracking almost identically to the software model
The LFA-R has been thoroughly tested too. In addition to having a 4 element 70MHz (4R4) installed at the InnovAntennas factory this summer, other early adopters have installed LFA-R's too. CT1HZE has a 4R4 installed in Portugal (see a conversation between Joe and I on 4m with us both using 4R4's HERE! I was using the call of M0LFA which is the InnovAntennas factory call sign and also, using just the Electraft KX3 with internal 4m transverter with only 3 Watts output!).
The 4R4 installed at CT1HZE above his large 6m LFA
In addition to the 4m examples, a new 6 element 6m has also been installed at several locations too. XE2X has a 6R6 for almost a year now that can be seen being installed by InnovAntennas/Force 12's own XE2K, Hector. Again, the 6m antenna really does pack a big punch for its size with around 12.2dBi on this relatively compact 6.5m long boom and yet still holds relatively respectable F/B too.
XE2K installs a 6R6 - 6 element 50Mhz LFA-R
This particular version has been made very HD with VDS (Vibration Damping System) element insulators installed on a large 45mm to 38mm boom. The boom itself tapering in both OD and wall thickness too in order that a guy system is not needed. SWR remains stable throughout as the new owner XE2X Jorge, can verify. Jorge also reported this as being the best 6m antenna he has installed to date! Take a look at the performance plots below.
A small amount of convergence correction is needed but still almost 12.2dBi is achieved on just 6.5m of boom
The 6R2 - 2 element 50MHz LFA-R measures just 51cms (boom). No excuses for not being on 6m now!
The 6R2 shows a very respectable SWR plot across the 'sweet spot' at the bottom end of the 6m band
Impressive! the tiny little 6R2 packs a punch and still has F/B to show for it too!
So, if you want to see it in the flesh, come along to the RSGB National Hamfest in a few weeks time and here we will have a number of built versions on display.
G0KSC gives a more detailed overview of the LFA-R in the current issue of DUBUS magazine (3/2014) www.dubus.org
See loads of new stuff as it happens, like us on facebook! 'innovantennas'
Until next time!
The InnovAntennas Team
Justin Johnson G0KSC will be at the JayCee open day this coming weekend and will conduct a talk on low temperature antennas. Be there if you can!
The new line of ultra-low noise UHF Yagis are being completed. This 24el 432Mhz LFA has been optimised for weak signal work including EME. This antenna is 20' long and yet weighs in at just 10lbs including all fixing hardware.
Note the new 'Computer Optimised' reflector array that helps this antenna achieve a Front to Rear figure (F/R, not F/B) of nearly 40 dB!!
The diagram below shows an over-lay of a standard LFA and one fitted with the new G0KSC optimised reflector array.
How cool would this look on your tower? Contact us directly or your closest InnovAntennas agent for more information or just like us on facebook and get all the news as it happens!
InnovAntennas Acquires Force 12
InnovAntennas has acquired the legendary Force 12 antenna company and product line and has moved the Force 12 factory from Bridgeport, Texas, to Grand Junction, Colorado, into a facility shared with InnovAntennas America. InnovAntennas Ltd in England is now manufacturing Force 12 products for the European market at its Canvey Island plant. The Grand Junction facility is up and running, manufacturing and shipping antennas. InnovAntennas says it plans to produce updated versions of classic Force 12 antennas as well as all-new models. InnovAntennas Founder Justin Johnson, G0KSC, was at the Colorado facility earlier this year to assist in setting up and laying out the factory, and the company expects full production to be underway by January.
An InnovAntennas customer in Sweden sent us this video of how his 10m OP-DES held up in the winds Europe had earlier this autumn. The wind speed was as 92m per second (around 93 MPH) and although the other antennas in the video are taking a real bashing, the OP-DES looks to be taking the storm in its stride.
InnovAntennas did not receive one single phone call or Email relating to damage during or after the storms. That has to be a good sign that we are doing things right!
The InnovAntennas Team
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