antennerna.se provides complete antenna systems for both Commercial and Amateur Radio use. Contact us, preferably by email with your requirements and we will help you get the very best.
Our larger antennas can be divided into the traditional yagi antennas, yet with very high performance as they are optimized to the very best. Newer designs of antennas opens up more opportunities for instance for higher gain and/or smooth pattern to help silence a noisy environment. Here is a short description of various antenna designs we provide.
The LFA (Loop Fed Array) Low-Noise Yagi is very different from the traditional dipole fed Yagi in many ways with its primary benefit being unwanted noise rejection. The LFA has a rectangular shaped, full wave loop driven element that is laid flat on the boom between and in-line with the parasitic elements . Then there is the way in which the loop functions. The smaller end sections which run parallel to the boom, are engineered to be 180 degrees out-of-phase with each other. This provides the same effect as is seen within ladder-line feeder; each side cancels the other out and therefore, minimum radiation occurs. In practice this translates to highly suppressed side lobes and side-on signal rejection. This feature also plays a role in reducing F/B (Front to Back ratio), F/R (Front to Rear ratio) and broad-banding of the antenna too. It is these attributes which help give the LFA class-leading all-round performance at almost any boom length and for any given band.
Here is a picture of a LFA yagi, more info can be found here on InnovAntennas web: LFA-yagis
The LFA-Q (Loop Fed Array Quad) Low-Noise Yagi takes a lot of the good points from the LFA Yagi and adds some more. the LFA-Q is a quad with a difference. Rather than placing symmetrical square or triangular shaped loops in a Yagi configuration, the LFA-Q uses the LFAYagi style loops to produce high levels of side suppression, the difference being every element is a loop rather than just the driven element.
The shape of the loops have been formed (compressed) until the short side sections are exactly 180 degrees out of phase with one another and therefore, a cancellation effect occurs in much the same way as balanced line feeder works. This means high levels of suppression to both the sides and the rear of the antenna can be achieved.
So if the LFA Yagi does this so well, why do something different with loops forming all elements? The primary reason is gain per meter/foot of boom on a full wave element antenna can be much greater than on a half wave element antenna such as the LFA. This results in compact, high gain antennas which are constructed to stand some serious weather conditions!
Here is a picture of a LFA-Q yagi, more info can be found here on InnovAntennas web: LFA-Q-yagis
The OWL (Optimised Wideband Low impedance) Low-Noise Yagi is another development of Justin Johnson, G0KSC. Originally the OWL formed the basis of a DUBUS magazine article which found that low impedance antennas need not be narrow band and unstable in wet or icy conditions.
Generally, the lower the impedance of an antenna, the better performance (in respect of forward Gain (Gain) and Front to Back ratio (F/B)) can be achieved.G0KSC extended his development with focus on 12.5Ω versions of the OWL for very good reason; if a 12.5Ω OWL has its split dipole changed to a folded dipole, the feed impedance is transformed from 12.5Ω to 50Ω and thus any 'would-be' matching losses are removed and ohmic loss reduced to insignificance.
While the swapping of a split dipole to a folded dipole within a Yagi is nothing new (generally done on 50Ω split dipole Yagis to give a new, 200Ω Yagi), G0KSC also established performance could be improved further if the whole antenna (including its new folded dipole) was computer optimized as a complete unit. The results have been more than impressive and with the addition of thru-boom parasitic elements and a folded dipole place above/below the boom, light weight and portability have entered into the equation resulting in a excellent all-rounder.
Here is a picture of a OWL yagi, more info can be found here on InnovAntennas web: OWL-yagis
The OP-DES (Opposing Phase - Driven Element System) Yagi is another development of Justin Johnson, G0KSC. The OP-DES Yagi has been specifically developed for HF applications where bandwidth and performance within one package is difficult to come by.
The OP-DES Yagi has one characteristic of all G0KSC developed Yagis, it has a 50 Ohm feed-point impedance and all impedance transformation is done within the driven element itself and therefore, the antenna is not susceptible to matching losses in the same way traditional Yagis are. For the wider of the HF bands many hams opt for the OWA (Optimized WidebandArray) style Yagi to give all-band performance. However, the OWA does not provide the levels of performance lower impedance antennas can albeit the OWA has the prefer split-dipole, 50Ohm feed-point.
The OP-DES has the ends of a split-dipole bent back towards the reflector element. This provides 2 functions. First of all, the current phase in each end section is in opposing phase and therefore cancel one another out, this helps to reduce/remove side lobes. Additionally, these end sections act as impedance controllers, taking this job away from D1 (first director) and thus making the adjustment of the antenna (while in computer optimization much easier resulting in better levels of performance. As with all of our antennas the OP-DES driven element has adjustable end sections in order that SWR fine-tuning is possible.
All band performance on bands from 40m to 12m is possible with 1MHz coverage on 10m too. When we say all band performance, we do not simply mean the SWR is at an acceptable level, the OP-DES provides excellent levels of gain and F/B throughout each band too. If you are looking for the ultimate in mono-band HF performance, look no further than the OP-DES Yagi !!
Here is a picture of a OP-DES yagi, more info can be found here on InnovAntennas web: OP-DES-yagis
The DESpole is so named after the OP-DES Yagi driven element which it adopts in a down facing direction on at least one band.
So what makes the DESpole what it is and why is it different? There are many reasons that the DESpole will provide excellent service, performance and long life. Some of these are mechanical but we will start first with the performance related benefits.
The DESpole as with all our antennas are extremely well made with attention being focused on ultra-high quality materials and build. All of our products go through a lengthy electromagnetic design process before a computer optimization of the mechanical structure is carried out. This ensures that our antennas will last and not blow down at the first sign of bad weather.
When comparing the DESpole to other rotating dipoles, you have no losses in traps and coils to worry about. over 98.5% of your input power is radiated. Punch out a HUGE signal without an amplifier with the DESpole!!
Here is a picture of DES-poles, more info can be found here on InnovAntennas web: DES-poles