Hockley Essex, United Kingdom – InnovAntennas Limited, The premier supplier of sophisticated and Innovative directional antenna systems announces today the release of a game changing HF multiband directional antenna; the new Band Optimised Log Periodic Array (BOLPA).
The first in the series of BOLPA Yagis provides exceptional performance on 5 HF Ham bands simultaneously form a single feed point so is ideally suited to the modern-day SDR radios such Apache Labs, Flex Radio Systems and Expert Electronics where multiple band receiver slices can be used at the same time.
What makes the BOLPA different to traditional Log Periodic Arrays (LPDA)?
The BOLPA is a result of 2 years’ worth of development and testing. Justin Johnson G0KSC embarked upon a project to test the monoband abilities of a log periodic. It is known that an LPDA in traditional form can provide usability over a very wide range. However, the compromise being performance in terms of gain and Front to Back (F/B) are generally average to poor.
The project started with Justin optimising a 3 element LPDA for the 20m band only. This produced an antenna with a very short (6’, 1.9m) boom with just under 7dBi forward gain and almost 25dB F/B. The BOLPA came from the combination of several Monoband logs, arranged upon the same boom. To start with, 3 x 3el monoband LPDAs where placed one in front of the other for 20m, 15m and 10m. Performance of each was excellent and a bonus band materialised from this 9-element array; 12m was delivered for free!
Therefore, this first pass with 9 elements gave 20m, 15m, 12m and 10m all in a very short package but 17m was missing. Justin shifted the 20m 3 element cell back on the boom and placed a single element between the 20m cell and the 15m cell and optimised this element for lowest SWR for 17m while carefully adjusting the position of the 20m and 15m cells ever side of it. The result? The BOLPA-10 which covers all bands from 20m through to 10m (usable right up to 30MHz) with exceptional performance throughout.
Not only did the director for 20m provide a reflector for 17m and the first of the 15m elements provide a director for 17m ensuring excellent results on that band, the dedicated 17m element added an additional element to the 15m cell (now totalling 4 close-spaced elements) which delivers over 7.5dBi on this band along with 28dB F/B.
The first customer reports have confirmed SWR figures on all ham band of around 1:1.1 with 12m reaching as high as 1:1.3. on the upper end of the HF spectrum, the BOLPA-10 remains extremely stable across 6 MHz (between 24MHz and 30MHz) resulting in another benefit on all bands for valve amplifier users, No retuning because of same-band QSY!
Mechanical Construction and Feed Requirements
Unlike many traditional LPDAs, the BOLPA-10 does not have a 200Ohm feed point, like all InnovAntennas Yagis it has a direct, 50Ohm feed and therefore, simple 1:1 or choke baluns can be used and in turn, this means higher power handling abilities (5KW+). In order the reduce complexity, the BOLPA-10 using twin, square booms one about the other which double as the feed lines between each element which again improves the ability for the antenna to handle QRO.
The BOLPA-10 is the first in a new generation of high performance directional antennas suited to getting the very best from the very latest SDR transceivers. More information and ordering can be done via the InnovAntennas factory in this UK who direct supply with very competitive shipping prices, the World over.
WHY DOES THE BOLPA-10 WORK SO WELL?
Log Periodic Arrays are generally produced by means of a calculator rather than being band specifically optimised and therefore, performance and SWR curves vary greatly through their range and optimimum performance is hit and miss as a result. The InnovAntennas BOLPA-10 has had hundreds of hours spent optimising both SWR and Performance within the Ham Radio designated band sections which has resulted in exceptional mono-band style performance.
The Twin-boom feedline of the BOLPA-10 can easily be seen in this image
If you are looking for the best of the best from both a performance and mechanical construction perspective then look no further, you have come to the right place!
Customer Comment from SJR Service, our dealer in Sweden:
‘My customer with the LPDA has sent me this info:
SWR:
20m 1:1
17m 1:1
15m 1:1
12m 1:3
10m 1:1
He says he should have bough this antenna years ago!’
Performance
Typical Gain: 6.9 – 7.5dBi
Typical F/B: 20dB+
Gain at 10m (33′) above ground @ 14.150MHz: 11.56dBi
Power Rating: 5kw
Feed Impedance: 50Ohm
Boom Length: 7.7m
Weight: 10Kg / 33LB
Turning Radius: 7.6m
Wind Loading: Upon Application
Wind Survival: 160KPH / 100MPH – Higher rated versions available upon request
SDR READY ANTENNA, 6 BAND SIMULTANEOUS PERFORMANCE!
The BOLPA-10 has all-bands-active at anyone time so will compliment the most sophisitcated SDR Tranceivers, with up to 6 slices on 6 different bands (20m, 17m, 15m, 12m, 11m, 10m) all at the sam time. With the right equipment, you can even transmit on one of these bands while listening on the other 5 bands at the same time!
Some of the Mechanical design benefits include:
- Marine grade Stainless Steel Fittings*
- Integrated feed-line/boom for maximum efficiency, minimum wind-load
- Mill finished for highest levels of accuracy and performance
- First-of-kind ‘Band Optimised’ LPDAs by G0KSC
Price : £1,295.00
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