Stephen Newlyn VK5VKA, the writer of this article has had an Amateur Radio Licence since 1991 and has been Shortwave Listening for about 30 Years. For a number of years he was Chief Editor for "DX Post" of the now closed Shortwave listening "Southern Cross DX Club", and has written articles for "CB Action" and "Two Way" magazine during the 1980's.
Photo courtesy of bhi Limited, United Kingdom
Since the demise of VNG (Australia's HF Time Signal Service) I have been trying to work out a way to receive time signal station WWVH from Hawaii on 15 Mhz with a clearer signal during the Australian daytime. Most days WWVH starts to fade into South Australia around 0300utc but the signal is noisy from natural noise as well as some local electrical interference.
Then I saw a review of the bhi http://www.bhi-ltd.co.uk/ NES10-2 DSP speaker in the UK publication "Shortwave Magazine" September 2002 edition which gave the product a good review and then finally I saw a review in the Australian publication "Radio and Communications" March 2003 edition.
I've heard about DSP on high end receivers and transceivers but because of the cost I was not prepared to buy one of those (well at least not until the DRM receiving mode is provided for, but that's another story!). Well; I decided to buy a NES10-2 speaker and spent $AU339 (including postage within Australia) from the official dealer, Andrews Communications in Sydney. They can be found on the Internet at (http://www.andrewscom.com.au/). Incidentally Lee of Andrews Communications is very responsive to emails and treats his customers as he would liked to be treated himself if he was buying a product from someone.
The speaker arrived double boxed so there was very little chance of damage during transit from Andrews and it was sent registered post.
The United Kingdom manufactured bhi NES10-2 is small in size, coloured black, rectangular in shape and it's size is W110 x H65 x D55 mm. The front is dominated by the speaker grille with the model number on the bottom left corner of the unit and a LED indicator on the top right. On the top of the unit there is a "Sensitivity Control" and a "On/Off Noise Cancellation" switch.
On the rear of the unit are "Dip Switches", a printed "Noise Cancellation Selection Table", "Audio Input Lead" and a "DC Power 2.1mm socket".
On the left side of the speaker is a "Headphone" socket. On both sides of the unit you have support for the supplied and fitted "Mounting Bracket".
Accessories supplied (for the Australian Market) include a Mounting Bracket, 2 Fixing Screws, 4 Small Self Adhesive Feet, 24 Page Operating Manual and a 2m DC Power cable.
After a good look at the manual, which is well written (Yes! I am one of those who reads the manual first!). I proceeded to hook up the unit to DC power, unfortunately due to how my radio shack is laid out the DC supply was 3 metres away so I had to make my own cable, as the supplied cable was 2 metres long.
I then connected the supplied 2 metre long speaker cable to the test receiver (in my case a Drake R8A Communications Receiver which needed a 6.5mm adaptor as the supplied cable uses a 3.5mm plug).
There is no actual on/off power switch for the speaker, so you just turn on any 12-28 volt dc power supply to operate the unit.
As power is turned on the LED light glows. The LED indicates which position the "On/Off Noise Cancellation" switch is set. If the LED is glowing red it indicates that DSP function is off and if it's coloured green it indicates the DSP function is on. If you are colour blind though the intensity of the LED changes with mode so you can easily see the mode change.
There are two controls which once set rarely need to be adjusted (unless of course you change the connected receiving equipment or encounter a signal that needs extra processing). They are the "Sensitivity Control" and the "Dip Switches".
The "Dip Switches" by default are already set to Level 6, this setting appears to be well thought out as I found pretty much that this is the optimum setting for general use. However you may find a lower or higher setting may be more suited to your situation.
The operating manual says that the "Sensitivity Control" is set at first, by turning it fully anti-clockwise and then turning it back a quarter of a turn." Further adjustment may be necessary but most modern equipment will accept the settings mentioned in the manual. By the way the "Sensitivity Control" is designed so that it cannot be easily changed (accidentally bumped etc.).
Well the next thing to do is to switch "On/Off Noise Cancellation" off and then find a signal which has a bit of noise. Then switch on the "On/Off Noise Cancellation" switch. It may take a couple of seconds for the DSP to work when you will notice a distinct improvement in audio quality with less noise and in most cases a much more listenable signal.
I've tried it on all types of signals including AM Shortwave Broadcast, Long Wave Beacons, SSB and Morse Code signals. Audio quality is improved substantially. The speaker may be small but the audio output is more than adequate for most situations.
On some signals there is a "Robotic" sound on some voice type signals but actual clarity is better than listening to the noisier unprocessed signal.
Leaving the "On/Off Noise Cancellation" switch on sometimes make you wonder whether the radio is actually working because it makes background noise almost disappear as the usual crackle and pop is virtually gone.
Some products when released, arrive with a lot of hype and fanfare and turn out to be not as expected; however in regard to the bhi NES10-2 speaker I believe that this is not the case. I would thoroughly recommend this product to any one wanting to improve their reception of radio signals without spending a huge amount of money on a new DSP based receiver or transceiver.
This product was bought outright by the reviewer and was not a free review unit. The unit was not tested with any test equipment apart from my ears and comparing signals. For USA based readers this product is sold as the GAP HEAR-IT. A review written by Bob Grove was featured in the May 2003 edition of "Monitoring Times". For more information please check the GAP web site at http://www.gapantenna.com/.
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