*PRODUCT REVIEW* BHI NEIM1031 DSP

If you’re looking to perk up the quality of your RX and don’t have the cash to throw at a new transceiver with the marvel of Digital Signal Processing (DSP), then this next wonder gadget may be for you…

Clearly, the major benefit of using any DSP unit is that you don’t have to put up with the harsh noise that can often dominate HF bands and render DXing or ragchew ops useless.

Enter the NEIM1031 which incorporates DSP technology to remove unwanted background noise and interference from speech, and you’re entering into a DX-citing new world of RX!

A while ago for the Dx Adventure Radio Club (DA-RC), I reviewed the NES10-2 Noise Eliminating Speaker (See right) and also the terrific Noise Cancelling Headphones by Heil (See below), but this next DSP product, for my part, ranks on the same stage.

The NEIM1031 is what’s called an ‘In-Line module’ and from all reports was developed by manufacturer bhi as a response to DXer feedback about the NES 10-2.

Evidently, some radio shack operatives indicated they’d like an inline unit without a speaker, not as a surrogate, but instead as an alternative profile.

Besides the improvement to RX and being able to pull in weak signals, another sizable attraction for me was that it can be fitted to an existing speaker.

In my opinion, this allows the fashion conscious Gen X DXer to stick with some of the more stylish speaker systems on the market rather than trade them in for a smaller, less sophisticated looking type with DSP.

The NEIM1301 module straight from the External Speaker socket, for example, worked effectively with my preferred Kenwood SP-23, which I’d be hesitant to exchange on a full time basis as it compliments my TS2000 so well.

At just 170 x 85 x 34 mm, the NEIM1031 was super easy to set up with my existing speaker and begin operation.

In fact, once power and audio leads were connected, including my Heil ‘Quiet’ headphones into the NEIM1031’s headphone socket, it was all systems go to start testing my new setup on some weak signals from other Australian states and territories.

As you’d hope, noise cancellation can be switched ON and OFF on the unit which provides some flexibility in use.

The input audio level can also be adjusted and a green LED (See below) indicates the input audio level is okay while a red LED illuminates if the level is too high.

With an eye on the LED’s, you can also adjust the audio input control.

Additionally, there is a control for audio output as well to set the volume for up to 2.5 Watts RMS into 8 Ohms.

That is stacks for most users by the way, but I’ve heard that some guys have added external amplification if you’re greedy lol.

The extent of noise cancellation by the NEIM1031 is inhibited by a small rotary BCD switch.

Here, minimum noise cancellation is at position ‘0′ while ‘7′ is the maximum.

As you’d expect, the level of noise cancellation is adjustable too while the unit is in use, nevertheless this is still a big attraction.

Essentially, how much noise cancellation you use is dependent of the operator, type and level of signal and amount of noise present on the band.

When noise cancellation is set at ‘7′ almost all noise is removed although the audio takes on a rather robotic sound when set at this level.

Normally you’d use such high processing for the most severely noise effected signals only or to draw out that rare DXpedition station which hovers at the back of the box amidst a wall of Indonesian fishing boat TX.

It most cases I use a setting of 3-5, however this is entirely subjective and it’s my thinking that every user will choose a level that suits them and their listening needs best.

Needless to say that some would favor no noise and accept some audio degradation, while others will have best audio and accept some noise.

This small rectangular unit is powered from an external DC plug pack, which is not supplied, with the acceptable input voltage range from 12-24 volts.

The audio in and out is connected either via a pair of RCA or 3.5mm jacks at one end of the case.

On the NES10-2 which I dealt with a few months ago, a dual in-line switch was used to adjust the degree of noise elimination whereas a rotatory switch performs the same adjustment on the NEIM1031.

It’s a trivial line of reasoning but a high profile knob would be better in my estimation.

One concern I had with the module was with the size of the rotary switch.

The numbers are tiny and require a microscope to see (almost!), although there is no real need to see them when all you care about it is the quality of the audio.

The NEIM1031 does come with optional extras which include a horizontal label and a mounting stand which firmly holds the unit during operation and I’d recommend these also.

If you are interested in adding DSP to your communications then the distributor for bhi in Australia is Andrews Communications in Sydney.