Kostas presents the NR-1 Noise Blanker!

Many due to SWLing Put up contributor, Kostas (SV3ORA), for sharing the next submit which initially appeared on his web site:

Replace June 1, 2024: Kostas is just not at the moment promoting the NR-1 as a product however has, as an alternative, made the whole challenge open and accessible for everybody to construct their very own. You might contact him for extra data.

I designed my very own noise blanker as a result of:

• • I used to be uninterested in that HF noise that might not be overwhelmed in any other case.
  • I wished to take away it earlier than it will get into my transceiver.
  • I couldn’t set up a separate “noise” antenna/coaxial for range.
  • I wished to take away noise interference from any path.

NR-1 is a revolutionary Noise Blanker which is the results of two-years of improvement and intensive testing by Kostas sv3ora.

NR-1 works straight on the antenna. This has important benefits over the traditional noise blankers which work on the intermediate levels of the receivers. It doesn’t require a second “noise” antenna for its operation.

Moreover, it’s not based mostly on cutting-off of amplifiers, in contrast to frequent noise blankers
do.

Due to these, the NR-1 is superior, in contrast tocommon inside Noise blankers of radios:

• • NR-1 removes noise earlier than it even reaches the receiver. Thus, the front-end RF
    levels of the receiver are unaffected by noise, in contrast to a standard noise blanker
    which removes the noise after it has first handed via the inner circuits
    of the receiver.
  • NR-1 removes high-level, high-repetition-rate noises that frequent noise blankers
    often can’t address.
  • NR-1 is just not affected by robust near-by alerts. As a substitute, frequent noise blankers
    carry out poorly when there are robust near-by alerts and so they distort the sign of the station we need to pay attention.
  • NR-1 can be utilized by many radios. As a result of it’s an exterior system, it may be
    related to numerous radios/receivers with out the necessity to modify them.
  • NR-1 has a built-in 8-band preselector and helps remove intermodulation (birdies)
    brought on by robust native medium and shortwave stations, on RF direct sampling
    radios (eg IC-7300). The preselector is comparatively wideband and doesn’t have an effect on
    the sensitivity or the waterfall spectrum within the newbie radio bands.
  • NR-1 has built-in variable acquire preamplifier and variable attenuator. Preamplification is
    notably helpful within the excessive frequency bands, the place some radios have restricted
    sensitivity. Variable attenuation helps to cut back band noise for extra
    snug listening to mid/excessive power stations.

Comparability of the NR-1 with different noise removing programs (eg. QRM eliminator, X-phase and so forth):

• • NR-1 doesn’t require a second (noise) antenna/coaxial-line to function. In contrast to QRM
    eliminators, NR-1 doesn’t require an extra “noise” antenna and
    subsequently no second coaxial cable out of the shack. The primary transmit and
    obtain antenna you might be already utilizing is enough.
  • NR-1 is straightforward to arrange. In distinction, QRM eliminators require systematic testing of
    varied noise antennas in numerous places to carry out satisfactorily.
  • NR-1 removes noise from each path concurrently. In distinction, QRM
    eliminators, relying on the noise antenna setup and their configuration,
    take away noise from one path solely every time. If the noise originates or
    “travels” via cables and reaches the antenna from totally different
    instructions, QRM eliminators don’t carry out nicely.
  • NR-1 removes multiple noise supply concurrently as a result of its precept of
    operation is just not associated to the part of the noise.
  • NR-1 doesn’t require fixed adjustment. As soon as set for one band, it often doesn’t must be reset. In distinction, QRM eliminators require resetting each few tens of KHz or so.

Kostas has documented all the small print of the NR-1 for his personal future reference in his web page.

He has additionally created some YOUTUBE movies as demonstrations of the operation and the effectiveness of this antenna noise blanker.

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