Universal NF-Filter ED 88 NF

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$220.00 *

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  • EFD1000014
What is an ED 88 NF - filter? The ED 88 NF is an electronic and active filter for the low... more
Product information "Universal NF-Filter ED 88 NF"

What is an ED 88 NF - filter?

The ED 88 NF is an electronic and active filter for the low frequency range. So far quartz or ceramic filters are used in the intermediate frequency part for selecting the receiver. By the ED 88 NF an additional selection for interference-free reception is possible. Thanks to special integrated circuits and a very thoughtful and a practice-based design our filters are able to improve the reception of the desired station, so that a surprisingly quiet and very understandable interference-free transmission of the information can be established.

The ED 88 NF is a further development of the proven mono notch and peak filter GD 66 NF, as well as the very popular double notch and peak filters GD 82 NF, GD 84 NF and GD 86 NF.

Why double-notch?
In contrast to various other filters with the ED 88 NF two or more interfering CW stations or tones of different frequencies as RTTY or SSTV can be filtered out simultaneously and independently or can be damped with over 60 dB (e.g. S 9 + 20 dB). They simply disappear, without affecting the information of the received station uncomfortably. With the bandwidth controller the notch widths between 70 Hz and 1,7 kHz can be adjusted commonly and steplessly.

Where is the filter attached?
It is simply connected to the headphone or speaker jack (e.g. "ext. speakers") of the receiver or transceiver. Without a modification of the receiver the filter is connected via a shielded cable between the receiver and the speaker or headphone. The connection cable from the filter to the receiver (RX1) is already fitted with a 3.5 mm jack. A built-in 3 W audio amplifier provides sufficient volume.

Why is the ED 88 NF filter used?
For suppression and isolation of whistling, crackling, scratching, humming, splatter interferences, tuning sounds and signals from other stations on the neighboring frequency, as well as the noise. The interfering frequencies or tones in the range of audibility are literally "cut off or cut out" by the steep filter pass band and continuously controllable bandwidth between 4.5 kHz down to 100 Hz.

Are the functions notch and peak available jointly in this filter?
Yes, in order to achieve an even better audibility for filtered SSB-, FM-, AM- and CW-signals. In the rotary switch positions „CW" and „Peak 2x" it can be easily and quickly switched to notch and peak by just a small toggle switch.

What operating voltage is necessary?
For the filter function only a DC voltage of 11-15 V DC is required at about 300 mA. On the back of the filter housing there is a connection cable for the external 12V DC power supply. The existing receiver also often has the necessary operating voltage.

For which frequency ranges is the filter suitable and is it also helpful in scanners and CB radios?
From long wave up to the gigahertz range, because the filter is used in the low-frequency or in the audible range. Everything that has been previously transmitted unfiltered to the speaker can now be processed using the active filter. Therefore, the great filter effect and the improved reception at each receiver is also recognizable in scanner or transceiver.

Is a direct connection of the recorder or sound cards possible?
At the rear of the filter housing a 5-pin DIN socket is mounted. This interface allows to connect the unfiltered or filtered desired signal for the recorder or directly the sound card (line-in) in the computer.

Can you actively raise one or more useful signals or specific frequencies, e.g. in digital modes or SSB, narrow-band from the QRM or noise?
You can by double peak! Because when switching from double notch via super peak to double peak reverse functions arise, i.e. which was suppressed by notch is actively raised by peak from the QRM/noise. The two peaks can also be set again in the width of the bandwidth controller steplessly from 70 Hz to 1.7 kHz. With the ED 88 NF the peaks are now adjustable independently and steplessly in the range of about 100 Hz to 4.5 kHz. This means that now the desired frequencies/tones at SSTV, FAX, packet radio and also on FM, AM and SSB are lifted out of the QRM and noise and therefore a better audibility arises.

Can the software programs of the existing computer be further improved by this audio, low-frequency filter?
For this an extra output (will not be turned off) was installed in the ED 88 NF for the sound card connector.

What happens to the filter when sending?
If the decoupled socket "PTT" on the filter housing back wall is connected in parallel with the PTT point on the transceiver (for example ACC socket) or microphone, in contrast to other filters no feedback or impairment of the sidetone emerges. The filter is bypassed when sending (automatic bypass).

Which plugs are provided?
A 3-pin 3.5 mm stereo jack and a 2-pin RCA plug.

Is the filter quick and easy to use?
By the built-in LED and large knobs the CW-, RTTY- or SSTV station can easily be set to maximum passage with the help of two separate potentiometers for the audio frequencies 1 and 2. In this case, the bandwidth of the passage can be independently adjusted steplessly with the third potentiometer between 100 Hz and 4.5 kHz (100 Hz - slim - 4.5 kHz - wide). The toggle switch "on/off" switches the filter from the preset range immediately back to the normal reception setting (bypass). A further LED indicates this operating state. Using the reverse circuit "Notch - Peak" and lever switch "Notch and Peak" it can be immediately determined, whether the audible signal should be suppressed or actively raised from the interferences.

Is this double notch and double peak filter also useful in the tropical band?
Absolutely! Because especially for this the passage and tuning range of the filter has been extended from 2.7 kHz to 4.5 kHz. This allows to notch filter the interference tones for AM and to suppress the bright noise.

Is the filter also suitable for RTTY, FAX, SSTV, packet radio?
Especially well because both RTTY frequencies are raised out of the QRM or noise very narrow-band in the operating position "2x Peak" by the controller tone frequency 1 and 2 as well as double peak. Here the width of the bandpass filters can be adjusted steplessly with the bandwidths regulator. The error rates fall - the image qualities rise. The thus filtered signal can then be passed on via the audio output to the sound card (line in).

What is supplied with the ED 88 NF?
In order to optimally integrate the filter into the existing station, e.g. into the speaker housing or other housings, the tested device is supplied with drawings, descriptions and 2 plugs.
Optionally, there is the connection cable audio filter to the sound card (line-in).

Does the filter also have a great effect in SSB, FM, AM on 2 m, 70 cm and SHF at OSCAR - and EME - connections?
Yes! By the steplessly adjustable bandwidth and double notch all disturbing frequencies in the audible range/noise can be "cut off" between 100 Hz and 4.5 kHz (ca. 50 dB attenuation). This means, for example, at a passband setting of 1 kHz, that all frequencies above 1 kHz are attenuated according to the brim. Lowpass = Both notches next to each other, above 1 kHz, notch filter out the frequency range up to 4.5 kHz. The noise is literally "cut off/notched".

Is it worth installing an ED 88 NF-filter even if the existing receiver is equipped with a crystal filter, a "WIDTH" controller or a passband tuning?
For sure! Because the double notch/peak function, additional selection, steplessly adjustable bandwidth and optical tuning aid ensure that the receiver is expanded to a top model (a comparison with other options will answer this question easily).

Is the ED 88 NF filter still useful when the existing transceiver or receiver already has one or two built-in notch filters and auto notch?
Only by the additional two notch functions in the low-frequency filter, it is now possible to fully and effectively eliminate double signals like RTTY, FAX, SSTV or similar. With the RF interferences from computers triple notching is often very helpful. Also the notches of the installed notch filters are not deep enough and in the beginning very wide, so that these filters can be switched off again in the case of an interference.

Has your transceiver/receiver peak functions?
In the ED 88 NF filter there are two functions, narrow or wide, depending on need.

Can this filter be used for other receivers or CB radios?
On the back of the filter an RCA socket is installed for connecting a second receiver. With the toggle switch "RX1 / RX2" on the front panel, the filter input can be switched, for example, to a shortwave transceiver and (in position 2) to an FM receiver or a CB radio.

Is the ED 88 NF better than a DSP filter (digital signal processing) or a NIR filter (noise and inteference reduction unit)?
The ED 88 NF filter is an ASP filter (analog signal processing). It is a general-purpose low-frequency filter. So a filter for all operating modes. Since all human ears are different, also the stepless adjustment of the filter functions analogous to the hearing and the necessary audibility is required. Various tests have shown that the ED 88 NF is the most useful and effective NF-filter against QRM and noise.

Why is the ED 88 NF, the flagship among reception / AF filters?

  • 2x independent notch functions
  • 2x peak, - reverse circuit -
  • Universal filter against QRM, roaring, whistling, humming
  • non-slip tuning knobs, attractive appearance, 2-colored elegant metal housing
  • external power supply 12 - 15V DC/ 0,3A
  • for all operating modes, SSB, CW, EME, AM, FM, SSTV, OSCAR, RTTY, AMTOR, PACKET RADIO...
  • optical frequency tuning aid with LED
  • bandwidth setting of 70 Hz - 4.1 kHz
  • 2 different connection plugs
  • very large notch depth to 70 dB
  • recorder connector 5 pin DIN socket
  • wide frequency range 100 Hz - 4.1 kHz
  • steplessly adjustable filter functions
  • very good "crystal filter replacement"
  • suitable for each recipient
  • from long-wave up to the GHz range
  • less noise
  • steplessly variable notch widths
  • you hear stations that have been previously obscured by interference from other stations
  • German, Dutch, Italian and French operating instructions
  • the most effective reception filter
  • extensive brochures for free
  • with built-in 3 W audio amplifier for the speaker
  • sound card connector (line in)
  • very amazing filter effect
  • over 25 years of experience with filters
  • filter effect - how your ears want it
  • large filter slope (SF CW 1.2)
  • filter bypass when sending with PTT
  • hear better - with A S P
  • operating voltage - reverse polarity protection
  • large input voltage range
  • easily and seamlessly to connect
  • less QRM
  • without operating voltage: filter bypassed
  • input switchable for 2 receivers/transceivers
  • many advantages in comparison with DSP, NIR or similar
  • super peak - CW filter, with "flattopping"
  • feel more comfortable with the filter
  • the flagship among audio filters
  • no attenuation of the desired signal
  • variable center frequencies, band-pass filters
  • new: combined notch and peak functions

The ED 88 NF filter is one of the most advanced audio filters in the world and represents the highest level of analog NF filter technology for many years by the use of low noise Bifet-ICs and a practice related conception.

Technical data:

  • sound pass / audible range of the filter: 100 Hz to 4.5 kHz, steplessly adjustable bandwidth
  • double notch: 2 frequency independent notches / holes
  • notch width of about 70 Hz to 1.7 kHz
  • damping / notch depth 2 x - 60 dB -- notch - peak = reverse circuit ---
  • attenuation of unwanted signals in CW, RTTY and SSTV with more than 50 dB
  • shape factor: CW 1.2
  • bandwidth of the CW, RTTY and SSTV sounds steplessly adjustable between 70 Hz and 1.7 kHz, in the audible range from 100 Hz to 4.5 kHz
  • operating voltage: + 11 - 15V = ca. 300 mA
  • input impedance: 4 Ohm - 10 k Ohm
  • output impedance: 4 - 16 Ohm / 5 kOhm
  • AF - output power ca. 3 W
  • 2 LEDs for power on and equal frequency of the two band-pass filters (max. passband)
  • sturdy steel housing, color powder coated (RAL 7016) with 4 rubber feet
  • front and rear panel labeled in yellow
  • housing - dimensions: height 45 mm, width 205 mm, depth 149 mm
  • by PTT no feedback or sidetone impairment during transmission (bypass)
  • available as a complete unit, with or without 230 V / AC - power supply
  • input and switching for 2nd receiver, e.g. for shortwave and FM-receiver TX/RX
  • output socket (DIN 5-pin) for recorder or sound card
  • easy-grip knobs

supply also includes: an operational guide in German language and two different connectors (RCA and 3.5 mm jack (stereo))

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