Clifton Laboratories 7236 Clifton Road  Clifton VA 20124 tel: (703) 830 0368 fax: (703) 830 0711

E-mail: Jack.Smith@cliftonlaboratories.com
 

The Z10020 Medium Wave (AM Broadcast) Band Reject Filter reduces signals in the 530 - 1700 KHz  range whilst passing frequencies below this range and above this range with minimal attenuation. For a wide range of the AM broadcast band, rejection levels of 80 dB and more are possible.

Photos

The Z10020 in an indoor enclosure with BNC connectors (the normal arrangement) is pictured below.

Four versions of  the Z10020 are available:

• Standard Design. Maximum AM medium wave band rejection. Unless otherwise stated, the performance figures on this page are for the standard design filter.
   
• Improved 160 Meter Design. By sacrificing some attenuation for medium wave frequencies above 1500 KHz, the loss at 1.800 MHz can be improved. The standard design filter exhibits approximately 3 dB loss at 1.800 MHz, rapidly declining as the frequency increases. The "Improved 160 Meter Design" reduces the 1.800 MHz loss to approximately 1.5 to 2 dB.
   
• NDB/NAVTEX Design. The Standard Design Z10020 begins to roll off at 450 KHz or so. At the request of customers interested in chasing non-directional beacon DX, or monitoring 518 KHz NAVTEX operations, or wishing to listen to the  500 KHz amateur radio experimental operations, the NDB/NAVTEX Design moves the low frequency cutoff point up to approximately 530 KHz. As may be expected, there is some sacrifice of medium wave rejection at the bottom end of the MW band.
   
• "I don't care about 160 meters" Design. A recent special design for a customer who wanted maximum rejection of the upper end of the AM medium wave band, and is not interested in 160 meter coverage. The upper -3 dB point is moved to 2.0 MHz and the lower -3 dB point to 440 KHz. This provides maximum rejection of AM medium wave signals, over the range 530 KHz - 1600 KHz. Measured attenuation 45 dB at 550 KHz and 50 db at 1560 KHz.

When ordering your Z10020 filter, please indicate which design you wish to purchase.

I've made available, with the consent of Warren, K2ORS, a detailed performance report on a Z10020 NDB/NAVTEX filter I recently built for him. Click here to read the report. It's a 300 kB PDF file. The standard performance documentation option does not include this level of detail.)
 

Typical Performance Plots

Note the ultimate rejection is 100 dB or more.

If the Z10020 is to be shipped to a location within the Commonwealth of Virginia, please add 5% sales tax.

Construction Options:

Opt U: UHF connectors, silver/Teflon (import) with interior hoods: $12.50
Opt U*: UHF connectors, import, nickel plated, no hoods: $8.00 (Filter performance is not guaranteed with this option.)
Opt N: Type N connectors, with interior hoods $12.50
Opt S: SMA connectors. $12.50
Opt WSFL: Hammond 1590WSFL flanged weatherproof enclosure $14.00
Opt WSF: Hammond 1590WSF flanged weatherproof enclosure $18.00
Opt 75: 75 ohm impedance instead of 50, built with 50 ohm connectors--no extra charge.
Opt 75N: 75 ohm impedance with 75 ohm Type N connectors: $22.50

Design Options:

Standard: Standard upper and lower 3 dB points
160 Meter: Reduced loss at 1.8 MHz, but lesser rejection in the medium wave band above 1500 KHz
NDB/NAVTEX: Lower 3 dB point moved to 530 KHz, with lesser rejection in the lower frequency portion of the medium wave band.

There is no price difference for the three Design Options.

The difference between Option WSFL and WSF is the flange location. Option WSFL has the flange on the enclosure lid and option WSF has the flange on the enclosure base. The weatherproof enclosure photograph at the top of the page is of the WSFL enclosure.

Options WSFL and WSF come with gasketed hardware - the 6-32 and 4-40 screws have recessed grooved heads with a Buna-S gasket to reduce water ingress.

These filters are assembled as orders arrive and most options will require an additional order interval. Normal order interval is one week.

Payment may be made with a check or money order payable to Clifton Laboratories at the address on the top of this page, or via PayPal to orders@cliftonlaboratories.com. If ordering a filter, please also send a separate E-mail with your order specifics and contact information.
 

To illustrate the effectiveness of the Z10020 Band Reject filter, the following spectrum analyzer shows the spectrum over the  range 0 - 2 MHz at Clifton VA. The antenna is a Clifton Laboratories Z1501C Active Antenna.

The blue trace is with the Z10020 out of the circuit, and the magenta trace is with the filter connected.
 

Ron, K8AQC, in contrast, is located in suburban Detroit in a location with many very strong medium wave signals. Ron has a Z10020 NDB/NAVTEX band-reject filter and kindly supplied a similar spectrum analyzer image. (Ron is also using a Z1501C Clifton Laboratories Active Antenna.)
 

The blue trace is direct and the magenta is with the Z10020 NDB/NAVTEX filter in place. Note that one station (WJR, 760 KHz) has been reduced from nearly 0 dBm into the spectrum analyzer noise floor, and the strongest station (1500 KHz) has been reduced from +5 dBm to -39 dBm, well within the range of reasonable signal strength to be handled by a typical receiver.
 

Hi Jack:

 I just wanted to add my name to your long list of testimonials regarding that AM reject filter.  Mine is working fabulously.  I have a software radio from RFSpace that was being totally overloaded as was my Icom IC-7000. (The FT-1000MP was mostly able to overcome the strong AM, but I put the filter in the receive loop and I think it does make a difference there too.)

Anyways, I am now able to use my SDR-14 the way it was intended and to use my IC-7000 again.

You are my hero!

73  Greg KN6MT

Hi Jack,

Received the filter today, it's performance is awesome!
It knocks 50kW locals into the noise.

Let me know when the active antenna and multicoupler are ready, I'm interested in both.

Many thanks!
Warren