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Filters and filter switching systems.
W3NQN Filters made by W3NQN himself or by Hamation ?
|Recently, we have become aware of some negative
comments about our bandpass filters. The claim is that since we supply
W3NQN bandpass filters that are made by our business partner, Hamation,
that the filters Hamation makes are somehow inferior to those made by
W3NQN himself. This is not true.
Hamation makes our W3NQN filters
using the same value components as those made by W3NQN and as a
result, the performance is virtually identical.
The measurement at the right shows, as just one example, both the
W3NQN-built 80m bandpass filter and the Hamation-built W3NQN filter.
With the exception of slightly better attenuation at higher
frequencies (above 8 MHz) on the Hamation built filter, they are
identical where it counts.
(Click the image to the right for a full size
version that you can inspect more closely).
These filters and filter switching systems are based on the article in the May and
June 1998 QST article by Ed Wetherhold, W3NQN.
We know these filters achieve a level of selectivity and a level of low in-band
insertion loss that will be the benchmark for all other filters to be measured by. Below
you will find detailed plots of the performance of these mono-band filters.
The design is based on a three-resonator filter configuration and uses very high
voltage, low loss, NPO ceramic capacitors, paralleled throughout to increase current
handling capability and reliability. We will first review the mono-band filters, then we
will show you systems that will enable the serious SO2R operator to achieve the highest
performance possible in reducing harmonics, hash, phase noise, and probably save your
receiver front ends.
These filters are absolutely necessary to prevent receiver front end damage in any
multiple HF radio environment.
W3NQN Single Band Transceiver Bandpass Filters including
WARC and MARS Bands
W3NQN Original mono-band band pass filters
|Array Solutions is very proud to be the exclusive distributor for for these Great
single band filters.
Single box design, made and tested by Ed Wetherhold,
W3NQN or K7MI @ Hamation to W3NQN specifications.
W3NQN Band Pass filters are the best single
band filters you can buy.
Each one is hand-made by W3NQN or by K7MI to W3NQN's specifications.
The performance of these W3NQN design filters, regardless of who assembles
them is the same. We will fill your order using the filters we have on
hand when you place your order.
Hamation's filters are those that have been used in our FilterMax units
for years and we are now also shipping them in single band packaging.
From time to time, we may be out of stock of one or more of them.
If you are planning a DXpedition or a contest expedition where you will
need these filters, please order in advance and let us know when you
actually need to have them in your possession. We will work with you to
meet your schedule.
Typical Specifications for these filters are as follows:
||Power <2:1 SWR
||Insertion loss in band
||Insertion loss 2nd harmonic
|160, 60,80, 40, 30, 20, 17, 15, 12, 10 Meters
||200 Watts CW, RTTY, SSB
|-50 to over 75 db depending on Band
These filters will tremendously reduce harmonic energy and wideband
phase noise transmitted by nearby transmitters, and reduce receiver de-sensing caused by
nearby transmitters, and closely located antennas in any multiple transceiver
For instance the single operator two radio (SO2R) contest operator,
multi-single (M/S) and Multi-Multi (M/M) operators looking for a new level of
performance. These kinds of filters should also be useful for monitoring facilities that
are also transmitting information on nearby antennas. We can custom design filters
for other frequency bands.
Specification Plots of the W3NQN filters
If you have trouble seeing the data just right click on the plot and move your curser
to "save as". You can then download it to your system for viewing with your photo
software or printing on your printer. I intentionally left the resolution high on
these plots to allow you to view or print this data on your system at high resolution.
10 Meter Plots
15 Meter Plots
20 Meter Plots
40 Meter Plots
80 Meter Plots
160 Meter Plots
|As can be seen the second harmonics are 70-80 db down from the fundamental and the
insertion loss is ~.2dB. These numbers are twice as good as the nearest
To make the filters more flexible for an SO2R type of operation it is necessary for
the operator to be able to listen on two bands at the same time, and be able to switch
bands quickly. A switching matrix can be added to a stack of six of these filters to
accomplish this. We call it the Filter Master or FM-6.
|We have added a 60 meter version of the filter. The specifications are
the same as the standard units above. Plot is below|
FM-6 Filter Master
|The Array Solutions FM-6 is a high quality 50 ohm strip line design RF matrix with
very high isolation between the filter ports. Using the available double shielded
cables, a set of 6 W3NQN bandpass filters can be easily configured externally
FM-6. They can be bound together with hook and loop fastening tape into a compact
package. The beauty of this set up is if you have a filter failure, it can be quickly
replaced with another mono-band filter section or bypassed temporarily. Also you can mix an match filters
from any manufacturer like our Array Solutions line of economical band pass filters. A set of two
FM-6s filter systems is the highest level of isolation between filters possible. And the
reliable W3NQN filters are the most robust and best performing filters on the market.
You can also use the less expensive Array Solutions AS-###
series of monoband filters to
create an efficient and cost-effective switching filter system with the FM-6
We also offer the COAX-12, which is a set of 12 double shielded
coax cables to properly connect your filters to the FM-6
To make it even easier we have set up various combination packages on the
FM-6-NQN - includes the FM-6, COAX-12, and
160/80/40/20/15/10m W3NQN mono-band filters
To control the FM-6 from a band decoder, you need to
source +12 per band. If no band is active in the FM-6, it is in bypass and
will allow operation on any frequency, 1.8 to 54 MHz.
|FM-6 on top of a W3NQN stack of 6 filters strapped together, all that remains
is to take off the red caps and hook up the COAX-12 cables.
|SWR from DC to 30 Mhz less than 1.1:1|
|Insertion loss DC to 30 Mhz less than .1 db |
|Relays 12 V DC 20 ma - 4 amp contacts small signal relay hermetically sealed gold
|Isolation between filter sections over 110db, we can't measure it since unused
sections are grounded|
|Power rating 250 Watts continuous @ 30 Mhz|
|Control connector DB9 and it is supplied with a 5 foot control cable|
|50 ohm micro-strip design on G10 solder masked protected double sided board |
|Connectors are silver plated SO239 and Teflon insulators |
|We can supply this unit with 12 matching double shielded high quality cables. This
is important for high isolation.|
Download the Users guide (acrobat .pdf)
2 kW High Power W3NQN RF Harmonic Filters
State of the art high current and high-Q capacitors
|2 kW Amateur band filters are available to solve those difficult interference
problems these are meant to be placed at the output of the amplifier, or at the output
of the SixPak antenna switch to add tremendous harmonic and hash reduction.
Bands available 80m, 40m, 20m only.|
INSERTION & RETURN LOSS RESPONSES OF 2 kW 40m FILTERS
Designed to attenuate the 2nd and 3rd harmonics of high power
NEW IMPROVED Design and Power handling 160m thru 20M now available! All
have similar plots.
Pass band insertion loss is under 0.15 db as can be seen in these plots where 20m is
.18 dB and the 40m filter is .15 dB. The 2nd Harmonics are over 80 dB down!
Dimensions 20m 15x4X3 inches
How well do they work?
At the NY4A contest station we use a long 20 meter Yagi suspended inside a long
40 meter quad. Models indicated a 30 db isolation between a 20m harmonic on the
40m antenna and the 20m station on the 20m antenna. Though this is good
considering the proximities in the design, we were concerned the 20m operator
stood to be crushed by 2nd harmonic garbage from the 40m station.
We purchased the W3NQN high-power 40m low pass filter and placed it in the line
right after the 40m amp to get another 80 db of isolation, bringing the total to
Afterward 20 meters was completely free of 40m hash and noise, and the 40m
harmonic was no louder than any middle strength station on the 20m band. Ran 1500
watts CW out into the filter all night long, no smoke, no funny smells.
Math: 1500 watts @ 50 ohms = 275 volts. 54 db down for for second harmonic from
amp = .549 volts (QST test on AL1200). 30 db down for antenna natural separation
= 17.4 millivolts. 80 db down for NQN filter = 1.74 microvolts. Just another
moderate 20m signal.
73, Guy K2AV
Co-located military, commercial radio, and marine
We have developed Short wave bandpass filters for military, commercial
and marine shortwave communications. They have the same electrical performance
shown in the plots above. But we can also design and manufacture special filters to
your application. For instance we have a 2-30 Mhz filter system that breaks up
this range into 10 segments.
|Custom bandpass filters are now also available for taking out special interference
problems as well. Such as a loud short-wave broadcaster who is de-sensing or
causing IMD problems in an amateur band.|
Pricing and Ordering
here for price list and ordering information see bandpass filter section.