BPFs maximum  applied power is the same as for 3000W BPFs because the same parts used but triplexer built on a PCB board and is up to 2000W. 

The project idea is to design and build a Triplexer with BPFs set for 1500 watt output power which is lighter and smaller than the 3000W  version of the Triplexer and BPFs.

This set  so-called “DX-pedition set” is easier to travel with and all boxes recommended to be installed one over another and not required a wall installation (it can be installed on a wall as well).

With total band isolation better than -75dB it can be used up to 2000W without any problems. 4O3A rated his set for 4500W ICAS  having -72dB  of  a band isolation between 10 and 15 meter bands( from 4O3A.com).

Some numbers for -75dB of band isolation with 1500 watt output power:

  • 1500W is 275V of effective voltage
  • -75dB attenuation decreases voltage from 275V to 50mV
  • -75dB attenuation decreases power from 1500W to 0.00005W (-13dBm)

Some short specification of the 1500W set:

  • All filter boxes are smaller compare to 3000W set and built with a thicker aluminum.
  • BPFs are the 4th order Chebyshev type with adjacent band isolation > – 45dB
  • BPFs can be the 5th order type built in a 2″ longer enclosure with isolation > – 55dB
  • BPFs together with Triplexer   are better than -75dB  ( – 85dB if 15 and 20 bands are the 5th order BPFs)
  • Lower BPFs order allows to have a lower Insertion Loss
  • More than -100 dB of isolation between 10 and 20 meter bands (with Triplexer)
  • It can be used without a fan cooling up to 1500 watts (CW/SSB 50% duty cycle)
  • All parts inside rated at 3500W output power
  • Triplexer built on three FR-4 PCB boards

Recommended BPF Power with antenna VSWR

  • With air cooling:   1500W CW/SSB /RTTY (2000W PEP)
  • Without fan installed:   1000W CW/SSB/RTTY

Enclosure is Hammond 1444-1573 for 4th order BPF :

  • Without Fan – 15″ x 7″ x 3″ (38 x 17.5 x 8 cm)
  • With Fan Installed –  15″ x 8″ x 3″ (38 x 19.5 x 8 cm)

Longer by 2″ enclosure is Hammond 1444-1773 for 5th order BPF :

  • Without Fan – 17″ x 7″ x 3″ (43 x 17.5 x 8 cm)
  • With Fan Installed –  17″ x 8″ x 3″ (43 x 19.5 x 8 cm)

On a photo below, Triplexer box installed between 10 and 15 meter band BPFs and this box order allows to use the shortest coax connection cables.

  • Coaxial cables between BPFs and Triplexer must be as short as possible.

VE3DZ 006

There are two cooling fans installed for each BPF because they are smaller and less powerful (60mm vs 92mm) than those installed on a 3000W set boxes. These cooling fans blow directly toward coils under stress and it woks quite efficiently.

For a 2″ longer box 1444-1773 and the 5th order BPFs three cooling fans can be installed to allow BPFs to be used up to 3000W of output power.

VE3DZ 007

Please, see completed 20M BPF graph below:

  • Insertion Loss < 0.25 dB
  • Band Isolation ( 15 M > 47 dB, 10 M > 72dB,  40M > 57dB)
  • VSWR  < 1.05  (Return Loss > 28 dB) 
  • Expected Band Isolation with Triplexer > 80dB


Band isolation can be easily increased to -50dB for 15M band with some different capacitor values. Increased band isolation brings Insertion Loss to a little higher value to -0.27-0.28dB value.

Please, see completed 15M BPF graph below:

  • Insertion Loss < 0.32 dB
  • Band Isolation ( 20 M > 52 dB, 10 M > 44dB,  40M > 80dB)
  • VSWR  < 1.07  (Return Loss > 28 dB) 
  • Expected Band Isolation with Triplexer > 75dB


Please, see 10M BPF 3rd order with 15M LC trap added graphs below:

  • Insertion Loss < 0.2 dB !!!
  • Band Isolation ( 20 M > 90 dB, 15 M > 65dB)
  • VSWR  < 1.08  (Return Loss > 27 dB) 
  • Expected Band Isolation with Triplexer > 85dB  ( > 120dB for 20M band)

10M band built  using the same circuit as for 3000 watt set.

The 10M band requires as much 20M isolation as possible to decrease the 2nd harmonics from 20M band to its minimum level.

Please, see two graphs below for 10M BPF (Wide and In-Band):


Please, see a Triplexer  pictures below. I publish no graphs for the triplexer because they are very close to any triplexer graphs published on this website.

  • Insertion Loss < 0.11 dB 
  • Band Isolation > 30 dB
  • VSWR  < 1.08  (Return Loss > 27 dB) 



10M Band Triplexer with all BPFs attached:

  • Insertion Loss < 0.3 dB 
  • Band Isolation (20 M >120 dB, 15 M > 88dB)
  • VSWR  < 1.08  (Return Loss > 27 dB) 


15M Band Triplexer with BPFs attached:

  • Insertion Loss < 0.4 dB 
  • Band Isolation ( 20 M > 90 dB, 10 M > 75dB)
  • VSWR  < 1.08  (Return Loss > 27 dB) 


20M Band Triplexer with BPFs attached:

  • Insertion Loss < 0.32 dB 
  • Band Isolation ( 15 M > 100 dB, 10 M > 120 dB, 40 M > 60 dB)
  • VSWR  < 1.08  (Return Loss > 27 dB) 


  • Triplexer is a balanced filter system and every port must see 50ohm load
  • You can build an antenna switch with 50 ohm loads on every band port using KK1L switch PCB (-67dB minimum port isolation)
  • You can buy a 2×6 switch with interlocking system from RemoteQTH.com (-71dB minimum port isolation) .
  • Some antennas switches can be modified to connect unused antenna ports  to 50 ohm resistors.

Connection coax cables between Triplexer and BPFs should be as short as possible for the best matching impedance between boxes.

Here is a simple diagram and filter’s location for this reason.