Thanks Peter.
Bear in mind that bandpass filters between transceiver and power
amplifier will protect the receiver, and double stubs, optimally located
along the transmission line, can provide more than 70 dB suppression of
the amplifier's second harmonic (in addition to the 30-40 dB provided by
the amplifier's output network).
http://k9yc.com/LocatingStubs.pdf
I'm using stubs like these on the amplifier output in addition to
5B4AGN's excellent TXBPF filter sets. See slides 16-20 in
http://k9yc.com/7QP.pdf for a practical installation.
Suitable stubs can be built, tuned, and installed for far less than the
cost of a high power bandpass filter -- it's the cost of the coax,
connectors, and adapters (Tees and barrels), and any decent RG8 or RG213
can handle far more than the 1.5kW output that's legal in much of the
world.
73, Jim K9YC
On Fri,4/28/2017 10:34 AM, Peter wrote:
Hi fellow hams/contest OP's
I just want to let you know that PI4CC is ready to bring there high
power bandpass filters pcb's available for the ham community.
This is hobby project and you can build a good bandpass filter your self!
We don't claim really high power, but its calculated for 1kW key down
and we tested them 15 min key down with the output of a Acom1000
without any issue.
During a 24 hour contest in SSB and CW its works great and weak
signals near a second harmonic (2Kc) could be easy copied.
It has better numbers as 4O3A, DG0SA, VA6AM.
Have a look at https://www.pi4cc.nl/tech-info/hp-filter/ for more info
and details.
We are is the stage of make an order for the pcb's, but its difficult
to get the correct amount.
Peter
PC2A
Reference :
4O3A http://www.4o3a.com/index.php/products/high-power-filters/series-xl/
DG0SA Funk march 2017 page 244
VA6AM https://va6am.com/
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