14 xtals @ 3300 Hz BW .1dB Chebycheff SSB filter
Very steep skirts on this!!
This will be a 75m SSB monoband TXVR driving a balanced pair of RD100HHF1 LDMOS FETs fro 200W Pout.
EMRFD 7/7 TX & RX boards.
I have adapted these to cover 80m & 40m & 20m with a Field Day agenda.
This 1st generation version only allows for 3 xtals (as presented in EMRFD)
I have a 2nd gen version that supports up to 5 xtals in the same board size.
That was considered worth the effort on the layout.
Also very convenient for using the LADPAC XLAD default of 5 xtals for Gaussian to -6dB polynomial.
Note that XLAD has a bug for 3 & 4 xtals that generates the wrong k & q values.
XLAD works fine for 3 & 4 xtals if you enter k & q values manually.
I decided I wanted to try a tuner without roller inductor.
This scenario works GREAT!
I can always see exactly where the tap is and the Q of the tap connection is
much better than most roller inductors can offer.
Also eliminates the meed for a dial mechanism.
Clear plexiglass is easy to work with for a front panel.
The wood base for top and bottom allows the caps to float without needing ceramic standoffs
that are required in a metal chassis.
Feb 2023: I have now confirmed that the wood and plastic cabinet was a really bad choice.
The lack of shielding allows high RF TX signal levels to be radiated into the shack.
The latter contributes to instability issues for unshielded TX chain modules on the bench
and the same for a poorly shielded TX chassis for power levels above around 10W.
Top unit is a 30W Wheatstone Bridge so the TX never gets a large VSWR presented to it during tuning.
This is a new layout for the Hybrid Cascode IF/AGC amp that Wes Hayward (W7ZOI) and I published in QST
back in December 2007. This was originally done as a PCB kit via Roger Hayward (KA7EXM) for a few years.
I decided I wanted a more efficient layout and silk screen. RX diode ring product detector is on the right.
Total rebuild of my late '80s multiband SSB/CW TXVR.
This uses a 9 MHz IF and high side LOs in a 1/1 tracking analog PLL.
It will cover 160m thru 10m, with the option of 4 more bands.
RX portion is working on 160/80/40/30/20/15/10 bands at this point.
SSB filter is 10 xtals at approx .1dB Chebycheff response at 3200 Hz BW.
There are two Guassian to -6db CW filters for 500 Hz & 250 Hz BW.
All filters were designed with LADPAC XLAD (Thank you W7ZOI!!!)
####----A 9 MHz IF does not work on 17m----####