PowerGenius XL SO2R Filters

Lewis Cheek

SO2R Filters. Usually ( at least for me ) one needs two sets of filters to operate SO2R. One to notch xmit signal on second receiver, and one to prevent harmonics from xmit, on Amp side. How does PowerGenius XL handle this, or is a set of lower power filters required as well?

73
Lew
N4CO

Ria

There is no receive filtering in PG XL. There is transmit low pass filtering (as is necessary in a solid state LDMOS amp) and it works very well. This is in addition to technologies such as MEffA which makes this one of the cleanest amps on the market, if not the cleanest solid state amp. However depending on antenna spacing you may want an additional filter set. I use a set of W3NQN filters in a package designed by 5B4AGN. I am assembling the 2nd unit right now. 

The 6600 has enhanced contest band receive filters, which do show some promise. However depending on your antenna configuration you may still need some external filters.

4O3A also makes external filters that can be used at the output of the amp. I haven't tried those but those should suppress harmonics generated by the amp even further. 

73
Ria
N2RJ

Stan VA7NF

Lewis,
Your note about Rx Notch filters was interesting.  We currently use the normal band-pass filters between Tx and amp.  With the threshold on other Rx A-D in the multi-multi environment I feel the need.
However my limited research didn't come up with any commercial filters.
Before starting a design project, please expand on your Rx loop RX filters.  I'm envisioning one filter per station (x3) with a switch in for all the contest bands (mix and match to whatever band the other stations are on)

Lewis Cheek

Stan,
At time I was doing SO2R (2008 or so ) I was using a pair of Elecraft K3's, two amps, and multi-antennas. I had purchased two sets of low power remotely controlled bandpass filters from Array Solutions for receive side, along with RG-213 coax stubs on output of each amp. If I recall correctly I also needed a pair of 1 x 6 high power switches controlled via a MicroHam station controller.  As you can see it takes a lot ( at that time ) of hardware to run SO2R at full power levels. I'm sure some of Alpha testers can answer your question based on using PG XL and one of the upcoming Flex rigs.

73
Lew
N4CO

ctate243

The need for external filtration will always depend on the situation and each is different.  some folks have antenna separation that don't require any, Some may find a 6600 is now good enough where before they needed them, and others may find the need for filters still.  This really and truly is fluid and dependent on your particular operating environment. 

Stan VA7NF

Agreed Chris, but when the reflected power meter on an antenna tuner moves from another station Tx it is time to consider various modes of signal reduction

ctate243

And to get a couple flats of torroids and start choking sfuff in the shack ;-).

Varistor

My station sits on 25 acres and regardless of the distance between antennas there is the need for filtering. People often think about harmonics, but phase noise must be considered as well. I run low power bandpass filters (Array Solutions) between the radios, managed by the microHam MK2R+ SO2R station controller, and the amps and 3 KW filters after the amp, one per EACH band. Between the low and high power filters I can have multiple operators on two bands at the same time, plus the in-band S&P radios, without any interference.

Personally, I do not believe in stubs. Stubs must be placed at a certain point along the feed line, in terms of impedance, and the only practical solution is to have two stubs one after another. This is way too much wasted coax, connectors, and general mess.