Finally we got the results even though as raw results:
To be able to work simultaneously on two adjacent bands like 40 and 20 m the isolation needs to be at least 90 dB. Of course this will depend on the following:
- antenna isolation – can be as low as 30-40 dB with close antennas or resonant antennas on harmonics.
- antenna port isolation on the transceiver- on the Flexradio series 6000 it is about 40-50 dB between the antenna ports.
So in total an isolation that can be as low as 70-90 dB. But is this a problem? Well with a 1.5 kW station you have a signal level of around +62 dBm which is way over S9+73 dB!!! And your station can not handle more than +10-20 dBm. To be on the safe side and also having the joy of working SO2R a good thumb of rule is at least 150 dB of isolation. This means that with a 1.5 kW station sending on say 40 m you will not have more than S 8 (+63 – 150 dB = -87 dB) . In this exercise I have more or less ignored effects of phase noise and second harmonics (which with an old TRX can be severe).
With my set-up I end up in the following isolation between the antennas and 4o3A High Power bandpass filters (they provide about -50 dB of isolation) :
As you see about 90 dB (green lines). To this we must add the transceiver isolation of 40-50 dB. So in total 130-140 dB of isolation or S7-S9. Not too bad. That is you may send with a kW on 40 m and do listening on 20 m with a 40 m signal at about S7-S9.
The band was in a good shape. On 40 and 20 m there were good openings to USA and Asia. Even on the nights.
WriteLog can now be used with only slices like Maestro. I have made a video showing some tweaks that must be made to get WL into two slices only. It is not completely ready yet. There is a link to YouTube so you may follow my settings.
How nice again after playing around with Flexradio 6700 and SO2R for some hours 🙂
Here is my remote station set-up.
The present antennas.
There are several contest loggers to be used with Flexradio. For contesting including remote contesting N1MM and WriteLog are in particular well suited if you run SO2R. WriteLog recently cam out with a simulator which is very realistic. You have a band scope and you may even check your log vs what was sent. A YouTube clip is found below.
Since Sept 2017 we have been working on configuring the new 24 m HD Alu tower that we installed just after the vacations. The mast weights about 1200 kg and is cable of 2 square meter of antenna load without any guying!
The tower will carry two JK 2015 antennas in a stack. An electric winsch that is remote controlled adds to the flexibility of the tower.