Several people asked for a summary of my findings, so here it is. My
DSL modem reports S/N 30 dB so I have a reasonable DSL signal. 50
watts on 160m causes the modem to lose sync. I have tried the
following, all of which made little or no difference. (No
measurable difference except as noted)
Moved modem to different locations.
Got rid of microfilters and installed outdoor DSL splitter; ran
shielded twisted pair from splitter to modem.
Replaced all POTS wiring in my home, using shielded twisted pair.
Tried completely disconnecting POTS wiring from splitter.
Installed RFI filter with >40 dB rejection at 1.8 MHz in AC line to
modem power supply.
Wound all cables to modem on toroids (proper cores still on
backorder, but absolutely no difference experimenting with different
cores I had on hand. If warranted I will update this later when I
get the backordered cores, but I don't hold out much hope for a
solution there)
Experimented with capacitors from both sides of DSL line to ground
inside modem. This did make about 3 dB improvement.
I have no problem at 1500 watts on 3.5 MHz or higher bands. Part of
my 160m antenna is very close to the phone line coming to my home
and I can't move it significantly. Antennas for other bands are
further away. I'm working on a new 160m transmit antenna, further
away from the house... but may not be able to get it completed
before really bad weather sets in.
I still wonder if a low pass filter in the DSL line might help, but
there is no such product available (that I could find).
I hope others who were having similar problems are having better
luck! It looks like I'm not going to win this one unless the new
antenna does the trick.
73,
Paul N1BUG
_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband
|