Peter Laws wrote:
> Or ferrite, as the case may be ...
>
> Background: I have a Spi-Ro D-56 80-10 trap dipole at about 26'.
> There is a Spi-Ro D-314 (30-12) at about 34' some 30' away. D-56 is
> fed with about 63' of 9913. Note that prior to the Fall, it was fed
> with about 110' of RG8X.
>
> There is an 8' ground rod in the soil outside the shack window and all
> coax feedlines have TransiTraps connected to the ground. There are
> also braids from the rig, power supply, and (recently) PC to the same
> ground. Rig is an IC746Pro with a RT Systems "ADMS" cable for CI-V
>
ADMS cable?
> control. There is also a Rig Blaster plus connected to one of the ACC
> ports.
>
> I've had issues with RF getting into the CI-V port all along, not to
>
The Icoms are good for "pin 1" problems. I'm surprised any thing gets
into the CI-V though. It uses a standard serial cable to the computer
and mini coax out. I run the legal limit (at times) into a variety of
antennas from 1.8 through 30 MHz, a KW on 50 MHz, several hundred watts
on 144, and 50 on 440 with nary a peep through any of the systems once I
really grounded pin one on the 756 Pro. Of course I lost a few functions
on the mike for doing that.
> mention the PC speakers and the telephone, but lately it's so bad that
> I couldn't use the CI-V at all on the low bands
This sounds like more than just getting into the CI-V. I have one fed by
an 8 or 12' serial cable with 6' mini coax runs from the CI-V to the 756
Pro and the Tokyo Hy-Power HL-1.5Kfx Even while running the other rig
driving the Alpha to the legal limit 160 - 10 there is no problem.
Although you may have a pin one problem, I'd bet "good" current chokes
at the antennas, and grounding the braid at the base of the antenna
support and where it comes in the house will get rid of most of those
problems.
Another question that comes to mind based on the wide spread RFI, do any
of the antennas run close to, or parallel to the telephone wires (in or
out of the house) or the speaker cables?
Nuther thought, does the ground for the rig also tie into the house
electrical ground?
> (40, 80) during SS
> SSB. RTTY Roundup is this coming weekend, and the 'puter becomes a
> little more important for that.
>
>
A single point ground helps for about anything except pin one problems.
For safety I would add a few more ground rods and cable.
>
> Man RFI is still eating my lunch. One of the traps is bad on my
> Spi-Ro D-56,
Step one, fix that as it can cause things other than non resonance on a
band.
> so it isn't even close to resonant on 10. 15-80 is fine
> (well, fine as it ever was - it's a trap dipole). The RFI happens on
> 40 and 80 and not on 20 or 15. The sweet spot on 80 has an SWR of
> 1.4:1 or so and on 40, it's 2.2:1. Worse further from the sweet spot
> as you'd expect. And the busted trap has not changed the RFI
> situation - it was there before the trap failed.
>
>
Still fix the trap. If any thing is broke, fix it as it can add to the
problem and it may have been unhealthy before it failed.
> I bought a Spi-Ro D-52 to replace it (longer, only 2 traps) but
> contrary to how Spi-Ro markets it, it's only an 80-40 dipole (fine
> antenna - make me an offer). So, I put the D-56 back up and have
> another homebrew dipole for 10.
>
>
> Bought a current balun kit from Palomar Engineers as someone here
>
Where do you ground the coax shield?
> suggested and installed it just now - no better. The CI-V connection
> STILL resets when transmitting.
>
That should not be a pin one problem.
> In N1MM, this shows up as a dialog box inviting me to "reset my
> radios". In DXLab Suite's Commander, it's not as obvious that you've
> lost the connection until you do something like change freqs.
>
> Commander's debug capture window, however, shows that after getting
> RFIed, it just sends a continuous stream of 0xFD. As an aside, I can
> also hear myself though my cheap PC speakers and in the telephone, but
> I don't care so much about those - I figure when I get the CI-V issue
> fixed, the rest will magically go away. :-)
>
OTOH the other stuff may be causing the CI-V problem.
> And yes, I've got ferrite on both ends of the serial cable (and a
> toroid on the speaker leads).
>
They shouldn't even be necessary so that makes me think you have a lot
of RF running around in there.
> Some other stuff I tried:
>
> Connected the PC chassis to the same ground as the radio. No change.
>
> Connected the PC chassis to the ground braid from the radio only (no
> connection to earth ground). No change.
>
>
It shouldn't be necessary to connect the PC chassis to the system
ground. Won't hurt (as long as they are on the same electrical circuit),
but I would have been really surprised if it made a difference.
Do you have to room to just stick up a plain old fashioned dipole on 40
as a comparison?
> I disconnected the ground entirely (as suggested below). No change.
>
>
That again shouldn't be necessary and could be dangerous in the long
run. OTOH it doesn't hurt to try.
> Other suggestions? RTTY RU is only days away!!!
>
>
Another thought: Completely disconnect the RigBlaster and see if
anything changes.
IOW start with the very basic station with only one coax even run into
the house and see what you get. It "sounds" like you possibly have a
pin one problem, but there if far too much RF running around in there.
How long are the speaker wires? Are they connected to the computers
while the computer is connected to the CI-V?
If you use the computer for control as it sounds, them make sure NOTHING
else is connected to the computers including the phone line. Again,
start with only the basic 746 and one antenna that you know is good and
that is not the antenna with a bad trap. Until you can get it to work
that way, the rest is going to be wasted effort. What does the antenna
system look like with an analyzer? Are you sure the connections are good
at both ends. What about the 9913 and coax connectors? I've had lots
of problems with 9913, but never RFI.
> Peter
>
>
>
> On Mon, Nov 17, 2008 at 12:33, Bill, W6WRT <dezrat1242@yahoo.com> wrote:
>
>> There is no downside that I know of,
As long as they are on the same circuit. It might pay to check out the
polarity of the AC outlets. Finding them reversed is not at all uncommon
and particularly so in older homes. Never assume.
>> in fact in my shack I have to
>> bond them together or 160 meter RF gets into the computer and wipes
>> out the soundcard. If possible, have the radio and the PC right next
>> to each other so the ground wire is as short as possible.
>>
>>
I run the legal limit on 160 and my network cables basically run
parallel to the 160 antenna with the cable modem, router, and switch
inches away from the coax. That network ties 5 computers together that
are in different buildings on different electrical feeds. The computers
at both ends are tied into the respective stations which are tied into a
respectable ground system. In addition the stations at both ends are
tied into a 6-pack and remote antenna switches. AND a common telephone
line. The phone line feeds a cordless phone system in the house and
another in the shop. There are also a pair of hard wired phones in the
house. Total length of the phone lines is on the order of 200' That
runs along with the CAT5 from the shack in the house to the computer and
rig in the shop. That CAT 5 is being replaced with 2 CAT6 lines
hopefully this week.
What I'm trying to say is I have all this wire, two stations complete
with computers in a rather intense RF field and I do not see the
problems described. Which brings to mind ... Oops, lost it, where'd it
go...wait...got it... <sigh> What kind and size of power supply do you
have in the computer? Not all computer supplies are equal and some are
prone to RFI (in and out) What kind of case does the computer have? All
computers here have metal cases and none are grounded. Three are full
size towers (Antec and ThermalTake) running dual core Athlon X2-6000s, 2
are mid size towers (Antec and cheap off brand) with one running a quad
core Athlon Phenom 9950 and a dual core Athlon FX (old name for X2-5600)
and one Athlon ...I forget which older single core. Most have external
USB or eSATA drives for lots more wire.
There are so many things tied together here that it raises some concerns
for me as to what is causing things to be hot RF wise.
>> Also, you mentioned having a separate ground rod for the rig. This
>> might be a source of trouble too, since you can't really 'ground' RF
>> in the sense of making it 'go away'. Your ground rod+wire is no doubt
>> acting as an antenna, although an inefficient one. Try removing the
>> ground and see if things improve.
>>
The rig should not have a separate ground, but rather a single point
ground tied into the house electrical system as well.
Again, I'd go back to the basic 746 and a single dipole for 40 if
possible and start from there (No computer, no rig blaster, no multiple
antennas, just one rig, one coax, and one antenna) then go one step at a
time. As I said before, trying to troubleshoot a whole system can be an
exercise in futility and finding a problem like that is mainly luck..
Taking it all apart and starting with the basics is a lot of work, but
usually less than trying to do the whole system. If you can get the
basic system working add just the CI-V, but not the computer. Does it
work? If yes, then connect it to the computer, but make certain
*nothing* else is connected to the computer. No phone line, no sound
system, no nothing. but if the CI-V doesn't work, disconnect the serial
cable and try again. Remember, just one piece at a time.
Good luck and 73
Roger (K8RI)
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|