Ground loop city. That's the cause of your ills and hum. Not a uncommon
issue with most ham station wiring and grounding. I don't consider it luck.
It is simply proper planning and correct grounding techniques applied
This says your station ground and AC mains ground are not bonded together
thus a difference in potential exists as you discovered. A great invitation
for lightning damage from a nearby strike. The RS transformer simply breaks
the ground loop but does nothing to provide proper grounding.
If you wish, I'll send you a paper on Lightning Protection for the Home and
the Station. Many ham stations are dangerously grounded. A separate E-Mail
request will get you the Microsoft Word document. It's about 128K in size.
73
Bob, K4TAX
----- Original Message -----
From: "joel hallas" <jrhallas@optonline.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Sunday, May 29, 2005 6:35 AM
Subject: Re: [TenTec] Omni vi plus input audio feed for psk
Bob,
You may be very lucky! With my Paragon (line out) to sound card input I
had a very loud hum on SSB xmit (I know that's the other side <g>), even
when the computer was off.
In my station, I have separate power feeds for radio equipment and other
stuff and it appears that there was a sufficient difference in "green
wire" ground voltage to cause a hum.
By putting a RS isolation transformer in that lead it took care of the
problem, for $1.75, I think. BTW, the transmit side was isolated in the
Rigblaster, or likely would have had the same problem.
Regards, Joel, W1ZR
Robert & Linda McGraw K4TAX wrote:
Denton:
First, the transformer may be "ringing" with square wave signals as a
result
of the transformer secondary not being correctly loaded.
At my station, I connect direct from the sound card line IN/OUT to the
Audio
In / Audio Out of the Omni VI+. No problem in adjusting levels with the
Mixer settings of the sound card and the MIC gain on the Omni VI+ runs
about
9 o'clock which is normal. I use VOX to do the switching and get great
reports at about 35 to 45 watts output.
I find that most folks "over engineer" the project.
73
Bob, K4TAX
----- Original Message -----
From: "denton" <denton@oregontrail.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Saturday, May 28, 2005 6:36 PM
Subject: [TenTec] Omni vi plus input audio feed for psk
I am currently using my omni vi plus for psk, with the output of the
soundcard going to an audio transformer to give me a good match to the
audio
input jack in the back of my Omni....on the air reports indicated good
imd
at 40 watts out of the rig at -31, but sometimes I get a ringing report
and
indication of minor sidebars.
What I want to do is bypass the mic audio amp to give me much better
linearity for the various soundcard modes.
From examining the schematic and its adjoining criteria, it seems that I
can
feed the audio out from the soundcard directly to the input of the
balanced
modulator, with appropriate filtering and limit the output of the rig to
about 35 watts or so.
Any thoughts on this?? thanks...
----- Original Message -----
From: "John L Merrill" <jmerrill1@adelphia.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Saturday, May 28, 2005 4:03 PM
Subject: Re: [TenTec] SSB recieve audio?
I have a MkV Field and an FT1000D and with internal or external speaker
they sound better to my inner or outer ears than my on the chopping
block Orion with external and internal speaker. The OmniVI+ with the
audio mod in it sounds better than an Orion.
John N1JM
denton wrote:
Wonder how the Orion's SSB audio sounds compared to an Omni VI??
For some reason, to my ears, my FT990 seems to sound better than my
Omni
VI
on ssb.
----- Original Message -----
From: "John L Merrill" <jmerrill1@adelphia.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Saturday, May 28, 2005 2:51 PM
Subject: Re: [TenTec] Propm RX
I have an R4A I've been repairing here on the bench and with the same
speaker, it sounds better than the Orion :-).
John N1JM
Grant Youngman wrote:
I agree. The receive audio is lousey on the Orion.
Maybe you just need a decent speaker. Or perhaps your inner ear
needs
some
work :-)
The Orion has excellent SSB receive audio, as good or better than any
HF
rig
I've used (many, new and old), and generally requires little in the
way
of
receive EQ. I do much prefer it with a little more than the usual
bandwidth
(say around 3 Khz or so), but that's no different than most radios
which
sound like cr*p at the typical narrow bandwidths everyone want to
use.
Of course, it would benefit greatly from a pair of P-P 6V6's in the
output
stage, but I doubt that's in the plan :-)
Grant/NQ5T
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