Jerry.Van wrote:
> Jerry,
>
> I must apologize for asking you this but today I was reminded about
> your earlier post on the TT reflector about the correct way of hooking
> up a mic to prevent RF feedback in the classic Orion. I've searched
> the archives but cannot seem to locate that post by you by searching
> on your name and title of the post. I've searched as far back as the
> June archives but still cannot seem to locate it. Any chance the
> title might be something less obvious? Any chance you made that post
> under another ID?
>
> Sorry to trouble you about this and I should have printed it off when
> you initially posted. Thanks in advance for the help and your post.
>
> Jerry N8BM
>
From Jerry, KG6TT
My Mistake (Doh!), I checked too and it seems that I only posted that
message on the Orion message board. Here it is:
___________________________________________________________
Perhaps some valuable information for Orion 565 newcomers.
I have owned my Orion 565 just about two months now (when I wrote this
posting).
And for most of
that time I was sure that there had to be something terribly wrong with
firmware version 2.056 that came with the Orion (bought directly from
Ten-Tec, was manufactured in 2005). I thought I had tried everything,
but alas I continued to receive unsolicited audio reports laced with
'RF', 'distorted', and 'muffled'. And it seemed that the only cure was
to go back to version 1.3x firmware!
[Now PLEASE resist the temptation to jump ahead and jump on me without
reading the rest.]
I bought a new Heil Studio One for my Orion and I already owned a Heil
Proset (HC4), and an HM-10 (HC4/HC5). The Studio One and HM-10 are boom
mounted and have Heil cables. All should have been right from the
box....yes? Well no actually (and as someone with professional broadcast
engineering experience in my resume.... shame on me).
A simplified explanation.
During the Orion's development there was much debate as to whether or
not the Orion would have a traditional 4-pin 'unbalanced' mic input to
remain compatible with all recent Ten-Tec gear or if it should set a new
standard (at that time) and use a fully 'balanced' audio input using and
XLR connector. A more or less 'last quarter' decision was made to remain
compatible, although the electronics behind the front panel supported a
balanced configuration. A big problem remained in that the traditional
4-pin connector did not have a pin for a separate '- mic' signal and
still have a pin for a shield ground. The fourth pin was used for +Vcc
so a user could still plug in a 705 or 706 electric condenser type
microphone. Of course there couldn't be a separate pin for both PTT send
and return lines so the PTT return line had to combined on the shield as
well. All problems inherent to the original Orion 565 mic connector have
been resolved (in a sort of strange but understandable way) with the new
8-pin mic connector on the Orion II.
The way the Orion was released with the standard Ten-Tec 4-pin mic
connector, Orion owners might actually get away with plugging in an
existing microphone used on...say an Omni-VI+... and with little ill
effect. Some did experience RF problems though (a subject that was
beaten to death on the reflectors for many months). What owners
discovered is that the microphone cable, from a 'balanced' microphone
such as the Studio One, connecting to the Orion, HAD to have the cable
shield/PTT return on the case of the connector ONLY, with the -mic on
pin 2, the +mic on pin 1, and the PTT send on pin 3. Connecting the -mic
and shield and PTT return signals in a way that had them all on both Pin
2 and the chassis at the connector at the same time was the source of
rather serious problems for many Orion owners.
Why did Ten-Tec go to a 'balanced' input? This one is easy. The
broadcasting industry (and later the professional audio industry)
standardized on balanced interconnects many, many years ago that they
might minimize hum and other unintentional stray RF pickup through the
wiring itself. In a balanced configuration the send and receive lines
are twisted together so that when an interfering signal passes around
and through the cable itself the interfering signal felt on the + and -
lines are always 180 degrees out of phase.... therefore they cancel each
other. Whether or not the twisted wire pairs have a shield wrapped
around them both isn't nearly as important. But if a shield is present
it is generally only grounded to the chassis of one piece of equipment
and not both (to prevent ground loops) and is NEVER attached to the -
lines at either end.
So why did Orion I owners experience far greater RF sensitivity using
firmware version 2.056 than the earlier version 1.3x? Well if you
haven't guessed it by now the Orion is far more than a traditional
transceiver design with some DSP attached. It is quite literally an SDR
transceiver (software defined). Version 2.056 configured the transceiver
to utilize and entirely different SSB generator design than what was
used in version 1.3x. And it appears that as a consequence the Orion,
running 2.056 (and version 2 firmware for that matter) became
dramatically more sensitive to any RF that might be superimposed on the
mic input. Now please understand that this is MY explanation and not an
official one from Ten-Tec. I am using my RF, digital, and analog
engineering experience and what I have been able to gleam out of various
published articles as well as discussions with Ten-Tec engineers and Bob
Heil to present my hypothesis.
It was pretty easy from my experience to notice a difference. With the
same exact physical shack configuration I had great audio reports with
version 1.3x and terrible ones with 2.x firmware. I went so far as to
totally remove my Orion from all but power supply (Ten-Tec switching)
and run its output directly to a cantenna dummy load. With my Studio One
connected (I thought, as per the Orion manual's requirement) I had what
appeared to be perfect audio with version 1.3x and horribly distorted
audio with 2.x. I experienced all the 'reflector' complaints of
non-functioning Speech Processor, et al.
A recent conversation with Paul at Ten-Tec (he was really great through
all of this) prompted me to actually take apart my new Studio One
microphone to see if parts that needed to make physical connection were
actually doing so or if extra paint from manufacturing was breaking the
ground paths in any way. And while I did find it necessary to scrape
away some paint what I found was far different. At one point I had the
cover off both the XLR connector and the 4-pin panel from the Studio One
totally exposed and still connected. It was at this time I found my
problem. The -mic and shield/PPT return signals were reversed between
the two connectors! (and not by me). I swapped the two connections in
the cable end and for the very first time my Orion worked wonderfully...
and in version 2.056.
So what is the final result? Well running 2.056 firmware I am
experiencing absolutely no RF distortion in my audio. The MIC gain
functions as normal with full range adjustability. The Speech Processor
works great too. And the MON function works even up to the 100 setting
with absolutely no crackling, etc.
Now on to the Heil ProSet which was also causing me the same transmit
audio problems with firmware version 2.x. Now this was a slightly
different situation when compared to the Studio One as the Heil ProSet
does not provide a balanced mic input. My fix though was really easy. I
just made sure that the PTT return from the ProSet to 4-Pin adapter I
had made was not connected in any way to the Orion's pin 2.
Unfortunately it was Once I split the signals at the connector correctly
all problems with the ProSet disappeared too. In my case the mic input
actually had a shield separate from the shield on the PTT breakout. I
put the mic shield on the Orion's mic connector pin-2, the mic hot on
pin-1, the PTT send on pin 3, and finally the PTT shield (return) on
the mic connector case ONLY. My RF problems were finally solved.
Conclusion
My problems existed initially even with the Orion on a test bench with
only power supply, dummy load and microphones attached. Before I fixed
the interconnection problems I was only able to use version 1.3x
firmware. There were days in which I tried to convince myself that the
problem was firmware 2.x but since I heard other hams using that
firmware that sounded great I didn't give up and kept looking. After
some fruitful conversations with Paul at Ten-Tec and Bob Heil I finally
found the wiring problem in my Heil mic cable. I swapped the incorrectly
wired signals and all my problems disappeared. I am now enjoying version
2.056 and it was well worth all the work.
Hope this helps other Orion 565 owners, especially newcomers who are
experiencing problems with version 2.056 firmware.
73,
_______________________________________________________
--
Ralph Jerald "Jerry" Volpe
Amateur Radio Operator KG6TT
ARRL Member & VE
FISTS 12304
788 Chestnut Drive
Fairfield, CA 94533
kg6tt@arrl.net
510 325-7724
707 399-8838 FAX
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