Stan, to get rid of the residual hash do one of the following:
1. assure you have the computer chassis and Omni 6 chassis properly bonded
to common station ground.
2. put an audio isolation transformer in the line between PC soundcard and
Omni 6 audio in
73, Barry N1EU
On Tue, Sep 18, 2018 at 2:41 AM, Stan Gammons <s_gammons@charter.net> wrote:
> Hi Bob,
>
> I removed the split core I had on the audio cable and put a solid core
> with several turns of the the audio cable wrapped around the core at the
> sound card output. That drastically reduced the hash picked up from the
> PC. So, it should have a MUCH cleaner digital signal now. Now when I
> remove the mic and short pin 3 to ground and turn the mic gain fully
> clockwise, the rig is putting out maybe 1 watt. Much better than the 100
> watts it was putting out when I tried the same thing before! Yeah, it is a
> bummer that both are hot all the time. I'll have to remember to
> disconnect the cable from the PC when operating phone. Would have been
> nice if one were able to select the audio source.
>
> Thanks for your help. Hopefully I'll sound better when I check into the
> net now :)
>
> 73
>
> Stan
> KM4HQE
>
>
>
> On 9/17/2018 9:25 PM, Bob McGraw K4TAX wrote:
>
>> Stan
>> Unfortunately that input on the rear is "hot" all of the time and the
>> signal (noise) is mixed with mike audio. It is isolated by a 10k ohm
>> resistor. The MIC gain and SP level controls both inputs.
>>
>> You must physically connect one or the other, but never both. There is no
>> provision in the radio to select between the two inputs.
>>
>> I wouldn't bother with chokes as any noise from the computer or interface
>> will appear in mike audio. Just the way it works. Bummer.
>>
>>
>>
>> Bob, K4TAX
>>
>>
>> Sent from my iPhone
>>
>> On Sep 17, 2018, at 9:16 PM, Stan Gammons <s_gammons@charter.net> wrote:
>>>
>>> Hi Bob,
>>>
>>> One thing I forgot to check before and I pretty sure I found out what
>>> the problem is. I have the PC soundcard out connected to the audio in on
>>> the back of the radio so I can use it for digital modes. Seems as though
>>> it's picking up hash from the PC and it's getting mixed with the audio from
>>> the mic. When I disconnect the cable from the PC, things are normal. Dang
>>> it! Guess I need to put another or more ferrite cores on the audio cable.
>>> I hear the computer hash when I test PTT with WSJT-X too. So it's
>>> transmitting a cruddy digital signal too. That's unacceptable. I have to
>>> fix that.
>>>
>>>
>>> 73
>>>
>>> Stan
>>> KM4HQE
>>>
>>> On 9/17/2018 8:51 PM, Bob McGraw K4TAX wrote:
>>>> Stan:
>>>>
>>>> First I suggest turning the speech processor OFF and forever leave it
>>>> OFF. If you want to use it, just remember, more is worse.
>>>>
>>>> Even though the mikes worked on the TR7, I view this is no indication
>>>> the wiring is correct for the Omni VI. I suggest checking the manual for
>>>> the correct mike wiring and physically confirm the mike of choice is wired
>>>> correctly. I find mike wiring standards to be as varied as dust
>>>> particles in a Texas sandstorm.
>>>>
>>>> Pin #1 is mike high or mike audio
>>>>
>>>> Pin #2 is ground and shield. Be sure the shield of the mike cable also
>>>> folds back into the Amphenol cable connector to make contact with the
>>>> shell.
>>>>
>>>> Pin #3 is PTT
>>>>
>>>> Pin #4 is +4 DCV for use with an Electrect mike.
>>>>
>>>> Check the plug in filters on the bottom to see they are seated
>>>> correctly and correct location. Again, contact cleaning of their pins
>>>> might be in order.
>>>>
>>>> One other test, disconnect the mike, turn the MIC gain fully
>>>> counterclockwise {off}, transmit and listen to the radio. With the 2nd
>>>> receiver, tune across the frequency and listen for carrier. In general all
>>>> should be quiet. If you hear significant carrier, there is a procedure to
>>>> null the carrier. Probably need an oscilloscope and dummy load to do that.
>>>>
>>>> Next would be to check the frequency of the BFO crystals. Again there
>>>> is an alignment procedure. This must be adjusted in the exact steps
>>>> outlined in the manual as there is interaction between the adjustments.
>>>> Repeat the procedure a couple of times. A frequency counter is required
>>>> for this adjustment. Don't skip one step just because you don't intend to
>>>> use that mode. There is interaction between the adjustments.
>>>>
>>>> And of course my last suggestion, which normally is my first
>>>> suggestion..........take time to pull each cable, using a Q-Tip moistened
>>>> with contact cleaner, scrub the male pins of each and every connector.
>>>> Then plug and unplug the connector a couple of times so as to wipe the
>>>> female contacts. Do this one at a time and double check to see each
>>>> connector is inserted fully and correctly.
>>>>
>>>> NEVER NEVER NEVER spray anything into the radio. {One fellow I know
>>>> [not me] removed the plugin IC's, sprayed into their sockets, and now he
>>>> has a radio full of issues and weirdness. Remember contact cleaner is
>>>> used to promote the flow of current. Imagine what takes place in a logic
>>>> IC socket that is wet with cleaner. ugh!!!! }
>>>>
>>>> With a radio of that age, it not at all unusual for the electrolytic
>>>> caps in the audio stage to deteriorate. One issue which can exist is the
>>>> output of a stage can drift negative a few millivolts. In effect it will
>>>> reverse polarize the coupling capacitor. The result is after time the 1
>>>> MFD cap will migrate to about 0.01 MFD. Not a good path for audio in these
>>>> circuits. Makes the radio sound funny too. I always replace the audio
>>>> coupling capacitors with nonpolar electrolytics of the same voltage and C
>>>> value. There is no need to change parameters. Problem solved. I had a
>>>> lengthy discussion with Tentec management and engineering on the subject
>>>> some years ago. It almost caused me to not buy a new Omni VI Plus.
>>>> Finally, I did and loved it.
>>>>
>>>> Hope this helps.
>>>>
>>>> 73
>>>>
>>>> Bob, K4TAX
>>>>
>>>>
>>>> On 9/17/2018 8:00 PM, Stan Gammons wrote:
>>>>> Hi All,
>>>>>
>>>>> I was tinkering with an old D-104 T-UG8 that I had put a Heil
>>>>> conversion kit in since the original element bit the dust. I ask for an
>>>>> audio report from some of the locals that know what I sound like and they
>>>>> said I sounded terrible. So, I switched to the Ten-Tec 707 mic, same
>>>>> report. So, I tried my trusty old EV-638. Same story. I didn't try it
>>>>> with
>>>>> the converted D-104 to see what it sounds like. They initially told me it
>>>>> sounded like the mic was picking up something like a fan maybe, so turning
>>>>> the gain down helped a little but not a lot. SO, today I decided to put
>>>>> the
>>>>> Omni VI on a dummy load and listen to it with my Drake TR7. Yuck! The
>>>>> Omni
>>>>> VI sounds terrible! It's almost like there is a little bit of a carrier
>>>>> and it has what sounds like digital hash on it. It gets worse the higher
>>>>> the mic gain is cranked. When I modulate, the audio sounds all distorted.
>>>>> Even without modulation, if I turn the processor on and crank it up, the
>>>>> digital hash in the audio seems to get even wo
>>>>>
>>>> rse. SO, just to make sure it wasn't something weird going on, I did
>> the same thing with the TR7. I put it on a dummy load and listened to it
>> with the Omni VI. I tried it with the same mics and the audio is clean. No
>> hash or anything. Anyone heard of a problem like this with an Omni VI?
>>
>>>
>>>>> 73
>>>>>
>>>>> Stan
>>>>> KM4HQE
>>>>>
>>>>> _______________________________________________
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>>>>> TenTec@contesting.com
>>>>> http://lists.contesting.com/mailman/listinfo/tentec
>>>>>
>>>>
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