[TenTec] Mike & Eagle

Tue Aug 26 21:33:54 EDT 2014

While James and I do generally concur on test and evaluation methods, I 
would comment  I've found the input impedance of the specific device {radio} 
will have some effect to significant noted effect on the sound of a given 
microphone.

While the radio may indicate an input impedance of 10 k ohms at 1 kHz, then 
one might ask what is the input impedance at 300 Hz. or some other 
frequency?  Another model radio specification states "Microphone Input: 
 200 - 50K ohms"  and then another model radio states "Microphone 2 K ohms - 
condenser".  These numbers range from 200 ohms to 50 K ohms.

My point, a given mike that may sound good on one radio and may not sound 
good on another for the reason that the input Z of the radio mike circuit 
will have a noted effect on the dynamic response of the mike of concern. 
Hence my basic reason for using the mike of choice on the radio of choice 
for performing critical evaluations.

Once done, I believe the method suggested is sufficiently accurate and 
repeatable, that on-air "how does my audio sound" is a mute point.  Besides 
you have no idea of how the station on the other end has their receiver 
configured nor of their listening conditions.

73
Bob, K4TAX

----- Original Message ----- 
From: "Richards" <jrichards at k8jhr.com>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Tuesday, August 26, 2014 5:24 PM
Subject: Re: [TenTec] Mike & Eagle

>I do something similar to Bob's test procedure -  I test every microphone 
>on my computer FIRST - because I figure if it sounds crappy on the computer 
>it is likely to sound crappy on the rig.  But Bob's further on-air test is 
>a swell way to make sure it not only sounds OK on the rig, but confirm your 
>speech processor, EQ, and other settings are in order, as well.
>
> My test protocol is similar to Bob's - he is the expert, so ultimately 
> listen to hims...  set the transceiver to Flat EQ, and no speech 
> processor, and transmit into a dummy load.   I employ one of my SW 
> receivers (usually a Kenwood R2000)  which has a LINE-OUT signal that is 
> plugged directly into the LINE-IN input on a computer sound card.  The run 
> the receiver with no antenna, or maybe just a short hank of wire, to avoid 
> overload, or I use a receive only antenna located in my front yard, far 
> enough from the transmit antennas, to avoid overloading it, and record 
> what it hears.   Only after I am satisfied with this result do I mess with 
> EQ and speech processor settings.
>
> I also get a couple of local hams monitor and record my signal.  I 
> distribute a really small recording applet to minimize variations, and 
> figure most sound card DACs are consistent enough for Government work. Not 
> as exacting as Bob specifies, but I don't worry about variations in DACs. 
> ;-)    I don't mess with the "reference" sample, but that may be a good 
> plan to assure the recording process is accurate in the first place - 
> kinda like measuring a control group against the experimental group.
>
> Anyway... just my take...
>
> ------------------  K8JHR --------------------
>
>
>
>
>
>
>
>
> On 8/26/2014 8:30 AM, Bob McGraw - K4TAX wrote:
>> Yes, the connectors are "tight" in terms of working space.  Too much
>> heat, i.e. too large of a tip will transfer too much heat and things
>> begin to melt.
>>
>> For audio quality determinations, I prefer to use the "comparison"
>> method. I'll outline my method.  This does require two suitable radios.
>>
>> Having the "monitor" radio being the 2nd radio connected to the computer
>> for digital modes, I use that signal path along with a free software
>> being AUDACITY to record the audio.  I first find a signal on the band
>> that I think sounds specially good and I record about 30 seconds of that
>> signal. That becomes my "reference" signal.  I also use external
>> speakers on the computer and listen to both the reference signal and my
>> test signal through these speakers.   Remember, the path much be
>> identical for accurate comparisons.
>>
>> Now using the mike and radio of choice on a dummy load, same mode,
>> frequency and such.  I transmit about 30 seconds while recording that
>> transmission and then listen to it and the other signal.  AUDACITY
>> allows one to easily switch between the two recorded segments.   By
>> doing this one is using the exact audio path, computer, speakers and
>> such to judge ones audio.  If it doesn't sound as you wish, then
>> adjustments of any nature should be made.  This includes mike-to-mouth
>> position or changes in audio levels, speech processing or even changing
>> mikes.  Again repeat the process and each time a change is made and
>> compare the new configuration to the reference signal that one thinks
>> sounds specially good.
>>
>> Now admittingly, ones personal voice will not typically sound exactly
>> like another's voice, but one can easily discern the differences.  When
>> finished, just note the various values on the radio, the mouth-to-mike
>> position and such.  From this one can be quite reasonably assured their
>> signal will always sound great on the air.
>>
>> In using this process, if humm, clicks, buzz or such is heard on the
>> comparative recordings, the source should be investigated and resolved.
>>
>> I will stress that using the Monitor mode or headphones while recording
>> ones audio will not accurately  reveal the true audio sound.
>>
>> 73
>> Bob, K4TAX
>>
>>
>>
>>
>> ----- Original Message ----- From: "John Farler" <k4avx1 at windstream.net>
>> To: <tentec at contesting.com>
>> Sent: Monday, August 25, 2014 8:57 PM
>> Subject: Re: [TenTec] Mike & Eagle
>>
>>
>>> Thanks for confirming what I've tried.  I think I'd better go
>>> back and check that 8 pin connector pin-out again.  For
>>> this old guys hands and eyes, I wish they had stayed with
>>> the 4 pin connector  :>)
>>>
>>> The mini-din on the back caused me much grief.  It wanted
>>> to melt - wonder if it came from radioshack!
>>>
>>> And yes, I was told that the headset mike I was using
>>> on the OMNI 6+ sounded as good as the TT desk mike with
>>> the same kind of element.  Ear piece quality is a consideration.
>>> 73,
>>> John, K4AVX
>>>
>>>> Message: 3
>>>> Date: Sun, 24 Aug 2014 16:23:44 -0400
>>>> From: Richards<jrichards at k8jhr.com>
>>>> To: Discussion of Ten-Tec Equipment<tentec at contesting.com>
>>>> Subject: Re: [TenTec] MIKE & Eagle
>>>> Message-ID:<53FA49D0.1040205 at k8jhr.com>
>>>> Content-Type: text/plain; charset=windows-1252; format=flowed
>>>>
>>>> John --
>>>>
>>>> My test for mic quality is to make a recording on the computer using a
>>>> low sampling rate, maybe 11.5 Hz - and if it sounds OK, then it should
>>>> sound OK on the air.  If not,  try another model.
>>>
>>> Message: 4
>>> Date: Sun, 24 Aug 2014 14:16:24 -0700
>>> From: Jim Brown<k9yc at audiosystemsgroup.com>
>>> To:tentec at contesting.com
>>> Subject: Re: [TenTec] MIKE & Eagle
>>>
>>>
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>>
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