[TenTec] Corsair II sidetone mod

[Paul Christensen]

Joe,

You sold me!  If a PCB board or a kit becomes available, I try a few.

Paul, W9AC

----- Original Message ----- 
From: "Joe" <joe at n4yg.com>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Sunday, October 16, 2011 3:40 PM
Subject: Re: [TenTec] Corsair II sidetone mod


>I agree Paul, if 2 or 3 bucks is important to you, then the Twin-T is the
> way to go. I agree, it is a more complex solution. The hardware might be
> slightly more complex, but I would venture a guess that the DDS solution 
> has
> fewer parts once the keying and interface components are added to the
> Twin-T. The firmware is complex, but is available at not cost. If you want
> to hear the artifact of the Corsair II's QSK, just disable the sidetone 
> and
> hit the key. You will hear the thump. It is not related to any sidetone
> implementation.
>
> I think the DDS solution is better. While the Twin-T gives a nice sine 
> wave,
> my observation of both on the oscilloscope shows less distortion in the 
> DDS
> sine wave. It also has more output. The waveform is much better with the
> DDS. Why? 1) When keyed, the DDS always begins and ends at zero phase 
> where
> as the Twin-T begins and ends at random phase. That makes for better 
> keying
> waveform. 2) The audio envelope shape is much better also because 
> amplitude
> weighting of the leading and trailing edges is accomplished in firmware by
> starting at -18 dB (relative to the max amplitude) on the leading edge and
> increased in 3db steps, each increase being applied at zero phase. The
> trailing edge is shaped in like manner.
>
> I have the DDS circuit in my Corsair II and I am very pleased with it. I 
> was
> not pleased with the Twin-T, but it was much better than the original. I
> also have the DDS circuit in a code practice oscillator. It is the best
> sounding one that I have ever heard.
>
> Joe, N4YG
> ----- Original Message ----- 
> From: "Paul Christensen" <w9ac at arrl.net>
> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
> Sent: Saturday, October 15, 2011 5:04 PM
> Subject: Re: [TenTec] Corsair II sidetone mod
>
>
>> Darn, for a small fraction of the circuit complexity and cost, the Twin-T
>> oscillator can be used.  I noticed that Joe, N4YG tried the Twin-T on his
>> Corsair II but stated that he "...could never get smooth keying..."
>>
>> Ten years ago, N4LQ suggested that I try a frequency-variable Twin-T,
>> stolen
>> direct from the Omni V schematic diagram.
>>
>> http://www.qsl.net/tentec/mods/sidetone.pdf
>>
>> N4LQ applied it to one of his Omni D transceivers and I used it in a
>> Triton
>> IV.  Neither of us heard the slightest trace of a QSK artifact.  Anyway, 
>> I
>> would first try the Twin-T as implemented by Ten Tec in the Omni V, then
>> explore the more complex alternative option if not satisfied.
>>
>> Paul, W9AC
>>
>> ----- Original Message ----- 
>> From: "Steve Hunt" <steve at karinya.net>
>> To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
>> Sent: Saturday, October 15, 2011 5:45 PM
>> Subject: Re: [TenTec] Corsair II sidetone mod
>>
>>
>>> Jerry,
>>>
>>> You would certainly get two of those boards within ExpressPCB's
>>> MiniBoardPro outline - maybe more. That option gives you 3 boards - and
>>> therefore at least 6 sidetone boards - for $75 plus delivery.
>>>
>>> 73,
>>> Steve G3TXQ
>>>
>>> On 15/10/2011 22:23, Jerry Haigwood wrote:
>>>> Glenn,
>>>>       I guess it would depend on how many people were interested.  To
>>>> keep
>>>> board prices down, you need to sell 50 or so PCBs.  The board would be
>>>> small
>>>> - maybe 1.5 inch x 1.5 inch and the cost of the parts should be low
>>>> also.
>>>> Just depends on how many people would want a board or kit.
>>>> Jerry W5JH
>>>>
>>>> -----Original Message-----
>>>> From: tentec-bounces at contesting.com
>>>> [mailto:tentec-bounces at contesting.com]
>>>> On Behalf Of Glenn
>>>> Sent: Saturday, October 15, 2011 3:34 PM
>>>> To: tentec at contesting.com
>>>> Subject: Re: [TenTec] Corsair II sidetone mod
>>>>
>>>> Wonder if Jerry would be interested in building some boards..Just a
>>>> thought.
>>>>
>>>>
>>>> Glenn WA4AOS
>>>> DSM Labs
>>>>
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: Barry N1EU<barry.n1eu at gmail.com>
>>>> To: Discussion of Ten-Tec Equipment<tentec at contesting.com>
>>>> Sent: Sat, Oct 15, 2011 11:54 am
>>>> Subject: [TenTec] Corsair II sidetone mod
>>>>
>>>>
>>>> N4YG developed a nifty and elegant sine wave sidetone mod for the
>>>> Corsair II.  I posted all the info with Joe's approval at:
>>>> http://corsair.wikidot.com/corsair-sidetone
>>>>
>>>> Joe is on this reflector, so any comments/questions can probably be
>>>> directed here.
>>>>
>>>> 73,
>>>> Barry N1EU
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