Howard,

Don't know if you got a reply on this.   The optional SO-3 TCXO is a 
temperature controlled crystal oscillator to improve frequency 
stability.   This was standard on the 2000, and I would guess on the 
990, but not on the 590 or 480.

I am sure that most of the 590's on the air don't have this installed. 
  It is a $120 option.  You need to remove a pcp board, solder it in, 
change a jumper, and do  some alignment with the included tool.  In 
comparison, the VGS-1 speech board is just a plug in module.

If you think you need it, go for it.  I've had my 590 just over 2 years, 
no TCXO and no problems.  I know some of the guys who are big on psk 
and other such modes find it helpful,  but again I think the vast 
majority of units out there don't have it.n

73, Steve KW3A.

On 8/9/2013 7:18 AM, Howard Traxler wrote:
> What is a T C X O; what does it do?
> Thanks & 73,
> The Other Howard, WA9RYF
> ----- Original Message -----=20
> From: "Butch Bussen" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Thursday, August 08, 2013 10:18 PM
> Subject: Re: ts590
>
>
>> One thing I would recommend is the optional t x o for frequency =
> stability.=20
>> I think Kenwood made a big mistake in the way this has to be =
> installed.=20
>> You remove a small board from the rig and solder the optional t c x o =
> onto=20
>> this board.  If you want this, it would cost extra, but well worth it =
> in=20
>> my opinion.  I don't recall what the t c x o cost, $90 I think.  That =
> rig=20
>> is absolutely rock stable now.
>> 73
>> Butch
>> WA0VJR
>> Node 3148
>> Wallace, ks.
>
>
>