Re: LF: Re: Modifications of Kenwood TS 950 SD and TS 50 S

["Marco Cadeddu" <marcocadeddu@tin.it>]

Hi Tom,

 

it's a really pity that no output is available below 160m.. but probably also in this case the reason is some "digital" block (I guess a diode somewhere) blocking the tx enable in order to save the final unit.

The TS950SD should had (at least my has) the high stability TCXO on board (stability ±0,5 ppm) but at least in my case I experienced the (whithin specification) drift only on tx (10MHz band) and it was cured using the external high stability 10 kHz reference derived from the Rb oscillator.

 

By the way use the TS950SD on rx with no change from the original (no replaced the xfmr as suggested from I2PHD) having satisfactory sensibility and only strange indications from the Smeter.

 

GL es DX

 

Marco IK1HSS

----- Original Message -----

From: DK1IS

To: rsgb_lf_group@blacksheep.org

Sent: Saturday, August 25, 2012 6:32 PM

Subject: Re: LF: Re: Modifications of Kenwood TS 950 SD and TS 50 S

Hello Marco,

modifying to general TX coverage results in a lowest TX QRG of 1620 kHz for the TS 950 and (heaven knows why) 1705 kHz for the TS 50.  At lower frequencies there is no driver output so these modifications are no solution for MF/LF.  But I hope someone knows a trick to override this behaviour.
Concerning the TX stability of TS 950 SD: using the internal TXCO my unit is very stable however showing an absolute deviation of abt. +5 Hz at 30 MHz. I have improved it similar to you by using a 10 kHz GPS reference (Jupiter board) synchronizing the alternative low-cost Xtal-oscillator on board of the TS 950 whose stand alone stability is much worse than that from the TXCO. Certainly you know you have to change two switches for activating the TXCO.

Tu, 73 es cuagn
Tom, DK1IS


Am 25.08.2012 18:49, schrieb Marco Cadeddu:

Hello Tom,

 

although the TS950SD is in my my shack since 1991..I never made the modification for general tx coverage. I don't think it can transmit on 500 kHz if you carry out the mod, but probably could be used as starting point unplugging the rear connection between driver and PA and replacing with a devoted external PA (I'm using this rig in such way to drive an external 137 kHz xvtr).

Just for info, I was disappointed about the frequency stability of TS950SD: a rock in reception (both direct on 137k or via the xvtr on the 10 MHz band) but on tx, although the PA was cutted out, not suitable for qrss with several Hz of drift...now I found a a 10MHz Rb oscillator that is used for LO on the xvrt and divided to 10 kHz to control the PLL via the rear input.

 

Let me know if you get a useful signal from the drive out socket on 470kHz.

 

73 de Marco. IK1HSS

----- Original Message -----

From: DK1IS

To: rsgb_lf_group@blacksheep.org

Sent: Saturday, August 25, 2012 3:14 PM

Subject: LF: Modifications of Kenwood TS 950 SD and TS 50 S

Hello dear LF-group,

does anyone have proven experiences about

• modification of TS 950 SD for transmitting CW on MF, perhaps LF too ("general coverage transmission" already realized)
  
• the same for TS 50 S,
• overriding the permanent ALC at TS 50 S ?

As usual, there were no answers on my inquiries to Kenwood - neither from the German office nor from Japan ;-)

Tu es 73,
Tom, DK1IS