[Elecraft] XV144 Advice Needed -- And Another Manual Goof Noted

[Don Wilhelm]

Jim,

With the XV144 jumpers set for 1 mW drive, the attenuator resistors are 
bypassed, and the Q6 gain stage is in-line.

The attenuator resistors (and the Q6 amplifier) are put into line (or 
out of line) with the plugging of  JP3, JP4, JP5 and JP6.  There is no 
dynamic switching - the XV144 is plugged for an input level ranging from 
1 mW to a maximum of 8 watts.  Once plugged for a particular input 
range, the Input Attenuator pot can be adjusted for any particular input 
level within that range.  There is no automated switching of the 
attenuators or the 28 MHz Q6 gain stage.  It is all in the way the 
jumpers are plugged.  It does not "switch in" - the user has to 
determine the drive level that is to be used and set the jumpers 
accordingly.

If you are using the K3 (or K2 with the K60XV) to drive the XV144 (and 
have the KXV3 option), set the TRNxx menu to  provide 1 mW (maximum) 
drive and set the XV144 jumpers to the 1 mW input level.

Then drive the XV144 with that 1 mW signal and adjust the Input 
Attenuator pot to produce 20 watts with the full 1 mW drive.  The K3 
(K2) power knob will then adjust the power drive to the XV144 up to 1 mW 
and will control the XV144 power output up to 20 watts.

Relay K7 has nothing to do with the setting of the power level (via the 
jumpers).  It always activates on transmit.  If the jumpers are set to 
JP3 and JP4 plugged to pins 1 and 2, the attenuator is bypassed.  
Jumpers JP5 and JP6 select whether the Q6 gain stage in in-line or 
bypassed.  For 1 mW input, you want the attenuator to be bypassed and 
the Q6 gain stage to be in-line.  That means JP3 and JP4 are plugged 
between pins 1 and 2 and JP5 and JP6 are plugged between pins 2 and 3.

Relays K6 and K7 control the path between transmit and receive so that 
both Q6 and the attenuator resistors are bypassed during receive and 
respond to the jumper settings during transmit.

73,
Don W3FPR

On 7/25/2014 8:15 PM, Jim Brown wrote:
> On 7/25/2014 4:28 PM, Don Wilhelm wrote:
>> Jim,
>>
>> I am looking at the XV transverter Owner's manual Rev F1 and cannot 
>> understand your statement about the ACC cable.  See Figure 7 on page 
>> 11.  It clearly shows 4 wires to the ACC connector, and one of them 
>> (pin 1 of the XV144 DB-9 connector and pin 12 of the K3 ACC end) is 
>> the return path.
>
> Yes, I just discovered the error -- it's my printer, that didn't 
> reproduce two color
> conductors.
>>
>> I am also concerned about your statement about the "right" level 
>> drive to the XV144.  In the XV144 there is no provision to switch in 
>> any fixed attenuation.
>
> It's on the control board in the form of relay K7 and three 160 ohm 
> resistors.
>
>>
>> Are you certain you are looking at the XV Transverter Owner's manual 
>> and *not* the K144XV internal option for the K3.
>
> I'm looking at an XV144, manual dated 2013.
>
>>
>> As for frequency stability of the XV144, without the crystal oven, 
>> the XV144 is usually stable enough for CW and SSB operation.  If 
>> greater frequency stability is desired, the addition of the crystal 
>> oven is desirable.  Plug the JP-9 header to pins 4 and 5 to provide 
>> power to the LO and xtal oven at all times that +12 volts is supplied 
>> to the XV144 for the greatest LO stability.
>
> Yes, I'm aware of the option for an oven.  In a quick conversation 
> while he was rushing to make the flight to CT, K6XX alerted me to the 
> stability issue, and said to choose drive levels to avoid dissipation 
> in that attenuator.  So I'm trying to get a handle on roughly where it 
> switches in.  He also suggested running XV at the minimum level needed 
> to drive an external amp, which also makes sense.
>
> After studying alignment instructions, I'm seeing a K3 output level of 
> 1 mW, so perhaps that's it.
>
> Thanks and 73, Jim
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