XV144 Advice Needed -- And Another Manual Goof Noted

[Jim Brown-10]

I've reclaimed an XV144 that I bought used in 2005 and have never used
from a friend to whom I loaned it. I'll be using it with a K3, that will
be dedicated to 2M. I'm told that frequency stability is a concern, and
that it's important to drive it at the "right" level so that fixed
attenuation is not switched in to protect the TX input. The question is,
what is the "right" level to minimize dissipation inside the XV144? So
far, I haven't found that in the manual or the specs.

Another observation. The latest manual for the XV-series converters
contains another massive goof in the wiring of the AUX cable. It shows
only two conductors with no return, depending on the coax to carry a
return signal. That's fine for DC, but our stations produce RF, so the
large loop formed by the coax and the control lines is a big antenna. TILT!

Time for another manual re-writing. And to fire the guy who conceived
the drawing.

73, Jim K9YC
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[Don Wilhelm-4]

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.

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.

Are you certain you are looking at the XV Transverter Owner's manual and
*not* the K144XV internal option for the K3.

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.

73,
Don W3FPR

On 7/25/2014 6:36 PM, Jim Brown wrote:

> I've reclaimed an XV144 that I bought used in 2005 and have never used
> from a friend to whom I loaned it. I'll be using it with a K3, that
> will be dedicated to 2M. I'm told that frequency stability is a
> concern, and that it's important to drive it at the "right" level so
> that fixed attenuation is not switched in to protect the TX input. The
> question is, what is the "right" level to minimize dissipation inside
> the XV144? So far, I haven't found that in the manual or the specs.
>
> Another observation. The latest manual for the XV-series converters
> contains another massive goof in the wiring of the AUX cable. It shows
> only two conductors with no return, depending on the coax to carry a
> return signal. That's fine for DC, but our stations produce RF, so the
> large loop formed by the coax and the control lines is a big antenna.
> TILT!
>
> Time for another manual re-writing. And to fire the guy who conceived
> the drawing.
>
> 73, Jim K9YC
> ______________________________________________________________
> Elecraft mailing list
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> Please help support this email list: http://www.qsl.net/donate.html
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>

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[Jim Brown-10]

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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[Johnny Siu]

Hello Jim,

I was once a XV144 user.  In my previous setup, I set the XV144 for the minimum drive from K3.  The output from KXVA3 can drive the XV144 to its full power.

In terms of power and frequency stability, which are the typical issues with XV144, apart from installing the oven, the contact points among the chasis and RF connectors MUST be properly sanded with sand paper to ensure good contact.

Heat issue is another concern.  The XV144 will be very very hot to operate at FM mode even at the factory stated specification of half output at 10W.  For light duty cycle, heat issue is not that apparent.

Hope this help.

73

Johnny VR2XMC
 

________________________________
 寄件人︰ Jim Brown <[hidden email]>
收件人︰ Reflector Elecraft <[hidden email]>
傳送日期︰ 2014年07月26日 (週六) 8:15 AM
主題︰ Re: [Elecraft] XV144 Advice Needed -- And Another Manual Goof Noted
 

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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[Jim Brown-10]

On 7/25/2014 5:15 PM, Jim Brown wrote:
>> 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.

Now that I've studied the schematic a bit more, I realize it's the
resistors switched in and out by JP3 and JP4, and the gain stage Q6,
that can be bypassed or not, as set by JP5 and JP6.

For the K3, instructions are to bypass the resistors, activate the gain
stage, and set the K3 for 1mW.

So I've got my answer, I think.

73, Jim
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[Don Wilhelm-4]

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
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

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[Jim Brown-10]

On 7/25/2014 6:56 PM, Don Wilhelm wrote:
> The attenuator resistors (and the Q6 amplifier) are put into line (or
> out of line) with the plugging of  JP3, JP4, JP5 and JP6.

As you can see from my last post (which crossed in the mail with this
one), I studied the drawings and jumper settings and figured it out.

Thanks, Jim
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[David Pratt]

Jim - I fitted an internal fan in my XV144.  Look at the XV432 manual.
It means drilling a circle of holes in the PCB where the fan is fitted.
Also, make sure you have some vent holes in the top cover (Early XV144s
did not have them).

73 de David G4DMP

In a recent message, Jim Brown <[hidden email]> writes
>On 7/25/2014 6:56 PM, Don Wilhelm wrote:
>> The attenuator resistors (and the Q6 amplifier) are put into line (or
>>out of line) with the plugging of  JP3, JP4, JP5 and JP6.
>
>As you can see from my last post (which crossed in the mail with this
>one), I studied the drawings and jumper settings and figured it out.

--
 + - - - - - - - - - - - - - - - - +
 | David M Pratt, Kippax, Leeds.   |
 | Website: http://www.g4dmp.co.uk |
 + - - - - - - - - - - - - - - - - +

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