On Fri, Oct 20, 2023 at 12:26 PM, mike/w1mt wrote:

Check out laptop stands or laptop cooling feet at amazon - B07772JBX1
or B09M9XX8ZV are just two such objects.

I have had good results with Amazon?B0BDZNFFLT tablet stand, for small radios and for a little audio mixer in the shack.? Height and angle adjust.
73, Don N2VGU?

Kind of off-topic, but the best things I have found for elevating the front of larger radios or lab instruments for better visibility are hockey pucks.??
They are a good height singly or can be stacked securely as they are non-slip.? Inexpensive and indestructible.
73, Don N2VGU

If it is of any help, have a look at
It gives all the key voltages that may be found in a Class E amplifier

73 David G4FTC

If you have access to a 3D printer there are several QMX, QDX, QCX mini stands. Check out: Or this: ? This one can be used in a portable setting as it has built-in battery capability:

Dennis
KK5DB

On Fri, Oct 20, 2023 at 05:30 PM, Afghan Kabulldust wrote:

See post further back in this thread.?

I missed that

thanks

Thanks guys - good info. Will give them a try.

?73
--
Jim / K7TXA
Eagle, ID

SKCC 10447C
BUG 301

开云体育

See post further back in this thread.?

I use one of these on the back of QMX. With it, QMX sits on the bottom edge and the new leg, so you might want a thin anti-slip sheet (scrap leather, silicone sheet or something) underneath.

Check out laptop stands or laptop cooling feet at amazon - B07772JBX1
or B09M9XX8ZV are just two such objects.

-mike/w1mt

On Fri, Oct 20, 2023 at 12:23?PM Jim Bennett / K7TXA via groups.io
<w6jhb@...> wrote:

Since my QMX usually sits on my desk I was thinking it would be nice if it could be slightly tilted towards me rather than sitting completely flat. Does anyone have info on some larger rubber feet I could replace the top two feet with?
--
Jim / K7TXA
Eagle, ID

SKCC 10447C
BUG 301

Since my QMX usually sits on my desk I was thinking it would be nice if it could be slightly tilted towards me rather than sitting completely flat. Does anyone have info on some larger rubber feet I could replace the top two feet with?
--
Jim / K7TXA
Eagle, ID

SKCC 10447C
BUG 301

On Thu, Oct 19, 2023 at 11:52 AM, Timothy Fidler wrote:

please dig out the article from QEX? and forward it? to me.

email pls

73

muhsin TA1MHS

It was a struggle because there was a NO log file to show. The logging program never made the connection until a day or so ago, thus nothing in the QMX CAT log file. Once the MLDX developer changed his program to not send a carriage return, QMX was able to connect and a log was available. Didn't take too long after that to see why audio went down the tubes. Anyway, water under the bridge now. QMX working pretty well (NEEDS AGC!) - lots of CW contacts and several FT8, including VK2LAW (20 M) and 5W1SA (30 M) a few minutes ago - both with my flagpole vertical!
--
Jim / K7TXA
Eagle, ID

SKCC 10447C
BUG 301

Stephan, you had asked for some simulation results.
I couldn't resist ;-)

The LTspice simulation below shows some of the fascinating properties
of the Tayloe detector.

The simulation uses ideal voltage controlled switches to perform the
MUX function of the detector. This avoids complications with
parasitics and device performance.The switch model also has an
optional internal resistance. Since the switches change state 'hard'
at defined voltage points, the four phase clock system can simply be
four sine generators staggered by phase. I used 2 X 4 just to keep the
visual clutter down. As shown, the clock is running at 1MHz.

The input signal is a single sharp spike, an approximation to the
Dirac Delta function, which produces a very wide spectrum.
The simulation output is selected as the voltage at the input winding
of the balun. As you might expect, it is also a single sharp spike.
The voltage at that node can be taken as a surrogate for the input
impedance of the detector.

The real treasure of the simulation is the FFT spectrum at that node,
shown. You can clearly see the intrinsic bandpass behavior of the
Tayloe circuit, as well as its receptivity at odd clock harmonics. As
the clock frequency changes, the response curve follows it. As the
Cacc parameter alters the values of the accumulating capacitors, the
bandwidth changes.

JZ KJ4A

This illustrates another characteristic of DC-DC converters, they have a negative resistance characteristic in that their current draw increases with decreasing voltage.??
I have had issues when feeding a DC-DC, especially when trying to ramp up from 0, the load draws excessive current trying to deliver its output voltage/power.?
Well-designed converters will not try to turn on until a workable input voltage has been applied, to avoid this issue.
Instead of starting from 0 you need to set the supply on the low side, connect it to the load and then adjust upwards.? And don't try to run it from a too-low voltage.
73, Don N2VGU

开云体育

Yes, voltage is 12 volts so = 1.4 watts. It doesn't seem to warm up the case significantly if left in that state for a while, but I have noticed it will increase to 130ma as the radio warms up.

See subject line.

-mike/w1mt

Perhaps mention what model you are talking about for better answers.? ?I'm guessing QMX but? . .??

Is there a design doc for a 6-Meter QDX-M ?
I would like to add to my BB-6 setup with a 7-Band combiner.

John
TI4JWC