On Sun, May 29, 2022 at 10:53 AM, David Wilcox K8WPE wrote:

A ham in the UK sent me this one he has sued successfully. I may order one.

I thought it looked too good "Output current: 200mA"
OK if you do not TX.

I should use your typo on the UK ham:-)

73 Alan G4ZFQ

Got it today, and will try to get it out Tues or Wed on to Jim W4QE.? Jim, your QRZ info accurate?

Bob
KG5GTE

开云体育

A ham in the UK sent me this one he has sued successfully. I may order one.

41 m EFHW and a 1: 41 transformer plus a chocke at 4 from the feedpoint and off you are on all bands. Tunes easily by folding back the far end and no tuners needed.

Martin DK3UW

On 28/05/2022 12:14, mweidle@... via groups.io wrote:

Thanks,
where is the picture ?

I was looking for my full text description, here Windows 7/8 serial driver and attach the two pictures here.

You may have to dismiss Windows warnings that it is the wrong driver.

73 Alan G4ZFQ

On 29/05/2022 01:18, Linus wrote:

The wires are different colours, if the input/output is completely
isolated then it would probably be OK but needs checking.
I have one at my desk and a multimeter. What is the method to test isolation?

Measure the resistance between the output wires and the input wires.

Most converters of this type have the input and output grounds common. Maybe they are although they are different colours.
If you see zero Ohms between them makes sure it is zero, there is a remote possibility there could be a low value resistor between them. My usual approach on an unknown like this is to look.

You probably will not find an infinite resistance between input/output. It is possible they may be completely isolated but I've never seen this on such converters.

73 Alan G4ZFQ

Amazon

What are the voltages at Q5 when in 20M mode?

“I believe, as in any oscillator, it goes something like: the thing has a gain greater than 1 at the resonant frequency of the tuned circuit. Noise gets amplified. Noise that is at a frequency away from the tuned circuit resonance just disappears as the gain is under 1. Noise at the resonance gets amplified as the gain is greater than one, there is positive feedback - and hence the thing starts singing. So basically noise starts it. But I am 100% sure there is someone here who can explain that a lot better than I can.”

This is how a violin works. The string is the resonator and the bow is a noise source.?

Having trouble getting any output on 20/30m on my QDX v3 wired for 9volt.?

**Credit for below chart copied (I inserted my values though) to Ryan Hand, AC9TU for someone else he helped with a similar problem on another thread**

When 80 meters is selected with the Audio Sweep terminal program what is the voltage on the stripe of:
D1 =? ?0.06? ? ? ? ? ? ? ? ?D4 = 0.06
D2 =? ?5.86? ? ? ? ? ? ? ? ?D5 = 5.87
D3 =? ?5.38? ? ? ? ? ? ? ? ?D6 = 5.38

When 40 meters is selected with the Audio Sweep terminal program what is the voltage on the stripe of:
D1 = 5.86? ? ? ? ? ? ? ? ? ?D4 = 5.86
D2 = 0.07? ? ? ? ? ? ? ? ? ?D5 = 0.07
D3 = 5.38? ? ? ? ? ? ? ? ? ?D6 = 5.38

When 20 meters (and of course 30 meters is the same) is selected with the Audio Sweep terminal program what is the voltage on the stripe of:
D1 =? 5.90? ? ? ? ? ? ? ? ? D4 = 5.90
D2 =? 5.90? ? ? ? ? ? ? ? ? D5 = 5.90
D3 =? 5.42? ? ? ? ? ? ? ? ? D6 = 5.42

D3 and D6 should be near 0 but do not change for 20/30. Also note, D3 and D6 are lower than the other diode readings for all bands. And shouldn't I be getting about 8 volts on those diodes that are active instead of sub 6 volts??

Transmit power on 80 meters at 4.1 watts and 40 meters at 3.2 watts. 0.0 on 20 and 30 meters. Using a QRPoMeter. Was looking for 5 watts as per the book. Related to my lower voltage on diodes? Fed with steady 9 volts from a LM317 buck module (12 volt battery feeding it). Checked voltage under transmit load (for the working bands) and it is steady at 9 volts.

Where to look next? Checked toroid joints for continuity. Reflowed again all low pass areas. Bad component?

Thanks,

Rick
K4LX

I use a 40m doublet fed with 300 ohm line, tunes anything from 40-10m with a BLT tuner (equivalent to the ZM-2). Works great if you can get the centre up at least 10m or so...

So an EFHW antenna should be exactly that: END FED HALF WAVE. Unfortunately many of the commercially, overpriced so-called EFHW antennas are not a half wave at all at the frequency of interest, but some random length wire with an overpriced balun at the end of them. Many won't tune certain frequencies even with an auto tuner and the RF at the feedpoint is very high and gets into the radio and other nearby devices.

For a 60m antenna that EFHW needs to be about 88' long and as high as possible. How long and high is yours???

Thank you Dave. I have noticed some strange behavior with my USB port.

If I cut the 5V from the USB will the computer still send data? I would like to monitor things while I am testing solar cells.?

Colin
K6JTH

Alan?
It is possible that you over drove the usb output on your computer usually they are set to kick out at .5amps .... it may come back after it cools down?
By hooking up usb and battery at the same time you have usb 5v dropping through a s4 diode trying to charge a lipo battery which could have exceeded the usb current limiting device on your computer usb drive ... try computer reboot and try the usb only with a different usb plug on the computer... it also may have fried the small s4 diode on the break off board.... check this diode with a meter and if it is open just replace with another schottky.?
Dave VE3KCL

Alan?
Disconnect the battery?
Do not try to run from both battery and Usb power at the same time
Dave VE3KCL

I had my U4B transmitting using a 3.7 Volt battery connected to the Battery and Ground terminals and I wanted to change the call sign as a test so I plugged-in my USB cable.

It no longer is able to enumerate on the USB bus.

I tried three different cable and have tried with and without the battery connected.

Windows says "Device descriptor request failed"
Linux says about 40 different things that amount to the same thing, failure to get the device descriptor.

I can still enumerate my other U4B on the same machine and the same cables.

Does anyone have any idea if this is something I should not have done?

Uh oh!

Alan KC1QHV

Hi Glen?
Yes here in Canada after a bird strike you will have to send the prop in for inspection ... but we are talking orders of magnitude that cause the damage.
A Canada Goose will put a pretty good dent in a leading edge?
A? house sparrow not so much?
A balloon transmitter? .... well look at the weights?
Canada Goose 5000 grams
House Sparrow? 45 grams?
U4B transmitter with solar panels and antenna 5 grams

I have a friend who is an engineer at Pratt,and his opinion about an engine ingestion of a U4B..... not a problem with such a small mass.

Dave VE3KCL

Hi Alan?
You may notice that your received spots are FN42kj
The U4B will only transmit M4 or FN42 but wsprnet is being smart and knows your call is located at kj so makes up a M6 location?
This screws up the decoding.as the decoder tries to add kj to FN42kj and it fails??
Change your call sign to something else and it should work properly??
In real life once you leave the FN42 M4 locator everything will work as wsprnet will not do that thing .
There may be a fix for this that is easier.
You can try my call for a brief test VE3KCL to verify?
Dave VE3KCL