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Help! I think I may have just ruined my 9 year old's Chanukah

tausciam@...
 

I'm very distressed right now. My 9 year old asked for one for Chanukah built inside a lunchbox. She studied and got her general just so she could have it. She's worked really hard and I've already given her an antenna and coax. Then, today I finished the build, and tried to test it.... and it failed.

Ok. I had built it with a buck converter (I think is what they're called) to turn 12v into 24 volts. So, the first thing I did was to turn RV1 all the way down. I hooked up a cable and a dummy load into the cable. I set my meter on 200ma. I measured from the DC plug to the on/off switch. I got 2.8 I think it was...it doubled when I clicked PTT. I tried measuring voltage from the dummy load and got nothing. I took the buck converter out of the circuit where it was powering the final. With 12 volts powering the final, no change. I tried adjusting both RV1 and RV136. No change. I tried tuning it to a frequency, tuning my HF rig to the same frequency, hooking up an actual antenna (laying on the wooden floor though) and transmitting. Didn't hear anything in the HF rig two feet away.

I had a computer mic hooked up as the mic. Tried saying hello in it loudly...nothing. I wired up the electret mic that came with the kit. Nothing in it either. When I push the PTT, I hear a click from the radio and it does double (milli amps?), but that's it.

Vince Vielhaber
 

The idle current you adjust is measured from the PA voltage and the on-off switch doesn't switch that (unless you hooked it up to the switch as well).

Also at 2 feet from the receiving rig, the dummy load is sufficient. No need for an antenna.

With the antenna, do you receive anything on the BitX?

Vince.

On 12/17/2017 12:26 AM, tausciam@... wrote:
I'm very distressed right now. My 9 year old asked for one for Chanukah
built inside a lunchbox. She studied and got her general just so she
could have it. She's worked really hard and I've already given her an
antenna and coax. Then, today I finished the build, and tried to test
it.... and it failed.

Ok. I had built it with a buck converter (I think is what they're
called) to turn 12v into 24 volts. So, the first thing I did was to turn
RV1 all the way down. I hooked up a cable and a dummy load into the
cable. I set my meter on 200ma. I measured from the DC plug to the
on/off switch. I got 2.8 I think it was...it doubled when I clicked PTT.
I tried measuring voltage from the dummy load and got nothing. I took
the buck converter out of the circuit where it was powering the final.
With 12 volts powering the final, no change. I tried adjusting both RV1
and RV136. No change. I tried tuning it to a frequency, tuning my HF rig
to the same frequency, hooking up an actual antenna (laying on the
wooden floor though) and transmitting. Didn't hear anything in the HF
rig two feet away.

I had a computer mic hooked up as the mic. Tried saying hello in it
loudly...nothing. I wired up the electret mic that came with the kit.
Nothing in it either. When I push the PTT, I hear a click from the radio
and it does double (milli amps?), but that's it.

tausciam@...
 

On Sat, Dec 16, 2017 at 09:34 pm, Vince Vielhaber wrote:
The idle current you adjust is measured from the PA voltage and the
on-off switch doesn't switch that (unless you hooked it up to the switch
as well).
The PA voltage is going through the switch as well. I measured from the DC plug to the base of the positive that feeds the PA. It does double when I click PTT, but that's it. I'm set on 200ma so I'm assuming I'm getting like 5.6 - 5.8 milliamps through it when I press PTT and 2.6-2.8 just idle.
Also at 2 feet from the receiving rig, the dummy load is sufficient. No
need for an antenna.

With the antenna, do you receive anything on the BitX?

Vince.
No. I didn't hear anything, but the antenna was on the floor. I tuned my HF rig to a really strong signal and tried to find it using the Bitx40 but it never picked anything up.

Vince Vielhaber
 

Ok, it sounds like the Raduino isn't providing a signal. Make sure it's correctly connected, there's a wiring color oddity between the two cables.

I'm also assuming you're working on a BitX40 and not a uBitX, right?

Vince.

On 12/17/2017 12:41 AM, tausciam@... wrote:
On Sat, Dec 16, 2017 at 09:34 pm, Vince Vielhaber wrote:

The idle current you adjust is measured from the PA voltage and the
on-off switch doesn't switch that (unless you hooked it up to the
switch
as well).

The PA voltage is going through the switch as well. I measured from the
DC plug to the base of the positive that feeds the PA. It does double
when I click PTT, but that's it. I'm set on 200ma so I'm assuming I'm
getting like 5.6 - 5.8 milliamps through it when I press PTT and 2.6-2.8
just idle.

Also at 2 feet from the receiving rig, the dummy load is sufficient. No
need for an antenna.

With the antenna, do you receive anything on the BitX?

Vince.

No. I didn't hear anything, but the antenna was on the floor. I tuned my
HF rig to a really strong signal and tried to find it using the Bitx40
but it never picked anything up.

tausciam@...
 

I followed the directions exactly. I know the oddity you're speaking of. The brown wire from the raduino connects to black on the board and the brown wire from the board connects to red. I did that correctly.

 

Yes. It's a Bitx40.

Vince Vielhaber
 

Ok, I just looked at the schematic and when you press the PTT you should be able to adjust the idle. Take a voltmeter and measure from ground or supply negative to the tab on the final FET. You should see 12v (or whatever your PA voltage is).

Vince.

On 12/17/2017 12:52 AM, tausciam@... wrote:
I followed the directions exactly. I know the oddity you're speaking of.
The brown wire from the raduino connects to black on the board and the
brown wire from the board connects to red. I did that correctly.



Yes. It's a Bitx40.

tausciam@...
 

Ok... I measured voltage. From supply negative to heat sink, I have 12 volts. From supply negative to IRF510 source (rightmost leg) I don't measure anything. The heatsink is isolated from the chassis.

 

Yes, you are supposed to be able to adjust the idle with that RV1 I was talking about. It does nothing

 

Something wrong here!

5-6mA and 2-3mA is too less. The relays probably take more than this.

Are the relays clicking ?

Switch to higher amps range on the meter and plug the leads into the right meter points.
I usually rely on my power supply meter for this.

Raj


At 17/12/2017, you wrote:

The PA voltage is going through the switch as well. I measured from the DC plug to the base of the positive that feeds the PA. It does double when I click PTT, but that's it. I'm set on 200ma so I'm assuming I'm getting like 5.6 - 5.8 milliamps through it when I press PTT and 2.6-2.8 just idle

 

The minimum position is FULLY clockwise.

You should see a voltage at the gate of the IRF when you turn the bios pot a little bit.

Raj

At 17/12/2017, you wrote:

Ok... I measured voltage. From supply negative to heat sink, I have 12 volts. From supply negative to IRF510 source (rightmost leg) I don't measure anything. The heatsink is isolated from the chassis.

Yes, you are supposed to be able to adjust the idle with that RV1 I was talking about. It does nothing

tausciam@...
 

I don't know if they're clicking or not. I think they are when I press PTT.

Switching to 10A, I get .01 at idle and .02 when I click PTT

tausciam@...
 

Getting no voltage even if I turn it a full turn counterclockwise. Getting 12 volts from drain

tausciam@...
 

Turning it fully counterclockwise gave me 12 volts on source.... and then my final blew when I was metering it.

So now I have officially ruined her chanukah present. Crap

tausciam@...
 

So, to reiterate, with RV1 turned fully clockwise, I was getting 12 volts on drain. With it turned fully counterclockwise, I was getting 12 volts on source....and then blew the final while metering

Dr Fred Hambrecht
 

Please email me at w4jle at w4jle dot com with your address and I will get youa couple of finals in the mail.

 

v/r

Fred W4JLE

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of tausciam@...
Sent: Sunday, December 17, 2017 02:04
To: BITX20@groups.io
Subject: Re: [BITX20] Help! I think I may have just ruined my 9 year old's Chanukah

 

Turning it fully counterclockwise gave me 12 volts on source.... and then my final blew when I was metering it.

So now I have officially ruined her chanukah present. Crap

tausciam@...
 

On Sat, Dec 16, 2017 at 11:27 pm, Dr Fred Hambrecht wrote:

Please email me at w4jle at w4jle dot com with your address and I will get youa couple of finals in the mail.

 

v/r

Fred W4JLE

 

Thank you Fred. I still don't know what's wrong with this crazy radio though. I followed the directions exactly.

I did make a few mods to it. I had replaced the heat sink with a power supply heat sink. I did the capacitor to cut down on the spurious emissions and make it legal. I did the dual diodes each pointing in the opposite direction to protect against blowing the receiver with a strong signal. I put amunter's sketch on it and took the unused A3 wire and wired it to a plug for calibration. I also plugged in that buck converter to give 24 volts to the finals, but took it out when things weren't working right.

She wants to use it for FT8 and SSB... so I tried to give her what she wanted.

Dr Fred Hambrecht
 

What are the specs on the buck boost converter you are using?

 

v/r

Fred W4JLE

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of tausciam@...
Sent: Sunday, December 17, 2017 02:37
To: BITX20@groups.io
Subject: Re: [BITX20] Help! I think I may have just ruined my 9 year old's Chanukah

 

On Sat, Dec 16, 2017 at 11:27 pm, Dr Fred Hambrecht wrote:

Please email me at w4jle at w4jle dot com with your address and I will get youa couple of finals in the mail.

 

v/r

Fred W4JLE

 

Thank you Fred. I still don't know what's wrong with this crazy radio though. I followed the directions exactly.

I did make a few mods to it. I had replaced the heat sink with a power supply heat sink. I did the capacitor to cut down on the spurious emissions and make it legal. I did the dual diodes each pointing in the opposite direction to protect against blowing the receiver with a strong signal. I put amunter's sketch on it and took the unused A3 wire and wired it to a plug for calibration. I also plugged in that buck converter to give 24 volts to the finals, but took it out when things weren't working right.

She wants to use it for FT8 and SSB... so I tried to give her what she wanted.

tausciam@...
 

This appears to be it

 

I bought it because I searched google and found others who had used it and it worked. But, once I saw the radio wasn't working, I took it out of the circuit and twisted the wires together. So, I was still having the same problems without it in the circuit

 

The source voltage is not controlled by the pot RV1, only the current. While adjusting RV1 you need to
monitor the current and not the voltage.

Please leave the portion of the message you are replying and delete the rest. If you leave the whole message
then it seems to get removed by the groups.io and we cannot make out to whom you are replying to and
about what!

Raj

At 17/12/2017, you wrote:
Turning it fully counterclockwise gave me 12 volts on source.... and then my final blew when I was metering it.

So now I have officially ruined her chanukah present. Crap

tausciam@...
 

On Sun, Dec 17, 2017 at 03:05 am, Raj vu2zap wrote:
The source voltage is not controlled by the pot RV1, only the current. While adjusting RV1 you need to
monitor the current and not the voltage.

I'd already done that. I could turn both RV1 and RV136 back and forth and not see any change in the current. But, you said "You should see a voltage at the gate of the IRF when you turn the bios pot a little bit." so that's what I was checking on.

 

If my meter is on 10A, then I get .01 on the readout on idle. I get .02 when I push PTT. Adjusting RV1 and RV136 counterclockwise to open it or clockwise to limit does not seem to make any difference. Speaking into the mic doesn't cause the amperage to move. I tried with my own mic plugged in, then wired in the electret mic included in the kit when that didn't work and it didn't cause any change either. Measuring from a dummy load inserted in the cable, I get no amperage, no voltage....nothing there either. I get a hiss in the speakers when I turn it on as if it is receiving static like normal. When I click PTT I hear a pop. The speaker goes dead like it's supposed to while I transmit. Then when I let up the speaker comes back on. But, I'm seeing no change in voltage or amperage.

 

The current is too low. As I remember I get more than 200mA and more than 300 when I press PTT.

If RV1 does not make a change then RV1 or the 5V regulator or the IRF is blown.

Keep the drive level control 136 at mid point till you get the rest working.

In any test vary only one variable and study/report. With more than one you cant tell what is the issue.

Raj

At 17/12/2017, you wrote:


If my meter is on 10A, then I get .01 on the readout on idle. I get .02 when I push PTT. Adjusting RV1 and RV136 counterclockwise to open it or clockwise to limit does not seem to make any difference.