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Hey Mike - I wouldn't worry too much about those readings - A lot of people have had similar numbers, see here. Also check out the It should be banned series of messages by searching the word "banned" in the search box. TLDR: I got on my first use of RWTST:

This is the third QMX I have built, each design improvement outperforming the last. Now on first powerup and testing RWTST on 12.00 volts I get the following output into a dummy load as per putty diagnostics:

40 meters 5.3 watts
30 meters 4.9 watts
20 meters 7.0 watts (amps went from .093 resting to 1.01 transmit)
80 meters 5.6 watts
60 meters 6.1 watts?

Per Hans advice I slightly spread the coils on L513 and got 20 meters down to between 6 and 7 watts. I have had over a thousand POTA contacts using this rig without problems.

Sandy KB3EOF

It's crossed my mind that they might be particulary hot transistors.

I don't know the current draw right off hand, nor have we keyed it long enough to notice any heating.

We do have a scope.

T37 AL is 1.5

on the table it takes 1.637 not consitent with the other Ls

73

muhsin TA1MHS

Ron, Jeffrey:

Thanks for the quick reply!

Turns out I had the worst kind of solder joint that you can experience. It was nice and shiny, was conductive, but it was high resistance, and it slowly increased its resistance.

Last night I was getting 3.5V on the Vcc pin. This morning it was 2.5, then it dropped to 2.1. The voltage regulator looked good, so I started resoldering pins for IC2 and surrounding components. When I traced L6, it showed 5V but the next solder joint towards the chip showed open, even though there was 2+ V at pin 7.

I resoldered that one joint, turned on power and got the opening message in the display.

Thanks for helping me focus on the power pins for IC2!

David
N7LL

L8 should be 13

page 30 L6 should be number of turns 22, not 21

?

Thanks Ron!
73, Rob?

Nope, that wasn't it.? He pulled the transformer and dissected it and it was wound right.? He rewound it with new wire and reinstalled it and the transmitter acts the same, too much power.

Nino,

Thank you for your response. All buttons work correctly for me, except the left encoder when turned either direction only raises the volume. I updated the firmware again, nothing changed. I am going to switch the encoders on the controls board when i get more time, that should tell me for sure if i have a hardware or software issue.

73 k9pz

See if Trip Lite has a length you like, they will come with ferrites on both ends. Not cheap but very well made. My TT 539 is very sensitive to RFI and would do all kinds of bizarre stuff with the Signalink and the netbook out camping in the wilderness. A 20 dollar fix and its been smooth sailing.?

Duh, thanks Mike. Everything looks and works as it should to the dummy load, so I guess that leaves me with RF from the antenna especially on 80m. It's going to be awhile before I get my tuner. I'll swap out the feed line and see what happens.

Steve

ooops, correcting errors...

area = 0.000308 sq inches = 0.199 sq mm

Typo, conclusion is unchanged

On Sun, Jan 7, 2024 at 12:44?PM John Z via groups.io
<jdzbrozek@...> wrote:

Razvan, more stuff just for you, and of course, anyone else interested.
I like building a case with numbers, so brace yourself, here come a
lot of numbers.

Using data for TN0110 taken from Microchip Technology datasheet:


The drain lead cross section area minimum = .014 inches x .022 inches
= .0038 sq inches = 0.3556 mm x 0.559 mm = 0.0199 sq mm
Lead Length (uncut) = 0.61 inches maximum = 15.49 mm

Lead thermal resistance = Length/(Area x Conductivity)
all dimensions in meters
Using 390 W/mK for copper conductivity,

Lead thermal resistance (full length) = (15.49/1000)/((0.0199/1e6) x
390) = 200 deg C per watt.

Now, no one will use the full lead length to mount the transistor, but
20% to 25% is more like it. That translates into a thermal resistance
0f 40 to 50 deg C per watt for the drain connection. We are neglecting
the length of lead buried within the package, and any additional
thermal resistance at the PCB, but that's OK for now.

The thermal resistance of the TN0110 is specified as 132 deg C per
watt junction-to-ambient. This is independent of lead length or PCB
copper flooding, and so represents just the package heat flux. While
the junction-to-case resistance is not specified, it would not be
unreasonable to take that as half the junction-to-ambient value, or
about 66 Deg C per watt. A similar division can be noted in the
datasheet for 2N2222.

We can draw the following conclusions:

1) The resistance of the drain lead and the resistance
junction-to-case are similar in value.
2) There is great benefit to keeping the drain lead very short.
3) The use of an effective heat sink at the case will help reduce the
case-to-ambient thermal resistance and improve overall thermal
performance.
4) Augmentation of drain heat flux through the use of thermal wick
technology may have some advantage, by reducing the PCB component of
total thermal resistance,

There. That was fun...JZ

On Sat, Jan 6, 2024 at 4:12?PM Jim Strohm <jim.strohm@...> wrote:

Most cases of berylliosis are associated with repeated or long-term exposure. Handle it carefully and you'll be fine.

It's one of those "it's DANGEROUS!!" ham radio chemicals like PCB oil and radium-painted R-390 meter faces and lead-based solder. Just handle them properly and with respect and you'll live a good long life.

73
Jim N6OTQ


On Sat, Jan 6, 2024 at 2:33?PM John Z <jdzbrozek@...> wrote:

Looking at several commercial and government online resources, it seems that while BeO can be an irritant and can cause a number of skin and lung ailments, it is not toxic to the point where a small exposure can be fatal. There seem to be conflicting claims about its carcinogenicity.

Still, I would rather not have it around.

JZ

On Sat, Jan 6, 2024, 3:14?PM Jim Strohm <jim.strohm@...> wrote:

How would I dispose of broken BeO? Not sure. For the intact block, as-is, I'd just put it back in the PA deck after my testing is finished and documented. Maybe someday we can use diamond for a BeO substitute.

The last time I looked into BeO disposal, the consensus of answers was to return it to the manufacturer of the product that contained it, with "BeO" written on the package. I'd have to recheck that now.

One known BeO problem is that some ceramic bodied RF transistors have beryllium in their ceramic packaging, and for the most part they're not marked. "Pink ceramic" is not a sure-fire guarantee that a part has BeO -- for example, my plasma cutter has pink ceramic nozzles but they fail the best non-destructive test for BeO, which is thermal conductivity.

To test, get a thermal diamond tester from fleabay -- about $15 -- and test your mystery ceramic against known radio porcelain, like a tube socket or coil form, The BeO will be highly conductive,the porcelain not so much.

73
Jim N6OTQ

On Sat, Jan 6, 2024 at 12:25?PM John Z <jdzbrozek@...> wrote:

Oh my, Jim...

How do you dispose of something like that?

JZ

On Sat, Jan 6, 2024, 1:08?PM John Z via groups.io <jdzbrozek@...> wrote:

Yes, Jim that is correct. Some day it could wind up somewhere that has no such control. My conscience is quieter if I don't use it.

BTW, do you remember the BeO envelopes on high power transmitting tubes? Same safety consideration noted.

73, JZ

On Sat, Jan 6, 2024, 1:03?PM Jim Strohm <jim.strohm@...> wrote:

John,

The article you cited includes this:

"the material (beryllium oxide) is safe to handle as long as dust is not generated during machining or handling."

73
Jim N6OTQ



On Sat, Jan 6, 2024 at 11:15?AM John Z <jdzbrozek@...> wrote:

Hi Don,

I had a similar thought, but then did a bit more digging.

I found that Kyocera also offers a similar thermal product called Q-Bridge:



Most of those are also Aluminum Nitride, although some are made of Beryllium Oxide, which is quite toxic.

Unlike most electrical insulators, which have very poor thermal conductivity, those two ceramics possess thermal conductivity on par with metals.

Pretty cool! (pardon silly pun :-)

This class of part could be extremely useful as the envelope gets pushed on cig-pack sized Ham radios!

73, JZ






On Sat, Jan 6, 2024, 11:10?AM Donald S Brant Jr <dsbrantjr@...> wrote:

On Sat, Jan 6, 2024 at 07:16 AM, John Z wrote:

The thermal wick chips I mentioned in the previous post offer an
interesting possibility for the future (especially if the price comes
down!)

Those "thermal wicks" sure look a lot like a regular chip resistor with no element; maybe that is exactly what they are.
I wonder what the thermal properties of an ordinary high-value (1M?)chip resistor might be.....?
The few I looked into had alumina substrates; not as good as aluminum nitride but better than air or PCB material.
73, Don N2VGU

I've been going through that transformer over and over in my head.? I didn't think it was possible to wind it wrong, but eventually I realized that after twisting the secondary lead to the primary, if the primary came back through the same hole in the binocular, then it would functionally be a 2:2 wind.? He's pulling it apart to check it.?