With all the political turmoil there, not bad at all!

?The USPS seems to like my order from Hans and is touring the north east states with it hopefully on it's way to Maine. After clearing customs it went to USPS in New York. Then it went to Ohio. Then it went to Pennsylvania. Then it went to New Jersey, which? is closer to New York Customs then any of it's trip so far. Doesn't the USPS make you? proud.?.? I am a very old man and wonder if I will live long enough to see my parts! Carl

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Hi Tom,

Thanks Alan for your suggestions, I will run through the RX alignment 
again.

Should be no need to repeat alignment, just how did it "feel" when you did it initially?
If you thought to your self, is this as good as it gets
or if its a poor RX performer then that perhaps points to the LPF stage having too much attenuation??

Exactly what voltage should the power supply be? I am using an old 12v 
30A adjustable supply.

That's more than adequate,
If something unfortunate were to happen, 30A through the QCX is going to do damage.
A fuse will help minimise damage beyond the initial failure.

How much power output? see should I get?

There is a table in the back of the assembly manual that plots typical power out verses TRUE PA voltage. if you are within 10 % then that's good enough in my book.
Even 20% off, maybe more trouble than it's worth... It's effort Verses "fractions of an S Point"
You state you have an adjustable 12v supply. If you tickle it up to get 12V after the protection diode, The book says you should achieve circa 3W
You reported in the order of 1W so you are only getting 33% to the antenna socket....
I would take that as an indication that it should be better

Whats your current consumption?
A QCX on TX making it's full output is circa 450mA
If yours is similar, this will provide a clue that it's likely the PA is making full output but it's not reaching the outside world,
it's got to be going somewhere.
?

I am reading the power with an Autech Research WM1 Computing meter into 
a dummy load.

Part of the suite of test equipment included in the QCX purchase price was a built in watt meter. See section 5.16 of the build manual
It doesn't claim to be anything other than a relative indication, but it won't cost anything to compare what that reads into the same dummy load......
It's probably the instrument that most people report their units performance with, and other QCX40 owners can give you their figures.

If you have not read the assembly manual & troubleshooting page recently, perhaps re-read it.
Don't skip sections you think don't apply!!

It's an old time radio mystery, the clues are there,
they just need picking out!

Alan

Will let you know how things work-out.

73???? Tom KS5X


On 8/19/2018 4:10 PM, Alan de G1FXB via Groups.Io wrote:

Tom,

Unusual report for a QCX40.

Did the RX alignment go as per the book, and have good performance?

Perhaps double check soldering / component placement, especially 
around the LPF

Check the continuity through the LP Filter windings, you need to check 
pad to pad not just the wire tails.

(not removing the enamel sufficiently is common but should also effect 
RX sensitivity.)


The QCX20 / 30 tend to be more finicky, however as a starter 


Paragraph beginning "Finally if you really think your power output is 
a lot lower than you expected"

Chances are you may need to remove one or more windings from the 
cores, as a last resort substitute the capacitors in the LPF.

(If it was truly just the capacitors "at fault" You may need to add 
turns back.....)


Report back what you find.


Alan


On 19/08/2018 22:34, Tom Gundlach wrote:

Into a dummy load only get 1 watt? Any suggestions on how to get 5 
watts?

Hi,
Just got a small parcel from QRPLabs with 20m QCX transceiver parts, order #21320. 27 days journey, not bad.
Thanks,
73!
Slav, SP3RXO

Thanks Alan for your suggestions, I will run through the RX alignment
again.

Exactly what voltage should the power supply be? I am using an old 12v
30A adjustable supply.

How much power output? see should I get?

I am reading the power with an Autech Research WM1 Computing meter into
a dummy load.

Will let you know how things work-out.

73???? Tom KS5X

--
Have a GREAT Day

Tom KS5X@...





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Hallo Klaus,

tnx for info! Die werde ich mal probieren.

73
Ulf DK5TX

Hi Tim,

I completely agree with everything you said.

We are in dire need of affordable, well performing kits for both
bands! Some are not trying these bands due to the build from scratch
and/or high cost aspects. Hans can speak for himself but I suspect
for most kit makers these bands are a bit hard to justify compared
to HF which is far more in demand.

I consider myself very fortunate that the U3S supports these bands.
Mine is happy cranking out WSPR on 2200m as I type. :-)

73,
Paul N1BUG

How are you measuring your power output?
--
de K2TL.. since 1964

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however you want to do it, just don't forget an old fashioned? $0.1 fuse of a suitable value.

Alan

Thank you all for the replies.? I did find this little board kit on eBay..The spec is for 56mv drop at 820ma, 13.4 volts.? ??.
The SUP75803-07-E3 on eBay also looks like a good choice.? Thanks again..great group here!
--
de K2TL.. since 1964

Tom,

Unusual report for a QCX40.

Did the RX alignment go as per the book, and have good performance?

Perhaps double check soldering / component placement, especially around the LPF

Check the continuity through the LP Filter windings, you need to check pad to pad not just the wire tails.

(not removing the enamel sufficiently is common but should also effect RX sensitivity.)


The QCX20 / 30 tend to be more finicky, however as a starter

Paragraph beginning "Finally if you really think your power output is a lot lower than you expected"

Chances are you may need to remove one or more windings from the cores, as a last resort substitute the capacitors in the LPF.

(If it was truly just the capacitors "at fault" You may need to add turns back.....)


Report back what you find.


Alan

Hi Paul,

Agree with all your sentiments here, but linear amplification is nice to have and we do have some SSB activity on 630m here in VK. Not much, but some, and generally by agreement of the wider 630m VK community on specific days and times.

+1 for 2200m, maybe as an expansion kit of some sort.

regards

Tim

On 20/08/2018 2:12 AM, N1BUG wrote:

True, but very few people need *linear* transmitters (amplifiers) on
630m.

[snip]

I would much rather see 2200m included myself. ;-)

--
VK2XAX : QF56 : ITU59 : CQ30

Hi Paul,

And herein lies the problem as you've stated...

On 20/08/2018 4:21 AM, N1BUG wrote:

The reality is if one wants TX and RX on LF/MF one must do some
scratch building or spend a lot of money on limited (and often
under-performing) commercial gear.

This is why I requested that 630m be added.

I recently gave a presentation on 630m to my local ARC and while there was some keen interest, the prospect of building something from scratch deters most.

We have to realize, that those of us here, in this community, are a collection of builders and tinkers whereas a significant population of AR are nothing more than operators.

Some of those operators can be coaxed into building stuff if a kit was available. We've proven this in our own ARC by having buildathons for antenna's, foxhunt kit etc. supervised by those of us with experience & knowledge of having done it before. Some operators have become builders & tinkers as a result, others built their toy-for-the-day and went back to operating. But at least we helped increase the utilization of our bands by getting people involved.

If no one makes a kit, or clear cogent instruction to modify existing radios of any pedigree, the bands such as 630m & 2200m will remain under utilized with the always present risk that a government might want it back for something else.

Just look at what Han's marvelous kits have already done for AR, the sea voyages, the balloons and other experimentation, need I saw more ?

regards

Tim

--
VK2XAX : QF56 : ITU59 : CQ30

Into a dummy load only get 1 watt? Any suggestions on how to get 5 watts?

--
Have a GREAT Day

Tom KS5X@...





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My QCX-20 says i have a "WSPR power" error, but the GLQ is working.? What gives? Bill/AA2YV

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Yes I am using it on the QCX.? I bought some SUP75803-07-E3 on ebay.? You ground the gate put power to the drain and output to the source.? With the FET like it is to be mounted on a heat sink the Gate is on the left the Drain is the center and the Source is on the right.? I had less than 100mv drop and thsi transistor is good for much more than what the QCX needs.

Jim Ford N6JF??

Having worked with mosfets as rectifiers.

As a parallel diode:
Don't.? The part needs some amount of voltage from gate to source to turn it on hard.
By then your stuff is fried.
A good robust diode is better.? A fuse before it? so you blow the fuse as a warning.

As a series switch. You need a pmos part, and series diode due to the substrate
diode.? Works poorly under 6V as you need enough Gate to source current
to turn the device on hard. You still have one diode drop (.3-.7V).? There are
parts for that not as common usualy built as back pairs.

If I feel I need reverse polarity protection I use a suitable small relay and a diode.
If the polarity is wrong the relay cant engage, no harm.? Also contacts are way
less loss than diodes or mosfets.? Price you pay is maybe 50ma for the relay coil.
Relay and diode maybe 1$.

Allison