¿ªÔÆÌåÓý

ctrl + shift + ? for shortcuts
© 2025 Groups.io
  1. QRPLabs
  2. Messages
Expanded Topics Messages Polls
Date
Re: Multi band QCX plus Party time...

 

Me: ham since 1954, retired 2009, no XYL even with a "no-radio-stuff" living room. Musta made a wrong turn somewhere...?? :>)

Jack, W8TEE

On Tuesday, April 16, 2019, 6:13:44 AM PDT, John Kirby <n3aaz_qrp_1@...> wrote:


?Jack,
?HI HI only been my XYL since 1964,
me a ham since 1956 dit dit


Hans BPFs (image) are a delight

L4 es C30 tweeking can be fun too but,? ?you will need three meters and,? ?a better understanding of class E efficency than I could muster ( retired 1997)

N3AAZ

Re: Multi band QCX plus Party time...

 

?Jack,
?HI HI only been my XYL since 1964,
me a ham since 1956 dit dit


Hans BPFs (image) are a delight

L4 es C30 tweeking can be fun too but,? ?you will need three meters and,? ?a better understanding of class E efficency than I could muster ( retired 1997)

N3AAZ
Re: Stock QCX-17 running a CW beacon on 12m again today

n4qa at_hotmail.com
 

BTW, every single spot of N4QA shown in the screen shot below of the current 'RBN week'? is from my stock QCX-17 :

Also seen here:


72 / 73,
Bill, N4QA
Stock QCX-17 running a CW beacon on 12m again today

n4qa at_hotmail.com
 

In an attempt to prove that she's an eight-band QCX rig, the stock QCX-17 is running a CW beacon, somewhere within the lower 5 kHz of the USA 12 meter band.
Power output is 200 milliwatts and the antenna is the GADS! ( Gutter And Down Spout ! ).
Looking at RBN spots for signs of world-wide CW activity at:


shows...see screen shot below.
It's a long shot but my stock QCX-17 doesn't seem to mind...
72 / 73,
Bill, N4QA
Re: Multi band QCX plus Party time...

 

Somebody is a bachelor or has a really understanding XYL.

Jack, W8TEE

On Tuesday, April 16, 2019, 7:31:46 AM EDT, John Kirby <n3aaz_qrp_1@...> wrote:


N3AAZ

Re: Multi band QCX plus Party time...

 

RE T1 and pcb de solder / re solder

As we all know T1 is prime RX ... If u can't hear-em can't QSO-EM

Solved my problem

N3AAZ?
Re: Easy lithium battery for QCX

 

Sorry, I meant to say QSX, so it should be suitable for either of the QRPLABS offerings.
Re: Easy lithium battery for QCX

 

That should be within the realm of QCX power though, right?? A 10W SSB rig should draw under 3A average by a pretty good margin.
Re: Multi band QCX plus Party time...

 

N3AAZ
Re: Multi band QCX plus Party time...

n4qa at_hotmail.com
 

Hey, John, N3AAZ,
Many thanks for the hint about the "variable (tunable)" audio filter.
I've been wanting to improve on my 7-band QCX rig's performance while receiving, for example, CHU on USB on its three freqs, as well as AM SWBC, JS8, FT8 etc on all my QCX-17's freqs !
72 / 73,
Bill, N4QA
Re: 5 watt PA on 630m

 

Vernon,

I have run the PA Amp on 630 M for over a year on WSPR and it is about 5 watts- except for last 30 days as I'm testing an MF Solutions transverter.??

I did mount the amp in the U3S case with a small fan inside monitoring the heat sink temperature for a few weeks.

It works quite?well!??

Regards,

Dave, W4VU
Re: Multi band QCX plus Party time...

 


OOPS image ?
N3AAZ
SETUP
Re: Multi band QCX plus Party time...

n4qa at_hotmail.com
 

Hey there, Nigel.
Not having a stock QCX-30, I can't speak to its performance on other bands.
But, as for my stock QCX-17, I have enjoyed more QSOs with it on 30m than on any other band...would love to QSO ZS6RN on 30m !
I was informed yesterday by Alan, G1FXB of the 6-band QCX rig by Andreas, DM5MU, found near the bottom of the page at:
?
Very interesting rig !
72 / 73,
Bill, N4QA
Re: Multi band QCX plus Party time...

 

?Niger,

Of course T1 is prime but not as critical as one thinks :>)

This pcb with 30m T1 is a four band xcvr

Parallel C1
and
Outboard LPF
and
Bypass onboard audio filter
and
Add variable (tunable) audio filter

This HB loop es set up 'WHISPERED' to Antarctic, Auz es NZ
before XYL said "%$flkx 345 , ## ¡ö x" rough xlation "get it OUT here!!!

72 73
John
N3AAZ
FM19
Re: Multi band QCX plus Party time...

 

There are 3 parts of the QCX that are band specific: input tuned circuit, output low pas filter and class E amplifier.

I also have a 30m QCX. We should have QCX activity that isn't a contest so that we aren't left out.
--
73
Richard
G4TGJ
Multi band QCX plus Party time...

 

Hello again from ZS land :-)

Following on from my posting yesterday in reply to Bill re: "A somewhat more complete description of my (ab)use of the QCX-17 and QCX-80 transceivers, today I became aware of (and interested in) the QCX qso party idea that started at the beginning of the year and on visiting the 3830scores site (first time, I have as yet to ever enter a contest so all new to me) I was reminded that the WARC bands are contest free.? So in order to participate (as mentioned, I have never in my 50+ years of being licensed taken part in a 'contest') using my QCX 30, I will need to configure for say 40M so the idea of a multi band QCX has merit, at least for me.

Reviewing the QCX schematic I can understand the need for appropriate band pass filter on transmit but not sure of how broad the design of the receive band pass filter is? Seems Bill has no problem(s) regarding sensitivity / selectivity on 'out of original band' working but maybe there are tweaks required?? So aside from experimenting, does anyone have advice or comment regarding what to expect on receive if I for example build the QCX 30 according to specification (specifically number of winding's on T1) and then set to operate on say 40M or 20M?

One thought I have considered would be to make the primary and secondary 3 of T1 switchable, perhaps using a tapped arrangement based on specifications for the 20 / 30 / 40 m bands (together with corresponding change to the output band pass filter arrangement) but I lack the design knowledge to know (hence option of experimenting but fear I would mess up the QCX pcb in the process!) if secondary 1 and 2 (the input to the quadrature detector) could remain 'as is' i.e. 30T?? It is the same number of winding's as 20M but 8 short for 40M.?

Can anyone please advise?? Many thanks in advance.

vy 73 Nigel

ZS6RN ex G8DEV
Re: QCX-20 power output

Chris Hobbs
 

Thanks for the tip Richard. I'm out of town for a couple of days, but I've got an LCR meter on order so I'll check those caps out when I get home, as well as my inductors. My first time winding toroids, so I'm not going to be too shocked if it turns out I did something wrong there. I know the counts are right, but looking at others' pictures it seems like mine are wrapped tighter.

Chris

On Mon, Apr 15, 2019 at 2:12 AM Richard Harris via Groups.Io <g3otk=[email protected]> wrote:
Hi Chris,

Several QCX 20m version builders, myself included,? found that the output filter capacitors C25 and C26 (390pF NPO ceramic) were quite lossy.? This may be due to a bad batch of capacitors from the manufacturer.? I found that holding the key down for a few seconds caused the output power to slowly rise and C25 and C26 to warm up - I checked this using an infra-red thermometer.? ?

I cut out C25 and C26 and soldered 330pF + 56pF NPO ceramic to be back of the PCB (I don't have any 390pF NPO in my new components box) and the power went up to about 3W using a 13,8V PSU.? It also remained constant when the key was held down for a few seconds.??

I believe that this problem has only been reported on the 20m version of the QCX..

Richard G3OTK





On Monday, 15 April 2019, 05:11:09 BST, Chris Hobbs <chris@...> wrote:


[I know there is a recent thread on this topic, but I think I'm experiencing something different]

Hi All!

I'm new to the QCX and finished building my -20 a couple of weeks ago. Other than a bad solder joint on the LED backlight everything seemed to be working well and I was able to go through the calibration steps.

Now that I've got an antenna up I'm ready to start actually playing with it, and I've discovered that I'm not getting anywhere close to the power I should be for my input voltage (13.7VDC from an Astron power supply). I'm only seeing 1.0W on my MFJ-971 tuner into a 50-ohm dummy load.

I've gone through the troubleshooting in section 6.5 of the manual. The pin at L1 is showing 0.74W on the internal watt-meter. The drains of all three BS170s however show 5.2W. I know the manual says this is an even less reliable measurement, but that's almost an order of magnitude difference.

The manual suggests that if you have power at the mosfets but not at L1 then the LPF is to blame. It doesn't cover what the issue might be if there is RF at L1 but it's really low.

I've read that removing turns from L1-3 can help, but I have a hunch the problem I've got is something more significant than what that solution might provide.

Any thoughts on what I should be looking at first?

Thanks in advance!

Chris W6VE

--
Chris Hobbs



--
Chris Hobbs
Re: QCX Rev 4 Build

 

Hi Al

Yes. Non-critical. The most non-critical place for the low one would be C21 or C22.

73 Hans G0UPL?
?

On Tue, Apr 16, 2019, 05:48 Al Lipinski <lipinski.al@...> wrote:
Section 3.16 of manual?

Install 1uF capacitors (3).??

I measured two caps at 0.978 uF
I measured one cap at 0.775uF? ?.? About - 22% tolerance
Should I install the low cap?????

Thanks,?

--
Al Lipinski



Re: Easy lithium battery for QCX

 

Turnigy makes a good product and I've used a lot of their packs...

However read the information its 2.2AH 1.5C? that means the max current is about 3.3A
and standard .5C charge rate.

For QCX that's fine but for something else it may not be.

Allison
Easy lithium battery for QCX

 

I found this on Amazon today:


It's a 3s li-po 2.2Ah pack w/ protection built in for under $25!

Seems like a great option for building intoia case for powering a QCX!

So far it's the only protected battery I have found intended for the drone market.? I've got an unprotected Turnigy 5Ah battery I have used before with good results, but the need for an external battery alarm or PCB has always been a drag.
111021 - 111040 of 144143