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Re: What are you QRP guys using to measure power?

danielu@upcnet.ro danielu@upcnet.ro
 

https://www.banggood.com/Digital-Radio-Frequency-Power-Meter-7516dBm-Power-Attenuation-Can-Be-Set-p-1221705.html?rmmds=buy&cur_warehouse=CN
I use this watt meter down to -40dBmW. It offers almost the same results in 10.7Mhz with two modified LPF filters qrp labs in series compared to RIGOL DS2072A set in 50Ohm.
73 Daniel Ungureanu  Y08SAK


Re: QCX Plus 50 Watt PA Combo

George Korper
 

Hans,
I am not clear on one thing. If you purchase the enclosure what is the best way
to use a development board without a QCX+ board? Ideas? Drill the bottom?
George

On Sat, May 30, 2020 at 1:14 AM Hans Summers <hans.summers@...> wrote:
Hi George


73 Hans G0UPL 

On Sat, May 30, 2020, 02:15 George Korper <georgekorper@...> wrote:
I actually would prefer it as is so I don't need to add a cutout for an LCD. 
Any other holes I can plug. If I don't use the LCD slot I will put a screen behind it. 


On Fri, May 29, 2020 at 5:04 PM Hans Summers <hans.summers@...> wrote:
Hi George 

The link is not working for me. 


Thanks for the info, I order cases with the AMP so I probably will settle for the elegant (Collins S Line) look.

Ha! In this case, a QRP Labs Q line

 So here is the question. Will separate enclosures   
be available for purchase? Like for a spectrum scope? Or SWR Meter tuner, etc. 

Separate QCX+ enclosures are already available. But I know you mean, the enclosure with plain front and back panels that you can make your own stuff in and have it match. So I'd have to buy some extra, blank panels. I suppose that's possible! Let me think about it! 

73 Hans G0UPL 


Re: What are you QRP guys using to measure power?

flatpickn@...
 

I also use a QRPoMeter. Forward and reflected power with built in dummy load. Excellent kit. Well thought out and fun to build. Buy on Tindie or eBay from Dave Cripe NM0S.
https://www.tindie.com/products/NM0S_qrp/qrpometer/

Or I use a dummy load (and a little math) built in a quart paint can filled with mineral oil. The QRP version of a Heathkit Cantenna. I based mine off of this one.
https://www.k4eaa.com/dummy.html
.


Re: 50W PA Damaged

geoff M0ORE
 

I don't think any ATU will prevent damage to a transmitter due to human error. The commercial and military  equipment employ extensive circuitry in the transmitter to take care of such mishaps and shut down to a safe level. A soldier under fire can be forgiven for not checking the aerial matching. Likewise, an aerial on a vehicle may be damaged without the operator being aware of the damage.

An ATU is basically a means of transforming one impedance to another. If no load is connected i.e. a very high impedance, then that is reflected back through the ATU to your transmitter as a very high impedance. Hence the blown finals.

You could design an interlock system such that if the aerial is not connected the transmitter does not power up.



On 30/05/2020 11:28, George Korper wrote:
Usually, it is just the finals. That has been my experience in the same exact circumstance. 

On Sat, May 30, 2020 at 2:22 AM J P Watters via groups.io <kc9kko=mac.com@groups.io> wrote:
I think this will be me at some point. 

My thought is to install a ATU like this one to protect the finals from transmitting into an open antenna.SDR rig to protect the finals. 
https://github.com/Dfinitski/N7DDC-ATU-100-mini-and-extended-boards
Will that ATU provide that kind of protection.

..jpw J P Watters
KC9KKO






Re: [help] Only noise being seen while IQ balance / phase lo / phase hi.

dl8lrz
 

I only see 2 options:
- Current flows to the ground via C22, the voltage at PIN6 becomes too low compared to PIN5. Then PIN7, 3, 2.1 can be nearly 12v.
- IC10 is defective.
Read how to remove circuits. The board can be destroyed
I wish you success
73 Reiner


Re: 50W PA Damaged

George Korper
 

Usually, it is just the finals. That has been my experience in the same exact circumstance. 


On Sat, May 30, 2020 at 2:22 AM J P Watters via groups.io <kc9kko=mac.com@groups.io> wrote:
I think this will be me at some point. 

My thought is to install a ATU like this one to protect the finals from transmitting into an open antenna.SDR rig to protect the finals. 
https://github.com/Dfinitski/N7DDC-ATU-100-mini-and-extended-boards
Will that ATU provide that kind of protection.

..jpw J P Watters
KC9KKO






Re: What are you QRP guys using to measure power?

Allan Nelsson
 

I use a mW-meter designed by OZ2CPU

http://webx.dk/oz2cpu/radios/miliwatt.htm I know it has been in high numbers and was also in Elektor once. I can ask OZ2CPU if there is an

 

interest in boards.

Allan, OZ5XN


Re: What are you QRP guys using to measure power?

Hans Summers
 

Me, I don't even have a power meter... 

I use an oscilloscope and QRP Labs dummy load. 

See also my article on RF power measurement:

73 Hans G0UPL 

On Sat, May 30, 2020, 10:58 Jim Mcilroy via groups.io <gts53=btinternet.com@groups.io> wrote:

I use a Trio PF-810 Funcion Power Meter into a QRP-Labs 20W dummy load.

The meter will handle up to 150W but I haven't used that for years.

Jim, G4EQX

On 30/05/2020 00:11, George Korper wrote:
Me too. The QRPoMeter ( I have two) is accurate, fun to build and worth every penny. 


On Fri, May 29, 2020 at 6:17 PM Al Clark <hotdogx@...> wrote:
I use the QRPoMeter by NM0S David Cripe.  https://www.ebay.com/itm/QRPoMeter-Digital-15W-QRP-Wattmeter-Dummy-Load-VSWR-Meter-Kit/254596727364?hash=item3b4725c244:g:fgAAAOSwlY1ZMMdT
Handles up to 15 watts, won't let your rig see a high SWR, and is accurate.  Easy to build and calibrate.

--
Al W4KY


Re: What are you QRP guys using to measure power?

Jim Mcilroy
 

I use a Trio PF-810 Funcion Power Meter into a QRP-Labs 20W dummy load.

The meter will handle up to 150W but I haven't used that for years.

Jim, G4EQX

On 30/05/2020 00:11, George Korper wrote:
Me too. The QRPoMeter ( I have two) is accurate, fun to build and worth every penny. 


On Fri, May 29, 2020 at 6:17 PM Al Clark <hotdogx@...> wrote:
I use the QRPoMeter by NM0S David Cripe.  https://www.ebay.com/itm/QRPoMeter-Digital-15W-QRP-Wattmeter-Dummy-Load-VSWR-Meter-Kit/254596727364?hash=item3b4725c244:g:fgAAAOSwlY1ZMMdT
Handles up to 15 watts, won't let your rig see a high SWR, and is accurate.  Easy to build and calibrate.

--
Al W4KY


Re: [help] Only noise being seen while IQ balance / phase lo / phase hi.

Alan G4ZFQ
 

Jose,

Measured voltage for IC10 are:   pin  1  ~ 8   : 1=11.7  /2= 11.7 / 3=11.7 /4=0 == 5=3.3 / 6=2.31 / 7=11.7 / 8=11.7   (Volts)
But, perhaps I should just replace the IC rather than
wondering if it's good or NG.
The voltages seem to indicate it is good. Pin 6 is much lower than pin 5 even though it is fed from pin 7 which is very high.
I've not been following too closely. Have you checked voltages each side of R37? Is C22 installed the correct way round? Is it leaky?

73 Alan G4ZFQ


Re: #ocxo #ocxo

KEN G4APB
 

Hi Giuseppe,
the picture you show looks fine, but this assembled board fits INSIDE the external screen, so it cannot touch IC1 unless you have assembled the external screen incorrectly. can you show a picture of the EXTERNAL screen ?

73 Ken G4apb 


Re: 50W PA Damaged

J P Watters <kc9kko@...>
 

I think this will be me at some point. 

My thought is to install a ATU like this one to protect the finals from transmitting into an open antenna.SDR rig to protect the finals. 
https://github.com/Dfinitski/N7DDC-ATU-100-mini-and-extended-boards
Will that ATU provide that kind of protection.

..jpw J P Watters
KC9KKO






50W PA Damaged

Curt M.
 

Hi guys, I did one of those things this evening that I never thought I’d do. I held down the key to my QCX connected to the 50w amp and noticed that it didn’t want to tune. I saw my power meter drop and realized that I had my antenna switch set for the wrong port. I’m using a bench power supply with the current limit set for 7amps. 


So it’s obvious that something happened to the amp but I’m too tired to get involved with it at 2am. Is there any chance that it’s just the final?  Not sure if I should order a couple of replacements which I know I don’t have on hand or just order a new kit. I’m sure someone else out there has done this same thing and I’m wondering what it took to bring it back to life?  

Curt M.


Re: What are you QRP guys using to measure power?

 

Thanks Paul,
Yeah, I fully understand the peak measurement part, that's easy; it's exactly that bit about "assuming your load is 50 ohms resistive) I was talking about ..

Back to the antenna theory book, I guess..

Julian N4JO.


Re: QCX Plus 50 Watt PA Combo

Hans Summers
 

Hi George


73 Hans G0UPL 

On Sat, May 30, 2020, 02:15 George Korper <georgekorper@...> wrote:
I actually would prefer it as is so I don't need to add a cutout for an LCD. 
Any other holes I can plug. If I don't use the LCD slot I will put a screen behind it. 


On Fri, May 29, 2020 at 5:04 PM Hans Summers <hans.summers@...> wrote:
Hi George 

The link is not working for me. 


Thanks for the info, I order cases with the AMP so I probably will settle for the elegant (Collins S Line) look.

Ha! In this case, a QRP Labs Q line

 So here is the question. Will separate enclosures   
be available for purchase? Like for a spectrum scope? Or SWR Meter tuner, etc. 

Separate QCX+ enclosures are already available. But I know you mean, the enclosure with plain front and back panels that you can make your own stuff in and have it match. So I'd have to buy some extra, blank panels. I suppose that's possible! Let me think about it! 

73 Hans G0UPL 


Re: What are you QRP guys using to measure power?

 

I usually use these dummy load power meters.
I did the first as a club project for CalQRP.
The second one was just for fun, but is pretty accurate from 10 to 80m and
very flat on my VNA at work.   This one was based on a Renesas processor
that I like.  I did a PCB version based on an Atmel part, but I lost interest in it
when nobody else wanted to solder 0402 parts :-)
They're all pretty much the same design though wrt sensing..

I'll build one of Johan Holstein's  meters when I get all the parts together.





Re: What are you QRP guys using to measure power?

Paul AI4EE
 

A peak detector does just that: it produces a DC voltage that is equal to the peak ac voltage. Once you have that (assuming your load is 50 oms resistive), the reactive components are not involved. If you don't have a resistive load, then things are a bit more complicated, but you needn't care -- your power will be lower than for the resistive load. How much lower depends on your SWR.

What you really want is to be able to measure both forward and reflected power. That's a bit trickier.


On 5/30/2020 12:34 AM, Julian Opificius wrote:
Simple math? Forgive my ignorance, but do we not consider power factor ? I find it hard to believe that with the inductance and capacitance scattered around the antenna circuit there isn't some phase error somewhere.
Am I missing something?


Re: What are you QRP guys using to measure power?

 

Simple math? Forgive my ignorance, but do we not consider power factor ? I find it hard to believe that with the inductance and capacitance scattered around the antenna circuit there isn't some phase error somewhere.
Am I missing something?


Re: What are you QRP guys using to measure power?

Samuel KJ4VPI
 

Yep, I'm also using a QRP Guys 12W Dummy Load, a DVM and simple math.
https://qrpguys.com/12w-dummy-load-power-meter
https://qrpguys.com/wp-content/uploads/2019/03/dummy_assy_020819.pdf

Nice little kit.


Re: What are you QRP guys using to measure power?

Mike Besemer - WM4B
 

the rest is just software”

 

Maybe to you, but I’m not a software nor an Arduino guy, nor am I interested in becoming one.  At my age, I have desires to do more things than I’ll ever accomplish in my lifetime and I don’t care to add to the list – especially if it involves mucking about with another damn computer.

 

Mike

WM4B

 

 

 

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of Arv Evans
Sent: Friday, May 29, 2020 9:39 PM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] What are you QRP guys using to measure power?

 

Mike

 

Should be easy to do.  Just a well designed Stockton bridge to sample 

both SWR and PWR, then use an Arduino ADC input to read volts and 

convert that to show amperes FWD, amperes REV, watts FWD, and 

watts REV.  Could also do some fancy things like output for limiting 

RF PA drive if the reflected power were excessive, and maybe even do 

rough frequency measurement by adding a divide-by-n ahead of one 

of the digital input ports.  Once you have the RF sample, the rest is 

just software.

 

Arv

_._

 

On Fri, May 29, 2020 at 4:01 PM Mike Besemer - WM4B <mwbesemer@...> wrote:

I think we need a QRP-Labs meter – 0 to 5 watts!

 

Mike

WM4B

 

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of ajparent1/KB1GMX
Sent: Friday, May 29, 2020 5:39 PM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] What are you QRP guys using to measure power?

 

I use...

QPSA, a Steve Webber design for over 10 years ago also SWR/frquency counter/aux
audio amp.

DL5NG terminated diode mount (up to 10mw or so, with calibration table.

A dummy load based on caddock resistors (25W) and diode for the
10mw to  20W range HF and calibrated.

Bird Model 43 throughline watteter. Large number of slugs for it.
Loads:  Bird Dummy load (100W), Heath cantenna for higher power.
A lower power 100W pint-enna  (high power (caddoc) resistor in Pint can.

RIgol DSA815T or HP8568B SA with 30DB 50W power attenuator (narda 7768-30)
Also a Bird 50W model similar.

All in cal.

Allison
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