Date   

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

Joe WB9SBD
 

I wonder how close I got doing this,
I have an old Radio Shack model, it has 3 power levels,
20, 200, 2000 watts

I trimmed the 20 watt position by running enough power to have it say best guess 2 watts, and then adjusted the trimmer so it was full scale.

I know probably far from Accurate, but still better than trying to read less than 2 watts on a 20 watt scale true?

Joe WB9SBD

The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com

On 5/30/2020 12:36 AM, Julian Opificius wrote:
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: 50W PA Damaged

George Korper
 

Of course if I choose not to wear a mask in the middle of an epidemic
then I would probably be an idiot. 

On Sat, May 30, 2020 at 8:08 AM George Korper <georgekorper@...> wrote:
Using Allison's suggestion, a 4 amp fuse sometimes will blow before the finals in the
event of no antenna connected. Also using Allsion's tapping technique is easy and makes
replacing the two IRF510's a breeze. 
Having this occur doesn't mean you're an idiot. 
Sometimes I have left the house without a mask, and then I feel like an idiot. 
Now I leave one in the car!
It happens to all of us one time or another. I have made use of three sets of spares (hi hi)
Just make sure you order 10 at a time (five sets) as they are not expensive and use a Vishay or equivalent high quality
part from a supplier like Digikey or Mouser. 

On Sat, May 30, 2020 at 7:46 AM Bill Cromwell <wrcromwell@...> wrote:
Hi,

It isn't possible to pass laws nor make any equipment of any kind "idiot
proof". As soon as we design or legislate to protect from idiots then
better idiots will be made :)

73,

Bill  KU8H

On 5/30/20 7:12 AM, geoff M0ORE via groups.io wrote:
> 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.

--
bark less - wag more




Re: 50W PA Damaged

George Korper
 

Using Allison's suggestion, a 4 amp fuse sometimes will blow before the finals in the
event of no antenna connected. Also using Allsion's tapping technique is easy and makes
replacing the two IRF510's a breeze. 
Having this occur doesn't mean you're an idiot. 
Sometimes I have left the house without a mask, and then I feel like an idiot. 
Now I leave one in the car!
It happens to all of us one time or another. I have made use of three sets of spares (hi hi)
Just make sure you order 10 at a time (five sets) as they are not expensive and use a Vishay or equivalent high quality
part from a supplier like Digikey or Mouser. 

On Sat, May 30, 2020 at 7:46 AM Bill Cromwell <wrcromwell@...> wrote:
Hi,

It isn't possible to pass laws nor make any equipment of any kind "idiot
proof". As soon as we design or legislate to protect from idiots then
better idiots will be made :)

73,

Bill  KU8H

On 5/30/20 7:12 AM, geoff M0ORE via groups.io wrote:
> 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.

--
bark less - wag more




Re: 50W PA Damaged

Bill Cromwell
 

Hi,

It isn't possible to pass laws nor make any equipment of any kind "idiot proof". As soon as we design or legislate to protect from idiots then better idiots will be made :)

73,

Bill KU8H

On 5/30/20 7:12 AM, geoff M0ORE via groups.io wrote:
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.
--
bark less - wag more


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.