Getting indication of rf


militaryoperator
 

Having several transverts now and a couple of low power amps most have a built in rf o/p indicator, 1 to 3v at the max.

I was thinking of how to meter this, guess putting a simple cheap voltmeter across the pin might just load it too much so was thinking of a 741 opamp say, nice hi z i/p but needing a split rail. 

Plenty of dc to +- units on ebay so should be quite simple/cheap. 

Just wondered what others use?  I know you can use an inline directional couple, costly for a good one, but I was thinking of a unit built into each system. 

Ben G4BXD


Andy G4JNT
 

There are plenty of rail-rail opamps that don't need a negative supply
My fave is the  LM358.    If you want the output  to go down to close to 0V, place an additional pull-down R on the output,  300 ohms is adequate.     But 1 - 3V, unity gain buffering, no problem



On Thu, 4 Jun 2020 at 11:06, militaryoperator via groups.io <Military1944=aol.com@groups.io> wrote:
Having several transverts now and a couple of low power amps most have a built in rf o/p indicator, 1 to 3v at the max.

I was thinking of how to meter this, guess putting a simple cheap voltmeter across the pin might just load it too much so was thinking of a 741 opamp say, nice hi z i/p but needing a split rail. 

Plenty of dc to +- units on ebay so should be quite simple/cheap. 

Just wondered what others use?  I know you can use an inline directional couple, costly for a good one, but I was thinking of a unit built into each system. 

Ben G4BXD


Neil Smith G4DBN
 

A simple voltmeter works fine Ben, you can pull a milliamp without much impact, but a 20kohm/V movement is fine.  I put the outputs from those at the masthead into a cheap PIC board with multiple analog to digital converters and send the values back over an RS485 link, but other folks use a multicore cable and send back the analogue voltages to the shack end.

If you can borrow a calibrated power meter, you can do a rough calibration of each of the detector outputs as measured by your meter setup.  I have a lookup table in memory to convert the voltages to approx power, but a curve plotted on a bit of graph paper is just as good really.

There are also lots of decent single-rail opamps which will work from rail to rail, but it isn't really worth the effort. A rotary switch, some trimmer potentiometers and a 50 microamp meter would work well.

Neil G4DBN


On 04/06/2020 11:06, militaryoperator via groups.io wrote:
Having several transverts now and a couple of low power amps most have a built in rf o/p indicator, 1 to 3v at the max.

I was thinking of how to meter this, guess putting a simple cheap voltmeter across the pin might just load it too much so was thinking of a 741 opamp say, nice hi z i/p but needing a split rail. 

Plenty of dc to +- units on ebay so should be quite simple/cheap. 

Just wondered what others use?  I know you can use an inline directional couple, costly for a good one, but I was thinking of a unit built into each system. 

Ben G4BXD
_._


militaryoperator
 

Subject: Re: [UKMicrowaves] Getting indication of rf

A simple voltmeter works fine Ben, you can pull a milliamp without much impact, but a 20kohm/V movement is fine.  I put the outputs from those at the masthead into a cheap PIC board with multiple analog to digital converters and send the values back over an RS485 link, but other folks use a multicore cable and send back the analogue voltages to the shack end.
If you can borrow a calibrated power meter, you can do a rough calibration of each of the detector outputs as measured by your meter setup.  I have a lookup table in memory to convert the voltages to approx power, but a curve plotted on a bit of graph paper is just as good really.
There are also lots of decent single-rail opamps which will work from rail to rail, but it isn't really worth the effort. A rotary switch, some trimmer potentiometers and a 50 microamp meter would work well.
Neil G4DBN


Hi Neil. pic board?, a/d converters?, RS485 rx/link?  wow. I was thinking more along the lines of a Tandy volt meter in each box!

OK on graph etc. Yes, I can measure the rf out on my HP Power Meter and mark the scale on the little panel meters as you say. probably I was thinking too hard, hi. 

cheers, Ben. 


Ed G3VPF
 

Ben

I use a simple 100 micro amp meter from R-S on the SG-Lab transverters and it works fine. Usually needs about 15K in series to give Full Scale Deflection.
Ed G3VPF


From: UKMicrowaves@groups.io <UKMicrowaves@groups.io> on behalf of Neil Smith G4DBN <neil@...>
Sent: Thursday, June 4, 2020 11:22:09 AM
To: UKMicrowaves@groups.io <UKMicrowaves@groups.io>
Subject: Re: [UKMicrowaves] Getting indication of rf
 

A simple voltmeter works fine Ben, you can pull a milliamp without much impact, but a 20kohm/V movement is fine.  I put the outputs from those at the masthead into a cheap PIC board with multiple analog to digital converters and send the values back over an RS485 link, but other folks use a multicore cable and send back the analogue voltages to the shack end.

If you can borrow a calibrated power meter, you can do a rough calibration of each of the detector outputs as measured by your meter setup.  I have a lookup table in memory to convert the voltages to approx power, but a curve plotted on a bit of graph paper is just as good really.

There are also lots of decent single-rail opamps which will work from rail to rail, but it isn't really worth the effort. A rotary switch, some trimmer potentiometers and a 50 microamp meter would work well.

Neil G4DBN


On 04/06/2020 11:06, militaryoperator via groups.io wrote:
Having several transverts now and a couple of low power amps most have a built in rf o/p indicator, 1 to 3v at the max.

I was thinking of how to meter this, guess putting a simple cheap voltmeter across the pin might just load it too much so was thinking of a 741 opamp say, nice hi z i/p but needing a split rail. 

Plenty of dc to +- units on ebay so should be quite simple/cheap. 

Just wondered what others use?  I know you can use an inline directional couple, costly for a good one, but I was thinking of a unit built into each system. 

Ben G4BXD
_._


militaryoperator
 

Subject: Re: [UKMicrowaves] Getting indication of rf

Ben

I use a simple 100 micro amp meter from R-S on the SG-Lab transverters and it works fine. Usually needs about 15K in series to give Full Scale Deflection.
Ed G3VPF



Ok Ed, I'm obviously overthinking the whole thing. 

cheers, Ben


Neil Smith G4DBN
 

I think the PIC board and everything for remote sensing came to £11, bit cheaper than meters and switches.  The same unit also takes the elevation sensor and compass signal, monitors temperature and voltage and GPS lock status and it all comes back to the shack over a pair of wires, but there is "simple" and "simple".  Meters and switches and pots work fine.

Neil G4DBN

On 04/06/2020 11:34, militaryoperator via groups.io wrote:


Hi Neil. pic board?, a/d converters?, RS485 rx/link?  wow. I was thinking more along the lines of a Tandy volt meter in each box!

OK on graph etc. Yes, I can measure the rf out on my HP Power Meter and mark the scale on the little panel meters as you say. probably I was thinking too hard, hi. 

cheers, Ben. 
_._,_._,_



geoffrey pike
 

Hi Ben,
Unfortunately the only method that proves you are radiating is a dish meter!
Inline image
This is what i use on 3 and 6 cms, the pcb is a Franco Board and the rf out is fed straight into
 a zero bias diode and then to the meter. The veroboard gives +5 and -5V for the fets
cheers
Geoff
GI0GDP

Inline image


On Thursday, 4 June 2020, 11:06:59 BST, militaryoperator via groups.io <military1944@...> wrote:


Having several transverts now and a couple of low power amps most have a built in rf o/p indicator, 1 to 3v at the max.

I was thinking of how to meter this, guess putting a simple cheap voltmeter across the pin might just load it too much so was thinking of a 741 opamp say, nice hi z i/p but needing a split rail. 

Plenty of dc to +- units on ebay so should be quite simple/cheap. 

Just wondered what others use?  I know you can use an inline directional couple, costly for a good one, but I was thinking of a unit built into each system. 

Ben G4BXD


Dominique Dehays
 

Hi all
I use a lm3915 with a ledbar.
Some are homebrew but since it is available for 4 EU  , I buy ready made
73
Dom

-------- Message d'origine --------
De : Neil Smith G4DBN <neil@...>
Date : 04/06/2020 12:41 (GMT+01:00)
À : UKMicrowaves@groups.io
Objet : Re: [UKMicrowaves] Getting indication of rf

I think the PIC board and everything for remote sensing came to £11, bit cheaper than meters and switches.  The same unit also takes the elevation sensor and compass signal, monitors temperature and voltage and GPS lock status and it all comes back to the shack over a pair of wires, but there is "simple" and "simple".  Meters and switches and pots work fine.

Neil G4DBN

On 04/06/2020 11:34, militaryoperator via groups.io wrote:


Hi Neil. pic board?, a/d converters?, RS485 rx/link?  wow. I was thinking more along the lines of a Tandy volt meter in each box!

OK on graph etc. Yes, I can measure the rf out on my HP Power Meter and mark the scale on the little panel meters as you say. probably I was thinking too hard, hi. 

cheers, Ben. 
_._,_._,_



militaryoperator
 

Subject: Re: [UKMicrowaves] Getting indication of rf

Ben

I use a simple 100 micro amp meter from R-S on the SG-Lab transverters and it works fine. Usually needs about 15K in series to give Full Scale Deflection.
Ed G3VPF


Ed, 

Do you take the v from the little pins inside the SGLab box? 
if so how do you get the wires out, there being no cutout like 
on the amp boxes which are for the fan connections?

Do you put a cut in the side wall or just feed under the top cover?

Only I was hesitant to just bring wires out, I guess the pads are 
decoupled but wondered what introducing two wires extra would do, stability wise.


Ben


John Lemay
 

Ben

 

I use these LED bar-graphs and bring the DB6NT indicator voltage down to the shack in a shielded multiway cable:-

 

https://www.w6pql.com/led_bar_graph_meter.htm

 

The advantage over a moving coil meter is the speed of response.

 

John G4ZTR

 

From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Dominique Dehays
Sent: 04 June 2020 11:52
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Getting indication of rf

 

Hi all

I use a lm3915 with a ledbar.

Some are homebrew but since it is available for 4 EU  , I buy ready made

73

Dom

 

-------- Message d'origine --------

De : Neil Smith G4DBN <neil@...>

Date : 04/06/2020 12:41 (GMT+01:00)

À : UKMicrowaves@groups.io

Objet : Re: [UKMicrowaves] Getting indication of rf

 

I think the PIC board and everything for remote sensing came to £11, bit cheaper than meters and switches.  The same unit also takes the elevation sensor and compass signal, monitors temperature and voltage and GPS lock status and it all comes back to the shack over a pair of wires, but there is "simple" and "simple".  Meters and switches and pots work fine.

Neil G4DBN

On 04/06/2020 11:34, militaryoperator via groups.io wrote:

 

 

Hi Neil. pic board?, a/d converters?, RS485 rx/link?  wow. I was thinking more along the lines of a Tandy volt meter in each box!

 

OK on graph etc. Yes, I can measure the rf out on my HP Power Meter and mark the scale on the little panel meters as you say. probably I was thinking too hard, hi. 

 

cheers, Ben. 


Martin Phillips G4CIO
 

An Arduino nano plus a 16x2 LCD display can be had for less than £7. With 8 analogue inputs you could switch between them, or display all eight at three digit resolution or fewer with some extra characters. Splash out a couple of quid more for a 20x4 display and there's loads of room. You don't need much more other than maybe a few decoupling capacitors and some resistors.

Martin/

On 4/6/20 11:06 AM, militaryoperator via groups.io wrote:
Having several transverts now and a couple of low power amps most have a built in rf o/p indicator, 1 to 3v at the max.

I was thinking of how to meter this, guess putting a simple cheap voltmeter across the pin might just load it too much so was thinking of a 741 opamp say, nice hi z i/p but needing a split rail. 

Plenty of dc to +- units on ebay so should be quite simple/cheap. 

Just wondered what others use?  I know you can use an inline directional couple, costly for a good one, but I was thinking of a unit built into each system. 

Ben G4BXD



Dominique Dehays
 

Wonderfull thousands of transistors only to display power...

-------- Message d'origine --------
De : Martin Phillips G4CIO <martin@...>
Date : 04/06/2020 14:55 (GMT+01:00)
À : UKMicrowaves@groups.io
Objet : Re: [UKMicrowaves] Getting indication of rf

An Arduino nano plus a 16x2 LCD display can be had for less than £7. With 8 analogue inputs you could switch between them, or display all eight at three digit resolution or fewer with some extra characters. Splash out a couple of quid more for a 20x4 display and there's loads of room. You don't need much more other than maybe a few decoupling capacitors and some resistors.

Martin/

On 4/6/20 11:06 AM, militaryoperator via groups.io wrote:
Having several transverts now and a couple of low power amps most have a built in rf o/p indicator, 1 to 3v at the max.

I was thinking of how to meter this, guess putting a simple cheap voltmeter across the pin might just load it too much so was thinking of a 741 opamp say, nice hi z i/p but needing a split rail. 

Plenty of dc to +- units on ebay so should be quite simple/cheap. 

Just wondered what others use?  I know you can use an inline directional couple, costly for a good one, but I was thinking of a unit built into each system. 

Ben G4BXD



Martin Phillips G4CIO
 

You should see the firmware in my fridge!

On 4/6/20 2:22 PM, Dominique Dehays wrote:
Wonderfull thousands of transistors only to display power...

-------- Message d'origine --------
De : Martin Phillips G4CIO <martin@...>
Date : 04/06/2020 14:55 (GMT+01:00)
Objet : Re: [UKMicrowaves] Getting indication of rf

An Arduino nano plus a 16x2 LCD display can be had for less than £7. With 8 analogue inputs you could switch between them, or display all eight at three digit resolution or fewer with some extra characters. Splash out a couple of quid more for a 20x4 display and there's loads of room. You don't need much more other than maybe a few decoupling capacitors and some resistors.

Martin/

On 4/6/20 11:06 AM, militaryoperator via groups.io wrote:
Having several transverts now and a couple of low power amps most have a built in rf o/p indicator, 1 to 3v at the max.

I was thinking of how to meter this, guess putting a simple cheap voltmeter across the pin might just load it too much so was thinking of a 741 opamp say, nice hi z i/p but needing a split rail. 

Plenty of dc to +- units on ebay so should be quite simple/cheap. 

Just wondered what others use?  I know you can use an inline directional couple, costly for a good one, but I was thinking of a unit built into each system. 

Ben G4BXD




Andy G4JNT
 

Think of it in terms of cost and effort instead.

Transistors and anything inside an IC is only silicon - one of the most abundant elements on Earth.  ICs churned out by the quintillion each day
Compare that with the cost, setting up, delicate mechanism, easy damage of an analogue meter
Who'd ever choose the latter, again
 


On Thu, 4 Jun 2020 at 14:22, Dominique Dehays <f6dro@...> wrote:
Wonderfull thousands of transistors only to display power...

-------- Message d'origine --------
De : Martin Phillips G4CIO <martin@...>
Date : 04/06/2020 14:55 (GMT+01:00)
Objet : Re: [UKMicrowaves] Getting indication of rf

An Arduino nano plus a 16x2 LCD display can be had for less than £7. With 8 analogue inputs you could switch between them, or display all eight at three digit resolution or fewer with some extra characters. Splash out a couple of quid more for a 20x4 display and there's loads of room. You don't need much more other than maybe a few decoupling capacitors and some resistors.

Martin/

On 4/6/20 11:06 AM, militaryoperator via groups.io wrote:
Having several transverts now and a couple of low power amps most have a built in rf o/p indicator, 1 to 3v at the max.

I was thinking of how to meter this, guess putting a simple cheap voltmeter across the pin might just load it too much so was thinking of a 741 opamp say, nice hi z i/p but needing a split rail. 

Plenty of dc to +- units on ebay so should be quite simple/cheap. 

Just wondered what others use?  I know you can use an inline directional couple, costly for a good one, but I was thinking of a unit built into each system. 

Ben G4BXD



Martin Phillips G4CIO
 

...or indeed the billions of amazingly complex cellules and interconnects that go into a nice plate of steak frites!

On 4/6/20 2:41 PM, Andy G4JNT wrote:
Think of it in terms of cost and effort instead.

Transistors and anything inside an IC is only silicon - one of the most abundant elements on Earth.  ICs churned out by the quintillion each day
Compare that with the cost, setting up, delicate mechanism, easy damage of an analogue meter
Who'd ever choose the latter, again
 


On Thu, 4 Jun 2020 at 14:22, Dominique Dehays <f6dro@...> wrote:
Wonderfull thousands of transistors only to display power...

-------- Message d'origine --------
De : Martin Phillips G4CIO <martin@...>
Date : 04/06/2020 14:55 (GMT+01:00)
Objet : Re: [UKMicrowaves] Getting indication of rf

An Arduino nano plus a 16x2 LCD display can be had for less than £7. With 8 analogue inputs you could switch between them, or display all eight at three digit resolution or fewer with some extra characters. Splash out a couple of quid more for a 20x4 display and there's loads of room. You don't need much more other than maybe a few decoupling capacitors and some resistors.

Martin/

On 4/6/20 11:06 AM, militaryoperator via groups.io wrote:
Having several transverts now and a couple of low power amps most have a built in rf o/p indicator, 1 to 3v at the max.

I was thinking of how to meter this, guess putting a simple cheap voltmeter across the pin might just load it too much so was thinking of a 741 opamp say, nice hi z i/p but needing a split rail. 

Plenty of dc to +- units on ebay so should be quite simple/cheap. 

Just wondered what others use?  I know you can use an inline directional couple, costly for a good one, but I was thinking of a unit built into each system. 

Ben G4BXD




Dominique Dehays
 

Lm3915 does the same , with much less resource,  inmy opinion it is overkill to use a processor for that , but if you do other things more complex like dbn does its different
73
Dom

-------- Message d'origine --------
De : Martin Phillips G4CIO <martin@...>
Date : 04/06/2020 15:50 (GMT+01:00)
À : UKMicrowaves@groups.io
Objet : Re: [UKMicrowaves] Getting indication of rf

...or indeed the billions of amazingly complex cellules and interconnects that go into a nice plate of steak frites!

On 4/6/20 2:41 PM, Andy G4JNT wrote:
Think of it in terms of cost and effort instead.

Transistors and anything inside an IC is only silicon - one of the most abundant elements on Earth.  ICs churned out by the quintillion each day
Compare that with the cost, setting up, delicate mechanism, easy damage of an analogue meter
Who'd ever choose the latter, again
 


On Thu, 4 Jun 2020 at 14:22, Dominique Dehays <f6dro@...> wrote:
Wonderfull thousands of transistors only to display power...

-------- Message d'origine --------
De : Martin Phillips G4CIO <martin@...>
Date : 04/06/2020 14:55 (GMT+01:00)
Objet : Re: [UKMicrowaves] Getting indication of rf

An Arduino nano plus a 16x2 LCD display can be had for less than £7. With 8 analogue inputs you could switch between them, or display all eight at three digit resolution or fewer with some extra characters. Splash out a couple of quid more for a 20x4 display and there's loads of room. You don't need much more other than maybe a few decoupling capacitors and some resistors.

Martin/

On 4/6/20 11:06 AM, militaryoperator via groups.io wrote:
Having several transverts now and a couple of low power amps most have a built in rf o/p indicator, 1 to 3v at the max.

I was thinking of how to meter this, guess putting a simple cheap voltmeter across the pin might just load it too much so was thinking of a 741 opamp say, nice hi z i/p but needing a split rail. 

Plenty of dc to +- units on ebay so should be quite simple/cheap. 

Just wondered what others use?  I know you can use an inline directional couple, costly for a good one, but I was thinking of a unit built into each system. 

Ben G4BXD




militaryoperator
 

I did a check the other day now I have a nice 8Ghz 30db 50W attenuator. 
My SG Lab 23Cm trvrt and 25W amp is giving me 20W but that was on a 12v battery probably 11.?. ?Will try that again with 13.5v on it.
My SG Lab 13Cm trvrt and 20W amp gave me 22W. Its pa runs off 28v from a little dc-dc unit.
My SG Lab 9Cm trvrt gave me a max of 4W ! with the lowest I can get out of my 817. I turned it down to 2.5W though. 
I haven't tried the Kuhne 3Cm yet but its paperwork says 310mW.  Dam and blast, I have to find a 10Ghz+ rated attenuator now. 
I have a 9Cm panel ant on its way and have ordered a couple of 60Cm new Giber dishes to get ready for freedome day, hi. 

All good fun. 

Ben G4BXD



Robin Szemeti - G1YFG
 

Let me know if you want a signal on 3cm to test with, I have a 50mw personal beacon and a horn I can point your way and leave on for a day or two, on roughly 10,368.690  ... it has a keyer that sometimes even works ...

On Thu, 4 Jun 2020 at 16:59, militaryoperator via groups.io <Military1944=aol.com@groups.io> wrote:
I did a check the other day now I have a nice 8Ghz 30db 50W attenuator. 
My SG Lab 23Cm trvrt and 25W amp is giving me 20W but that was on a 12v battery probably 11.?. ?Will try that again with 13.5v on it.
My SG Lab 13Cm trvrt and 20W amp gave me 22W. Its pa runs off 28v from a little dc-dc unit.
My SG Lab 9Cm trvrt gave me a max of 4W ! with the lowest I can get out of my 817. I turned it down to 2.5W though. 
I haven't tried the Kuhne 3Cm yet but its paperwork says 310mW.  Dam and blast, I have to find a 10Ghz+ rated attenuator now. 
I have a 9Cm panel ant on its way and have ordered a couple of 60Cm new Giber dishes to get ready for freedome day, hi. 

All good fun. 

Ben G4BXD




--
Best regards,

Robin Szemeti

Redpoint Consulting Limited

E: robin@...
T: +44 (0) 1299 405028
M: +44 (0) 7971 883371

CONFIDENTIALITY NOTICE
The information contained in this e-mail is intended only for the
confidential use of the above named recipient. If you are not the
intended recipient or person responsible for delivering it to the
intended recipient, you have received this communication in error
and must not distribute or copy it.
Please accept the sender's apologies, notify the sender immediately
by return e-mail and delete this communication.

Thank you.


John E. Beech
 

Problem is that most silicon is locked up as silicon dioxide. Extracting it and purifying so that it can be made precisely impure enough to make it semi-conduct takes an enormous amount of energy and effort and exactly how robust are they? They don't like it up 'em Mr Mainwaring! Voltage spikes that is.

de John G8SEQ

-------Original Message-------
From: Andy G4JNT <andy.g4jnt@gmail.com>
To: UK Microwaves groups.io <UKMicrowaves@groups.io>
Subject: Re: [UKMicrowaves] Getting indication of rf
Sent: Jun 04 '20 14:42

Think of it in terms of cost and effort instead.

Transistors and anything inside an IC is only silicon - one of the
most abundant elements on Earth. ICs churned out by the quintillion
each day
Compare that with the cost, setting up, delicate mechanism, easy
damage of an analogue meter
Who'd ever choose the latter, again