Date   
Re: Where can I buy floater balloon?

J68HZ
 

See below in RED.

 

 

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

 

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

 

Owner – Operator

Villa Grand Piton – J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com

Like us on Facebook! facebook icon

 

Moderator – North American QRO Group at Groups.IO.

 

email:  bill@...

 

 

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of Jerry Gaffke via Groups.Io
Sent: Saturday, May 25, 2019 10:30 AM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] Where can I buy floater balloon?

 

Bill,

Excellent answer, thanks for taking the time to explain this!

As I understand it, in summary,   H2 combines with trace water vapor to form Hydronium,
and Hydronium can react with the hydrocarbons in grease.
Sounds like this could happen at room temperature and atmospheric pressure.

One often hears of the dangers of grease on oxygen regulators and valves.
I see references on the web stating one should never use grease on any regulators,
but assumed this was just generalizing the rule regarding grease around oxygen
to make it easier to follow.  But apparently this also applies to at least hydrogen.
(There are special greases not based on hydrocarbons that can be safely used.)
 
A few questions:

> Hydrogen gas leaking into external air may spontaneously ignite.

That could be nasty, we need to drill down a bit on that one.
Under exactly what conditions may it spontaneously ignite?
Does this apply when working with a cylinder of hydrogen using a regulator
to bring it down to a few psi?  40 psi? 
Or does it only apply to high pressure H2 discharges of 1000+ psi?

 

Well this depends on the activation energy for the pathway the molecules take to ignite.  It’s pretty much linear in pressure (the Arrhenius function for H2 combustion is multiplicative in H2 concentration… and concentration is proportional to pressure.  See this reference:  https://www.chemguide.co.uk/physical/basicrates/arrhenius.html).  This can occur at near zero pressure… just slower than if it’s at elevated pressure.  If it’s via a hydronium ion, it won’t work without at least trace water molecules and then temperatures above the freeze point of water.  That was probably obvious.  However, other modes that are possible by just heat or heat plus a catalyst are way more difficult to predict.  Completely dependent on the catalyst type (steel, aluminum, rare earth metal, etc.).  Here is a general discussion of catalysts:    

https://en.wikipedia.org/wiki/Catalysis  Using the right catalyst, the reaction path can take place at almost any temperature and pressure.  Therefore you may not even be safe with H2 brought through a regulator in very cool conditions.

>  You could literally walk into an area with leaking H2 and only feel heat,
>  and because H2 is generally under pressure, it can act like an invisible
>  blow-torch that an unsuspecting victim may find too late.
    

Can we assume that if our H2 is not more than 40 psi above ambient pressure
and has no significant oxygen in the mix, the danger is minimal?

At 40 psi, is there any danger in using plastics such as polyethylene, PVC,
or polycarbonate to contain H2?

 

I would say the danger is minimal without any O2 or water.  Also, blowtorching occurs with elevated pressure H2 only…. The same mechanics as you would use for a butane, propane, or acetylene torch.  A few pounds won’t mean much.. but once you get up two atmospheres (15 PSIG), torching will begin and just get worse with pressure.  PVC is interesting here… I don’t know if the matrix is small enough to contain H2 or not… the thing to investigate here is the average bonded structure size versus the diameter of the H2 molecule.  My wild guess is that it will not contain H2… and may replace some bonds causing it to break over time.  Mylar actually does contain H2.  Evidently the bonded structure of Mylar is smaller than H2.

 

These are quick answers as the family is calling to go out on this beautiful holiday weekend!  Enjoy.

Jerry, KE7ER


On Thu, May 23, 2019 at 09:46 AM, J68HZ wrote:

Just back from traveling so now I can answer this…  Please excuse and delete if this topic is o no value to you…

 

There are several mechanisms by which Hydrogen (H2) can react and the mere reaction by one mechanism can avalanche into others at a rapid pace.  H2 is at the top of the list of what is called Brostead Lowry acidic proton donors… so if there any trace of moisture nearby, H2 + 2H2O forms 2H3O+, called Hydronium, which is an extremely reactive acid.  It’s formation is catalyzed (meaning the activation energy for formation of the specie is drastically lowered by) metals; noble metals give the lowest activation energy…(this is all equationally captured by Arrhenius rate chemistry that I will not go into here)… but aluminum and steel are still fine catalysts that can lower the temperature of formation from about 500C as required to happen spontaneously, to about 3C with a suitable catalyst.  Once formed the Hydronium will attack anything neutral or negatively charged with enormous energy release… including oxygen in the air… which is electron rich. (nb.  Refineries use metals like platinum, nickel, and rhodium on supports like diatoms as a catalysts in their unit ops, but control the reaction rate with temperature, pressure, and reacting reagent concentration).  Pure hydrogen burning in air emit ONLY ultraviolet waves (non-visible to the human eye), and thus ultraviolet glasses or some sort of ultra violet detectors are used to tell if there is danger in commercial plants.  You could literally walk into an area with leaking H2 and only feel heat, and because H2 is generally under pressure, it can act like an invisible blow-torch that an unsuspecting victim may find too late.

 

So how does this self-ignite with hydrocarbons?  A hydronium ion is constantly seeking sources of electrons to neutralize.  Carbon rich hydrocarbon chains like grease will make an ideal source of fuel for such molecules which react could violently, but most often is controlled by diffusion of Hydronium in air.  In this case, flames from the burning hydrocarbons are blue (smaller molecules like butane) to yellow in color (pentane and to decane) or even black (C10+).  The reaction needs no catalyst because the activation energy is negative signed at ambient temperatures and pressures.  H3O+ and HxCy… form H2O plus a number of fractional hydrocarbons from the burning process.

 

An additional note (from other sources);  H2 can dissolve in many metals, leak out, and have adverse effects on them, like hydrogen embrittlement that leads to cracks and explosions. Hydrogen gas leaking into external air may spontaneously ignite. Moreover, hydrogen fire, while being extremely hot, is almost invisible, and thus can lead to accidental burns

 

Cite:

1.      "Liquid Hydrogen MSDS" (PDF). Praxair, Inc. September 2004. Archived from the original (PDF) on 27 May 2008. Retrieved 16 April 2008.

2.     "'Bugs' and hydrogen embrittlement". Science News. 128 (3): 41. 20 July 1985. doi:10.2307/3970088. JSTOR 3970088.

3.     Hayes, B. "Union Oil Amine Absorber Tower". TWI. Archived from the original on 20 November 2008. Retrieved 29 January 2010.

4.     Walker, James L.; Waltrip, John S.; Zanker, Adam (1988). John J. McKetta; William Aaron Cunningham (eds.). Lactic acid to magnesium supply-demand relationships. Encyclopedia of Chemical Processing and Design. 28. New York: Dekker. p. 186. ISBN 978-0824724788. Retrieved 20 May 2015.

 


Virus-free. www.avg.com

Re: Minimally modified QCX-17 has been heard on 80, 60, 40, 30, 20, 17, 15, 12, 10m this UTC day !

Steve Johnston
 

Michael -

I doubt it is practical to interface the Ultimate a Relay Switched LPF kit to automatically choose the correct filter for the band in use, but it would be easy to connect a five position rotary switch to manually select the correct filter on the relay board.  Simple, elegant and inexpensive...

Steve WD8DAS

Re: Wspr problem ultimate 3/qrss/wspr #u3s

M0RON
 

Hi Erik, 
Glad it's sorted, the frequencies in the manual are good apart from 80m, this should be, 3570000-3570200.
Andy
--
The universe is made up of Protons, Neutrons, Electrons but contains only one M0RON.

Is the CLK0 pin of si5361a supposedly up to driving an HEF4013 direct?

Chris Wilson
 

Chris Wilson 25 May 2019


I have been using my U3S as an exciter for LF and my friend uses his
in the same way on MF. We take the CLK0 pin of the si5351a via either
a 100nF or 220nF poly cap respectively direct to the input pin of an HEF4013
flip flop, which in turn is capacitively coupled via 100 or 220nF poly
caps to the Class D amp FET driver IC(s). I have now been told the
output of the si5351a is too low a voltage to drive from directly and
we should use a level converter to get 5V out. What are your thoughts
on this please? It appeared to work OK as is... Thanks. The suggested
level converter is shown in the second schematic on this page.

http://www.hobbytronics.co.uk/mosfet-voltage-level-converter

If the feeling is this is desirable can we use a BS170 instead of the
2N7000 FET?

I have another Class D amp question that may well be right up
Allison's street, but I'll create a separate (slightly off topic but
possibly interesting to the group) post.



--

2E0ILY
Best regards,
Chris mailto:chris@...



--
Best regards, Chris Wilson (2E0ILY)

Re: Is the CLK0 pin of si5361a supposedly up to driving an HEF4013 direct?

@CurtisM
 

Chris

Your results seem to indicate that you have a good solution,  possibly its doing the same function. If you have a scope, measure it. If not, your output power tells the story.

BS170 are electrically similar to 2n7000, and they are preferred since bs170 can handle higher dissipation. 

Curt

Re: Minimally modified QCX-17 has been heard on 80, 60, 40, 30, 20, 17, 15, 12, 10m this UTC day !

geoff M0ORE
 

I use a very simple device called PIC-A Switch which was an article in RadCom in Sept 2001. It uses a PIC to measure the frequency and then switches the filter appropriate to that frequency. It can be used to switch anything you like and can be powered via the coax if you want to switch aerials.

I don't know if it is still available on the web though.

Geoff

On 25/05/2019 17:47, Steve Johnston via Groups.Io wrote:
Michael -

I doubt it is practical to interface the Ultimate a Relay Switched LPF kit to automatically choose the correct filter for the band in use, but it would be easy to connect a five position rotary switch to manually select the correct filter on the relay board.  Simple, elegant and inexpensive...

Steve WD8DAS

Re: Is the CLK0 pin of si5361a supposedly up to driving an HEF4013 direct?

Chris Wilson
 

Hello wb8yyy,

Saturday, May 25, 2019

Is the gate capacitance too high for up to 950kHz driven by the
si5351a? The U3S will be in X2 mode for driving a Class D amp.Just a
thought, and thank you for your very fast reply. I see mention of
SN74AHCT1G125 when Googling which might be a better device, albeit I
would need a breakout board tto use one


Best regards,
Chris 2E0ILY mailto:chris@...


wvGI> Chris

wvGI> Your results seem to indicate that you have a good solution,
wvGI> possibly its doing the same function. If you have a scope,
wvGI> measure it. If not, your output power tells the story.

wvGI> BS170 are electrically similar to 2n7000, and they are
wvGI> preferred since bs170 can handle higher dissipation.

wvGI> Curt
wvGI>



--
Best regards, Chris Wilson (2E0ILY)

Re: Is the CLK0 pin of si5361a supposedly up to driving an HEF4013 direct?

Arv Evans
 

Chris

It depends...
Since you are driving a digital circuit the real requirement is to make that circuit toggle between
0V and 5V.  It it does that already then there is no problem.  If the digital circuit is biased at 2.5V
then only a few millivolts are needed to drive it between 0V and 5V output. 

Arv
_._


On Sat, May 25, 2019 at 11:58 AM Chris Wilson <chris@...> wrote:
Chris Wilson 25 May 2019


I  have  been using my U3S as an exciter for LF and my friend uses his
in  the same way on MF. We take the CLK0 pin of the si5351a via either
a  100nF  or  220nF poly cap respectively direct to the input pin of an HEF4013
flip flop, which in turn is capacitively coupled via 100 or 220nF poly
caps  to  the  Class D amp FET driver IC(s).  I have now been told the
output of the si5351a is too low a voltage to drive from directly and
we  should  use a level converter to get 5V out. What are your thoughts
on  this please? It appeared to work OK as is... Thanks. The suggested
level converter is shown in the second schematic on this page.

http://www.hobbytronics.co.uk/mosfet-voltage-level-converter

If  the  feeling is this is desirable can we use a BS170 instead of the
2N7000 FET?

I  have  another  Class  D  amp  question  that  may  well be right up
Allison's  street,  but I'll create a separate (slightly off topic but
possibly interesting to the group) post.



--

 2E0ILY
Best regards,
 Chris                            mailto:chris@...



--
Best regards, Chris Wilson (2E0ILY)



QCX Message Trigger

n3fel@aol.com
 

I've programmed my message in 2.1 Messages but can't find in the manual how to initiate a message.  Please advise.
--
Howard, n3fel

Re: 40M QCX 14.8V on Voltage Regulator Output

James Daldry W4JED
 

Hi, Mike

Oh - is that why it's getting dark and I can only see my shoes? And said shoes are getting wet? And when I look up I can only see a round patch of sky? Thanks for the info. Uh, could somebody pass me a ladder?

73

Jim W4JED

On 5/25/19 9:47 AM, Mike wrote:
James,
When you realise that you are digging a hole for yourself, its generally a
good idea to stop digging.
But to realise that there is a hole requires knowledge

On 25 May 2019 at 9:22, James Daldry W4JED wrote:

Hi, Fred

I read the symptom description and looked at the picture. I know it's
highly unlikely that there's anything major wrong. My first guess is to
look at the microprocessor socket and make sure that all the pins went
into the socket, that one isn't outside the socket or buckled. Not only
been and done, but proudly wear the T-shirt. BUT-

The fact that our intrepid Tech managed to read a negative voltage in a
system with only 1, positive, power supply indicates to me that he
probably couldn't get light out of a flashlight bulb, a piece of wire,
and a "D" cell. This is not intended as a put-down. We aren't taught
this stuff in school.  To trouble-shoot a circuit you first have to know
what a circuit is. I've had, on multiple occasions, to fix the results
of someone without quite enough skill attempting a repair. The things
that make this an amazingly high-performance radio in a little package
make it an amazingly difficult thing to repair without half destroying
the board. You could write a book on how to trouble-shoot and repair it.
Our Tech doesn't own that book.

So - getting a person that has a job, that has to eat and sleep,
probably has to interact with family, and at the same time go from
square zero to apprentice electronic technician is going to take a
substantial amount of time. Probably years. In the process things will
get burnt by soldering equipment, parts will get hooked up wrong and
destroyed, probes will slip and gates punctured. That's life.

I just wanted to get an almost-a-radio converted into a radio in the
minimum amount of time, with minimum destruction.

Jim W4JED

On 5/24/19 8:11 PM, Fred Lodden wrote:
Jim,
You might want to tone it down a little.
The original poster has been licensed with a Technician class licence
for less than 20 days. He would be new to the hobby. On the steep part
of the learning curve. He does not have 50 years of tech experience
under his belt.
Got himself a low cost CW transceiver kit, put it together (probably
with great excitement) turned it on and did not see what he expected.
He seeks help from the group.
I find that his report of the issues was very good. A couple of photos
and some voltages from various parts of the circuit. So much more
information than many trouble reports provide.
I still think that there might not be any real big problem with the unit.
Perhaps it is just an unsoldered lead or a cold joint somewhere.
The fact that the LCD backlight comes on says that there is some
voltage somewhere, and it is not reverse polarity otherwise the LCD
backlight LED would not come on at all. From the photos the power
connections appear to be correct. Measuring voltages around the 7805
regulator (with reference to ground) will further help to diagnose any
issue.
I seriously hope that he is not deterred and persists with the
diagnosis, and the hobby.
73 Fred VK2EFL


Re: QCX Message Trigger

Alan de G1FXB
 

Howard,
Sending from message positions 1- 12?
is Page 77 of the current manual informative??


Alan


On 25/05/2019 20:19, n3fel@... via Groups.Io wrote:
I've programmed my message in 2.1 Messages but can't find in the manual how to initiate a message.?? Please advise.
--
Howard, n3fel

Re: Where can I buy floater balloon?

Jerry Gaffke
 

Bill,

Again excellent!
Thanks for the response.

My take-away is that one should carefully follow recommended procedures
when working with cylinders of high pressure H2 and associated regulators.
If messing around with balloons and electrolysis and such, do it outside
(or a room with a hole in the roof) and keep working pressures to a minimum. 

With that sorted out, I should probably move on to
thinking about how I store the lawnmower gas.

Jerry, KE7ER



On Sat, May 25, 2019 at 09:34 AM, J68HZ wrote:

See below in RED.

 

 

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

 

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

 

Owner – Operator

Villa Grand Piton – J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com

Like us on Facebook! facebook icon

 

Moderator – North American QRO Group at Groups.IO.

 

email:  bill@...

 

 

Hide quoted text

 

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of Jerry Gaffke via Groups.Io
Sent: Saturday, May 25, 2019 10:30 AM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] Where can I buy floater balloon?

 

Bill,

Excellent answer, thanks for taking the time to explain this!

As I understand it, in summary,   H2 combines with trace water vapor to form Hydronium,
and Hydronium can react with the hydrocarbons in grease.
Sounds like this could happen at room temperature and atmospheric pressure.

One often hears of the dangers of grease on oxygen regulators and valves.
I see references on the web stating one should never use grease on any regulators,
but assumed this was just generalizing the rule regarding grease around oxygen
to make it easier to follow.  But apparently this also applies to at least hydrogen.
(There are special greases not based on hydrocarbons that can be safely used.)
 
A few questions:

> Hydrogen gas leaking into external air may spontaneously ignite.

That could be nasty, we need to drill down a bit on that one.
Under exactly what conditions may it spontaneously ignite?
Does this apply when working with a cylinder of hydrogen using a regulator
to bring it down to a few psi?  40 psi? 
Or does it only apply to high pressure H2 discharges of 1000+ psi?

 

Well this depends on the activation energy for the pathway the molecules take to ignite.  It’s pretty much linear in pressure (the Arrhenius function for H2 combustion is multiplicative in H2 concentration… and concentration is proportional to pressure.  See this reference:  https://www.chemguide.co.uk/physical/basicrates/arrhenius.html).  This can occur at near zero pressure… just slower than if it’s at elevated pressure.  If it’s via a hydronium ion, it won’t work without at least trace water molecules and then temperatures above the freeze point of water.  That was probably obvious.  However, other modes that are possible by just heat or heat plus a catalyst are way more difficult to predict.  Completely dependent on the catalyst type (steel, aluminum, rare earth metal, etc.).  Here is a general discussion of catalysts:    

https://en.wikipedia.org/wiki/Catalysis  Using the right catalyst, the reaction path can take place at almost any temperature and pressure.  Therefore you may not even be safe with H2 brought through a regulator in very cool conditions.

>  You could literally walk into an area with leaking H2 and only feel heat,
>  and because H2 is generally under pressure, it can act like an invisible
>  blow-torch that an unsuspecting victim may find too late.
    

Can we assume that if our H2 is not more than 40 psi above ambient pressure
and has no significant oxygen in the mix, the danger is minimal?

At 40 psi, is there any danger in using plastics such as polyethylene, PVC,
or polycarbonate to contain H2?

 

I would say the danger is minimal without any O2 or water.  Also, blowtorching occurs with elevated pressure H2 only…. The same mechanics as you would use for a butane, propane, or acetylene torch.  A few pounds won’t mean much.. but once you get up two atmospheres (15 PSIG), torching will begin and just get worse with pressure.  PVC is interesting here… I don’t know if the matrix is small enough to contain H2 or not… the thing to investigate here is the average bonded structure size versus the diameter of the H2 molecule.  My wild guess is that it will not contain H2… and may replace some bonds causing it to break over time.  Mylar actually does contain H2.  Evidently the bonded structure of Mylar is smaller than H2.

 

These are quick answers as the family is calling to go out on this beautiful holiday weekend!  Enjoy.

Jerry, KE7ER


On Thu, May 23, 2019 at 09:46 AM, J68HZ wrote:

Just back from traveling so now I can answer this…  Please excuse and delete if this topic is o no value to you…

 

There are several mechanisms by which Hydrogen (H2) can react and the mere reaction by one mechanism can avalanche into others at a rapid pace.  H2 is at the top of the list of what is called Brostead Lowry acidic proton donors… so if there any trace of moisture nearby, H2 + 2H2O forms 2H3O+, called Hydronium, which is an extremely reactive acid.  It’s formation is catalyzed (meaning the activation energy for formation of the specie is drastically lowered by) metals; noble metals give the lowest activation energy…(this is all equationally captured by Arrhenius rate chemistry that I will not go into here)… but aluminum and steel are still fine catalysts that can lower the temperature of formation from about 500C as required to happen spontaneously, to about 3C with a suitable catalyst.  Once formed the Hydronium will attack anything neutral or negatively charged with enormous energy release… including oxygen in the air… which is electron rich. (nb.  Refineries use metals like platinum, nickel, and rhodium on supports like diatoms as a catalysts in their unit ops, but control the reaction rate with temperature, pressure, and reacting reagent concentration).  Pure hydrogen burning in air emit ONLY ultraviolet waves (non-visible to the human eye), and thus ultraviolet glasses or some sort of ultra violet detectors are used to tell if there is danger in commercial plants.  You could literally walk into an area with leaking H2 and only feel heat, and because H2 is generally under pressure, it can act like an invisible blow-torch that an unsuspecting victim may find too late.

 

So how does this self-ignite with hydrocarbons?  A hydronium ion is constantly seeking sources of electrons to neutralize.  Carbon rich hydrocarbon chains like grease will make an ideal source of fuel for such molecules which react could violently, but most often is controlled by diffusion of Hydronium in air.  In this case, flames from the burning hydrocarbons are blue (smaller molecules like butane) to yellow in color (pentane and to decane) or even black (C10+).  The reaction needs no catalyst because the activation energy is negative signed at ambient temperatures and pressures.  H3O+ and HxCy… form H2O plus a number of fractional hydrocarbons from the burning process.

 

An additional note (from other sources);  H2 can dissolve in many metals, leak out, and have adverse effects on them, like hydrogen embrittlement that leads to cracks and explosions. Hydrogen gas leaking into external air may spontaneously ignite. Moreover, hydrogen fire, while being extremely hot, is almost invisible, and thus can lead to accidental burns

 

Cite:

1.      "Liquid Hydrogen MSDS" (PDF). Praxair, Inc. September 2004. Archived from the original (PDF) on 27 May 2008. Retrieved 16 April 2008.

2.     "'Bugs' and hydrogen embrittlement". Science News. 128 (3): 41. 20 July 1985. doi:10.2307/3970088. JSTOR 3970088.

3.     Hayes, B. "Union Oil Amine Absorber Tower". TWI. Archived from the original on 20 November 2008. Retrieved 29 January 2010.

4.     Walker, James L.; Waltrip, John S.; Zanker, Adam (1988). John J. McKetta; William Aaron Cunningham (eds.). Lactic acid to magnesium supply-demand relationships. Encyclopedia of Chemical Processing and Design. 28. New York: Dekker. p. 186. ISBN 978-0824724788. Retrieved 20 May 2015.

 

 


Virus-free. www.avg.com

Re: QCX Message Trigger

n3fel@aol.com
 

Wish it was that obvious but I've read that section a dozen times.  All I find there is how to enter and edit messages.  Not sending messages.  Please advise actual key strokes. Thanks!  Howard, n3fel

Re: QCX Message Trigger

David
 

Hi Howard, page 140 operation reference "cheat sheet".
Encoder dbl or long press: choose stored message. Then Left to send repeatedly, Centre to send once or Right to cancel.
73 Dave M3PMG

Re: QCX Message Trigger

Dan Pflugrath
 

Check out the cheat sheet, next to last page of the manual.  A long press of the tuning control allows you to select and send a message.

Dan KA7GPP

 

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of Alan de G1FXB via Groups.Io
Sent: Saturday, May 25, 2019 1:07 PM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] QCX Message Trigger

 

Howard,
Sending from message positions 1- 12?
is Page 77 of the current manual informative??

 

Alan

 

On 25/05/2019 20:19, n3fel@... via Groups.Io wrote:

I've programmed my message in 2.1 Messages but can't find in the manual how to initiate a message.?? Please advise.
--
Howard, n3fel



Re: QCX Message Trigger

n3fel@aol.com
 

Thanks all!  Working well.  Howard, n3fel

10 Watt HF Linear PA

K2DB Paul Mackanos
 

In preparation of buying the upcoming qsx, I purchased and just finished the amplifier. Now I will put it in the drawer and wait for the release of the qsx. It was a great little kit to build.
73 Paul K2DB

Re: Minimally modified QCX-17 has been heard on 80, 60, 40, 30, 20, 17, 15, 12, 10m this UTC day !

Michael Sharp
 

OK, but what about the notorious T1 toroid? If one is going to mod their QCX as a Multiband QCX, should you initially wind T1 for 80m? (I’m thinking harmonics, like 40, 20, 10, etc...)

-Michael / KD9MED

Re: Where can I buy floater balloon?

Mikael Dagman
 

The balloon was filled and stored in the same room in the house.

There is some unknown factors in play here, probably the material change characteristics at altitude, be it temperature, pressure, lack of moisture and that the He have expanded and is now filling the whole envelope and just not concentrated to the top part of the balloon as it is a ground level.

So anyway, if you going to fly fill just before lauch and not a day or two before.

/Mikael

Re: Where can I buy floater balloon?

J68HZ
 

Some science here.

 

Balloons lift (are buoyant) on the basis of Archimedes principle (cite: https://en.wikipedia.org/wiki/Archimedes%27_principle) which has the corollary that less dense material will rise above more dense material.  It’s the same principle that causes oil to float on water… and with gases, it causes the lightest one (less dense gas) to rise above a heavier gas.  Even hot air will rise above ambient air just because the density of the air in the balloon is less than that of ambient air.

 

In the buoyancy calculation, the force of lift is proportional to the relative differences between the densities of the gases… and in this case, that would be H2 (or whatever the lift gas is) and air.  Now, the density of a gas can be calculated from the ideal gas law… P*V=n*R*T, or rewriting, P=p*R*T/Mw where “p” is the gas density and “Mw” is the molecular weight of the gas.  The ratio for lift is then [P1*Mw1/T1]/[P2*Mw2/T2].  Plug in the numbers and you can determine where the lift will cease.  Of course you need to do a force balance for the real lift and include the weight of the payload and the balloon.

 

The point here is that the buoyancy can vary based on the ambient temperature and pressure… even of the temperature and pressure of the gas in the balloon stays constant.

 

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

 

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

 

Owner – Operator

Villa Grand Piton – J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com

Like us on Facebook! facebook icon

 

Moderator – North American QRO Group at Groups.IO.

 

email:  bill@...

 

 

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of Mikael Dagman
Sent: Sunday, May 26, 2019 1:28 AM
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] Where can I buy floater balloon?

 

The balloon was filled and stored in the same room in the house.

There is some unknown factors in play here, probably the material change characteristics at altitude, be it temperature, pressure, lack of moisture and that the He have expanded and is now filling the whole envelope and just not concentrated to the top part of the balloon as it is a ground level.

So anyway, if you going to fly fill just before lauch and not a day or two before.

/Mikael


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