Date   

Re: Failed IRF510 in BJ

Jim, N5IB
 

I forgot to address the last question.

Ought not be a one-time protection.
The IRF510 is rated 100V Drain-Source breakdown, and the gate leakage is specified at a up to +/- 20V Gate to Source. So "normal" reverse polarity (due to a short circuit between the headphones - hi) shouldn't damage it.

Jim, N5IB


---In 4sqrp@..., <djwilcox01@...> wrote :
 Does reverse voltage cause the IRF510 to short out but still pass voltage when the voltage polarity is corrected? It is a ONE TIME protection? Important to know for all of us who might use this form of protection in the future.


Re: Failed IRF510 in BJ

Jim, N5IB
 

Very likely not a "dead short" failure. The gate structure isn't suposed to pass current at all, so even if it's compromised it may end up being a "lower" resistance path. To make a non-heatsinked TO-220 really hot doesn't take much current. The IRF510 junction-to-ambient thermal resistance is spec'ed at 62 deg C per W. So a couple watts gets you better than a 100 dec C rise. And 2 W at 12 V is just 170 mA or so. That would be some 4 amp-hr per day drained from your battery.

Now, that doesn't take into account heat that is transferred away via the soldered pins, but even if that reduced the temperature rise by a factor of 10, you could get a 50 deg C rise above ambient (90 F - pretty hot to touch) with 8 W. That would be less than 700 mA and wouldn't blow the 1 A fuse.

It would be an interesting and useful interesting data point if you could do a quick measurement of that current before you make the repairs, just to test the above theory.

In normal operation the voltage drop, Source to Drain, is so small with the device fully turned on that the power dissipation is very small as well. With an on-resistance of less than half an ohm, the 750 mA Tx current will cause less than 0.4V drop, and dissipate less than 300 mW. And, in theory, there's no current at all Gate to Source.

Proverb ---  "In theory, there is no difference between theory and practice, but in practice ....."

Jim, N5IB


Failed IRF510 in BJ

David Wilcox
 

Thanks for the replies. A few questions.

Since the IRF510 failed into short mode why didn't it blow the 1 amp fuse in the line? The BJ was connected to a large JetSki (like a motorcycle) battery that I use in the shack in the winter to keep it active for the next season.

Why did it continue to pass voltage to the BJ if it was shorted? A friend of mine sent me a couple of articles as to why mosfets fail but they didn't address these issues. It sure got hot though but no smoke let out. I discovered it being hot by mistake touching it while looking for bad solder joints.

I touched the case of my MFJ 969 antenna tuner before and during handling the IRF510 instead of wearing my wrist strap. My feet are on the metal base of an elevated architects chair and not rubbing on the carpet. Humidifier on.

I will be up front with every one here. I did reverse the voltage by mistake a few days before this all happened. No smoke. Short prayer of thanks for those wise enough to protect the elderly and stupid. Then went on to use the BJ and have fun. Does reverse voltage cause the IRF510 to short out but still pass voltage when the voltage polarity is corrected? It is a ONE TIME protection? Important to know for all of us who might use this form of protection in the future.

Dave K8WPE


Re: Member List

J.K. Wright
 

Been to Grayling once- left town in a canoe and went to Oscoda!!! Great area, but a bit remote. Nowhere to charge the batteries:)

On Feb 8, 2017 10:30 PM, "Bill Cromwell wrcromwell@... [4sqrp]" <4sqrp@...> wrote:
 

Here ya go...

Move OzarkCon to Grayling Michigan!

73,

Bill KU8H

On 02/08/2017 09:07 PM, David Martin davemrtn@... [4sqrp] wrote:
>
> That would be a 'historic' OzarkCon event !
>
> How do we make it happen !!! ????
>
> David Martin - NA1MH <https://www.qrz.com/lookup/na1mh> - Mountain
> Home, Ar. -----------------------------------------
> On 2/8/2017 19:41, ktalbott ktalbott@... [4sqrp] wrote:
>> It would be interesting to see them all at Ozarkcon!
>> Ken ke4rg
>>
>>
>> Sent from Samsung Mobile
>>
>>
>>
>> -------- Original message --------
>> From: "Johnny Matlock jomatlock@... [4sqrp]"
>> <4sqrp@...>
>> Date: 02/08/2017 5:54 PM (GMT-05:00)
>> To: 4sqrp@...,davemrtn <davemrtn@...>
>> Subject: Re: [4sqrp] Member List
>>
>>
>> Look out SKCC here we come!!
>> Thanks for the info Dave
>> Johnny AC0BQ
>> On Wed, Feb 8, 2017 at 1:40 PM davemrtn davemrtn@...
>> <mailto:davemrtn@centurytel.net> [4sqrp] <4sqrp@...
>> 4sqrp@...>> wrote:
>>
>> WOW !!!
>>
>> I see the 4SQRP member count very recently surpassed 1300.
>>
>> Way to go 4SQRP team and members.
>>
>> David -NA1MH
>>
>>
>>
>> Sent from my Verizon, Samsung Galaxy smartphone
>>
>> --
>> Sent from Gmail Mobile
>
>

--
bark less - wag more


Re: Member List

Ken Talbott
 

Shhhh!  Don’t tell them about the great door prizes at the banquet.  Who wouldn’t drive 10 or 12 hours for a new rig?

Ken ke4rg

 

From: David Martin [mailto:davemrtn@...]
Sent: Wednesday, February 8, 2017 9:08 PM
To: 4sqrp@...; ktalbott
Subject: Re: [4sqrp] Member List

 

That would be a 'historic' OzarkCon event !

How do we make it happen !!!   ????

David Martin - NA1MH - Mountain Home, Ar. -----------------------------------------

On 2/8/2017 19:41, ktalbott ktalbott@... [4sqrp] wrote:

 

It would be interesting to see them all at Ozarkcon!

Ken ke4rg

 

 

Sent from Samsung Mobile




-------- Original message --------
From: "Johnny Matlock jomatlock@... [4sqrp]" <4sqrp@...>
Date: 02/08/2017 5:54 PM (GMT-05:00)
To: 4sqrp@...,davemrtn
Subject: Re: [4sqrp] Member List


 

Look out SKCC here we come!!

Thanks for the info Dave

Johnny AC0BQ 

On Wed, Feb 8, 2017 at 1:40 PM davemrtn davemrtn@... [4sqrp] <4sqrp@...> wrote:

 

WOW !!!

 

I see the 4SQRP member count very recently surpassed 1300.

 

Way to go 4SQRP team and members.

 

David -NA1MH

 

 

 

Sent from my Verizon, Samsung Galaxy smartphone

--

Sent from Gmail Mobile

 


Re: Member List

davemrtn
 

In fact if someone wants to see where people have come from to attend OzarkCon, just look at this web page.......


www.ozarkcon.com/attendanceHistory



David Martin - NA1MH - Mountain Home, Ar. -----------------------------------------

On 2/8/2017 22:01, Tim McDonough N9PUZ tim.n9puz@... [4sqrp] wrote:
 

There are people who come to OzarkCon from Michigan now! Why move?

:-) Tim N9PUZ

On 2/8/2017 9:28 PM, Bill Cromwell wrcromwell@... [4sqrp] wrote:
>
>
> Here ya go...
>
> Move OzarkCon to Grayling Michigan!
>
> 73,
>
> Bill KU8H
>
> On 02/08/2017 09:07 PM, David Martin davemrtn@... [4sqrp] wrote:
>>
>> That would be a 'historic' OzarkCon event !
>>
>> How do we make it happen !!! ????
>>
>> David Martin - NA1MH - Mountain
>> Home, Ar. -----------------------------------------
>> On 2/8/2017 19:41, ktalbott ktalbott@... [4sqrp] wrote:
>>> It would be interesting to see them all at Ozarkcon!
>>> Ken ke4rg
>>>
>>>
>>> Sent from Samsung Mobile
>>>
>>>
>>>
>>> -------- Original message --------
>>> From: "Johnny Matlock jomatlock@... [4sqrp]"
>>> <4sqrp@...>
>>> Date: 02/08/2017 5:54 PM (GMT-05:00)
>>> To: 4sqrp@...,davemrtn
>>> Subject: Re: [4sqrp] Member List
>>>
>>>
>>> Look out SKCC here we come!!
>>> Thanks for the info Dave
>>> Johnny AC0BQ
>>> On Wed, Feb 8, 2017 at 1:40 PM davemrtn davemrtn@...
>>> [4sqrp] <4sqrp@...
>>> > wrote:
>>>
>>> WOW !!!
>>>
>>> I see the 4SQRP member count very recently surpassed 1300.
>>>
>>> Way to go 4SQRP team and members.
>>>
>>> David -NA1MH
>>>
>>>
>>>
>>> Sent from my Verizon, Samsung Galaxy smartphone
>>>
>>> --
>>> Sent from Gmail Mobile
>>
>>
>
> --
> bark less - wag more
>
>



Re: Member List

Tim N9PUZ
 

There are people who come to OzarkCon from Michigan now! Why move?

:-) Tim N9PUZ

On 2/8/2017 9:28 PM, Bill Cromwell wrcromwell@gmail.com [4sqrp] wrote:


Here ya go...

Move OzarkCon to Grayling Michigan!

73,

Bill KU8H

On 02/08/2017 09:07 PM, David Martin davemrtn@centurytel.net [4sqrp] wrote:

That would be a 'historic' OzarkCon event !

How do we make it happen !!! ????

David Martin - NA1MH <https://www.qrz.com/lookup/na1mh> - Mountain
Home, Ar. -----------------------------------------
On 2/8/2017 19:41, ktalbott ktalbott@gamewood.net [4sqrp] wrote:
It would be interesting to see them all at Ozarkcon!
Ken ke4rg


Sent from Samsung Mobile



-------- Original message --------
From: "Johnny Matlock jomatlock@gmail.com [4sqrp]"
<4sqrp@yahoogroups.com>
Date: 02/08/2017 5:54 PM (GMT-05:00)
To: 4sqrp@yahoogroups.com,davemrtn <davemrtn@centurytel.net>
Subject: Re: [4sqrp] Member List


Look out SKCC here we come!!
Thanks for the info Dave
Johnny AC0BQ
On Wed, Feb 8, 2017 at 1:40 PM davemrtn davemrtn@centurytel.net
<mailto:davemrtn@centurytel.net> [4sqrp] <4sqrp@yahoogroups.com
<mailto:4sqrp@yahoogroups.com>> wrote:

WOW !!!

I see the 4SQRP member count very recently surpassed 1300.

Way to go 4SQRP team and members.

David -NA1MH



Sent from my Verizon, Samsung Galaxy smartphone

--
Sent from Gmail Mobile
--
bark less - wag more


Re: Member List

Bill Cromwell
 

Here ya go...

Move OzarkCon to Grayling Michigan!

73,

Bill KU8H

On 02/08/2017 09:07 PM, David Martin davemrtn@centurytel.net [4sqrp] wrote:

That would be a 'historic' OzarkCon event !

How do we make it happen !!! ????

David Martin - NA1MH <https://www.qrz.com/lookup/na1mh> - Mountain Home, Ar. -----------------------------------------
On 2/8/2017 19:41, ktalbott ktalbott@gamewood.net [4sqrp] wrote:
It would be interesting to see them all at Ozarkcon!
Ken ke4rg


Sent from Samsung Mobile



-------- Original message --------
From: "Johnny Matlock jomatlock@gmail.com [4sqrp]" <4sqrp@yahoogroups.com>
Date: 02/08/2017 5:54 PM (GMT-05:00)
To: 4sqrp@yahoogroups.com,davemrtn <davemrtn@centurytel.net>
Subject: Re: [4sqrp] Member List


Look out SKCC here we come!!
Thanks for the info Dave
Johnny AC0BQ
On Wed, Feb 8, 2017 at 1:40 PM davemrtn davemrtn@centurytel.net <mailto:davemrtn@centurytel.net> [4sqrp] <4sqrp@yahoogroups.com <mailto:4sqrp@yahoogroups.com>> wrote:

WOW !!!

I see the 4SQRP member count very recently surpassed 1300.

Way to go 4SQRP team and members.

David -NA1MH



Sent from my Verizon, Samsung Galaxy smartphone

--
Sent from Gmail Mobile
--
bark less - wag more


Re: 43SQRP net

Paul Smith
 

Thanks for the report Charles,

I was getting some thunderstorm static as well. not sure from where but it was there

de Paul N0NBD


Sent from Outlook




From: Charles Moizeau
Sent: Thursday, February 9, 2017 2:13 AM
To: 4sqrp@...; Paul Smith
Subject: Re: 43SQRP net
 

Condx in NJ are very noisy with a major snow storm arriving here in six hours.  At 0130Z-ish I heard Wayne at 449.  Normally WA9PWP is the sig champ, but I didn't hear him.  Surprisingly, the other Paul, N0NBD, was nearly 569.


Charles, W2SH 






From: 4sqrp@... <4sqrp@...> on behalf of Paul Smith psmith61@... [4sqrp] <4sqrp@...>
Sent: Wednesday, February 8, 2017 8:57 PM
To: 4sqrp@...
Subject: [4sqrp] 43SQRP net
 
 

WOW I had a bunch of noise here tonight I did get 

WA0ITP Terry

WA8PWP Paul

WN0WWY Dale.

Thanks Terry for the relay.de Paul N0NBD


Sent from Outlook


Re: 43SQRP net

w2sh@...
 

Condx in NJ are very noisy with a major snow storm arriving here in six hours.  At 0130Z-ish I heard Wayne at 449.  Normally WA9PWP is the sig champ, but I didn't hear him.  Surprisingly, the other Paul, N0NBD, was nearly 569.


Charles, W2SH 






From: 4sqrp@... <4sqrp@...> on behalf of Paul Smith psmith61@... [4sqrp] <4sqrp@...>
Sent: Wednesday, February 8, 2017 8:57 PM
To: 4sqrp@...
Subject: [4sqrp] 43SQRP net
 
 

WOW I had a bunch of noise here tonight I did get 

WA0ITP Terry

WA8PWP Paul

WN0WWY Dale.

Thanks Terry for the relay.de Paul N0NBD


Sent from Outlook


Re: Member List

davemrtn
 

That would be a 'historic' OzarkCon event !

How do we make it happen !!!   ????

David Martin - NA1MH - Mountain Home, Ar. -----------------------------------------

On 2/8/2017 19:41, ktalbott ktalbott@... [4sqrp] wrote:
 
It would be interesting to see them all at Ozarkcon!
Ken ke4rg


Sent from Samsung Mobile



-------- Original message --------
From: "Johnny Matlock jomatlock@... [4sqrp]" <4sqrp@...>
Date: 02/08/2017 5:54 PM (GMT-05:00)
To: 4sqrp@...,davemrtn
Subject: Re: [4sqrp] Member List


 
Look out SKCC here we come!!
Thanks for the info Dave
Johnny AC0BQ 
On Wed, Feb 8, 2017 at 1:40 PM davemrtn davemrtn@... [4sqrp] <4sqrp@...> wrote:
 
WOW !!!

I see the 4SQRP member count very recently surpassed 1300.

Way to go 4SQRP team and members.

David -NA1MH



Sent from my Verizon, Samsung Galaxy smartphone
--
Sent from Gmail Mobile


43SQRP net

Paul Smith
 

WOW I had a bunch of noise here tonight I did get 

WA0ITP Terry

WA8PWP Paul

WN0WWY Dale.

Thanks Terry for the relay.de Paul N0NBD


Sent from Outlook


Re: Member List

Ken Talbott
 

It would be interesting to see them all at Ozarkcon!
Ken ke4rg


Sent from Samsung Mobile



-------- Original message --------
From: "Johnny Matlock jomatlock@... [4sqrp]" <4sqrp@...>
Date: 02/08/2017 5:54 PM (GMT-05:00)
To: 4sqrp@...,davemrtn <davemrtn@...>
Subject: Re: [4sqrp] Member List


 

Look out SKCC here we come!!
Thanks for the info Dave
Johnny AC0BQ 
On Wed, Feb 8, 2017 at 1:40 PM davemrtn davemrtn@... [4sqrp] <4sqrp@...> wrote:
 

WOW !!!

I see the 4SQRP member count very recently surpassed 1300.

Way to go 4SQRP team and members.

David -NA1MH



Sent from my Verizon, Samsung Galaxy smartphone

--
Sent from Gmail Mobile


Re: Hot IRF510

David Wilcox
 

Thank you to all the responses.  Will evaluate further and replace the IRF510.

Dave K8WPE

On Feb 8, 2017, at 6:24 PM, nw8l@... [4sqrp] <4sqrp@...> wrote:

 

Oops, the link to the ARRL note was truncated, here it is again:



Bob NW8L



---In 4sqrp@..., wrote :

Yes, I ran into the same problem, Q6 failed and was running extremely hot etc. not long after I built the kit.

At first I removed it and completed the (-) path with a piece of wire, later I replaced it to restore the polarity protection it offers.

The gate of Q6 (a MOSFET) is directly connected to the (+) input power pin. I suspect that it was damaged by static discharge, so now I'm very careful when connecting the power to the radio.

Eventually I'll lift the gate lead of Q6 and kludge in an RC ESD protection network like that seen in figure 2 of this ARRL note:


If that works out I'll have additional peace of mind, it's very dry here in NM and electrostatic discharge can be a problem.

Bob NW8L


---In 4sqrp@..., wrote :

I am finding that my reverse voltage IRF510 is running hot enough to burn my fingers, even when the BJ is switched off. I was questioning why my Jet Ski battery was running down after a few days of "just sitting on the bench" while connected to the turned off BJ.

Any suggestions?

Also the receiver oscillator transistor seems to be the temp sensitive wandering part. I sprayed lightly each part with coolant air and that part seems to move frequency the fastest and the farthest. The toroid is also temperature sensitive but less so.

Dave K8WPE

Dave K8WPE


Re: Hot IRF510

Jim, N5IB
 

Sounds like that may be another instance of a failed Q6. That is a clever circuit that minimized voltage drop in the supply line, but the IRF510 can be damaged by esd. When (if) you replace it, tack a 470K or a 1 Meg in parallel with a 0.01 uF cap across from gate to source. That will protect it from most esd, and will only pull a few uA from your power source.

On the temp stability.... the iron powder of the toroid core has a positive temperature coefficient. One trick you can do is replace C20 with a polystyrene capacitor. They have a negative coefficient. Don't expect to cancel the drift, but at least they'll be going in opposite directions.

N5IB


Re: Hot IRF510

Bob NW8L
 

Oops, the link to the ARRL note was truncated, here it is again:


Bob NW8L



---In 4sqrp@..., <nw8l@...> wrote :

Yes, I ran into the same problem, Q6 failed and was running extremely hot etc. not long after I built the kit.

At first I removed it and completed the (-) path with a piece of wire, later I replaced it to restore the polarity protection it offers.

The gate of Q6 (a MOSFET) is directly connected to the (+) input power pin. I suspect that it was damaged by static discharge, so now I'm very careful when connecting the power to the radio.

Eventually I'll lift the gate lead of Q6 and kludge in an RC ESD protection network like that seen in figure 2 of this ARRL note:


If that works out I'll have additional peace of mind, it's very dry here in NM and electrostatic discharge can be a problem.

Bob NW8L


---In 4sqrp@..., <djwilcox01@...> wrote :

I am finding that my reverse voltage IRF510 is running hot enough to burn my fingers, even when the BJ is switched off. I was questioning why my Jet Ski battery was running down after a few days of "just sitting on the bench" while connected to the turned off BJ.

Any suggestions?

Also the receiver oscillator transistor seems to be the temp sensitive wandering part. I sprayed lightly each part with coolant air and that part seems to move frequency the fastest and the farthest. The toroid is also temperature sensitive but less so.

Dave K8WPE

Dave K8WPE


Re: Hot IRF510

Bob NW8L
 

Yes, I ran into the same problem, Q6 failed and was running extremely hot etc. not long after I built the kit.

At first I removed it and completed the (-) path with a piece of wire, later I replaced it to restore the polarity protection it offers.

The gate of Q6 (a MOSFET) is directly connected to the (+) input power pin. I suspect that it was damaged by static discharge, so now I'm very careful when connecting the power to the radio.

Eventually I'll lift the gate lead of Q6 and kludge in an RC ESD protection network like that seen in figure 2 of this ARRL note:


If that works out I'll have additional peace of mind, it's very dry here in NM and electrostatic discharge can be a problem.

Bob NW8L


---In 4sqrp@..., <djwilcox01@...> wrote :

I am finding that my reverse voltage IRF510 is running hot enough to burn my fingers, even when the BJ is switched off. I was questioning why my Jet Ski battery was running down after a few days of "just sitting on the bench" while connected to the turned off BJ.

Any suggestions?

Also the receiver oscillator transistor seems to be the temp sensitive wandering part. I sprayed lightly each part with coolant air and that part seems to move frequency the fastest and the farthest. The toroid is also temperature sensitive but less so.

Dave K8WPE

Dave K8WPE


Re: Second Sunday Sprint

Bry Carling <af4k@...>
 

Bravo


This will give us something fun to do after most things are finished at the Orlando Hamcation!


Bry, AF4K / WN4NRR



From: 4sqrp@... <4sqrp@...> on behalf of 'John R. Lonigro' jonigro@... [4sqrp] <4sqrp@...>
Sent: Wednesday, February 8, 2017 9:06 AM
To: 4SQRP
Subject: [4sqrp] Second Sunday Sprint
 
 

The Second Sunday Sprint is this coming Sunday, February 12th, 7:00-9:00
pm CST (Monday, 0100-0300Z). The rules are simple. Go to the 4SQRP
website and click on "4SQRP on air activities" Scroll
down to the bottom of that page and you will see a summary of the rules,
plus links to where you submit your score and where you can get the
complete rules.

If you tried to participate but nobody heard you (or you heard nobody),
feel free to enter a score of 0 points, as long as you made an honest
try for at least 15 minutes. Obviously, reporting a score of 0 is
optional and won't affect anything, but it will give me an idea of how
many people are participating.

I don't have 80M capability, but I understand 80M has been more friendly
than 40M lately. It might be worth listening down there for a while.

72,

John, AA0VE
4SQRP Contest Coordinator


Re: Member List

Johnny AC0BQ
 

Look out SKCC here we come!!
Thanks for the info Dave
Johnny AC0BQ 

On Wed, Feb 8, 2017 at 1:40 PM davemrtn davemrtn@... [4sqrp] <4sqrp@...> wrote:

WOW !!!

I see the 4SQRP member count very recently surpassed 1300.

Way to go 4SQRP team and members.

David -NA1MH



Sent from my Verizon, Samsung Galaxy smartphone

--
Sent from Gmail Mobile


Re: Ocon Oscillator Hunt

WA0ITP
 

Hi Bill,
Fb on the Alex Loop, sounds like a good DF loop. Bet quite a few of the guys have them or another magloop.  The hunt is on!
72 WAØITP
I love this radio stuff.
www.wa0itp.com
www.4sqrp.com
On 2/8/2017 3:45 PM, dekle wrote:

Terry,
 
I just looked at the "Snoop Loop" you referenced and it got me thinking.
I realized that I already had a DF loop - the Alex Loop.
Although it is bigger and requires a receiver, it can be easily hand-held.
I tried it with a HB-1B and it works great.
The null is broadside to the loop and very sharp.
It doesn't have front/back directional discrimination, but with a little triangulation, the Hidden Oscillator would be easy to find.
A little team work would be an asset here, but the "team" will have to decide who gets the prize.
 
Thanks for the reference!
 
Bill
KV6Z
 
 
 
 
----- Original Message -----
Sent: Wednesday, February 08, 2017 2:01 PM
Subject: [4sqrp] Fwd: Ocon Oscillator Hunt

 

I'll try again, didn't see the first post.

Just ran across this article on direction finding antennas.  Some versions look easy to build and would be good for the Ocon Oscillator Hunt. The Snoop Loop abt halfway down the page looks quite good for our purposes.
http://www.ce5prd.cl/documentos/antenna_handbook/14.pdf

72 WAØITP
I love this radio stuff.
www.wa0itp.com
www.4sqrp.com


-------- Forwarded Message --------
Subject: Ocon Oscillator Hunt
Date: Wed, 8 Feb 2017 13:47:00 -0600
From: WA0ITP
Reply-To: wa0itp@...
To: 4sqrp@... <4sqrp@...>


Just ran across this article on direction finding antennas.  Some vbersions look easy to build and would be good for the Ocon Oscillator Hunt. The Snoop Loop abt halfway down the page looks very good for our purposes.
http://www.ce5prd.cl/documentos/antenna_handbook/14.pdf
-- 
72 WAØITP
I love this radio stuff.
www.wa0itp.com
www.4sqrp.com



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