Elecraft

Tuner bug

Classic

List

Threaded

12 messages Options

ANDY DURBIN

Tuner bug

My top band antenna is an OCF wire running round my back yard wall at about 5 ft above ground. It has been through a number of iterations to make it tunable on 160 and to handle 500 W.

500 W capability was achieved with a home brew feed point L match consisting of a large air-spaced variable capacitor and an inductor wound on PVC pipe. It worked fine until the small hours of Saturday morning when the SWR jumped to a really high value and tripped my KPA500 reflected power monitor. Some quick tests showed it worked fine up to about 200 W but anything over that gave an instant transition from low SWR to very high SWR. All easily seen in my station controller's data log. It seemed likely there was an insulation breakdown somewhere, but where?

Careful inspection of the air-spaced variable revealed a small bug between the plates. It was carefully extracted and viewed under the microscope. It was well charred!

Quick check on 160 m and the antenna will handle 500 W again. Now ready to try for a few missing states in ARRL Sweep Stakes.

Not all bugs are neatly categorized as either hardware or software.

73,
Andy, k3wyc

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

ANDY DURBIN

Tuner bug

"Careful inspection of the air-spaced variable revealed a small bug between the plates. It was carefully extracted and viewed under the microscope. It was well charred!"

For the detail oriented - bug was identified as attagenus pellio (carpet beetle). They are common here in Arizona. They have a very high crush resistance but it seems poor tolerance of high RF voltage.

https://en.wikipedia.org/wiki/Attagenus_pellio

73,
Andy, k3wyc

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Michael Chowning-2

Re: Tuner bug

Opportunity looms - RF carpet cleaners!
Mike, N8TTR

> On Nov 7, 2020, at 11:28 AM, Andy Durbin <[hidden email]> wrote:
>
> "Careful inspection of the air-spaced variable revealed a small bug between the plates. It was carefully extracted and viewed under the microscope. It was well charred!"
>
> For the detail oriented - bug was identified as attagenus pellio (carpet beetle). They are common here in Arizona. They have a very high crush resistance but it seems poor tolerance of high RF voltage.
>
> https://en.wikipedia.org/wiki/Attagenus_pellio
>
> 73,
> Andy, k3wyc
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

NK7Z

Re: Tuner bug

In reply to this post by ANDY DURBIN

Andy,

You have far too much time on your hands... :)

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources

On 11/7/20 8:28 AM, Andy Durbin wrote:

> "Careful inspection of the air-spaced variable revealed a small bug between the plates. It was carefully extracted and viewed under the microscope. It was well charred!"
>
> For the detail oriented - bug was identified as attagenus pellio (carpet beetle). They are common here in Arizona. They have a very high crush resistance but it seems poor tolerance of high RF voltage.
>
> https://en.wikipedia.org/wiki/Attagenus_pellio
>
> 73,
> Andy, k3wyc
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

James Driskell

Re: Tuner bug

In reply to this post by ANDY DURBIN

The first bugs in the old large 1st generation computers were actually insects (bugs) that were raising havoc with the insulation. Hence, "bugs" has become our favorite term!

73,

Jim, W7OWI

________________________________
From: [hidden email] <[hidden email]> on behalf of Andy Durbin <[hidden email]>
Sent: Saturday, November 7, 2020 07:50
To: [hidden email] <[hidden email]>
Subject: [Elecraft] Tuner bug

My top band antenna is an OCF wire running round my back yard wall at about 5 ft above ground. It has been through a number of iterations to make it tunable on 160 and to handle 500 W.

500 W capability was achieved with a home brew feed point L match consisting of a large air-spaced variable capacitor and an inductor wound on PVC pipe. It worked fine until the small hours of Saturday morning when the SWR jumped to a really high value and tripped my KPA500 reflected power monitor. Some quick tests showed it worked fine up to about 200 W but anything over that gave an instant transition from low SWR to very high SWR. All easily seen in my station controller's data log. It seemed likely there was an insulation breakdown somewhere, but where?

Careful inspection of the air-spaced variable revealed a small bug between the plates. It was carefully extracted and viewed under the microscope. It was well charred!

Quick check on 160 m and the antenna will handle 500 W again. Now ready to try for a few missing states in ARRL Sweep Stakes.

Not all bugs are neatly categorized as either hardware or software.

73,
Andy, k3wyc

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Dick Dievendorff-4

Re: Tuner bug

I think the term predates computers, but I have heard the story.

https://www.atlasobscura.com/places/grace-hoppers-bug

73 de Dick, K6KR

> On Nov 7, 2020, at 10:53, James Driskell <[hidden email]> wrote:
>
> The first bugs in the old large 1st generation computers were actually insects (bugs) that were raising havoc with the insulation. Hence, "bugs" has become our favorite term!
>
> 73,
>
> Jim, W7OWI
>
> ________________________________
> From: [hidden email] <[hidden email]> on behalf of Andy Durbin <[hidden email]>
> Sent: Saturday, November 7, 2020 07:50
> To: [hidden email] <[hidden email]>
> Subject: [Elecraft] Tuner bug
>
> My top band antenna is an OCF wire running round my back yard wall at about 5 ft above ground. It has been through a number of iterations to make it tunable on 160 and to handle 500 W.
>
> 500 W capability was achieved with a home brew feed point L match consisting of a large air-spaced variable capacitor and an inductor wound on PVC pipe. It worked fine until the small hours of Saturday morning when the SWR jumped to a really high value and tripped my KPA500 reflected power monitor. Some quick tests showed it worked fine up to about 200 W but anything over that gave an instant transition from low SWR to very high SWR. All easily seen in my station controller's data log. It seemed likely there was an insulation breakdown somewhere, but where?
>
> Careful inspection of the air-spaced variable revealed a small bug between the plates. It was carefully extracted and viewed under the microscope. It was well charred!
>
> Quick check on 160 m and the antenna will handle 500 W again. Now ready to try for a few missing states in ARRL Sweep Stakes.
>
> Not all bugs are neatly categorized as either hardware or software.
>
> 73,
> Andy, k3wyc
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

k6mkf

Re: Tuner bug

I was fortunate to have met Rear Admiral Grace Hopper at a Holiday reception when I worked as a DoD contractor at the Washington Navy Yard in 1985. I had been using COBOL for programming business systems for years and had the opportunity to thank her for it. She remarked that she was 'particularly proud' of that accomplishment.

I also think that the term 'bug' meaning an error or anomaly predates digital computers. My Father was trained during WW2 by the UASAAF in avionics and told me there were a lot of 'bugs' in the early airborne radar systems. I don't think my Father knew anything at all about computers ...

- 73 and good DX de Mike, K6MKF, NCDXC Secretary

> -----Original Message-----
> From: [hidden email] <elecraft-
> [hidden email]> On Behalf Of Dick Dievendorff
> Sent: Saturday, November 07, 2020 10:58
> To: James Driskell <[hidden email]>
> Cc: Elecraft Reflector <[hidden email]>
> Subject: Re: [Elecraft] Tuner bug
>
> I think the term predates computers, but I have heard the story.
>
> https://www.atlasobscura.com/places/grace-hoppers-bug
>
> 73 de Dick, K6KR
>
> > On Nov 7, 2020, at 10:53, James Driskell <[hidden email]> wrote:
> >
> > The first bugs in the old large 1st generation computers were actually insects
> (bugs) that were raising havoc with the insulation. Hence, "bugs" has become
> our favorite term!
> >
> > 73,
> >
> > Jim, W7OWI
> >
> > ________________________________
> > From: [hidden email]
> > <[hidden email]> on behalf of Andy Durbin
> > <[hidden email]>
> > Sent: Saturday, November 7, 2020 07:50
> > To: [hidden email] <[hidden email]>
> > Subject: [Elecraft] Tuner bug
> >
> > My top band antenna is an OCF wire running round my back yard wall at
> about 5 ft above ground. It has been through a number of iterations to make
> it tunable on 160 and to handle 500 W.
> >
> > 500 W capability was achieved with a home brew feed point L match
> consisting of a large air-spaced variable capacitor and an inductor wound on
> PVC pipe. It worked fine until the small hours of Saturday morning when the
> SWR jumped to a really high value and tripped my KPA500 reflected power
> monitor. Some quick tests showed it worked fine up to about 200 W but
> anything over that gave an instant transition from low SWR to very high SWR.
> All easily seen in my station controller's data log. It seemed likely there was
> an insulation breakdown somewhere, but where?
> >
> > Careful inspection of the air-spaced variable revealed a small bug between
> the plates. It was carefully extracted and viewed under the microscope. It
> was well charred!
> >
> > Quick check on 160 m and the antenna will handle 500 W again. Now ready
> to try for a few missing states in ARRL Sweep Stakes.
> >
> > Not all bugs are neatly categorized as either hardware or software.
> >
> > 73,
> > Andy, k3wyc
> >
> >
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email]
> >
> > This list hosted by: http://www.qsl.net Please help support this email
> > list: http://www.qsl.net/donate.html Message delivered to
> > [hidden email]
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email]
> >
> > This list hosted by: http://www.qsl.net Please help support this email
> > list: http://www.qsl.net/donate.html Message delivered to
> > [hidden email]
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html Message
> delivered to [hidden email]

weaverwf@usermail.com

Re: Tuner bug

In reply to this post by James Driskell

As a politically correct engineer in order to not insult any bugs, I referred to them as anomalous behaviors. :-)

73,
Bill WE5P

Comfortably Numb

> On Nov 7, 2020, at 13:52, James Driskell <[hidden email]> wrote:
>
> The first bugs in the old large 1st generation computers were actually insects (bugs) that were raising havoc with the insulation. Hence, "bugs" has become our favorite term!
>
> 73,
>
> Jim, W7OWI
>
> ________________________________
> From: [hidden email] <[hidden email]> on behalf of Andy Durbin <[hidden email]>
> Sent: Saturday, November 7, 2020 07:50
> To: [hidden email] <[hidden email]>
> Subject: [Elecraft] Tuner bug
>
> My top band antenna is an OCF wire running round my back yard wall at about 5 ft above ground. It has been through a number of iterations to make it tunable on 160 and to handle 500 W.
>
> 500 W capability was achieved with a home brew feed point L match consisting of a large air-spaced variable capacitor and an inductor wound on PVC pipe. It worked fine until the small hours of Saturday morning when the SWR jumped to a really high value and tripped my KPA500 reflected power monitor. Some quick tests showed it worked fine up to about 200 W but anything over that gave an instant transition from low SWR to very high SWR. All easily seen in my station controller's data log. It seemed likely there was an insulation breakdown somewhere, but where?
>
> Careful inspection of the air-spaced variable revealed a small bug between the plates. It was carefully extracted and viewed under the microscope. It was well charred!
>
> Quick check on 160 m and the antenna will handle 500 W again. Now ready to try for a few missing states in ARRL Sweep Stakes.
>
> Not all bugs are neatly categorized as either hardware or software.
>
> 73,
> Andy, k3wyc
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

k6dgw

Re: Tuner bug

"Anomaly" is [or at least was during Apollo] NASA's universal term for
anything that was unexpected ... from an intermittent pilot light to the
rocket landing pointy end down in the desert outside Tucson. The
equivalent USAF term is "mishap" which can range from a faulty drag
chute to landing in a ball of flames in that same Tucson desert. 😉

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 11/7/2020 11:42 AM, [hidden email] wrote:
> As a politically correct engineer in order to not insult any bugs, I referred to them as anomalous behaviors. :-)
>
> 73,
> Bill WE5P
>
> Comfortably Numb
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Elecraft mailing list

Re: Tuner bug

In the software world these days we call them “undocumented features”.

Or, the issue is in the documentation… ;-)

73!
Jack, W6FB

> On Nov 7, 2020, at 11:50 AM, Fred Jensen <[hidden email]> wrote:
>
> "Anomaly" is [or at least was during Apollo] NASA's universal term for anything that was unexpected ... from an intermittent pilot light to the rocket landing pointy end down in the desert outside Tucson. The equivalent USAF term is "mishap" which can range from a faulty drag chute to landing in a ball of flames in that same Tucson desert. 😉
>
> 73,
>
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
>
> On 11/7/2020 11:42 AM, [hidden email] wrote:
>> As a politically correct engineer in order to not insult any bugs, I referred to them as anomalous behaviors. :-)
>>
>> 73,
>> Bill WE5P
>>
>> Comfortably Numb
>>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

NK7Z

Re: Tuner bug

In reply to this post by k6dgw

Is that like the "Rapid Disassembly Event" that happens during rocket
launches now and then?

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources

On 11/7/20 11:50 AM, Fred Jensen wrote:

> "Anomaly" is [or at least was during Apollo] NASA's universal term for
> anything that was unexpected ... from an intermittent pilot light to the
> rocket landing pointy end down in the desert outside Tucson. The
> equivalent USAF term is "mishap" which can range from a faulty drag
> chute to landing in a ball of flames in that same Tucson desert. 😉
>
> 73,
>
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
>
> On 11/7/2020 11:42 AM, [hidden email] wrote:
>> As a politically correct engineer in order to not insult any bugs, I
>> referred to them as anomalous behaviors. :-)
>>
>> 73,
>> Bill WE5P
>>
>> Comfortably Numb
>>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

k6dgw

Re: Tuner bug

RDE is somewhat more descriptive of what actually happened than
"Anomaly" or "Mishap". Mishap could describe the pilot falling off the
ladder while boarding his A/C as well as crashing onto the deck of the
aircraft carrier ... which generally makes you very unpopular with the
Sailors and the Captain.😉

73,

Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 11/7/2020 12:14 PM, Dave Cole wrote:

> Is that like the "Rapid Disassembly Event" that happens during rocket
> launches now and then?
>
> 73, and thanks,
> Dave (NK7Z)
> https://www.nk7z.net
> ARRL Volunteer Examiner
> ARRL Technical Specialist, RFI
> ARRL Asst. Director, NW Division, Technical Resources
>