Re: Stacking Ferrite Cores

Jonathan Poland

Lee,

I think you should expect to see double the inductance per turn when you stack 2 cores.  Inductance is proportional to the cross-sectional area of the toroid.

Another way to convince yourself of this is to think about 2 identical toroid inductors wired in series: obviously they have double the inductance.  Stack them on top of each other and they are still double.  The wires between the 2 toroids cancel each other because the currents are flowing in opposite directions, so in this thought-experiment you can eliminate them.  What you have left is what you are trying to build.

Of course, theory and reality are not always identical...

jon, N0WL

On 4/23/2019 07:52, Leland L. Bahr wrote:

Thanks, Jim but a FT82-61 is too tall for my project box.  Diz is sending me twenty five FT50-61 cores.  I'll use Alchemy to determine the turns for my required value.  Just wanted to approach it more scientifically by calculating the needed turns on stacked cores

Lee, w0vt.

On 4/23/2019 1:22 AM, Jim Pruitt wrote:
Hello Lee.

I see that Diz has FT82-61's (6 for \$5) at
http://www.kitsandparts.com/toroids.php

http://toroids.info/FT82-61.php

Would those work for you?

Thank you.

Jim Pruitt
WA7DUY

On 4/22/2019 9:40 PM, Leland L. Bahr wrote:
Need some input.  I want to wind a choke using FT50-61 cores.  I want to use #20 magnet wire and not smaller wire.  This core size allows around 23 turns of #20 wire.  However the inductance I will get with 23 turns is somewhat less then I want.  I don't want to overlap the turns.  So I am thinking of stacking two FT50-61 cores.  (I don't see FT68-61 cores easily obtainable.)  Is there a chart somewhere or a calculator somewhere that will calculate the inductance stacking two of these cores?  I know the inductance will be more with stacked cores vs using a single core per turn, but how much more?  I realize the easy way out is to just wind up a stacked core and adjust the turns for the wished inductance. But that would be too easy!  (I'll actually do this once my cores arrive, but it would be nice to be able to calculate the required turns for a particular inductance using stacked cores, or at least get me in the "ball park".)  Is there a chart or a rule of thumb available for this?  I have no feel for how much stacking will do to inductance per turn when using two cores instead of one core. I realize core material effects all this, but I'm only interested in 61 mix.

All Choked Up,

Lee, w0vt

--
Jim Pruitt
WA7DUY

Re: Stacking Ferrite Cores

Leland L. Bahr

Thanks, Jim but a FT82-61 is too tall for my project box.  Diz is sending me twenty five FT50-61 cores.  I'll use Alchemy to determine the turns for my required value.  Just wanted to approach it more scientifically by calculating the needed turns on stacked cores

Lee, w0vt.

On 4/23/2019 1:22 AM, Jim Pruitt wrote:
Hello Lee.

I see that Diz has FT82-61's (6 for \$5) at
http://www.kitsandparts.com/toroids.php

http://toroids.info/FT82-61.php

Would those work for you?

Thank you.

Jim Pruitt
WA7DUY

On 4/22/2019 9:40 PM, Leland L. Bahr wrote:
Need some input.  I want to wind a choke using FT50-61 cores.  I want to use #20 magnet wire and not smaller wire.  This core size allows around 23 turns of #20 wire.  However the inductance I will get with 23 turns is somewhat less then I want.  I don't want to overlap the turns.  So I am thinking of stacking two FT50-61 cores.  (I don't see FT68-61 cores easily obtainable.)  Is there a chart somewhere or a calculator somewhere that will calculate the inductance stacking two of these cores?  I know the inductance will be more with stacked cores vs using a single core per turn, but how much more?  I realize the easy way out is to just wind up a stacked core and adjust the turns for the wished inductance. But that would be too easy!  (I'll actually do this once my cores arrive, but it would be nice to be able to calculate the required turns for a particular inductance using stacked cores, or at least get me in the "ball park".)  Is there a chart or a rule of thumb available for this?  I have no feel for how much stacking will do to inductance per turn when using two cores instead of one core. I realize core material effects all this, but I'm only interested in 61 mix.

All Choked Up,

Lee, w0vt

--
Jim Pruitt
WA7DUY

Re: Stacking Ferrite Cores

Jim Pruitt

Hello Lee.

I see that Diz has FT82-61's (6 for \$5) at
http://www.kitsandparts.com/toroids.php

http://toroids.info/FT82-61.php

Would those work for you?

Thank you.

Jim Pruitt
WA7DUY

On 4/22/2019 9:40 PM, Leland L. Bahr wrote:
Need some input.  I want to wind a choke using FT50-61 cores.  I want to use #20 magnet wire and not smaller wire.  This core size allows around 23 turns of #20 wire.  However the inductance I will get with 23 turns is somewhat less then I want.  I don't want to overlap the turns.  So I am thinking of stacking two FT50-61 cores.  (I don't see FT68-61 cores easily obtainable.)  Is there a chart somewhere or a calculator somewhere that will calculate the inductance stacking two of these cores?  I know the inductance will be more with stacked cores vs using a single core per turn, but how much more?  I realize the easy way out is to just wind up a stacked core and adjust the turns for the wished inductance. But that would be too easy!  (I'll actually do this once my cores arrive, but it would be nice to be able to calculate the required turns for a particular inductance using stacked cores, or at least get me in the "ball park".)  Is there a chart or a rule of thumb available for this?  I have no feel for how much stacking will do to inductance per turn when using two cores instead of one core. I realize core material effects all this, but I'm only interested in 61 mix.

All Choked Up,

Lee, w0vt

--
Jim Pruitt
WA7DUY

Stacking Ferrite Cores

Leland L. Bahr

Need some input.  I want to wind a choke using FT50-61 cores.  I want to use #20 magnet wire and not smaller wire.  This core size allows around 23 turns of #20 wire.  However the inductance I will get with 23 turns is somewhat less then I want.  I don't want to overlap the turns.  So I am thinking of stacking two FT50-61 cores.  (I don't see FT68-61 cores easily obtainable.)  Is there a chart somewhere or a calculator somewhere that will calculate the inductance stacking two of these cores?  I know the inductance will be more with stacked cores vs using a single core per turn, but how much more?  I realize the easy way out is to just wind up a stacked core and adjust the turns for the wished inductance. But that would be too easy!  (I'll actually do this once my cores arrive, but it would be nice to be able to calculate the required turns for a particular inductance using stacked cores, or at least get me in the "ball park".)  Is there a chart or a rule of thumb available for this?  I have no feel for how much stacking will do to inductance per turn when using two cores instead of one core. I realize core material effects all this, but I'm only interested in 61 mix.

All Choked Up,

Lee, w0vt

Re: New Shack Sloth, J.C. Martin, W6IPA

Rex Vokey

Congrats, J.C.!  Always love to get you in the log.

73,
Rex KE6MT

Re: The next Cal-QRP Club Kit

Rex Vokey

Amazing!

I put a basic version together on a breadboard when I was first learning CW.  SUPER capable keyer.  Can't wait to see what you guys have put together!  Wish I could make the meeting.

73,
Rex KE6MT

On Mon, Apr 22, 2019 at 9:18 PM Doug Hendricks <ki6ds1@...> wrote:
We have a working prototype.  J.C. Martin delivered the finished prototype to me today at 4:30.  The next Cal-QRP group project will be the W6IPA designed hardware for a K3NG keyer.  Guys, you won't believe what this keyer will do.  For those of you learning CW, check out the features by searching K3NG keyer features.   The practice mode is awesome.  One feature I like is the abc sending feature.  You send the alphabet, and if you send the correct letter, it beeps, if you make a mistake, it bongs.  Pretty neat.  It will certainly improve my sending, and everyone knows I can stand some improvement, a lot, actually.

We will have 8 complete kits, including a neat case that J.C. designed out of acrylic sheet and standoffs.  The cost of the parts is \$30, and we are selling 8 kits at the meeting in May.  That is the actual cost of the parts and postage.  All parts needed to build the kit are included.  You must attend to buy a kit.  They will not be shipped.  But don't despair.  J.C. will post the BOM, with part numbers and sources, plus gerber files will be made available so that you can order your own pc boards.  J.C will also post a manual on line that will make it a snap to build.  I will have the kits at the May meeting.

THanks to J.C. for heading up this great project.  He did a ton of work, and I want to thank him publicly for his efforts.  Pictures will be posted soon.  Doug

Re: The next Cal-QRP Club Kit

Doug Hendricks

We have a working prototype.  J.C. Martin delivered the finished prototype to me today at 4:30.  The next Cal-QRP group project will be the W6IPA designed hardware for a K3NG keyer.  Guys, you won't believe what this keyer will do.  For those of you learning CW, check out the features by searching K3NG keyer features.   The practice mode is awesome.  One feature I like is the abc sending feature.  You send the alphabet, and if you send the correct letter, it beeps, if you make a mistake, it bongs.  Pretty neat.  It will certainly improve my sending, and everyone knows I can stand some improvement, a lot, actually.

We will have 8 complete kits, including a neat case that J.C. designed out of acrylic sheet and standoffs.  The cost of the parts is \$30, and we are selling 8 kits at the meeting in May.  That is the actual cost of the parts and postage.  All parts needed to build the kit are included.  You must attend to buy a kit.  They will not be shipped.  But don't despair.  J.C. will post the BOM, with part numbers and sources, plus gerber files will be made available so that you can order your own pc boards.  J.C will also post a manual on line that will make it a snap to build.  I will have the kits at the May meeting.

THanks to J.C. for heading up this great project.  He did a ton of work, and I want to thank him publicly for his efforts.  Pictures will be posted soon.  Doug

New Shack Sloth, J.C. Martin, W6IPA

Doug Hendricks

Since he is not going to post, I will.  J.C. Martin is the newest Shack Sloth, scoring over 1000 points chasing SOTA.  J.C. did it remarkably fast, starting on Nov. 10, 2018 working Jeff, AA6XA as his first contact.  He uses only 5 Watts, running a KX2 and most of his contacts were made portable from the Baylands, using a 9:1 Unun with a 17 ft. random wire.  Congrats to the newest Shack Sloth in W6.  Doug, KI6DS

QRPGuys corrected url

Ken wa4mnt

Sorry bout that.... The correct url for the Mini 40m-10m UnUnTenna is <https://qrpguys.com/qrpguys-40m-10m-mini-ununtenna>

QRPGuys new products

Ken wa4mnt

```Gang,QrpGuys has released two new products. They are small portable versions
of our popular "80m-10m No Tune Endfed Antenna" and the "40m-10m
UnUntenna", called the "Mini 80m-10m No Tune End Fed Half Wave Antenna"
and "Mini 40m-10m UnUnTenna respectively. Each weigh in at about 1.5oz.
Check them out at:

https://qrpguys.com/qrpguys-mini-80m-10m-no-tune-end-fed-half-wave-antenna

https://qrpguys.com/qrpguys-40m-10m-mini-ununtenna

73's

ken - wa4mnt```

Re: The next Cal-QRP Club Kit

Doug Hendricks

We will be putting the manual, bom and Gerber files online later so it can be reproduced by anyone

The next Cal-QRP Club Kit

Doug Hendricks

J.C. Martin talked to me after the last meeting and said he had an idea for a really neat kit for the club to do as  club project.

We ordered the parts and J.C. built the prototype today.  It works great.  We will have 9 kits of parts at the next club meeting and will sell them for the cost of parts and prorated shipping.  You must come to the meeting to get a kit and no, I won't mail one.

More details later when I have the final cost figure.

73, Doug

W6IPA and KI6DS are operating QRPTTF today

Doug Hendricks

Listen for us and join in the fun.  We will be at Baylands Park in Palo Alto.

QRP To The Field this Saturday

Doug Hendricks

Norcal may be dead and gone, but QRP To The Field lives on.  This Saturday, QRP To The Field will be held again.  The contest runs from 8:00 AM to 8:00 PM local time.  Paul and Jan Harden, NA5N have sponsored the contest for years and have done a fantastic job.  The main idea of the contest is to have fun, and boy have I had some fun times in the past.  Paul and Jan always have a theme for the contest.  Last year it was water, this year it is "Any old park".  In the past they have had run to the borders, weird places, etc.  Paul and I used to meet every year and operate.  One year we went to Riley (did I tell you about the wind), New Mexico where we had 50-60 mph winds and an airplane mobile.  One of the operators at Riley was Brian Miloshosky, who was 15 years old.  Brian grew up to be the second vice President of the ARRL.  Wow!  Paul and I gave him a kit and he now has his Extra.  Neat story.

Another year we went to the edge of "Area 51" and operated with Monte Stark and Bob from Utah.  We met in Vegas and drove out the next day.  We met in Vegas another time and operated from the place where Arizona, Nevada and California meet.  We gave out all three states.  Then there was the time we went to El Paso, TX and operated where Texas, New Mexico and Old Mexico meet.  Bob and Bertie Hightower drove all the way from Phoenix to operate with us, as well as old friend Tim Pettibone.  I almost got arrested by the border patrol on that one, Not the US Border Patrol, but the Mexican Border Patrol.  They were just joking, but it sure scared me.

So How about operating with a buddy this Saturday.  Set up portable, try out that new radio, get some sun, and have fun.  Here is some info that I copied from a posting by Paul, NA5N, on the qrp-tech list.  He monitors this list and may add a comment or two.  I probably should have asked permission to repost, but didn't.  I'm guilty.

QRPTTF runs from 0800-1800 your local time for safe daylight travel to and  from your selected spot.  The theme this year is very relaxed to keep ops  relatively close to home so about any location qualifies.  This was done  due to so much of the country still buried in snow, adverse weather,  floods, damaged roads and bridges, burned forests, park closures, etc. to  reduce travel and stay safe.

2019 Rules at: http://www.zianet.com/qrp/qrpttf/2019/ttf.htm

The WA7BNM contest calendar is at:
https://www.contestcalendar.com/weeklycont.php

It incorrectly links to last year's rules.  I have fixed that so it routes  you to this year's rules.

QRP-TECH related: Maybe next year we should have bonus points for using  vintage QRP gear, such as anything from the FT-817 or older to include the  early Elecraft, SGC 2020, TenTec Argonauts, HW-8, and the like, and of  course, NorCal 40s, a Dave Benson rig, 2N2/xx, and anything else homebrew.   We all seem to have such rigs on the shelf collecting dust that need some  love and attention by putting them on the air.  Sorry I didn't think of  that for this year! :-(

72, Paul NA5N

If you hear J.C. and I calling, give us a call.  That is KI6DS and W6IPA.  We will be operating NA5N style.  If you don't know what that is.  I will explain.  I hear NA5N calling CQ TTF.  I call him and work him, then I hand the paddles to J.C. and he then works him.  J.C. keeps the paddles, and works the next station first, then hands the paddles to me and I work him.  Fun way to operate, and it doubles the amount of qso's in the contest from us.  See you on the air.  Doug, KI6DS

PS, thanks to Paul and Jan for all of their hard work at providing the qrp community with an activity that is fun. And thanks for having the website and rules up to date.  That is not always the case, as we found out recently.

Re: KX2 for FT8 setup notes

Doug Hendricks

Thanks for the great demo.  You answered all of my questions and I appreciate the hard work you did

KX2 for FT8 setup notes

Steve KC6ZKT

The following message is information Doug KI6DS requested at our meeting
today.

----------
KX2 Setup Notes for FT8

Components:

- Elecraft KX2 transceiver
- Elecraft KXUSB serial cable
- Sound card: I used the iMic [
- Audio cables: 3.5mm stereo male, both ends (qty 2)
- Computer (laptop?) running WSJT-X version 2.n
- Antenna...

Crucial KX2 settings:

- AFX MD = OFF
- AGC MD = OFF
- MICBIAS = OFF
- MIC BTN = OFF
- TX CMP = 0

In WSJT-X preferences:

- Select radio type = KX3
- Transceiver control = CAT

The rest depends more on your computer and unique setup.
-----

With my KX2 and the standard Buddistick antenna, we made 8 QSOs in about
an hour on 30M, to stations as far as Alberta at 5 watts, and as far as
Albuquerque at 1 watt.

--
--... ...--
SteveSgt, KC6ZKT, @CM97bj73

Re: Carpool to Sunday's meeting

David W Crocker

Corey,

I would be happy to carpool with you. Here is my contact info:

Dave Crocker
50 Kings Rd
Brisbane

415 467 8108

Give me call,  Dave W6VYC

On Fri, Apr 5, 2019 at 10:10 PM, Corey Siegel KJ6LDJ
<kj6ldj@...> wrote:
Hi all,

I'm planning to head to Sunday's meeting from SF. Anyone interested in carpooling? I'm happy to drive or hitch a ride. PM me if you're interested.

73,
Corey KJ6LDJ

On Fri, Apr 5, 2019, 09:18 Doug Hendricks <ki6ds1@...> wrote:
Steve Sargeant has volunteered to give an FT8 demo Sunday at the meeting.  He has WAS on FT8, so he has a lot of experience.  John Sutter is bringing a bunch of projects heis working on, and I will have couple of new products to show and a new paddle from Russia.  JC should have the latest version of his palm paddles, and I am sure Ernie will be there with something for us to see.

Sunday, 1-3 pm, patio of Denny's, 1140 Hillsdale, San Jose

Carpool to Sunday's meeting

Corey Siegel KJ6LDJ

Hi all,

I'm planning to head to Sunday's meeting from SF. Anyone interested in carpooling? I'm happy to drive or hitch a ride. PM me if you're interested.

73,
Corey KJ6LDJ

On Fri, Apr 5, 2019, 09:18 Doug Hendricks <ki6ds1@...> wrote:
Steve Sargeant has volunteered to give an FT8 demo Sunday at the meeting.  He has WAS on FT8, so he has a lot of experience.  John Sutter is bringing a bunch of projects heis working on, and I will have couple of new products to show and a new paddle from Russia.  JC should have the latest version of his palm paddles, and I am sure Ernie will be there with something for us to see.

Sunday, 1-3 pm, patio of Denny's, 1140 Hillsdale, San Jose

Re: Sunday's Meeting

John

It looks like a nice meeting with lots to see and learn

anyone have an icom 7200 or 7100 for sale or a KX2 or KX3?

John ve3ips

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On Fri, Apr 5, 2019 at 12:11 PM Doug Hendricks <ki6ds1@...> wrote:
Perfect!! I am looking forward to it.  See you there

Re: FT8 Demo at Sunday's meeting a go

John

I will bring the sotabeams wsprlite to run off a w6IP whip

I was going to bring my 160m 2 element wire beam but it wont fit in carryon
John ve3ips