Re: Topband: Beverage transformers tht work down to 630 m

[Mike Waters]

Send me an SASE, and I'll send you one, Chuck. Then you can measure it for
yourself.

73, Mike
www.w0btu.com

On Mon, Jul 16, 2018 at 5:50 PM, Chuck Hutton  wrote:

> Tim -
>
>
> What spec on 73 material are you referring to? I have never seen a
> published Al value for the 287300292 (BN73-202). Here's the Fair-Rite page
> with the 287300292:
>
> https://www.fair-rite.com/product-category/suppression-compo
> nents/multi-aperture-cores/
>
> And here's the Amidon page for the BN73-202:
>
> http://www.amidoncorp.com/bn-73-202/
>
>
> The BN73-202 has been discussed before here and Al of 8500 was quoted.
> However, way back upon prodict release someone posted an Al od 2500.   Kits
> and Parts quote an Al of 12000. My rqo caores have an average Al of
> 13,333.  I;ve seen no manufacturer Al data.
>
>
> But bottom line I think we borh believe the true Al is higher than might
> be believed and therefore better low end response.
>
>
> Note these turns versus frequency curves:
>
> http://www.qsl.net/in3otd/ham_radio/160m_transformers/160m_trafos.html
>
>
> The 3rd chart down is the heart of the issue.
>
>
> Two turns is of the edge of the cliff. Better to use 3 turns I believe.
>
>
> Chuck.
>
>
>
>
> 
> From: Tim Shoppa 
> Sent: Monday, July 16, 2018 5:07 AM
> To: Chuck Hutton
> Cc: kd9sv; topband@contesting.com
> Subject: Re: Topband: Beverage transformers tht work down to 630 m
>
> I think the spec on 73 material permeability is also conservative. Few EMI
> suppressing customers suffer if the impedance is higher than guaranteed.
> The Fair-Rite 73 curves also show permeability peaking up even higher in
> the 500 kHz region.
>
> W8JI has in the past made some remarks about stray winding capacitance
> which would get worse with more turns. I believe his drawing shows some
> “dummy turns” put in on the far side of ground, to cancel the stray
> capacitance?
>
> An important advantage of fewer turns, is that you can use ordinary
> plastic insulated hookup wire or kynar wire wrap wire to put the small
> number of turns through the holes. If I use enamel magnet wire with these
> cores to get more turns I end up nicking the enamel insulation on the core
> corners.
>
> Tim N3QE
>
> > On Jul 15, 2018, at 8:49 PM, Chuck Hutton  wrote:
> >
> > Yes, I think we all agree on the meaning of the 4X rule and the other
> basics.
> >
> > The mystery to me remains that a 1 turn transformer was good to 270 kHz
> in the Clifton data. I calculate at 500 kHz:
> >
> > 1 turn on a BN73-202 with Al = 8500 gives 9 uH
> >
> > 9 uH is only 28 Ohms
> >
> > For reference, 2 turns = 34 uH and 107 Ohms. 3 turns is 77 uH and 242
> Ohms.
> >
> >
> > So theory seems to tell me I need 3 turns.
> >
> >
> > Chuck
> >
> >
> >
> > 
> > From: kd9sv 
> > Sent: Sunday, July 15, 2018 4:43 PM
> > To: 'Chuck Hutton'
> > Subject: RE: Topband: Beverage transformers tht work down to 630 m
> >
> > Guys, the 4x rule is to my understanding that the measured impedance at
> the
> > lowest frequency to be used at should be at least 4 times the operating
> > impedance.  In other words a 50 ohm system would require 200 ohms open
> > circuit impedance measured at the primary winding of the xfmr.  If 2
> turns
> > only measures about 100 ohms then 3 turns would likely be close enough
> and 4
> > turns would also work and would measure 400 ohms which is 8 times the
> > operating impedance of the antenna system.  My test equipment can only
> > measure down to about 450khz so below that I cannot give an opinion.
> >
> > 73, de gary...ps: the BN202-73 will likely work well with two/6 turns and
> > 3/9 for a 9:1 system for 50 ohms
> > -Original Message-
> > From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Chuck
> > Hutton
> > Sent: Sunday, July 15, 2018 7:26 PM
> > To: Tim Shoppa
> > Cc: topband@contesting.com
> > Subject: Re: Topband: Beverage transformers tht work down to 630 m
> >
> > Tim:
> >
> >
> > Thanks for digging that out. It makes me worry much less about using
> > BN73-303's with 2 or 3 turns in the primary at 630m.
> >
> >
> > My only problem is that I don't understand why the low end is so good for
> > the 1 turn primary. Using the "4x" rule for the transformer, 4 turns
> should
> > be needed.
> >
> > Since I don't understand the response and I don't care about the high end
> > response, I'm still tempted to use 4 turns and be sure.
> >
> >
> > Perhaps part of the answer is that reality and theory do not coincide.
> > According to the published Al, 2.7 turns is need at 500 kHz. to have 64
> uH
> > and satisfy the 4X rule. Yet my 3 turn windings measure 108 uH and 120
> uH.
> > That explains a good bit of the low end response.
> >
> >
> > Chuck
> >
> >
> >
> > 
> > From: Tim Shoppa 
> > Sent: Sunday, July 15, 2018 3:50 PM
> > To: Chuck Hutton
> > Cc: topband@contesting.com
> > Subject: Re: Topband: Beverage transformers tht work down to 630 m
> >

Re: Topband: Beverage transformers tht work down to 630 m

[Chuck Hutton]

Tim -


What spec on 73 material are you referring to? I have never seen a published Al 
value for the 287300292 (BN73-202). Here's the Fair-Rite page with the 
287300292:

https://www.fair-rite.com/product-category/suppression-components/multi-aperture-cores/

And here's the Amidon page for the BN73-202:

http://www.amidoncorp.com/bn-73-202/


The BN73-202 has been discussed before here and Al of 8500 was quoted. However, 
way back upon prodict release someone posted an Al od 2500.   Kits and Parts 
quote an Al of 12000. My rqo caores have an average Al of 13,333.  I;ve seen no 
manufacturer Al data.


But bottom line I think we borh believe the true Al is higher than might be 
believed and therefore better low end response.


Note these turns versus frequency curves:

http://www.qsl.net/in3otd/ham_radio/160m_transformers/160m_trafos.html


The 3rd chart down is the heart of the issue.


Two turns is of the edge of the cliff. Better to use 3 turns I believe.


Chuck.





From: Tim Shoppa 
Sent: Monday, July 16, 2018 5:07 AM
To: Chuck Hutton
Cc: kd9sv; topband@contesting.com
Subject: Re: Topband: Beverage transformers tht work down to 630 m

I think the spec on 73 material permeability is also conservative. Few EMI 
suppressing customers suffer if the impedance is higher than guaranteed. The 
Fair-Rite 73 curves also show permeability peaking up even higher in the 500 
kHz region.

W8JI has in the past made some remarks about stray winding capacitance which 
would get worse with more turns. I believe his drawing shows some “dummy turns” 
put in on the far side of ground, to cancel the stray capacitance?

An important advantage of fewer turns, is that you can use ordinary plastic 
insulated hookup wire or kynar wire wrap wire to put the small number of turns 
through the holes. If I use enamel magnet wire with these cores to get more 
turns I end up nicking the enamel insulation on the core corners.

Tim N3QE

> On Jul 15, 2018, at 8:49 PM, Chuck Hutton  wrote:
>
> Yes, I think we all agree on the meaning of the 4X rule and the other basics.
>
> The mystery to me remains that a 1 turn transformer was good to 270 kHz in 
> the Clifton data. I calculate at 500 kHz:
>
> 1 turn on a BN73-202 with Al = 8500 gives 9 uH
>
> 9 uH is only 28 Ohms
>
> For reference, 2 turns = 34 uH and 107 Ohms. 3 turns is 77 uH and 242 Ohms.
>
>
> So theory seems to tell me I need 3 turns.
>
>
> Chuck
>
>
>
> 
> From: kd9sv 
> Sent: Sunday, July 15, 2018 4:43 PM
> To: 'Chuck Hutton'
> Subject: RE: Topband: Beverage transformers tht work down to 630 m
>
> Guys, the 4x rule is to my understanding that the measured impedance at the
> lowest frequency to be used at should be at least 4 times the operating
> impedance.  In other words a 50 ohm system would require 200 ohms open
> circuit impedance measured at the primary winding of the xfmr.  If 2 turns
> only measures about 100 ohms then 3 turns would likely be close enough and 4
> turns would also work and would measure 400 ohms which is 8 times the
> operating impedance of the antenna system.  My test equipment can only
> measure down to about 450khz so below that I cannot give an opinion.
>
> 73, de gary...ps: the BN202-73 will likely work well with two/6 turns and
> 3/9 for a 9:1 system for 50 ohms
> -Original Message-
> From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Chuck
> Hutton
> Sent: Sunday, July 15, 2018 7:26 PM
> To: Tim Shoppa
> Cc: topband@contesting.com
> Subject: Re: Topband: Beverage transformers tht work down to 630 m
>
> Tim:
>
>
> Thanks for digging that out. It makes me worry much less about using
> BN73-303's with 2 or 3 turns in the primary at 630m.
>
>
> My only problem is that I don't understand why the low end is so good for
> the 1 turn primary. Using the "4x" rule for the transformer, 4 turns should
> be needed.
>
> Since I don't understand the response and I don't care about the high end
> response, I'm still tempted to use 4 turns and be sure.
>
>
> Perhaps part of the answer is that reality and theory do not coincide.
> According to the published Al, 2.7 turns is need at 500 kHz. to have 64 uH
> and satisfy the 4X rule. Yet my 3 turn windings measure 108 uH and 120 uH.
> That explains a good bit of the low end response.
>
>
> Chuck
>
>
>
> 
> From: Tim Shoppa 
> Sent: Sunday, July 15, 2018 3:50 PM
> To: Chuck Hutton
> Cc: topband@contesting.com
> Subject: Re: Topband: Beverage transformers tht work down to 630 m
>
> I agree the usual rule of thumb (Transformer winding Z should be several
> times larger than nominal line impedance) would cause you to think you
> should have more turns.
>
> The old Clifton Labs website is no more. But an archived page of
> measurements of transformers shows that the frequency response extends well
> below what you might think, from the rule of thumb. Archived page:
> 

Re: Topband: Power / Control cable

[Richard (Rick) Karlquist]

On 7/16/2018 8:36 AM, Eric NO3M wrote:
I'm in the process of finding a replacement cable to supply power 
(+24VDC) and differential serial signaling (RS-485) to my remote RX 
switching matrix and vertical arrays.  Total run is about 600ft. The 


Consider converting your remote equipment to run on 48 volts.
It's very simple these days.  Go to mouser.com and search on
DC to DC converters made by "MEAN WELL".  Easy and cheap.
Now you can drop down 6 gauges on your cable; that's 1/4 of
the copper you had before.  Since the DC to DC converters
also regulate, you might be able to go to even smaller wires
by feeding say 60V out to the remote.

At the control end, add a +24 to -24V converter that runs off
your existing +24 supply.  The remote converter has an isolated
input so you can run it on +/-24V for its 48V input.  This
avoids any shock hazard since no voltage is more than 24V
from ground, as before.

Rick N6RK
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Re: Topband: Power / Control cable

[Joe Subich, W4TV]

If you don't need twisted pair for the signaling lines, look at multi-
wire sprinkler cables.  The big box stores list them in 18/4, 18/5,
18/7, and 18/10 in 500 ft rolls.  Should be available from the sprinkler
supply houses in 1000' spools.  Sprinkler cable may be a bit more rugged
than CAT5 (#18 vs. #24) ...

OTOH the big box stores seem to be more expensive (18/5 x 500' @ $155)
than places like Cable Wholesale (1000' gel filled direct burial
*copper* CAT5e @ $110).


73,

   ... Joe, W4TV


On 2018-07-16 11:36 AM, Eric NO3M wrote:
I'm in the process of finding a replacement cable to supply power 
(+24VDC) and differential serial signaling (RS-485) to my remote RX 
switching matrix and vertical arrays.  Total run is about 600ft. The 
original cable was outdoor rated, gel infused CAT5 using 3-cond for 
VDC+, 3-cond for VDC-, and the remaining two cond for serial. It lasted 
almost 7 years.


Recent searches for a reasonably priced replacement CAT5 have brought up 
a lot of candidates, but with CCA (copper clad aluminum) conductors. I'd 
prefer pure copper as far as the power lines are concerned, but price 
increases dramatically.


Any recommendations on a suitable and decently priced cable to do the 
job, supplier?  Perhaps parallel runs of 18/2 or 16/2, 18/4 or 16/4, or 
a good deal for CAT5 with pure copper?


Thanks
73 Eric NO3M

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Re: Topband: KH1 QSL's on LOTW

[Wes Stewart]

Despite several emails to clear up the fact that I donated but wasn't on the 
donor list, I was assured that I was and would be getting early LoTW 
confirmation.  Didn't happen.


Although I have enough paper cards to have 100 confirmed I've been waiting for 
some time for #100 via LoTW.  This one would be it. Oh, well.


Wes  N7WS

On 7/16/2018 7:18 AM, Bill Gillenwater wrote:

For those who donated to the KH1 effort, the QSL's hit LOTW.

73 Bill K3SV
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Topband Reflector Archives - http://www.contesting.com/_topband

Topband: Power / Control cable

[Eric NO3M]

I'm in the process of finding a replacement cable to supply power 
(+24VDC) and differential serial signaling (RS-485) to my remote RX 
switching matrix and vertical arrays.  Total run is about 600ft. The 
original cable was outdoor rated, gel infused CAT5 using 3-cond for 
VDC+, 3-cond for VDC-, and the remaining two cond for serial. It lasted 
almost 7 years.


Recent searches for a reasonably priced replacement CAT5 have brought up 
a lot of candidates, but with CCA (copper clad aluminum) conductors.  
I'd prefer pure copper as far as the power lines are concerned, but 
price increases dramatically.


Any recommendations on a suitable and decently priced cable to do the 
job, supplier?  Perhaps parallel runs of 18/2 or 16/2, 18/4 or 16/4, or 
a good deal for CAT5 with pure copper?


Thanks
73 Eric NO3M

_
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Topband: KH1 QSL's on LOTW

[Bill Gillenwater]

For those who donated to the KH1 effort, the QSL's hit LOTW.

73 Bill K3SV
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Re: Topband: FT8 Tonight

[Grant Saviers]

Interesting.  Must be a fun place in the middle of Antarctic winter and 
keeping a 160m antenna up.  OTOH, they can lay wire on the ice for a 660 
ft elevated dipole.


I had 3 SSB QSO's with them on 20m when I was MM in the Southern Ocean 
Jan 2017.  From the newbies on the radio I think getting a ham license 
is a popular recreation.


Grant KZ1W

On 7/15/2018 21:15 PM, W0MU Mike Fatchett wrote:
Once again being decoded at DP0GVN  -15db.  No contact is it appear 
they are just listening.


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Re: Topband: Beverage transformers tht work down to 630 m

[Tim Shoppa]

I think the spec on 73 material permeability is also conservative. Few EMI 
suppressing customers suffer if the impedance is higher than guaranteed. The 
Fair-Rite 73 curves also show permeability peaking up even higher in the 500 
kHz region.

W8JI has in the past made some remarks about stray winding capacitance which 
would get worse with more turns. I believe his drawing shows some “dummy turns” 
put in on the far side of ground, to cancel the stray capacitance?

An important advantage of fewer turns, is that you can use ordinary plastic 
insulated hookup wire or kynar wire wrap wire to put the small number of turns 
through the holes. If I use enamel magnet wire with these cores to get more 
turns I end up nicking the enamel insulation on the core corners.

Tim N3QE

> On Jul 15, 2018, at 8:49 PM, Chuck Hutton  wrote:
> 
> Yes, I think we all agree on the meaning of the 4X rule and the other basics.
> 
> The mystery to me remains that a 1 turn transformer was good to 270 kHz in 
> the Clifton data. I calculate at 500 kHz:
> 
> 1 turn on a BN73-202 with Al = 8500 gives 9 uH
> 
> 9 uH is only 28 Ohms
> 
> For reference, 2 turns = 34 uH and 107 Ohms. 3 turns is 77 uH and 242 Ohms.
> 
> 
> So theory seems to tell me I need 3 turns.
> 
> 
> Chuck
> 
> 
> 
> 
> From: kd9sv 
> Sent: Sunday, July 15, 2018 4:43 PM
> To: 'Chuck Hutton'
> Subject: RE: Topband: Beverage transformers tht work down to 630 m
> 
> Guys, the 4x rule is to my understanding that the measured impedance at the
> lowest frequency to be used at should be at least 4 times the operating
> impedance.  In other words a 50 ohm system would require 200 ohms open
> circuit impedance measured at the primary winding of the xfmr.  If 2 turns
> only measures about 100 ohms then 3 turns would likely be close enough and 4
> turns would also work and would measure 400 ohms which is 8 times the
> operating impedance of the antenna system.  My test equipment can only
> measure down to about 450khz so below that I cannot give an opinion.
> 
> 73, de gary...ps: the BN202-73 will likely work well with two/6 turns and
> 3/9 for a 9:1 system for 50 ohms
> -Original Message-
> From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Chuck
> Hutton
> Sent: Sunday, July 15, 2018 7:26 PM
> To: Tim Shoppa
> Cc: topband@contesting.com
> Subject: Re: Topband: Beverage transformers tht work down to 630 m
> 
> Tim:
> 
> 
> Thanks for digging that out. It makes me worry much less about using
> BN73-303's with 2 or 3 turns in the primary at 630m.
> 
> 
> My only problem is that I don't understand why the low end is so good for
> the 1 turn primary. Using the "4x" rule for the transformer, 4 turns should
> be needed.
> 
> Since I don't understand the response and I don't care about the high end
> response, I'm still tempted to use 4 turns and be sure.
> 
> 
> Perhaps part of the answer is that reality and theory do not coincide.
> According to the published Al, 2.7 turns is need at 500 kHz. to have 64 uH
> and satisfy the 4X rule. Yet my 3 turn windings measure 108 uH and 120 uH.
> That explains a good bit of the low end response.
> 
> 
> Chuck
> 
> 
> 
> 
> From: Tim Shoppa 
> Sent: Sunday, July 15, 2018 3:50 PM
> To: Chuck Hutton
> Cc: topband@contesting.com
> Subject: Re: Topband: Beverage transformers tht work down to 630 m
> 
> I agree the usual rule of thumb (Transformer winding Z should be several
> times larger than nominal line impedance) would cause you to think you
> should have more turns.
> 
> The old Clifton Labs website is no more. But an archived page of
> measurements of transformers shows that the frequency response extends well
> below what you might think, from the rule of thumb. Archived page:
> https://groups.io/g/BITX20/attachment/27529/0/clifton%20Labs%20IMD%20in%20Br
> oadband%20Transformers.pdf
> Clifton Laboratories 7236 Clifton Road Clifton VA 20124
> ... 20Broadband%20Transformers.pdf>
> groups.io
> Clifton Laboratories 7236 Clifton Road Clifton VA 20124 tel: (703) 830 0368
> fax: (703) 830 0711 E-mail: jack.sm...@cliftonlaboratories.com
> 
> 
> 
> He finds that BN73-202 transformers wound with a single turn winding, have a
> -3dB point at 270kHz.. A two turn winding would be good 4 times as low. So
> the rule of thumb seems very conservative.
> 
> I have made step-up power converters using these cores and have been super
> impressed how well they work at frequencies well below the rule of thumb. I
> have run 30+ watts through these dinky cores with them just barely getting
> warm.
> 
> Tim N3QE
> 
> On Sun, Jul 15, 2018 at 6:29 PM, Chuck Hutton
> mailto:charle...@msn.com>> wrote:
> The commercially available Beverage transformers I have seen are like the
> W8JI model: 2 primary turns on a BN73-202 core.
> 
> My calculations say 4 turns are needed at 630 m.
> 
> 
> Does anyone know of 

Re: Topband: Beverage transformers tht work down to 630 m

[Tracey Gardner via Topband]

There are a couple of good articles on this subject by John Bryant with Bill 
Bowers and Nick Hall-Patch , VE7DXR and the other by Mark Connelly WA1ION which 
are worth taking a look at.
The first article includes measurements from 100kHz up to 7MHz.

www.dxing.info/equipment/impedance_matching_bryant.doc

http://www.qsl.net/wa1ion/bev/bb_antenna_matching.pdf


73s Tracey G5VU

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