> On Tuesday, August 20, 2019 at 8:00:20 PM UTC-7, amdx wrote:
>> On 8/20/2019 12:47 PM, amdx wrote:
>>> On 8/20/2019 11:11 AM, Tim Williams wrote:
>>>> "amdx" <nojunk@knology.net> wrote in message
>
>> >> I had a BOG before and used a bedds...
>>
>> >I still don't know what you're writing. It ain't English...
>>
>> >Well, "bog" aside. But that means something different in English
>> >English.
>> >;-)
>>
>> I'll try to get a good nights sleep tonight!
>> BOG = Beverage On Ground
>
> Sun streaking cold
> An old man wandering lonely
> Taking time
> The only way he knows
> Leg hurting bad
> As he bends to pick a dog-end
> He goes down to the BOG
> And warms his feet
> Feeling alone
> The army's up the road
> Salvation a la mode and
> A cup of tea
>
BOG = Beverage On Ground
A beverage antenna is generally described as a 1 wavelength antenna,
(more or less)
Mike
Reply by Simon S Aysdie●August 23, 20192019-08-23
On Tuesday, August 20, 2019 at 8:00:20 PM UTC-7, amdx wrote:
> On 8/20/2019 12:47 PM, amdx wrote:
> > On 8/20/2019 11:11 AM, Tim Williams wrote:
> >> "amdx" <nojunk@knology.net> wrote in message
> >> I had a BOG before and used a bedds...
>
> >I still don't know what you're writing. It ain't English...
>
> >Well, "bog" aside. But that means something different in English
> >English.
> >;-)
>
> I'll try to get a good nights sleep tonight!
> BOG = Beverage On Ground
Sun streaking cold
An old man wandering lonely
Taking time
The only way he knows
Leg hurting bad
As he bends to pick a dog-end
He goes down to the BOG
And warms his feet
Feeling alone
The army's up the road
Salvation a la mode and
A cup of tea
Reply by amdx●August 22, 20192019-08-22
On 8/22/2019 12:43 PM, upsidedown@downunder.com wrote:
> On Tue, 20 Aug 2019 12:47:54 -0500, amdx <nojunk@knology.net> wrote:
>
>> On 8/20/2019 11:11 AM, Tim Williams wrote:
>>> "amdx" <nojunk@knology.net> wrote in message
>>> news:qjgbfo$1la$1@dont-email.me...
>>>> In previous responses I gave the proposed use is for a
>>>> "Beverage on Ground" antenna.
>
> I have some understanding of normal Beverages, but are there reliable
> comparative data for BOG or slinky antennas ? Until there are some
> reliable comporarative and calibrated comparison between real Beverages
> and BOGs and slinky antennas I really do not want to mess with them.
>
If I had 1000ft to put up a Beverage, I would. I have a 10ft by
250ft area that is great for a Bog. I don't know any comparison papers.
I just know I had 3 antennas, The BOG was the best listening to the
North from the gulf.
>
>>>> I had a BOG before and used a beads that had a Q of 1 or 2.
>>>> so if I could get 20 it would be better.
>
> The main selling point of Beverages is that it is wide band, you
> definitely _do_not_ want any high-Q (i.e. low bandwidth) constructs.
Yes but when it is short you lose directivity.
Mikek
Reply by ●August 22, 20192019-08-22
On Wed, 21 Aug 2019 14:37:58 -0500, amdx <nojunk@knology.net> wrote:
>On 8/21/2019 11:10 AM, legg wrote:
>> On Wed, 21 Aug 2019 07:59:39 -0500, amdx <nojunk@knology.net> wrote:
>>
>>> On 8/21/2019 1:55 AM, Jasen Betts wrote:
>>>> On 2019-08-21, legg <legg@nospam.magma.ca> wrote:
>>>>> On Tue, 20 Aug 2019 14:06:17 -0500, amdx <nojunk@knology.net> wrote:
>>>>>
>>>>>> On 8/20/2019 11:41 AM, legg wrote:
>>>>>>> On Mon, 19 Aug 2019 19:53:28 -0500, amdx <nojunk@knology.net> wrote:
>>>>>>>
>>>>>>>> I'd like to have a Variable 100uh inductor, that is controlled to full
>>>>>>>> saturation with dc through the 100uh coil.
>>>>>>>> I see some two winding coils, but the dc control winding has huge
>>>>>>>> inductance. Working range 500kHz to 4MHz.
>>>>>>>> Is this possible?
>>>>>>>>
>>>>>>>> Thanks for your thoughts, Mikek
>>>>>>> A cpnventional current-controlled inductor has two magnetic paths that
>>>>>>> are configured to carry antiphase windings, with the third 'inductor
>>>>>>> winding sharing both. The control windings' AC flux, from the third
>>>>>>> winding, cancels out.
>>>>>>>
>>>>>>> You can do this with an e-core (control windings on outer arms), two
>>>>>>> toroids (each with control winding - sandwitched to support single
>>>>>>> 'inductor' winding around both) or solenoids (two solenoid cores
>>>>>>> support control windings, 'inductor' wound around both.).
>>>>>>>
>>>>>>> RL
>>>>>>>
>>>>>>
>>>>>> As state previously, My question was not ask well, I only want one
>>>>>> winding with both ac and the dc to saturate it.
>>>>>>
>>>>>> Thanks, Mikek
>>>>>
>>>>> An ideal current source is easy to simulate, but in real life, it's
>>>>> voltage compliance limits, stray loading and real power loss will set
>>>>> limits on what you can do.
>>>>>
>>>>> The conventional multiple winding is the more realistic approach.
>>>>>
>>>>> Parasitics from the lower-powered control circuit are also easier to
>>>>> isolate.
>>>>>
>>>>> RL
>>>>
>>>> AIUI this is for a recieve antenna so the AC signal will be failrly
>>>> small, I expect that the current source only needs enough compliance
>>>> to overcome earth resistance and a little headroom.
>>>>
>>> It is a receive only antenna.
>>> And if you are suggesting a dc return through the earth, that was not
>>> part of my plan. I think electrolysis would be a problem..
>>> So a two wire dc system.
>>> Mikek
>>
>>
>> I don't see such a restriction to be a valid design goal in a new
>> product. What's the selling point? Electrolysis????? Even in a
>> retrofit, the addition of an external field-generating winding might
>> be easiest.
>>
>> A modest current source can be decoupled from a tuned/tuning circuit,
>> over a known frequency range using a series choke. In small signal
>> circuitry, it's an issue you'd try to avoid, as resistors do the job
>> pretty well at low current.
>>
>> A tuned circuit with an ungrounded terminal might benefit from a
>> re-examination of the schematic. Ground is, after all, everywhere. You
>> should use that feature, rather than compound it's potential problems.
>>
>> If the aim is repeatable, calibratable 'L' values, I forsee a host of
>> issues with this technique.
>>
>> Closed circuit, low frequency magnetics have to be re-evaluated for
>> function, when located within close proximity to large magnets, but a
>> magnet on a stick doesn't fit in well with typical solid-state circuit
>> aims.
>>
>> RL
>>
>
> Start here.
>> https://www.w8ji.com/beverages.htm
>
>Then see Loaded beverages here,
>> https://www.w8ji.com/slinky_and_loaded_beverages.htm
>
> Now, I want to load a beverage on ground.
>I don't have enough room for BOG long enough to have good
>directionality in the BCB, therefore, I want to load it,
Beverages are nice, _if_ you have space for 0.5 - 2 wavelengths long
wires. If you don't have that space, you should seriously really study
other antenna alternatives.
>reducing the VF and changing the pattern.
> If it is loaded to make it directional at 1MHz then it doesn't look
>good at 4 MHz, So I want variable inductors.
So a 150 m long Beverage is 0.5 wavelengths at 1 MHz and 2 wavelengths
at 4 MHz.
Have you considered installing a grounding resistor at 38 m (for 4
MHz) and at 75 m (for 2 MHz) and final termination resistance at 150 m
(for 1 MHz) ? The intermediate grounding resistors are then selected
by relays. Feed some audio tones along the wire to activate those
intermediate relays (with some audio frequency selective rectifiers).
> It doesn't look good, the mixing products concerns me and finding a
>material or combination that I can cause to reduce inductance as
>frequency increases is not jumping out.
If you use relays to select grounding point no need to worry about
ferrite nonlinearity or mixing products.
>
> Thanks, Mikek
>
>
>
Reply by ●August 22, 20192019-08-22
On Wed, 21 Aug 2019 16:52:01 -0500, amdx <nojunk@knology.net> wrote:
>On 8/20/2019 10:00 PM, amdx wrote:
>> On 8/20/2019 12:47 PM, amdx wrote:
>>> On 8/20/2019 11:11 AM, Tim Williams wrote:
>>>> "amdx" <nojunk@knology.net> wrote in message
>>>> news:qjgbfo$1la$1@dont-email.me...
>>>>> In previous responses I gave the proposed use is for a
>>>>> "Beverage on Ground" antenna.
>>>>> �I had a GOG before and used a beds that had a Q of 1 or 2.
>>>>> �so if I could get 20 it would be better.
>>>>
>>>> What power level?� Frequency range?
>>>>
>>>> Tim
>>>>
>>> ��Man, what time did I write the above?
>>> What I meant to say was,
>>> I had a BOG before and used a bedds that had a Q of 1 or 2.
>>> �� so if I could get 20 it would be better.
>>>
>>> It's for a receive only antenna, so microwatts, maybe milliwatts.
>>> 500kHz to 4 MHz.
>>>
>>> ��������������������������������� Mikek
>>>
>>> ��Another possible solution,
>>> ��Is there a combination of L's and Cs the would approximate such an L
>>> reduction over frequency?
>>>
>> �One of those times, I could see you posted but nothing in the post, so
>> I went to google groups.
>>
>> >>� Man, what time did I write the above?
>> >> What I meant to say was,
>> >> I had a BOG before and used a bedds that had a Q of 1 or 2.
>> >>�� so if I could get 20 it would be better.
>>
>> >I still don't know what you're writing.� It ain't English...
>>
>> >Well, "bog" aside.� But that means something different in English
>> >English.
>> >;-)
>>
>> I'll try to get a good nights sleep tonight!
>> �BOG = Beverage On Ground
>> �bedds was supposed to be beads/sleeves which were actually a #73
>> binocular core that I only used one hole of. I just passed the antenna
>> wire through it. About 24 ohms R and 42 ohm XL at 1MHz.
>>
>>
>> >>
>> >> It's for a receive only antenna, so microwatts, maybe milliwatts.
>> >> 500kHz to 4 MHz.
>>
>> >What about just low noise JFETs?� It's not like you need any antenna
>> >gain in
>> >those bands.
>>
>> Well, maybe, but usually the receive has enough gain, the bog signal is
>> down, maybe -25dbi to -40dbi.
>> But that is not the problem, by adjusting characteristics with frequency
>> you can narrow the beam width and increase the front to back ratio.
>> btw, I do have a high input impedance FET follower with low output
>> impedance, no gain but you do unload the antenna so get 3db. I'll be
>> trying that.
>
> I had the Gain from adding a FET follower incorrect, unloading the
>antenna gets you 3 db, then not have a 450ohm:50ohm impedance matching
>(step down) transformer gives you another ~10db. Probably not quite as
>much on a BOG because it has a lower feed impedance.
>> https://www.okdxf.eu/lankford/J310%20-%20J271%20FET%20Follower.pdf
>
>Ignore the chest pounding by Lankford he had a spat going with Trask,
>may still have.
> Mikek
A simple passive stage (such as a transformer), can have voltage or
current gain but the power gain is at best 0 dB. To have real power
gain, you need an active device.
Reply by ●August 22, 20192019-08-22
On Tue, 20 Aug 2019 12:47:54 -0500, amdx <nojunk@knology.net> wrote:
>On 8/20/2019 11:11 AM, Tim Williams wrote:
>> "amdx" <nojunk@knology.net> wrote in message
>> news:qjgbfo$1la$1@dont-email.me...
>>> In previous responses I gave the proposed use is for a
>>> "Beverage on Ground" antenna.
I have some understanding of normal Beverages, but are there reliable
comparative data for BOG or slinky antennas ? Until there are some
reliable comporarative and calibrated comparison betwen real Beverages
an BOGs and slinki antennas I really do not want to mess with them.
>>> �I had a GOG before and used a beds that had a Q of 1 or 2.
>>> �so if I could get 20 it would be better.
The main selling point of Beverages is that it is wide band, you
definitely _do_not_ want any high-Q (i.e. low bandwidth) constructs.
>>
>> What power level?� Frequency range?
>>
>> Tim
>>
> Man, what time did I write the above?
>What I meant to say was,
>I had a BOG before and used a bedds that had a Q of 1 or 2.
> so if I could get 20 it would be better.
>
>It's for a receive only antenna, so microwatts, maybe milliwatts.
>500kHz to 4 MHz.
>
> Mikek
>
> Another possible solution,
> Is there a combination of L's and Cs the would approximate such an L
>reduction over frequency?
Reply by Tim Williams●August 22, 20192019-08-22
"amdx" <nojunk@knology.net> wrote in message
news:qjhg76$qde$1@dont-email.me...
> Can you explain physically how that would look? My only experience with
> half turns is, we put a 4-1/2 turn inductor in a medium power circuit.
> The coil over heated, 4 turns were fine, 5 turns were fine, we never did
> a half turn inductor again.
> OH wait you only mean a single half turn as we did above, so if I need 12
> turns make it 12-1/2 turns. Is that correct?
> Any way to do 1/2 turn on a toroid?
I wrote an article in part discussing that, recently:
https://www.seventransistorlabs.com/DC-DC_RE/index.html
Measurements are included, showing the imbalance in external flux.
The correct way to make half turns is to put a figure-eight winding on the
legs to enforce flux balance. These can even be intentionally unbalanced
(say 1:2), to get even more interesting fractions of turns (1/3, 1/4, etc.).
With a corresponding hit in Phi_sat of course, because the one side
saturates first. I link to a Unitrode appnote which discusses this.
Tim
--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/
Reply by Phil Hobbs●August 21, 20192019-08-21
On 8/21/19 8:57 PM, jlarkin@highlandsniptechnology.com wrote:
> On Wed, 21 Aug 2019 20:36:36 -0400, Phil Hobbs
> <pcdhSpamMeSenseless@electrooptical.net> wrote:
>
>> On 8/21/19 7:50 PM, amdx wrote:
>>> On 8/21/2019 4:45 PM, Phil Hobbs wrote:
>>>> On 8/20/19 3:04 PM, amdx wrote:
>>>>> On 8/20/2019 11:28 AM, Phil Hobbs wrote:
>>>>>> On 8/20/19 4:41 AM, Clive Arthur wrote:
>>>>>>> On 20/08/2019 01:53, amdx wrote:
>>>>>>>> I'd like to have a Variable 100uh inductor, that is controlled
>>>>>>>> to full saturation with dc through the 100uh coil. I see some
>>>>>>>> two winding coils, but the dc control winding has huge inductance.
>>>>>>>> Working range 500kHz to 4MHz. Is this possible?
>>>>>>>>
>>>>>>>> Thanks for your thoughts, Mikek
>>>>>>>
>>>>>>> Some RM cores and pot cores have a central hole through which you
>>>>>>> could wind your 100uH, and the DC winding goes on the bobbin...
>>>>>>>
>>>>>>> https://uk.farnell.com/ferroxcube/rm10-i-3c95/ferrite-core-rm-i-3c95/dp/2103458?st=rm%20core
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> ...this is a 5.5uH core so approx 4 turns for 100uH if it were
>>>>>>> wound on the bobbin, I don't know how many if wound through the
>>>>>>> hole, but I'd guess it would be similar. I'd try to grind the
>>>>>>> hole edges to take off the sharp edge if possible.
>>>>>>>
>>>>>>> Cheers
>>>>>>
>>>>>> One minor tweak to that idea is to run an odd number of half-turns
>>>>>> on the bobbin, and use a high-mu pot core with an adjustable centre
>>>>>> gap.
>>>>>>
>>>>>> The extra half-turn will generate a large field going round the
>>>>>> outside of the core (avoiding the post) and so will saturate it
>>>>>> fairly readily.
>>>>>>
>>>>>> Cheers
>>>>>>
>>>>>> Phil Hobbs
>>>>>>
>>>>>>
>>>>> Can you explain physically how that would look?
>>>>
>>>> With pot cores you usually twist the two leads together and bring them
>>>> out through a slot in the side of the core. If there are two or more
>>>> slots, the wire goes in through one slot and comes out through a second
>>>> one, 180 degrees away.
>>>>
>>>>
>>>>> My only experience with half turns is, we put a 4-1/2 turn inductor
>>>>> in a medium power circuit. The coil over heated, 4 turns were fine, 5
>>>>> turns were fine, we never did a half turn inductor again. OH wait you
>>>>> only mean a single half turn as we did above, so if I need 12 turns
>>>>> make it 12-1/2 turns. Is that correct? Any way to do 1/2 turn on a
>>>>> toroid?
>>>>
>>>> Nope. It's just the threading count.
>>>
>>> Thread count? Huh?
>>>
>>> ^ Room for explanation ^
>>
>> Not like bed sheets. ;)
>>
>> The inductance contributed by the toroid goes as N**2, where N is the
>> number of times the wire goes through the aperture of the toroid. No
>> half turns need apply.
>>
>
>
> A half turn in a pot core can have impressively bad effects.
>
>
Yup. Or in this case, potentially useful ones.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.nethttp://hobbs-eo.com
Reply by ●August 21, 20192019-08-21
On Wed, 21 Aug 2019 20:36:36 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
>On 8/21/19 7:50 PM, amdx wrote:
>> On 8/21/2019 4:45 PM, Phil Hobbs wrote:
>>> On 8/20/19 3:04 PM, amdx wrote:
>>>> On 8/20/2019 11:28 AM, Phil Hobbs wrote:
>>>>> On 8/20/19 4:41 AM, Clive Arthur wrote:
>>>>>> On 20/08/2019 01:53, amdx wrote:
>>>>>>> I'd like to have a Variable 100uh inductor, that is controlled
>>>>>>> to full saturation with dc through the 100uh coil. I see some
>>>>>>> two winding coils, but the dc control winding has huge inductance.
>>>>>>> Working range 500kHz to 4MHz. Is this possible?
>>>>>>>
>>>>>>> Thanks for your thoughts, Mikek
>>>>>>
>>>>>> Some RM cores and pot cores have a central hole through which you
>>>>>> �could wind your 100uH, and the DC winding goes on the bobbin...
>>>>>>
>>>>>> https://uk.farnell.com/ferroxcube/rm10-i-3c95/ferrite-core-rm-i-3c95/dp/2103458?st=rm%20core
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> ...this is a 5.5uH core so approx 4 turns for 100uH if it were
>>>>>> wound on the bobbin, I don't know how many if wound through the
>>>>>> hole, but I'd guess it would be similar.� I'd try to grind the
>>>>>> hole edges to take off the sharp edge if possible.
>>>>>>
>>>>>> Cheers
>>>>>
>>>>> One minor tweak to that idea is to run an odd number of half-turns
>>>>> on the bobbin, and use a high-mu pot core with an adjustable centre
>>>>> gap.
>>>>>
>>>>> The extra half-turn will generate a large field going round the
>>>>> outside of the core (avoiding the post) and so will saturate it
>>>>> fairly readily.
>>>>>
>>>>> Cheers
>>>>>
>>>>> Phil Hobbs
>>>>>
>>>>>
>>>> Can you explain physically how that would look?
>>>
>>> With pot cores you usually twist the two leads together and bring them
>>> out through a slot in the side of the core.� If there are two or more
>>> slots, the wire goes in through one slot and comes out through a second
>>> one, 180 degrees away.
>>>
>>>
>>>> My only experience with half turns is, we put a 4-1/2 turn inductor
>>>> in a medium power circuit. The coil over heated, 4 turns were fine, 5
>>>> turns were fine, we never did a half turn inductor again. OH wait you
>>>> only mean a single half turn as we did above, so if I need 12 turns
>>>> make it 12-1/2 turns. Is that correct? Any way to do 1/2 turn on a
>>>> toroid?
>>>
>>> Nope.� It's just the threading count.
>>
>> Thread count? Huh?
>>
>> �^� Room for explanation ^
>
>Not like bed sheets. ;)
>
>The inductance contributed by the toroid goes as N**2, where N is the
>number of times the wire goes through the aperture of the toroid. No
>half turns need apply.
>
A half turn in a pot core can have impressively bad effects.
Reply by amdx●August 21, 20192019-08-21
On 8/21/2019 7:36 PM, Phil Hobbs wrote:
> On 8/21/19 7:50 PM, amdx wrote:
>> On 8/21/2019 4:45 PM, Phil Hobbs wrote:
>>> On 8/20/19 3:04 PM, amdx wrote:
>>>> On 8/20/2019 11:28 AM, Phil Hobbs wrote:
>>>>> On 8/20/19 4:41 AM, Clive Arthur wrote:
>>>>>> On 20/08/2019 01:53, amdx wrote:
>>>>>>> I'd like to have a Variable 100uh inductor, that is controlled
>>>>>>> to full saturation with dc through the 100uh coil. I see some
>>>>>>> two winding coils, but the dc control winding has huge
>>>>>>> inductance. Working range 500kHz to 4MHz. Is this possible?
>>>>>>>
>>>>>>> Thanks for your thoughts, Mikek
>>>>>>
>>>>>> Some RM cores and pot cores have a central hole through which you
>>>>>> could wind your 100uH, and the DC winding goes on the bobbin...
>>>>>>
>>>>>> https://uk.farnell.com/ferroxcube/rm10-i-3c95/ferrite-core-rm-i-3c95/dp/2103458?st=rm%20core
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> ...this is a 5.5uH core so approx 4 turns for 100uH if it were
>>>>>> wound on the bobbin, I don't know how many if wound through the
>>>>>> hole, but I'd guess it would be similar. I'd try to grind the
>>>>>> hole edges to take off the sharp edge if possible.
>>>>>>
>>>>>> Cheers
>>>>>
>>>>> One minor tweak to that idea is to run an odd number of half-turns
>>>>> on the bobbin, and use a high-mu pot core with an adjustable centre
>>>>> gap.
>>>>>
>>>>> The extra half-turn will generate a large field going round the
>>>>> outside of the core (avoiding the post) and so will saturate it
>>>>> fairly readily.
>>>>>
>>>>> Cheers
>>>>>
>>>>> Phil Hobbs
>>>>>
>>>>>
>>>> Can you explain physically how that would look?
>>>
>>> With pot cores you usually twist the two leads together and bring them
>>> out through a slot in the side of the core. If there are two or more
>>> slots, the wire goes in through one slot and comes out through a second
>>> one, 180 degrees away.
>>>
>>>
>>>> My only experience with half turns is, we put a 4-1/2 turn inductor
>>>> in a medium power circuit. The coil over heated, 4 turns were fine, 5
>>>> turns were fine, we never did a half turn inductor again. OH wait you
>>>> only mean a single half turn as we did above, so if I need 12 turns
>>>> make it 12-1/2 turns. Is that correct? Any way to do 1/2 turn on a
>>>> toroid?
>>>
>>> Nope. It's just the threading count.
>>
>> Thread count? Huh?
>>
>> ^ Room for explanation ^
>
> Not like bed sheets. ;)
>
> The inductance contributed by the toroid goes as N**2, where N is the
> number of times the wire goes through the aperture of the toroid. No
> half turns need apply.
>
>
>>
>> Just because I left out the details, my 4-1/2 turn inductor was a
>> potcore inductor, easy to add that 1/2 turn.
>
> Right. And that half turn completely changes the saturation behaviour,
> at least if the centre post has a gap.
>
> Cheers
>
> Phil Hobbs
>