Here you go. Use Fair Rite No. 31
Make your own chokes with Jims "cookbook"
http://k9yc.com/2018Cookbook.pdf
Bob
K6UJ
> On Nov 3, 2019, at 11:48 AM, GIL ARROYO <gilcanyon@comcast.net> wrote:
>
> How about a specific recommendation for HF Ferrites? gil KI7SJC
>
>
>> On November 3, 2019 at 9:00 AM towertalk-request@contesting.com wrote:
>>
>>
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>>
>> Today's Topics:
>>
>> 1. Re: Ferrites 31 vs. 77 material (jimlux)
>> 2. Ferrites 31 vs. 77 material (Jim Thomson)
>> 3. Re: Ferrites 31 vs. 77 material (jimlux)
>> 4. Re: Ferrites 31 vs. 77 material (David Gilbert)
>> 5. Re: Ferrites 31 vs. 77 material (Jack Brindle)
>> 6. Re: Ferrites 31 vs. 77 material (David Gilbert)
>> 7. Re: Ferrites 31 vs. 77 material (Don)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Sat, 2 Nov 2019 09:32:13 -0700
>> From: jimlux <jimlux@earthlink.net>
>> To: towertalk@contesting.com
>> Subject: Re: [TowerTalk] Ferrites 31 vs. 77 material
>> Message-ID: <a5380ed3-fb89-095a-9b4d-3473784f6f02@earthlink.net>
>> Content-Type: text/plain; charset=utf-8; format=flowed
>>
>> On 11/2/19 2:28 AM, Jim Brown wrote:
>>> On 11/1/2019 6:40 PM, Roger Parsons via TowerTalk wrote:
>>>> I would imagine that processing has improved since then, but this must
>>>> still be to some extent true.
>>>
>>> You have a vivid imagination. :) I have measured data to prove that.
>>> Also see N6RK's post. As luck would have it, I gave a talk to a Silicon
>>> Valley club tonight on a very different topic, but afterwards fielded
>>> questions about chokes from several engineers who had worked in
>>> manufacturing. When I described my work described in an earlier post
>>> about dealing with component tolerances, they nodded their heads in
>>> agreement.
>>>
>>> My first gig after college was at Motorola, which is where I first
>>> learned that a circuit design has to work with every part that gets
>>> plugged in to the circuit board, which means that the design has to work
>>> with components with tolerances that you can and did buy.
>>>
>>
>>
>> I haven't checked the catalogs, but I'll bet that the tolerances for
>> parts intended for general purpose choking and transformers are wider
>> than those intended for building inductors. If a transformer core has a
>> higher mu than expected, it still works just fine as a transformer,
>> barring issues with loss and/or self resonance. Likewise, for something
>> being used as a lossy choke (as opposed to a resonant choke) you just
>> care that the loss is high enough - if it's twice as high as you
>> expected that's all the better.
>>
>> On the other hand, if you're buying inductors for filters or for
>> switching power supplies, the core material has to be pretty consistent.
>>
>> Since there *is* some crossover among applications for cores, you could
>> wind up using a poor tolerance core and having it work in a high
>> tolerance application, as a prototype.
>>
>>
>>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Sat, 2 Nov 2019 10:18:23 -0700
>> From: "Jim Thomson" <jim.thom@telus.net>
>> To: <towertalk@contesting.com>
>> Subject: [TowerTalk] Ferrites 31 vs. 77 material
>> Message-ID: <55DEC5CD8B0146FCA2EBBE3276D17FC0@DESKTOPSV54DBH>
>> Content-Type: text/plain; charset="utf-8"
>>
>> Date: Sat, 2 Nov 2019 13:25:19 +0000 (UTC)
>> From: Roger Parsons <ve3zi@yahoo.com>
>> To: "Tower and HF Antenna Construction Topics."
>> <towertalk@contesting.com>, "jim@audiosystemsgroup.com"
>> <jim@audiosystemsgroup.com>
>> Subject: [TowerTalk] Ferrites 31 vs. 77 material
>>
>> <Very funny.
>> <The posts from both N6RK and AB7E support my statement that variability in
>> ferrite parameters has been known for a very long time. You're the one who
>> asserted that it has just been discovered and that therefore Steve G3TXQ
>> could not have known about it.
>>
>> <73 RogerVE3ZI
>>
>> ## I believe it was N3RR that bought 700, (seven hundred) type
>> 31 cores from one supplier, all from the same lot number..2 years
>> ago. He used a simple 1 turn link to test them..and then graded them.
>> They were all over the map, + and ? 22%. Thats a whopping 44%
>> spread. No 2 ferrites the same! ALL made in China......so what do
>> you expect ? So much for fairite moving their factory to China. QC
>> down the tubes ever since.
>>
>> Jim VE7RF
>>
>>
>>
>> ------------------------------
>>
>> Message: 3
>> Date: Sat, 2 Nov 2019 10:51:26 -0700
>> From: jimlux <jimlux@earthlink.net>
>> To: towertalk@contesting.com
>> Subject: Re: [TowerTalk] Ferrites 31 vs. 77 material
>> Message-ID: <9213c7ec-2021-0f3e-6424-f68844ac6650@earthlink.net>
>> Content-Type: text/plain; charset=utf-8; format=flowed
>>
>> On 11/2/19 10:18 AM, Jim Thomson wrote:
>>> Date: Sat, 2 Nov 2019 13:25:19 +0000 (UTC)
>>> From: Roger Parsons <ve3zi@yahoo.com>
>>> To: "Tower and HF Antenna Construction Topics."
>>> <towertalk@contesting.com>, "jim@audiosystemsgroup.com"
>>> <jim@audiosystemsgroup.com>
>>> Subject: [TowerTalk] Ferrites 31 vs. 77 material
>>>
>>> <Very funny.
>>> <The posts from both N6RK and AB7E support my statement that variability in
>>> ferrite parameters has been known for a very long time. You're the one who
>>> asserted that it has just been discovered and that therefore Steve G3TXQ
>>> could not have known about it.
>>>
>>> <73 RogerVE3ZI
>>>
>>> ## I believe it was N3RR that bought 700, (seven hundred) type
>>> 31 cores from one supplier, all from the same lot number..2 years
>>> ago. He used a simple 1 turn link to test them..and then graded
>>> them. They were all over the map, + and ? 22%. Thats a whopping 44%
>>> spread. No 2 ferrites the same! ALL made in China......so what
>>> do you expect ? So much for fairite moving their factory to China.
>>> QC down the tubes ever since.
>>>
>>
>>
>> +/- 20% is a reasonable tolerance for this kind of component -
>>
>> from Dexter Epcos:
>> "Even with the best grinding methods known today, a certain degree of
>> roughness on ground surfaces cannot be avoided, so that the usual term
>> ?without air gap? or ?ungapped? does not imply no air gap at all. The AL
>> values quoted allow for a certain amount of roughness of the ground
>> faces. The tolerance of the AL value for ungapped cores is ?20 to +30%
>> or ?30 to +40%. Closer tolerances are not available for several reasons.
>> The spread in the AL values of ungapped cores practically equal the
>> spread in ring core permeability (?20% ? ?30%), and the AL value largely
>> depends on the grinding quality of the matching surfaces."
>>
>>
>> https://www.ferroxcube.com/en-global/download/download/11
>>
>> the "filter" materials (material 3C11, page 77) show mu has a +/- 20%
>> tolerance (yeah, it's for a lower frequency, but I didn't want to go
>> hunting for one for HF...)
>>
>> There's also a strong temperature dependence on some of these
>> materials.. mu might go from 1500 at 0C to 2000 at 50C.
>>
>>
>>
>>
>>
>> ------------------------------
>>
>> Message: 4
>> Date: Sat, 2 Nov 2019 11:21:42 -0700
>> From: David Gilbert <xdavid@cis-broadband.com>
>> To: towertalk@contesting.com
>> Subject: Re: [TowerTalk] Ferrites 31 vs. 77 material
>> Message-ID: <9b9950d8-42e6-8e8a-4674-8aac1a97cb59@cis-broadband.com>
>> Content-Type: text/plain; charset=utf-8; format=flowed
>>
>>
>> I find that kind of China bashing pretty funny.? Ridiculous as a
>> generalization.
>>
>> I worked for a large semiconductor manufacturer for over thirty years
>> and we ended up putting a joint venture manufacturing operation in China
>> ... not simply for low cost, but also to be able to serve the Asian
>> market better and to be able to head off future tariff concerns within
>> China.? We spec'd our own equipment, we trained all the operators, and
>> we put our own managers in key positions.? Most of those positions are
>> now staffed by locals.? The resulting quality was literally
>> best-in-class on a world basis. MANY other U.S., European, and even
>> Japanese companies have done exactly the same, and nothing says that
>> Fair-Rite hasn't as well.
>>
>> It is certainly true that many of the smaller locally owned companies in
>> China have sloppy process and quality control, but companies like the
>> large subcontract outfits in China put equivalent U.S. manufacturing to
>> shame for overall manufacturing excellence.
>>
>> In the case of ferrites, the problem is the inherent variability of the
>> process itself and the problem previously existed wherever the ferrites
>> were previously manufactured ... including here in the U.S.? Why you
>> think the variability was less before the manufacturing went to China is
>> beyond me.? Several of us here have already explained that it wasn't.
>>
>> Dave?? AB7E
>>
>>
>>
>> On 11/2/2019 10:18 AM, Jim Thomson wrote:
>>> Date: Sat, 2 Nov 2019 13:25:19 +0000 (UTC)
>>> From: Roger Parsons <ve3zi@yahoo.com>
>>> To: "Tower and HF Antenna Construction Topics."
>>> <towertalk@contesting.com>, "jim@audiosystemsgroup.com"
>>> <jim@audiosystemsgroup.com>
>>> Subject: [TowerTalk] Ferrites 31 vs. 77 material
>>>
>>> <Very funny.
>>> <The posts from both N6RK and AB7E support my statement that variability in
>>> ferrite parameters has been known for a very long time. You're the one who
>>> asserted that it has just been discovered and that therefore Steve G3TXQ
>>> could not have known about it.
>>>
>>> <73 RogerVE3ZI
>>>
>>> ## I believe it was N3RR that bought 700, (seven hundred) type
>>> 31 cores from one supplier, all from the same lot number..2 years
>>> ago. He used a simple 1 turn link to test them..and then graded
>>> them. They were all over the map, + and ? 22%. Thats a whopping 44%
>>> spread. No 2 ferrites the same! ALL made in China......so what
>>> do you expect ? So much for fairite moving their factory to China.
>>> QC down the tubes ever since.
>>>
>>> Jim VE7RF
>>>
>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>
>>
>> ------------------------------
>>
>> Message: 5
>> Date: Sat, 2 Nov 2019 13:48:13 -0700
>> From: Jack Brindle <jackbrindle@me.com>
>> To: David Gilbert <xdavid@cis-broadband.com>
>> Cc: towertalk@contesting.com
>> Subject: Re: [TowerTalk] Ferrites 31 vs. 77 material
>> Message-ID: <A87D4CF5-535F-4325-A270-ECD678646771@me.com>
>> Content-Type: text/plain; charset=utf-8
>>
>> Sadly, there is much evidence. Fair-rite quality really took a hit after
>> they moved production to Asia. So much so that many companies have had to
>> institute new QA procedures on incoming product to see if the
>> characteristics come close to fitting the requirements. One of the biggest
>> ones is large 60Hz transformer toroids that were failing in normal service
>> because of the manufacturing issues. The company does still have some
>> non-Asia manufacturing capability, and many companies are specifying product
>> only from those sites.
>>
>> So yes, the toroids do have issues that are very problematic.
>>
>> Jack, W6FB
>>
>>> On Nov 2, 2019, at 11:21 AM, David Gilbert <xdavid@cis-broadband.com> wrote:
>>>
>>>
>>> I find that kind of China bashing pretty funny. Ridiculous as a
>>> generalization.
>>>
>>> I worked for a large semiconductor manufacturer for over thirty years and
>>> we ended up putting a joint venture manufacturing operation in China ...
>>> not simply for low cost, but also to be able to serve the Asian market
>>> better and to be able to head off future tariff concerns within China. We
>>> spec'd our own equipment, we trained all the operators, and we put our own
>>> managers in key positions. Most of those positions are now staffed by
>>> locals. The resulting quality was literally best-in-class on a world
>>> basis. MANY other U.S., European, and even Japanese companies have done
>>> exactly the same, and nothing says that Fair-Rite hasn't as well.
>>>
>>> It is certainly true that many of the smaller locally owned companies in
>>> China have sloppy process and quality control, but companies like the large
>>> subcontract outfits in China put equivalent U.S. manufacturing to shame for
>>> overall manufacturing excellence.
>>>
>>> In the case of ferrites, the problem is the inherent variability of the
>>> process itself and the problem previously existed wherever the ferrites
>>> were previously manufactured ... including here in the U.S. Why you think
>>> the variability was less before the manufacturing went to China is beyond
>>> me. Several of us here have already explained that it wasn't.
>>>
>>> Dave AB7E
>>>
>>>
>>>
>>> On 11/2/2019 10:18 AM, Jim Thomson wrote:
>>>> Date: Sat, 2 Nov 2019 13:25:19 +0000 (UTC)
>>>> From: Roger Parsons <ve3zi@yahoo.com>
>>>> To: "Tower and HF Antenna Construction Topics."
>>>> <towertalk@contesting.com>, "jim@audiosystemsgroup.com"
>>>> <jim@audiosystemsgroup.com>
>>>> Subject: [TowerTalk] Ferrites 31 vs. 77 material
>>>>
>>>> <Very funny.
>>>> <The posts from both N6RK and AB7E support my statement that variability
>>>> in ferrite parameters has been known for a very long time. You're the one
>>>> who asserted that it has just been discovered and that therefore Steve
>>>> G3TXQ could not have known about it.
>>>>
>>>> <73 RogerVE3ZI
>>>>
>>>> ## I believe it was N3RR that bought 700, (seven hundred) type
>>>> 31 cores from one supplier, all from the same lot number..2
>>>> years ago. He used a simple 1 turn link to test them..and then
>>>> graded them. They were all over the map, + and ? 22%. Thats a
>>>> whopping 44% spread. No 2 ferrites the same! ALL made in
>>>> China......so what do you expect ? So much for fairite moving their
>>>> factory to China. QC down the tubes ever since.
>>>>
>>>> Jim VE7RF
>>>>
>>>> _______________________________________________
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> TowerTalk mailing list
>>>> TowerTalk@contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>
>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>
>>
>> ------------------------------
>>
>> Message: 6
>> Date: Sat, 2 Nov 2019 16:14:24 -0700
>> From: David Gilbert <xdavid@cis-broadband.com>
>> To: towertalk@contesting.com
>> Subject: Re: [TowerTalk] Ferrites 31 vs. 77 material
>> Message-ID: <9f5664d9-22ab-3249-18a9-2632e1827b2c@cis-broadband.com>
>> Content-Type: text/plain; charset=utf-8; format=flowed
>>
>>
>>
>> Well, if that's the case it means that Fair-Rite did a poor job of
>> transferring the manufacturing, and yes ... I've seen a bunch of other
>> companies do the same crappy job of it especially when all they were
>> looking for was quick cost reduction.? Those companies who made a
>> commitment to do it right have found a large pool of highly
>> conscientious technical labor in China just like we did.? Those who
>> merely tried to port their processes over to some existing facility
>> usually failed.
>>
>> My gripe is that simply bashing anything made in China is decades out of
>> date and a bad generalization.
>>
>> 73,
>> Dave?? AB7E
>>
>>
>> On 11/2/2019 1:48 PM, Jack Brindle via TowerTalk wrote:
>>> Sadly, there is much evidence. Fair-rite quality really took a hit after
>>> they moved production to Asia. So much so that many companies have had to
>>> institute new QA procedures on incoming product to see if the
>>> characteristics come close to fitting the requirements. One of the biggest
>>> ones is large 60Hz transformer toroids that were failing in normal service
>>> because of the manufacturing issues. The company does still have some
>>> non-Asia manufacturing capability, and many companies are specifying
>>> product only from those sites.
>>>
>>> So yes, the toroids do have issues that are very problematic.
>>>
>>> Jack, W6FB
>>>
>>>> On Nov 2, 2019, at 11:21 AM, David Gilbert <xdavid@cis-broadband.com>
>>>> wrote:
>>>>
>>>>
>>>> I find that kind of China bashing pretty funny. Ridiculous as a
>>>> generalization.
>>>>
>>>> I worked for a large semiconductor manufacturer for over thirty years and
>>>> we ended up putting a joint venture manufacturing operation in China ...
>>>> not simply for low cost, but also to be able to serve the Asian market
>>>> better and to be able to head off future tariff concerns within China. We
>>>> spec'd our own equipment, we trained all the operators, and we put our own
>>>> managers in key positions. Most of those positions are now staffed by
>>>> locals. The resulting quality was literally best-in-class on a world
>>>> basis. MANY other U.S., European, and even Japanese companies have done
>>>> exactly the same, and nothing says that Fair-Rite hasn't as well.
>>>>
>>>> It is certainly true that many of the smaller locally owned companies in
>>>> China have sloppy process and quality control, but companies like the
>>>> large subcontract outfits in China put equivalent U.S. manufacturing to
>>>> shame for overall manufacturing excellence.
>>>>
>>>> In the case of ferrites, the problem is the inherent variability of the
>>>> process itself and the problem previously existed wherever the ferrites
>>>> were previously manufactured ... including here in the U.S. Why you think
>>>> the variability was less before the manufacturing went to China is beyond
>>>> me. Several of us here have already explained that it wasn't.
>>>>
>>>> Dave AB7E
>>>>
>>>>
>>>>
>>>> On 11/2/2019 10:18 AM, Jim Thomson wrote:
>>>>> Date: Sat, 2 Nov 2019 13:25:19 +0000 (UTC)
>>>>> From: Roger Parsons <ve3zi@yahoo.com>
>>>>> To: "Tower and HF Antenna Construction Topics."
>>>>> <towertalk@contesting.com>, "jim@audiosystemsgroup.com"
>>>>> <jim@audiosystemsgroup.com>
>>>>> Subject: [TowerTalk] Ferrites 31 vs. 77 material
>>>>>
>>>>> <Very funny.
>>>>> <The posts from both N6RK and AB7E support my statement that variability
>>>>> in ferrite parameters has been known for a very long time. You're the one
>>>>> who asserted that it has just been discovered and that therefore Steve
>>>>> G3TXQ could not have known about it.
>>>>>
>>>>> <73 RogerVE3ZI
>>>>>
>>>>> ## I believe it was N3RR that bought 700, (seven hundred)
>>>>> type 31 cores from one supplier, all from the same lot
>>>>> number..2 years ago. He used a simple 1 turn link to test
>>>>> them..and then graded them. They were all over the map, + and ? 22%.
>>>>> Thats a whopping 44% spread. No 2 ferrites the same! ALL
>>>>> made in China......so what do you expect ? So much for fairite
>>>>> moving their factory to China. QC down the tubes ever since.
>>>>>
>>>>> Jim VE7RF
>>>>>
>>>>> _______________________________________________
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> TowerTalk mailing list
>>>>> TowerTalk@contesting.com
>>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>> _______________________________________________
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> TowerTalk mailing list
>>>> TowerTalk@contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>
>>
>> ------------------------------
>>
>> Message: 7
>> Date: Sat, 2 Nov 2019 16:42:28 -0700
>> From: Don <w7wll@arrl.net>
>> To: towertalk@contesting.com
>> Subject: Re: [TowerTalk] Ferrites 31 vs. 77 material
>> Message-ID: <d53e8d18-e7dc-423f-a307-ea892bb6da41@arrl.net>
>> Content-Type: text/plain; charset=utf-8; format=flowed
>>
>> Dave is spot on.
>>
>> In a couple of cases I'm familiar with, China not only delivered goods
>> with quality equal to or better than US manufactured items but with
>> their technical capability and desire to excel, were able to offer
>> suggestions that improved the product AND lowered the manufacturing
>> cost. China is not the only example. A significant number of other
>> countries are just as capable as the US to produce high quality goods.
>> Just look at some of the amateur radio 'stuff' available on the market.
>>
>> We aren't the only ducks in the pond anymore, and don't blame politics.
>>
>> Don W7WLL
>>
>> On 11/2/2019 4:14 PM, David Gilbert wrote:
>>>
>>>
>>> Well, if that's the case it means that Fair-Rite did a poor job of
>>> transferring the manufacturing, and yes ... I've seen a bunch of other
>>> companies do the same crappy job of it especially when all they were
>>> looking for was quick cost reduction.? Those companies who made a
>>> commitment to do it right have found a large pool of highly
>>> conscientious technical labor in China just like we did. Those who
>>> merely tried to port their processes over to some existing facility
>>> usually failed.
>>>
>>> My gripe is that simply bashing anything made in China is decades out
>>> of date and a bad generalization.
>>>
>>> 73,
>>> Dave?? AB7E
>>>
>>>
>>> On 11/2/2019 1:48 PM, Jack Brindle via TowerTalk wrote:
>>>> Sadly, there is much evidence. Fair-rite quality really took a hit
>>>> after they moved production to Asia. So much so that many companies
>>>> have had to institute new QA procedures on incoming product to see if
>>>> the characteristics come close to fitting the requirements. One of
>>>> the biggest ones is large 60Hz transformer toroids that were failing
>>>> in normal service because of the manufacturing issues. The company
>>>> does still have some non-Asia manufacturing capability, and many
>>>> companies are specifying product only from those sites.
>>>>
>>>> So yes, the toroids do have issues that are very problematic.
>>>>
>>>> Jack, W6FB
>>>>
>>>>> On Nov 2, 2019, at 11:21 AM, David Gilbert
>>>>> <xdavid@cis-broadband.com> wrote:
>>>>>
>>>>>
>>>>> I find that kind of China bashing pretty funny.? Ridiculous as a
>>>>> generalization.
>>>>>
>>>>> I worked for a large semiconductor manufacturer for over thirty
>>>>> years and we ended up putting a joint venture manufacturing
>>>>> operation in China ... not simply for low cost, but also to be able
>>>>> to serve the Asian market better and to be able to head off future
>>>>> tariff concerns within China.? We spec'd our own equipment, we
>>>>> trained all the operators, and we put our own managers in key
>>>>> positions.? Most of those positions are now staffed by locals.? The
>>>>> resulting quality was literally best-in-class on a world basis. MANY
>>>>> other U.S., European, and even Japanese companies have done exactly
>>>>> the same, and nothing says that Fair-Rite hasn't as well.
>>>>>
>>>>> It is certainly true that many of the smaller locally owned
>>>>> companies in China have sloppy process and quality control, but
>>>>> companies like the large subcontract outfits in China put equivalent
>>>>> U.S. manufacturing to shame for overall manufacturing excellence.
>>>>>
>>>>> In the case of ferrites, the problem is the inherent variability of
>>>>> the process itself and the problem previously existed wherever the
>>>>> ferrites were previously manufactured ... including here in the
>>>>> U.S.? Why you think the variability was less before the
>>>>> manufacturing went to China is beyond me. Several of us here have
>>>>> already explained that it wasn't.
>>>>>
>>>>> Dave?? AB7E
>>>>>
>>>>>
>>>>>
>>>>> On 11/2/2019 10:18 AM, Jim Thomson wrote:
>>>>>> Date: Sat, 2 Nov 2019 13:25:19 +0000 (UTC)
>>>>>> From: Roger Parsons <ve3zi@yahoo.com>
>>>>>> To: "Tower and HF Antenna Construction Topics."
>>>>>> <towertalk@contesting.com>, "jim@audiosystemsgroup.com"
>>>>>> <jim@audiosystemsgroup.com>
>>>>>> Subject: [TowerTalk] Ferrites 31 vs. 77 material
>>>>>>
>>>>>> <Very funny.
>>>>>> <The posts from both N6RK and AB7E support my statement that
>>>>>> variability in ferrite parameters has been known for a very long
>>>>>> time. You're the one who asserted that it has just been discovered
>>>>>> and that therefore Steve G3TXQ could not have known about it.
>>>>>>
>>>>>> <73 RogerVE3ZI
>>>>>>
>>>>>> ##? I? believe it? was? N3RR? that? bought? 700,?? (seven
>>>>>> hundred)?? type? 31? cores? from? one? supplier,? all? from the?
>>>>>> same? lot number..2 years? ago.? He? used? a? simple? 1 turn? link
>>>>>> to test them..and then? graded them.? They were all? over the?
>>>>>> map,? + and ? 22%.?? Thats a whopping? 44% spread.? No? 2 ferrites?
>>>>>> the? same!???? ALL? made? in China......so what do? you expect ??
>>>>>> So? much? for? fairite moving? their? factory? to? China.?? QC?
>>>>>> down? the? tubes ever? since.
>>>>>>
>>>>>> Jim?? VE7RF
>>>>>>
>>>>>> _______________________________________________
>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> TowerTalk mailing list
>>>>>> TowerTalk@contesting.com
>>>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>>> _______________________________________________
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> TowerTalk mailing list
>>>>> TowerTalk@contesting.com
>>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>> _______________________________________________
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> TowerTalk mailing list
>>>> TowerTalk@contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>
>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>
>>
>> ------------------------------
>>
>> Subject: Digest Footer
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk@contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>
>> ------------------------------
>>
>> End of TowerTalk Digest, Vol 203, Issue 3
>> *****************************************
> _______________________________________________
>
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>
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