[TowerTalk] TowerTalk Digest, Vol 203, Issue 3
Robert Harmon
k6uj at pacbell.net
Sun Nov 3 16:16:30 EST 2019
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 at comcast.net> wrote:
>
> How about a specific recommendation for HF Ferrites? gil KI7SJC
>
>
>> On November 3, 2019 at 9:00 AM towertalk-request at contesting.com wrote:
>>
>>
>> Send TowerTalk mailing list submissions to
>> towertalk at contesting.com
>>
>> To subscribe or unsubscribe via the World Wide Web, visit
>> http://lists.contesting.com/mailman/listinfo/towertalk
>> or, via email, send a message with subject or body 'help' to
>> towertalk-request at contesting.com
>>
>> You can reach the person managing the list at
>> towertalk-owner at contesting.com
>>
>> When replying, please edit your Subject line so it is more specific
>> than "Re: Contents of TowerTalk digest..."
>>
>>
>> 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 at earthlink.net>
>> To: towertalk at contesting.com
>> Subject: Re: [TowerTalk] Ferrites 31 vs. 77 material
>> Message-ID: <a5380ed3-fb89-095a-9b4d-3473784f6f02 at 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 at telus.net>
>> To: <towertalk at contesting.com>
>> Subject: [TowerTalk] Ferrites 31 vs. 77 material
>> Message-ID: <55DEC5CD8B0146FCA2EBBE3276D17FC0 at DESKTOPSV54DBH>
>> Content-Type: text/plain; charset="utf-8"
>>
>> Date: Sat, 2 Nov 2019 13:25:19 +0000 (UTC)
>> From: Roger Parsons <ve3zi at yahoo.com>
>> To: "Tower and HF Antenna Construction Topics."
>> <towertalk at contesting.com>, "jim at audiosystemsgroup.com"
>> <jim at 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 at earthlink.net>
>> To: towertalk at contesting.com
>> Subject: Re: [TowerTalk] Ferrites 31 vs. 77 material
>> Message-ID: <9213c7ec-2021-0f3e-6424-f68844ac6650 at 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 at yahoo.com>
>>> To: "Tower and HF Antenna Construction Topics."
>>> <towertalk at contesting.com>, "jim at audiosystemsgroup.com"
>>> <jim at 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 at cis-broadband.com>
>> To: towertalk at contesting.com
>> Subject: Re: [TowerTalk] Ferrites 31 vs. 77 material
>> Message-ID: <9b9950d8-42e6-8e8a-4674-8aac1a97cb59 at 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 at yahoo.com>
>>> To: "Tower and HF Antenna Construction Topics."
>>> <towertalk at contesting.com>, "jim at audiosystemsgroup.com"
>>> <jim at 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 at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>
>>
>> ------------------------------
>>
>> Message: 5
>> Date: Sat, 2 Nov 2019 13:48:13 -0700
>> From: Jack Brindle <jackbrindle at me.com>
>> To: David Gilbert <xdavid at cis-broadband.com>
>> Cc: towertalk at contesting.com
>> Subject: Re: [TowerTalk] Ferrites 31 vs. 77 material
>> Message-ID: <A87D4CF5-535F-4325-A270-ECD678646771 at 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 at 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 at yahoo.com>
>>>> To: "Tower and HF Antenna Construction Topics."
>>>> <towertalk at contesting.com>, "jim at audiosystemsgroup.com"
>>>> <jim at 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 at contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>
>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>
>>
>> ------------------------------
>>
>> Message: 6
>> Date: Sat, 2 Nov 2019 16:14:24 -0700
>> From: David Gilbert <xdavid at cis-broadband.com>
>> To: towertalk at contesting.com
>> Subject: Re: [TowerTalk] Ferrites 31 vs. 77 material
>> Message-ID: <9f5664d9-22ab-3249-18a9-2632e1827b2c at 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 at 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 at yahoo.com>
>>>>> To: "Tower and HF Antenna Construction Topics."
>>>>> <towertalk at contesting.com>, "jim at audiosystemsgroup.com"
>>>>> <jim at 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 at contesting.com
>>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>> _______________________________________________
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> TowerTalk mailing list
>>>> TowerTalk at contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>
>>
>> ------------------------------
>>
>> Message: 7
>> Date: Sat, 2 Nov 2019 16:42:28 -0700
>> From: Don <w7wll at arrl.net>
>> To: towertalk at contesting.com
>> Subject: Re: [TowerTalk] Ferrites 31 vs. 77 material
>> Message-ID: <d53e8d18-e7dc-423f-a307-ea892bb6da41 at 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 at 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 at yahoo.com>
>>>>>> To: "Tower and HF Antenna Construction Topics."
>>>>>> <towertalk at contesting.com>, "jim at audiosystemsgroup.com"
>>>>>> <jim at 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 at contesting.com
>>>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>>> _______________________________________________
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> TowerTalk mailing list
>>>>> TowerTalk at contesting.com
>>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>> _______________________________________________
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> TowerTalk mailing list
>>>> TowerTalk at contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>
>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>
>>
>> ------------------------------
>>
>> Subject: Digest Footer
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>
>> ------------------------------
>>
>> End of TowerTalk Digest, Vol 203, Issue 3
>> *****************************************
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
More information about the TowerTalk
mailing list