[TowerTalk] homebrew 1:1 current balun

[Gary K9GS]

Jim is correct on much of his post below.  I have done several purchases 
of Fair-Rite 2631803802. These are the #31 2.4" OD cores. I found best 
pricing from Arrow Electronics.  I purchased 100 a year ago and they 
were $4.12/ea.  Mouser has them too..on their web page now for $5.42 in 
100 pc quantities.

You do NOT want to buy a partial box..they will arrive broken.  I had 
that happen but the supplier replaced them.

A somewhat sad story..I delivered some cores to a friend at FD.  As he 
was carrying the box from his car at home he dropped the box. They all 
shattered :((  They are very brittle.



On 12/4/2015 12:13 PM, Jim Brown wrote:
> On Thu,12/3/2015 9:59 AM, Kelly Taylor wrote:
>> Their prices are about $1 better than KF7P on the Mix 31 2.4” OD 
>> cores, and $2 worse than KF7P on the Mix 31 Biggest Clamp-ons ($16.95 
>> at pro audio vs. 14.95 at KF7P).
>
> While it's great that guys like Howard are distributing #31 cores in 
> small quantity, a far better approach is to organize a group purchase. 
> I've done several, and been a part of several organized by others. 
> Some givens. #31 is the material we want for HF, and I've zeroed in on 
> three parts as most useful.  They are the 2.4-in o.d. toroids (often 
> called FT240 by those who sell them at huge markups), what I call the 
> "biggest clamp-on", which is 1-in i.d., and a medium clamp-on that is 
> 0.75-in i.d. The first two parts are most useful on antennas; the 
> smaller part is ideal for choking victim equipment (hi-fi gear, 
> computers, etc.) and noise sources.
>
> If you can group the purchase of active hams in several local clubs 
> (I'm thinking contest and DX clubs here), you can buy from 
> distributors at prices that are half the cost of the lowest cost 
> retailers. In a group purchase, I've never paid more than $5 for 
> 2.4-in o.d. cores; shipping and tax adds 10-12%. In 2013, I paid $9.08 
> ($10.25 w/tax and shipping) for the "biggest clamp-ons" and $2.28 
> ($2.65 with tax and shipping) for the 3/4-in i.d. clamp-ons. The best 
> vendors I've found are Dexter Magnetics (near Chicago) and Lodestone 
> Pacific (Anaheim). I bought 770 of the smaller 3/4-in clamp, 160 of 
> the 1-in i.d. clamp, and only about 100 of the "FT240" cores (I had 
> recently done a much larger purchase of them).
>
> An important rule for group purchases is to NEVER re-ship cores, 
> because they are fragile. Distribute the cores at club meetings, 
> letting members pass along deliveries to the guys who live a bit 
> further away and can't make meetings. The recommended vendors will 
> take your charge card and bill when they ship; this gives you time to 
> pass out the cores and collect the most of the money in time to pay 
> your credit card.
>
> These vendors WILL drop ship to multiple locations, so it's easy to 
> combine a group purchase with clubs that are geographically separated. 
> The first group purchase I organized in 2005 (with the help of K9OR) 
> included clubs around Chicago, where I lived then, Milwaukee, and 
> Indianapolis. To minimize breakage, ship only in full box quantities. 
> Ferrites are fragile. I've never seen breakage in full boxes.
>
> 73,Jim K9YC
>
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> -- 
> 73,
>
> Gary K9GS
>
> Greater Milwaukee DX Association: http://www.gmdxa.org
> Society of Midwest Contesters: http://www.w9smc.com
> CW Ops #1032   http://www.cwops.org
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