Strong words, Jim but you are right on. Type 31 material is easily
available from Mouser (no minimum order size) and other electronic parts
houses. Poor baluns, even if they do not fail with legal power, allow
the coax outer shield to be part of your antenna. Who wants their coax
outer shield radiating part of your power and picking up noise when
receiving? The info on your web site about your tests takes some careful
reading to understand but is worth the effort.
Keep up the good work, Jim.
73, Dan, N5AR
On 5/20/2010 7:01 AM, Jim Brown wrote:
> On Wed, 19 May 2010 13:17:43 -0700, Jim Thomson wrote:
>
>
>> You can`t get water into em.. and you can`t blow them up. The EB1 and EB2
>> baluns are excellent as well.
>>
> "Excellent" is a wild exageration with respect to these so-called "baluns,"
> which are nothing more than simple-minded "string of beads" common mode
> chokes. True that you probably can't blow them up with the illegal power that
> you like to run, but they aren't very effective as common mode chokes either.
> Manufacturer's published data is quite inferior to what any ham can make by
> winding multiple turns of RG8 or RG11 through #31 toroids and they are VERY
> conservatively rated for max legal ham power. Detailed instructions and
> MEASURED data are on my website in http://audiosystemsgroup.com/RFI-Ham.pdf
>
> As to "hams are cheap" -- yes we are, but we are also stupid, buying into
> advertising claims, and buying inferior junk from companies run by salesmen
> that know nothing but advertise in QST for 40 years. The common mode chokes
> described in my tutorial (cited above) are fully documented, and the tutorial
> completely describes how they work. And I'm not selling anything! The cheap
> junk you buy from salesmen like Amidon, Palomar, and their ilk is completely
> undocumented and vastly inferior. They re-sell Fair-Rite parts at huge mark-
> ups (4-5X cost), but disguise that fact by creating their own new part
> numbers. That so-called technical data on their websites is next to useless!
>
> 73,
>
> Jim K9YC
>
>
>
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