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Old April 19th 05, 05:31 AM
Telamon
 
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In article ,
"Michael A. Terrell" wrote:

David wrote:

I have built these suckers resonant at 6 mHz and survived tropical
storms. The purpose of DC ground (easily verified with a DVM with a
buzzer) is to bleed static charges, not substitute for accepted
lightning amelioration SOP.

As far as the perfomance at lower frequencies, the little suckers work
just fine. Don't let the 5-900 mHz specs fool you. As long as there
are no serices caps inside, they work way lower than 5 mHz.

Co-ax Seal under Scotch 33+ makes anything weatherproof.

These are definitely workingman's antennas, quite modest but also very
capable. They are more wideband than their single wire equivalents
(though theoretically not usable on even harmonics.) Make 3, one for
6, one for 10, one for 15. use an A/B/C switch and you'll have a lot
of fun.


The losses are already bad at 5 MHz and get worse as you go lower.
You may get away with them, but you might not hear a really weak signal
you're looking for because of the added losses. Have you measured the
insertion losses for properly terminated two way splitters? I would
open the case, remove the directional coupler and install a couple
hybrid amps and protection circuits to help match the 50 Ohm impedance
and maybe give a dB or two of gain. Have you measured the return loss
of any of the splitters?

I built a 1 in, 32 out distribution amplifier for Microdyne to
distribute their 10 Mhz in house frequency standard. I used the LH0002
buffer amps, but there are newer parts with even better performance.
The advantage of individually buffered outputs is that any noise
generated by one load isn't reflected back into another load and you can
connect or disconnect equipment without affecting other loads.


Yes, the active devices will provide good output to output isolation.

One drawback of any passive splitter is poor isolation.

--
Telamon
Ventura, California


 
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