[AARA] 443.0 Discussion

Charles Morrison cmorrison at lusfiber.net
Thu Oct 29 20:31:27 CDT 2015


Doug, I believe your use of non standard fonts has caused the reflector to
strip your email.  Its best suggested when sending to this reflector to not
use HTML formatted emails, as the system sees it as an attachment and strips
it out.  I've cleaned up Doug's email below.

In reply, as the trustee of the repeater I feel that at its current usage,
coverage and performance that its working well within our expectations, and
as such have no current plans to change the antenna or the power output.
The only difference in lightning damage between the fiberglass antenna and
the aluminum antenna is likely in the integrity of the antenna itself.  The
DB Products antenna may survive the direct strike, whereas the fiberglass
will most certainly be destroyed.  With a direct hit on either, its up to
luck as to the outcome of the radios themselves.  I would expect their
failures would be similar regardless of which antenna is chosen.

Charlie
N5WE



Fred is correct! I was unaware of the short length of feed line used on it's
application. But the other suggestion of going to full power should be
strongly opposed. This is why:

(1). According to what I here that the specs are from Vertex/Yaesu is the rf
deck is rated for 100% duty cycle at 20 watts, any more heat stress to the
MOSFETs would eventually degrade them into failure during nets and heavy
traffic.

(2) From what is mentioned from Fred, the antenna is shown as a DB-420,
Most of those that are used in the 440 ham band are (usually) resonant at
455 mhz in some 440 band application. Assuming all the info is correct on my
end, the 443 down link is 12 mhz away from full resonance, and is most
likely showing some reflected power that adds additional heat stress to the
above mentioned and less radiated power. DB-420s do exist cut and phased the
440 ham band but are extremely rare, ...but can be obtained over time. I
have seen fully resonant resonant DB-420's at 200 ft elevation cover 50
miles and occsionally more (with no band opening) reliably on 5/8 wave
mobile installation both ends at or around 25 watts and multi side
supported16 bay DB's more than that due to their particular lower angle of
radiation. It is agreed that going with a Comet or a Diamond increases
lightning damage chances quite dramatically so lets never go there whatever
future decisions are made...

...Just some additional thoughts on an interesting subject.  -Doug-

PS: Herman is sounding good on that Baofang @ 1 watt!






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