[CQ-Contest][CQ-Contest] Band-pass filters-insertion loss

[PETER BARRON]

The stock numbers given on this subject don't seem too bad
But users experience seem to warrant  a closer look

LOSS
dB	Ratio Power	For 100 W IN
-0.10	0.98		97.72
-0.25	0.94		94.41
-0.35	0.92		92.26
-0.45	0.90		90.16
-0.55	0.88		88.10
-0.65	0.86		86.10
-0.75	0.84		84.14
-0.85	0.82		82.22
-0.95	0.80		80.35
-1.00	0.79		79.43
-2	0.63		63.10
-3	0.50		50.12

I'd expect to see app 0.75 dB or so for a small size filter and <0.5 dB for
the larger types
IF the filter is giving a genuine 20 W or so loss it may be getting a bit
warm inside. IF the loss is caused by filtering out 10W of harmonics that is
another problem

I'd remove covers then  re-check the loss then after key down for a while
(SWITCH OF RF FIRST) then feel for hot or warmer parts
 >
Peter A Barron
ve3pn at igs.net


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>From ve6nap at ve6nap.com" <ve6nap at ve6nap.com  Mon May  7 09:07:13 2001
From: ve6nap at ve6nap.com" <ve6nap at ve6nap.com (Gerald Caouette)
Date: Mon, 7 May 2001 02:07:13 -0600
Subject: [CQ-Contest] E-QSLs
Message-ID: <01C0D69A.6F085AA0.ve6nap at telusplanet.net>


In the rush to play with new technology we must also remember
that when we talk to the world,  there are those who do not always
have access to the same level of connectivity  or technology that we enjoy ..

Besides ,  nothing replaces the magic of a hard copy QSL

remember back to your first 100 countries  and the card from each
that was submitted for consideration towards your DXCC
I will  bet that some still hold a fond place in your heart
and possibly prime space on your wall

Regards
Gerald Caouette
9116 - 79 street
Edmonton, Alberta
Canada
T6C 2R4

ve6nap at ve6nap.com

http://www.ve6nap.com


-----Original Message-----
From:	Darryl Wagoner [SMTP:darryl at shecora.com]
Sent:	Sunday, May 06, 2001 9:17 PM
To:	CQ-Contest at contesting.com
Subject:	Re: [CQ-Contest] E-QSLs


Jim and the group,

  > N0FP while enthusiastic has missed a whole element of WHY e-QSLing may not
  > be the solution to collecting cards.

  > In my opinion DXCC's standard of quality as an award was lessened when 
field
  > checking was established...I am not pointing fingers but know there is NOW
  > an uncertain element - kinda like when we used to wonder about the hams 
with
  > Conditional Class licenses....
  >
  > There are certain "characteristics" present in a hard copy of a QSL which
  > CANNOT at this point in technology exist in an E-QSL...yes, we have come a
  > long way with the internet and high tech but a "bad" forgery is not 
going to
  > bite you when you look at it in a E-QSL like it would when a hard QSL 
passes
  > through your fingers!  A unique signature is no longer present, etc.

This is where I have to disagree, digital signatures CAN NOT be forged.
While I understand your concern because of your personal experience with
your debit card, but I can ensure you that encryption wasn't to blame.

When digital signature are used to authenticate E-QSL cards the only
way to beat the system will be to a) steal the private key off of
the user home PC, b) fake out the CA like they did on the Microsoft
certificate from Verisign.

  >From what I know of digital signatures and I know quite a bit, there
is NO WAY to break them, except for brute force, which will take a very
long to break (ie: 10^20 years or so).  If you don't believe me I can
point you to some great books on the subject.  Plus I can give you
the fairly simple math that makes it work.  What makes it work is
the BIG NUMBERS!  In the TrustedQSL source I use public key that
is 704 bits long.  How big of number is 704 bits?  I am glad you ask.
Is it big enough to count the number of atoms in the planet Earth? Yep
there is only 2^170.  How about the Sun?  Yep, it is only 2^190.  Ok,
it is big but is it big enough for the whole galaxy?  You bet, the
Milky Way is 2^223.  Well what about the entire Universe.  Sure enough
the Universe is only 2^265 atoms (dark matter excluded).

I know I can hear it now Darryl you are full of it, but I didn't make
it up.  It comes from Dyson's paper "Time Without End: Physics and
Biology in an Open Universe,"  in Reviews of Modern Physics, v.52, n. 3,
July 1979, pp 447-460 and quoted in Applied Cryptography.

  > Coupling the lack of security present in the internet and the inherent lack
  > of tactile feedback form an E-QSL being in a hurry to accept them is an
  > error in judgment.

With digital signatures there will be no rush to judgment.  It is a simple
test.  It was either signed and unaltered by the person who owns a given
private key or it is rejected.  No gray areas.

  > what one man made THE award to have, the one that set you apart - saying "I
  > have DXCC" used to really be an awesome thing, it is not as impressive
  > anymore and a misguided rush to adopt E-QSLs would further cheapen THE ham
  > radio community's banner award.

Given what I have just said and if digital signatures are used, how
does it cheapen the award?  All it does it to allow for receiving
EQSL quickly which can be trusted.  This would only be true if
the act of collecting and chasing the paper cards is part of what
you get the award for.  I don't think that is/was the intent of the
award.

73
--
Darryl Wagoner - WA1GON

"Evil triumphs when good men do nothing."  - Edmund Burke [1729-1797]

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