In light of the fact that it's 1998, and that the electronic
age is upon us, I think it's time maybe we rethink QSL
cards altogether.
I also think it's time to do this due to the fact that I have
been the KH2 QSL bureau manager on and off for the
last ten years and have forwarded many thousands of
QSL cards to Mr. Dumpster.
The QSL bureau system, in my opinion, is a horrific
waste of time and money. In many cases, bureaus are
manned by volunteers who mean well, but obviously
are prefix illiterate. I base this observation on the many
hundreds of QSL cards received at the Guam bureau
with WP2, KP2, KH0, KH3, KH4, and KG6 prefixes. I
also base it on the fact that the bureau here has been
instructed to forward all cards to certain stations
received here to Mr. Dumpster, and on the fact that
a call sign no longer signifies the QTH of a station,
since the inception of the vanity DX call sign scam
program. Many cards received here are not claimed.
Contest logs are submitted electronically, comments to
the FCC are submitted electronically, and soon our
licenses will be renewed electronically.
Many DX'peditions now have logs on the internet, so
that stations can verify QSO's. I realize a lot of people
will probably still want paper QSL cards as a memo of
a certain contact, but I think it's time the ARRL DXCC
desk seriously consider taking logs from DX'peditions
and DX stations that are submitted electronically, and
using the electronic logs to give people DXCC credit.
I would be more than happy to submit all my logs
to the ARRL electronically, as I have been using
computerized logging since 1986.
73, Jim KH2D
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>From Guy Olinger, K2AV" <k2av@qsl.net Wed Aug 12 02:26:27 1998
From: Guy Olinger, K2AV" <k2av@qsl.net (Guy Olinger, K2AV)
Subject: [CQ-Contest] Collins Filters in Contest Rigs
Message-ID: <001401bdc590$3ae6ab00$2417fea9@guy>
Well, I *don't* have any affiliation with INRAD, just sharing what made the
160m cw tests sufferable. From the figures below, and a typical contest
situation: Rig is the FT1000MP.
My frequency: 1820.
Station up 1820.5
Station down 1819.5
Too close for comfort? Depends on which filter you are using. With the
Collins filter, -60db is 1820.75, which includes station up, and 1819.25
which includes station down.
Using the INRAD, -60db is 1820.37, which does not include station up, and
1819.62 which does not include station down.
If one has the matching filter at 8mhz if, and can assume the skirts proceed
something like straight line, we can make some approximations as to signal
strength of stations up & down in the passband. These figures do describe
what I experienced as a stunning difference.
First the Collins filter... takes (1500-600)/2 = 450 hz to drop 54 dB or
12 dB per 100 hz. Station up is 200 hz above -6db point. so 24 dB for 200 hz
plus the 6db makes station up off 30 dB. If Station up is 20 over S9 on
center, it will be ~S8 up 500. Even if you use dsp to narrow the audio to
the wanted signal, two s8 signals in the IF passband outside the DSP will
pump the AGC something fierce.
Now for the INRAD... takes (745-400)/2 =172 hz to drop 54 dB or 31 dB per
100 hz. Station up is 300 hz above -6db point or 93+6 = 99 dB dB down.
Starting at 20 over S9 gets to 79 below S9. 56 dB takes signal to S zero
with 23 dB more attenuation to go.
In my experience, as I said earlier, this translates to inaudible. The crud
on frequency is S1 or S2, with intercept optimization on, and a couple of
notches of input attenuation to get rid of BC band crud.
I doubt that the INRAD 455 if filter by itself has ultimate skirt
attenuation of -99, but the two in cascade do seem to go way, way down.
The 400 hz on a run frequency is still wide enough to get someone in my
passband calling the guy up or down.
Wouldn't you call adjacents going from S7/S8 to inaudible, stunning?
Particularly if you paid the bux supposedly to get the king of filters, the
incomparable Collins Mechanical Filter? I think I got a mediocre Rockwell
product that's only a faint echo of those spendid filters I used in the 75Ax
and 75Sx receivers.
Again, hearing is believing. Anyone wants to listen, email me and we'll set
up a phone call.
73, y'all. Guy
---
Guy L Olinger K2AV
Apex, NC, USA
From: George Cutsogeorge <w2vjn@rosenet.net>
>
>Here are some measured numbers for those of us that like to see data.
>Mechanical filters have bandwidths specified at -3 dB and crystal filters
>are specified at -6 dB. To make the comparison, both types were measured
>at -6 dB.
>
>Filter -6 dB -60 dB Loss, dB
>
>Collins "500 Hz" 600 1500 2.2
>Inrad 703 400 745 3.3
>
>Collins "2.6 kHz" 2700 5200 1.4
>Inrad 702 2150 3300 3.6
>
>George
>w2vjn@rosenet.net
>
>Yes, I am associated with International Radio.
>----------
>
>
>
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>
>
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