>From Scott's original post:
>You are cordially invited to attend
>the wedding of
>Laurie Mashak and Scott Neader
>on August 19th, 1995.
> .
> .
> .
>Hams in the wedding: Mike N0BSH & Chad WE9V.
>Also attending: Paul WX9E, Paul KS9K, and possibly Paul W0AIH
Where's the bride registered? Ham Radio Outlet?
Bill "Paul" Frede AA0WO
>From Tony Brock-Fisher <fisher@hp-and.an.hp.com> Fri Aug 4 15:11:12 1995
From: Tony Brock-Fisher <fisher@hp-and.an.hp.com> (Tony Brock-Fisher)
Subject: Best RX antenna over salt marsh?
Message-ID: <9508041411.AA10516@hp-and.an.hp.com>
Hi. As a part-time station designer, I have been asked to recommend
a low-band receiving antenna for a location that has unusually good
ground; i.e. a salt marsh. I have heard many times (I think it is in
ON4UN's book) that beverages don't work so well over spectacular
grounds, as it is the ground losses that actually refract incoming
waves to produce a horizontal component parallel to a beverage
conductor. So the question is: how do EWE antennas work over
excellent ground? Anyone have experience in condx like this?
Recommendations solicitied: antenna needs to be ready for WAE!
I'll be attempting to model the EWE while awaiting replies...
-Tony, K1KP, fisher@hp-and.an.hp.com
>From peterj@netcom.com (Peter Jennings) Fri Aug 4 15:57:59 1995
From: peterj@netcom.com (Peter Jennings) (Peter Jennings)
Subject: Computer and RFI
Message-ID: <199508041457.HAA11293@netcom9.netcom.com>
> CT) and now I'm having problems. When I run anything 100W or more, I get RF
> into the computer that makes characters print and makes the keyboard lock up,
> as well as the computer beeping.
If characters are printing by themselves, it is RF getting in
via the keyboard and its cable. The beeping is the keyboard
buffer overflowing. The computer is probably not usually locked up,
it just has a buffer full of characters it doesn't know what to
do with.
Put snap-on ferrites on the keyboard cable where it enters the
computer. That has been the most common problem I have had with
RFI and computers here. It can almost always be solved with ferrites.
The keyboard and cable make a nice antenna.
Peter AB6WM
-- peterj@netcom.com
URL: http://mall.turnpike.net/~jc/
>From sfraasch@ATK.COM (Steve Fraasch) Fri Aug 4 17:59:25 1995
From: sfraasch@ATK.COM (Steve Fraasch) (Steve Fraasch)
Subject: Best RX antenna over salt marsh?
Message-ID: <1995Aug04.100100.1180.20992@msm.atk.com>
Tony:
The EWE should work great over a marsh, because the basic EWE is two
electrically-short verticals 90 degree phase shifted. Although the EWE and
beverage look alike, the principle of operation of the beverage is quite
different. The beverage is a travelling-wave antenna, where an incoming
plane-wave tilts as the lossy ground induces slowing velocity of prop near
ground to induce a travelling wave in the horiz piece. In the EWE, the
horizontal forms a transmission line with the ground and acts as the phasing
line to put the two electrically short verticals in 90 quadrature. Now, the
horizontal transmission line (wire) may need to be shortened slightly for
perfect phasing over salt water (water's permittivity of 78 vs. a much
smaller number for normal ground), but you can play with it or tweak on NEC
(use permittivity er=78, and conduct 5 Mhos/m for salt water).
With a -20 or so gain, you may find that you'll need a pre-amp in the EWE,
whereas the beverage is a -10 dB or so antenna (even on my 400' bev I find I
need a pre-amp in Minnesota). You're on the E. Coast, so the DX may
overcome the 25 dB noise figure you'll have w/o a pre-amp.
Now, the beverage is much more directive than the EWE, given the EWE's
electrically small aperture, but it's a good antenna for nulling power line
noise. On 75/160 for many of us, that's usually the battle.
WA2WVL's EWE is pretty darn nifty. I design antennas (millimeter wave
microstrip and radomes) for a living, and I must say that's a sharp idea.
Wished I thought of it.
73,
Steve Fraasch, K0SF
>From sellington" <sellington@mail.ssec.wisc.edu Fri Aug 4 16:03:34 1995
From: sellington" <sellington@mail.ssec.wisc.edu (sellington)
Subject: Noise-cancelling headset
Message-ID: <n1404591851.61950@mail.ssec.wisc.edu>
I found this thing at the EAA air show, and bought one with the idea of
making it a little easier to copy weak signals through the roar of the
fans on my amplifiers. It consists of a headset with little microphones
built into the ear pieces, and a control circuit to provide negative feedback
which cancels noise at low frequencies. There's an external audio input.
(The external audio is unaffected by the noise cancellation.)
Although I haven't had a chance to use it in a contest yet, it seems to
be very effective. One guy described the effect as "like sticking your
head in a bale of cotton." It seems to only affect frequencies below
about 500 Hz. I'd estimate a 20 dB reduction in typical blower noise.
The headset is a lightweight open design, which probably won't be as
comfortable for long periods as something like the Heil Proset, nor does
it block out external high frequency sound. (Because of the built-in
microphones, you can't substitute an ordinary headset.) For SSB operation,
one would have to figure out some way to mount a boom mike. The whole
thing seems well made, and comes with a bunch of adapters and cables so one
can easily hook up the receiver audio.
It's called the "Noisebuster", model NB-DX. Vendor is Noise Cancellation
Technology, (800) 278-3526. They were selling for $79 at the air show.
(I have no connection with the vendor.)
Scott K9MA
sellington@ssec.wisc.edu
>From Gary Schwartz <garyk9gs@solaria.sol.net> Fri Aug 4 16:08:37 1995
From: Gary Schwartz <garyk9gs@solaria.sol.net> (Gary Schwartz)
Subject: Any VE1's in Halifax??
Message-ID: <Pine.3.02.9508041037.A4870-a100000@solaria.mil.wi.us>
Are there any DX'ers or CONTESTERS reading these reflectors that live in
or near Halifax, NS?? Please e-mail me direct.
73,
Gary K9GS
________________________________________________________________
| |
| Gary Schwartz K9GS E-Mail: garyk9gs@solaria.sol.net |
| Society of Midwest Contesters Packet:K9GS@WA9KEC.WI.USA.NOAM |
| Greater Milwaukee DX Association Member |
|________________________________________________________________|
|