I designed a loop for 100 ohm impedance and fed with coax and 1/4 wave
transformer. It has worked well for years. I got the bright idea to
replace the coaxial feed with 35' of 450 ohm ladder line and a Bliss
remote tuner. This combination would not match. I experimented. A
nice dip in VSWR
I have another perspective on this. For those of you that are pilots,
my QTH is on the ring of Class C airspace. Accordingly, many airplanes
fly under the "shelf" so they do not have to talk to ATC, go to and
leaving from airports that are near the Class C airspace. OK, but they
should not b
Everything takes time. I have a great example of audio latency.
Kitchen has television with direct cable input and family room has
digital cable box with HDML to large screen LED set. When watching
events, like superbowl, both sets might be on. It is highly obvious
which television displays
Heading back to the states in a few minutes. Quickly, wondering if one
could measure antenna currents in the vertical portion of antenna with a
pickup loop at various heights and compare with measuring ground
currents at a common feed point before radials start or along a tight
string pulled a
I receive the list archived and this makes replying to individual posts
difficult.
It seems to me W0BTU summed it up succinctly. There are time delays and
depending on the setup, it it varies from no factor to disabling.
I don't know what others have for remote stations. I can tell you, I
I use the following after years of failure and this has been very good
for me.
GALVANIZED electrical conduit. About 2.5cm diameter. Cut in 1.25m
length. Pound in ground. Use Gray PVC conduit 3m length (4-5cm
diameter) to hold beverage. Slide PVC over galvanized conduit. Easy.
Fast. Ine
Just a few more observations with receive antennas. This past year, I
did a lecture at the DX club about low band receive antennas.
Basically, I gave points for various characteristics of the antennas as
I employ them at my QTH. I compared the DX engineering circle 8 vs SAL
vs Beverage vs K9
I recently put reviews about the SAL-20 and SAL-30 on eham.net if anyone
is interested. Two on air demonstrations of the F/B are on YouTube.
Please refer to: http://www.youtube.com/watch?v=tVi5xQIXnXU (160m) and
http://www.youtube.com/watch?v=F_S7JwfEpQ8 (80m).
--
David J Rodman MD
Assistant
Thank you very much for inviting me. I was very impressed with the
facility, how ideas were exchanged and attendees, although I do know
them individually.
I tried to advocate intravitreal injection of MTX or retuxan but not
sure how far it will go.
My resident is presenting the case next Th
I made this video to help me identify a source and get some help with a
carrier and broadband interference noted on the low bands. I have
identified two general signals. They have a significant AC hum. One is
strongest to the West of my location and peaks at about 20dB over S9 On
the meter.
Looking for some help matching my 160 loop. I made three changes to the
system this year and the VSWR has increased to about 2:1 at resonance
which is about the same frequency. Here is what I have.
The antenna is fed at a convenient point up from a bottom corner and is
hung apex high at abou
I have been looking for information or opinions or experience if vertically
polarized antenna
receive enhanced low angle signal transmission when located near salt water
only or is the
situation equivalent for fresh water bodies as well. Thanks.
David J Rodman, MD
Assistant Clinical Professo
My 160m antenna died several weeks ago from a bad coax feed line and was
restored
just Sunday after the contest. I have tried several antenna analyzers and none
seem to work with the loop antenna. I designed the antenna for 100 ohm feed and
always wanted to put a half wavelength coax on an analy
Just came in from installing the inverted L and FCP. Tuned it with an SWR box
at
the antenna but have no connectors to attach coax so have to wait a day or so to
put it on the air. This is an 80m version. Pretty much a whole day project.
Reading I have done say to ground the system 5-6 feet fr
I was having an educational discussion with a friend tonight about the
ramifications of feeding a vertical with an elevated transmission line. The
situation would be he does not want to dig up the mesh for the 20' around the
base. It was suggested to bring the transmission line out of the ground
I have all the materials for an inverted L, using K2AY FCP and have read his
article attached to the web page. After I paid much more attention to the page,
I noted that the highlighted diagrams seem to show three different ways to
arrange the wiring and attachment to the transformer. One shows t
I should be operating the contest, but spent some of the afternoon
troubleshooting my DXE circular receive array. One thing led to another and I
decided to bench test one of the receivers. We pulled out my service monitor
(RF
signal source) and played with the jumpers on circuit board while list
Hi does anyone happen to have an EZNEC (or similar file, source or description)
that I can use to model the K9AY loop? I have a 150' distance at my location
that I would be tempted to try a phasing arrangement but would like to model
first. Thanks.
David J Rodman, MD
Assistant Clinical Professo
Sorry if I seemed incompetent this morning at 1200Z with VP6T. My transceiver
had a software malfunction and would not transmit down, no matter how many times
I tried to tell it to do so. I had just worked them on 80 "up" without
difficulty. I just shut down and went to work, patients were waiti
Here is my situation. I am pretty sure noise is from switching power supplies.
Unfortunately, it tends to put noise right where I don't want it. Like bottom
of
160, 80 and 40m. Typically the noise is 20-25 kHz of S8-9. One hears
modulations on it and the whole band moves up and down in freque
20 matches
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