The resistance sounds about right Martin. Most of the conductivity
comes from the copper strands.
Steel strands have high mechanical strength, but poor conductivity.
I square R loss is low as signal current is very low.
73
Bruce-K1FZ
www.qsl.net/k1fz/beveragenotes.html
The
I square R loss is low as signal current is very low.
Thinking I^2 R with low current (because of being in a small signal
application) might mislead us. The absolute value of current would just
tell us conductor heat, if we actually knew RF resistance (which is always
higher than dc
That would be the right ballpark. 3 paralleled strands of 29 AWG copper
running for 400m would be 36 ohms. 3 paralleled strands of 30 AWG copper
running for 400M would be 45 ohms. (Usually when I do these calculations
for traction power networks we are paralleling multiple 600 or 1000kcmil
One thing that would affect RF conductor resistance is the paramagnetic
properties of the conductor. If, for example, it was bare iron or magnetic
steel wire, then we would have eddy current losses. And those losses could
very well be much larger than the ohmic losses measured at DC.
The wire
Thanks for all the replies. I'm finally beginning to realize that the DX
Window was for an earlier time when 160m band allocations were much
different.
I see that there's nothing about any window for the Stew at
http://www.kkn.net/stew/stew.rules.txt
I assume that unless contest rules explicitly
Thank you, Petr. Some of this is mentioned at
http://www.pacificdxpedition.com/download/160m-frequencies.pdf which I have
hanging next to my radio. The 1830-1835 DX Window is on that chart, and
that's one of the reasons I had this stuck in my head. :-)
73, Mike
www.w0btu.com
On Tue, Dec 2, 2014
I didn't realize that what I mentioned was on Owen's new site.
For example, a 0.5mm diameter mild steel wire has skin depth of 0.006mm at
1.8MHz, and as explained at http://owenduffy.net/calc/SkinDepth.htm ,
Rrf/Rdc is approximately diameter/(4*δ), so 0.5/(4*0.006)=21... RF
resistance is 21 times
Hi Peter
I don ´t think so. :)
I have just 2x BOGs, 1x Hi-Z vertical and MiniDiamond W2PM loop all
connected to
wireless antenna switch. If You will add the
time for tunning around frequency using RIT + playing with four rx
antennas and tx antenna
then You have about 5sec...
Well of course
Topbanders,
thank you for your comments.
Looks like this wire was a good choice (in fact, i couldn't resist as it
was free), many use it for their beverages.
Thank you all.
Now back to the shop building that switchbox.
Hear you soon.
--
Ohne CW ist es nur CB..
73, Martin DM4iM
On Monday, July 28, 2014 10:00:36 PM Jim Brown wrote:
Online chatter about what rigs were used at WRTC and why got me to
pursuing something that's been bugging me for a long time -- the band
pollution produced by many of today's transmitters. K6XX tackled it in
talk to NCCC last fall, and over
Is there an officially designated frequency band for RTTY operation in
the U.S.?
73 Lou KE1F
_
Topband Reflector Archives - http://www.contesting.com/_topband
For about a decade I used a K8UR/bent dipole four square array on 80m. The
array was supported from the 120' guy ring of my rotating tower and was a great
performer. Several years ago I took it down, mainly for some environmental (no
not global warming) and logistical reasons, and decided to
Are you asking because of the upcoming TARA RTTY Melee that seems to
include 160M?
Many band plans (e.g. ARRL's) show RTTY concentrating in 1.80-1.81.
I have 15 RTTY 160M QSO's in my log almost all from W1AW/portables this
year. They tend to cluster in 1.805-1.810 and 1.840-1.845. But with ARRL
One thing that would affect RF conductor resistance is the paramagnetic
properties of the conductor. If, for example, it was bare iron or magnetic
steel wire, then we would have eddy current losses. And those losses could
very well be much larger than the ohmic losses measured at DC.
Copper has
I would not worry too much about 40 ohms resistance in a 600 ohm impedance
antenna that already has an intentional terminating resistance at the end.
Although I've never modeled what happens when the resistance is somewhat
distributed instead of lumped at the end, probably some loss in
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