- Hi all,
I just wanted to mention that I found out today that there are 6 narrow
bandwidth SSTV modes in the free MMSSTV software which can be downloaded
The scan signals occupy 2044Hz - 2300Hz and the sync is at 1900Hz. The whole
thing is 400Hz wide.
MP73-N (320x256) 73 seconds
MP110-N (320x256) 110 seconds
MP140-N (320x256) 140 seconds
MC110 (320x256) 110 seconds
MC140 (320x256) 140 seconds
MC180 (320x256) 180 seconds
I can see no reason why these modes are not legal on 30m in FCC areas
(certainly, MFSK SSTV is allowed) - if anybody thinks different let me know!
but assuming I am correct I suggest we could add these to our list of modes
It would be possible to make contact either by initially sending an SSTV CQ
picture and continue that way or to initiate contact with a digimode first
(perhaps DominoEX, a 500Hz Olivia mode or even PSK31 if you remember that
you will need at least 400Hz of empty spectrum for the transmission so watch
out for adjacent signals. I would suggest that your digimode AF center
should be 2100Hz which would put it right in the middle of the (to be
transmitted) SSTV passband.
If you have Windows XP you can use the same soundcard in different software
programs at the same time which would allow you to run MixW/MultiPSK (for
the initial digimode) and MMSSTV together - just switch to MMSSTV when you
want to send the picture.
The MMSSTV software includes a FSKID which can be used to send callsign info
after a picture has been sent and also a VIS code (transmitted at the start
of the picture) which allows automatic mode determination.
If there is enough interest in operating SSTV perhaps the group as a whole
(democratically!) could determine a possible calling frequency which would
encourage operation at a known reference point (similar to the 14.230 spot
frequency on 20m).
Here's to some interesting "multimedia" QSOs on 30m!
73, Sholto KE7HPV
- What I have done is used clothes line wire in the trees I wish to hang my
wire. I then attach it to the antenna at the point I wish to bring up, I
then tie bricks or some kind of weith to the bottom of the clothes line so
it will sway in the tree with very little pulling of the antenna it self. We
have very tall poplar , spruce and pine trees in my area, and I find the
plastic coated clothes line wire because it does move will not grow into the
tree like robe or other tiedowns will do..
YouKits Canada Rep.
SATERN Amateur Radio Liaison Officer Great Lakes Region
DEC Amethyst District ARES
On Tue, 22 Feb 2011 01:08:31 +0000
Scott Currier <scott_currier@...> wrote:
I haven't got the perfect solution but after years of using copper wire
antennas I have come to the conclusion that you don't use copper wire with
supports that move. Everytime I had a problem, the antenna wire broke, not
I now use copper clad steel wire and a lot of extra rope.
I also let the antenna hang down a bit rather than pull it tight.
The idea is that the copper clad steel is strong and the extra rope is to
allow for stretching if the trees move in opposite directions.
Rather than having the antenna break to spare the rope, I'd rather have
rope stretch and the whole setup remain up in the trees. If something is
to break, I'd prefer it to be the rope.
I had a email conversation with a small antenna mfg, I forget who he was,
he was offering an antenna I was interested in but it was made of copper
rather than steel wire and he didn't or wouldn't do a version with copper
steel wire so I didn't buy it.
The antenna I have now came as copper wire but it is a single wire design
I just ordered enough copper clad steel wire and rebuilt it.
All my antennas now will be made with the copper clad steel.
Took me a long time to learn something so simple. Oh well.
73 all and good dx.
Scott KT1B Haverhill, MA
Date: Tue, 22 Feb 2011 00:26:12 +0000
Subject: Re: [30MDG] Re: Antenna in swaying tree, was : SSTV
I second the idea of bungee cord. It has a limited life in sunsine, but I
several years each....
Using a weight is a bad idea, in that if the tree hits a sudden gust the
weight can free fall, and then it snatches as the wire goes tight (or
alternatively the antena holds the tree still for a moment for the other
direction of gust...) Both generate avoidable shock loads in the winds we
(I fear bungee would fail to operate if it was soaking wet and then it froze
solid, so might be a problem in severe winters. But then, the pulley may ice
up, or the wires.)
On Sun, 20 Feb 2011 14:12:20 -0000
"Daithi" <gi7omy@...> wrote:
> What I have done with wires was to use a bungee cord (the sort of elastic--
> rope with hooks at each end that you use to hold luggage on a car roof rack
> or a motor bike pillion). They will keep tension but will also stretch when
> 73 de Daithi