[pskmail] Re: A few things we could improve ?

  • From: Per Crusefalk <per@xxxxxxxxxxxx>
  • To: pskmail@xxxxxxxxxxxxx
  • Date: Sun, 08 Apr 2007 09:51:44 +0200

Hi Walt,

I agree with you on these antennas. The T2FD was very quiet and was
excellent for reception. I replaced the T2FD with a random wire at the
same position and RFI jumped to an S9 (from nothing), the random wire
was unusable just because of that. The T2FD was inadequate also for
another reason: mounting. There was a strong wind (with snow) up in
those mountains and I had a tough time getting it up in the trees. The
dipole and the wire were much easier to get to a better position. I
guess 6-8 dB tx loss on the T2FD could be about right. Its homemade and
the first I have made so I may have done a less than perfect job on the
balun and resistor too.
The 1/2 wavelength dipole was mounted low (too low) due to its length
and restrictions on good trees. It was mounted at abt 9 feet (3 meters)
but worked despite of that. I figured NVIS was what I needed anyway and
it seems thats what I got.

Your description of an inverted vee for 80 matches what I use from OH0.
I have the feed point at the house there and the legs somewhere near 120
degrees spread out. That is the best "portable" antenna I have used and
I have very good results with my FT-817 there. The antenna works so well
that I figured I didn't need any more power than 5 watts (I have seen
the need for that now). I also tried to make a multiband fan dipole of
it but it prooved too difficult to get to a good position.

I would like to find a smaller antenna, easier to erect, with equal or
better performance to the dipole. But, I guess its true that big
antennas are good antennas and small antennas are...crap.

73 de Per, sm0rwo



sön 2007-04-08 klockan 02:13 -0500 skrev Walt DuBose:
> Note on antennas...
> 
> The T2DF is OK if you want a low noise receive antenna but it has about 6 to 
> 8 
> dB less radiation than a dipole or Inverted V at the same feedpoint heigth.  
> If 
> you use a 90-120 ft T2DF, it starts becoming directional between 10-12 MHz.
> 
> A long wire is a strange animal and can mean different things to individuals. 
>  I 
> think of a long wire as something like 3-7 wavelength.  Otherwise, I think of 
> a 
> random wire more like an Inverted L.  In that case, its good to have the 
> horz. 
> element 15 - 35 ft above ground and the antenna must NOT be a mutiple of a 
> 1/2 
> wavelength.  I have and excellent performance with a 90 ft wire on 80/40M 
> that 
> was 15 ft above ground.
> 
> No doubt that a 1/2 wavelength dipole (or Inverted V) with the feedpoint at 
> 17% 
> of a wavelength above ground is an excellent NVIS antenna with a feed point 
> of 
> 50 ohms.
> 
> If using a Inverted V, try to  make the  angle between the two legs of the 
> "V" 
> no less than 120 deg. (its hard).  I find that making the ends of the "V' at 
> least 10 ft above ground works fairly well for 40M and even 80M but would try 
> to 
> the then ends of an 80M Inverted V up 15 ft above ground.  The 50 ohm 
> feedpoint 
> for 40M is about 27 ft and 40 ft for 80M.  30-35 ft seems to be a nice 
> compromise for 80/40M.
> 
> One always should consider their need for a high angle of radiation antenna 
> (NVIS) or low angle of radiation antenna depending on the desired length of 
> the 
> desired path.  I generally prefer a verticle on 30/20M but sometimes a dipole 
> on 
> 30M and most generally a dipole or Inverted V on 80/40M.
> 
> 73 All and Happy Easter.
> 
> Walt/K5YFW
> 
> Per Crusefalk wrote:
> > Hi,
> > 
> > I'm not really back from our trip up north yet (just 3 hours to go) but
> > I figured I should write down some of the things I noticed during the
> > trip. We were in a cabin in Orsa, right next to the bear park, and I
> > tested three different kinds of antennas:
> > (We did go to the bear park as well and looked at Kamchatka bears, lynx,
> > foxes and more).
> > 
> > 1. T2FD, worked great for rx but not vy good for tx
> > 2. Random wire (7 meters) with tuner, worked well for tx but it picked
> > up RFI and made the band unusable
> > 3. A standard dipole for 80 meters, the antenna that worked...
> > Also, I use an FT-817 and I have had much fun with it but I have now
> > decided that life is too short for QRP... I need more power.
> > 
> > So, back to the pskmail things. This is a list containing a lot of work
> > for me and Rein. But, I'm not just going to complain here. I intend to
> > work on these things too. Here are the things I noticed:
> > 
> > 1. View and clear "mailfile/headers/sendfile/mail archive"
> > 
> > This works but takes a while to get used to. Could we change this into
> > an "inbox, sent and unsent" ? Also, I forget to clear the sendfile at
> > times and that causes me to resend old stuff. Could we move the messages
> > to sent when they are ?
> > 
> > 2. Favourites/bookmarks/get web page
> > 
> > Works great and I would like to extend it. I would like to see more of a
> > firefox bookmark approach and I would like to be able to save/load a
> > file containing bookmarks. Also, need to reevaluate the use of
> > lynx/links on the server.
> > 
> > 3. QTC?, Download and Read
> > 
> > These buttons are connected to the input field on the bottom of the
> > client. If I would like to read message 149 then I need to enter that in
> > the field before pressing the button. I would like it to ask me about
> > what message to read if that field is empty. That way I won't initiate a
> > new download of the entire message list if I just forget to enter a
> > message number before pressing the button.
> > 
> > 4. Binary downloads
> > 
> > Works but does not handle swedish characters (ISO-8859-1).
> > 
> > 5. Invisible functions...
> > 
> > There are functions that you can only use from the "command line", I'm
> > thinking abt PSKaprs messages and partial message listings (well,
> > mentioned that above). Anyway, I would like a menu shortcut at least and
> > a tiny window where pskaprs messages can be edited. Also, I would these
> > very nice functions to be visible to the novice. So, all the "hidden"
> > functions need to be more visible.
> > 
> > Time for breakfast here so 73 for now de Per, sm0rwo
> > 
> > 
> > 
> > 
> > 
> 
> 


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