Projects
USB Printer Switch (2PC's to 1 printer)
A 20m dipole using the guanella transformer
2m J-Pole hidden antenna
RMK Keyer chip built into MFJ9020
Micro SWR Meter (DL2AVH) tried
This low-cost antenna has been published by DF8ZR in cq-DL 7/2001. I
did not used exactly the same material but achieved almost the same good
results. Instead of the 50mm tube I only had a 40mm tube in the box, but
I did alsoo used 2 x0.75 sqmm wire.
Here are some pictures of the feed point:
On the picture to the right you can recognize the
cheap'n'dirty insulators I'm using here. The PL socket was put into
a film roll box, cutted halfways. It is also strapped to the tubing.
If you hang up this thing into the air it does look like a professional
antenna!
2m J-Pole hidden antenna
Do you need an antenna that cannot be recognized by your neighbours as
such? Here is another idea... just have a look at the pictures.
And here are some construction details:
Additional note: The gamma match originally used a clamp that can be
moved up- and downwards.
Because this is not a secure connection on pure wire I have soldered
the connection. One has to experiment
a bit to find out the best SWR point, though.
RMK Keyer chip built into MFJ9020
Note: This article is written in German. You
can download the article, the Eagle-schematic and the picture zipped here
Micro SWR Meter (DL2AVH) tried
Note: This article is written in German. You
can download the article and the picture zipped here
USB Printer Switch
This cheap'n'dirty USB switch connects 2 PC's to one USB printer. The
one I'm using is a Canon i550 which works just fine.
Just look at the schematic and the picture. I've never checked with the
USB spec if the 5V connection can be made by using schottky diodes, but
as my printer won't draw any current of the USB port, it is just that it
detects the connection. Please keep in mind I don't give any warranty that
this cuircitry will work for you nor prevent your parts from damage.
