Search found 147 matches

by snn47
Tue Feb 07, 2017 8:04 am
Forum: Antennas
Topic: Simple dipole for FM-BC reception. To balun or not to balun?
Replies: 9
Views: 8803

Re: Simple dipole for FM-BC reception. To balun or not to ba

Most FM-BC antennas are vertically polarized, unless you want directivity, a 1/4 wave ground plane is mechanically shorter. A 1/4 wave ground plane is basically a 1/2 wave dipole, were the 1/4 vertical radiatior is reflected by a conducting ground/counterpoise or 1/4 wave radials, it is asymetrical ...
by snn47
Mon Feb 06, 2017 9:37 pm
Forum: Antennas
Topic: L-Band receive antenna (960 MHz to 1215 MHz)
Replies: 10
Views: 10340

Guidelines for choosing coaxcable for use >1000 MHz

Guidelines for choosing coax cable for use >1000 MHz possibly not complete, but that should suffice for a start: Know which impedance receiver has and you know what impedance your coax cable and connector should have Decide if you desire low loss, max. shielding or both While low loss per dB/m (or ...
by snn47
Tue Jan 31, 2017 11:37 am
Forum: Antennas
Topic: L-Band receive antenna (960 MHz to 1215 MHz)
Replies: 10
Views: 10340

Re: L-Band receive antenna

If you look for NARCO transponder (e.g. AT-155), you'll find the cheaper alternative antenna to a blade antenna used by GA (see second picture). It is basically a 1/4 stub and requires a conductive counterpoise/groundplane. The small ball on top reduced the physical length a bit,but will have also i...
by snn47
Sun Jan 22, 2017 10:04 am
Forum: Antennas
Topic: L-Band receive antenna (960 MHz to 1215 MHz)
Replies: 10
Views: 10340

Re: L-Band receive antenna

That is the L-Band Blade in use 1948 and not an ILS-GP antenna. While today's Blade antennas are in use also on lower bands like e.g. for VHF- and UHF-Com. For ILS-GP and ILS-LLZ the folded V-dipole or alford loopd design was commonly used in 1948. Today there are many non L-Band- or multi-band-Blad...
by snn47
Sat Jan 21, 2017 8:16 pm
Forum: Antennas
Topic: L-Band receive antenna (960 MHz to 1215 MHz)
Replies: 10
Views: 10340

Re: L-Band receive antenna

Sorry I, I should have used diamond antennae instead of spade, for a lack of the correct designation in english, but I could not correct my post. Everytime I tried I could not save it, because I received the message " This message was flagged as spam and has been denied." On second thought would fla...
by snn47
Sat Jan 21, 2017 8:01 pm
Forum: Antennas
Topic: L-Band receive antenna (960 MHz to 1215 MHz)
Replies: 10
Views: 10340

Re: L-Band receive antenna

Since I first mentioned the L-Band Blade antenna used on aircraft, I started to look for information on blade antenna design without much success. The design is old <1948, I couldn’t find a patent, nor anything on the design. The only cutaway picture of an L-Band Blade antenna showing the design I k...
by snn47
Sat Jan 21, 2017 8:25 am
Forum: Antennas
Topic: L-Band receive antenna (960 MHz to 1215 MHz)
Replies: 10
Views: 10340

L-Band receive antenna (960 MHz to 1215 MHz)

continuation of discussion started at http://www.rtl-sdr.com/radio-for-everyone-new-posts-building-an-ads-b-station-easy-homemade-beginner-ads-b-antennas/#comments I understand and appreciate your aim “keep it simple” and that it is diffuicult to achieve. What I was trying to point out that guidance...