ARRL

xof7fox

Joined: Sat, Jul 7th 2012, 16:27 Roles: N/A Moderates: N/A

Latest Topics

Topic Created Posts Views Last Activity
If I am Tx'ing a VHF GrndWave of how much value is a Beam Antenna? Jan 6th, 16:54 4 219 on 14/1/14
Impedance per current General Manual p.6-6/fig.6-5 ? Nov 13th 2013, 16:48 1 169 on 13/11/13
Why is 72 Ohm Impedance center feed point desireable? Oct 2nd 2013, 21:10 3 274 on 3/10/13
Impedance Matching HF Aug 1st 2013, 22:18 3 497 on 3/8/13
Folded Dipole 40M Aug 1st 2013, 22:04 3 460 on 17/9/13

Latest Posts

Topic Author Posted On
If I am Tx'ing a VHF GrndWave of how much value is a Beam Antenna? xof7fox on 14/1/14
Thank you Zack.
Thank you Martin.
- Fred K4XXK.
If I am Tx'ing a VHF GrndWave of how much value is a Beam Antenna? xof7fox on 6/1/14
I am struggling to understand the value of a Beam Antenna for 2 Meters IF I am Transmitting an FM Vertically Polarized Groundwave. And, in advance, I thank you for taking the time to read this Post and, further, trying to advise me if you can.
HERE IS MY QUESTION: Does a Beam/Directional help me push the FM Groundwave past the otherwise LOS limitation by some anticipate-able % greater amount?
Meanwhile, with regard to all of the above I do understand that:
1. A Beam will help me Receive (this Q is exclusively about Transmitting).
2. If I am going after a bounce off of Meter/or 'equivalent' Scatter, or making it to a satellite or the space station then the Beam adds to my effective Transmit distance.(this Q is exclusively about Groundwave/LOS, not Skywave).
MANY thanks,
Fred k4xxk.
Impedance per current General Manual p.6-6/fig.6-5 ? xof7fox on 13/11/13
While in the current General/Level 2 Licensing Manual (7/1/11-6/30/15) on Page 4-18 "Impedance" is defined as: "...a general term for the opposition to current flow in an AC circuit caused by Resistance, Reactance or any combination of the two."... the Figure 6-5 (GLM0003) on Page 6-6 graphs Impedance over perfect ground per height of a Half-Wave Dipole in Wavelengths, yet it does not say, unless I am missing it, IF the Impedance is that of Resistance OR Reactance. Should the reader assume that the Impedance in Fig. 6-5 is purely Resistance (i.e., that Reactance is zero)?
Many thanks in advance to anyone who can offer to me some guidance on this matter.... Fred K4XXK
Why is 72 Ohm Impedance center feed point desireable? xof7fox on 3/10/13
Thank you for your time, your thoughts and your guidance Zack.
Am heading to Amazon for Antennas by Jack D. Kraus.
Why is 72 Ohm Impedance center feed point desireable? xof7fox on 2/10/13
Hello - I have read more than one ARRL article that report that the typical 40 M coax single wire center feed dipole in theoretical 'free space' can be expected to provide a 72-73 Ohm Impedance at the center feed point. My confusion has to do with wondering why I would want that if I should be matching the center feed point with the 50 Ohm Impedance signal coming at it from my Transceiver. In other words, if there were some other wire design/composition that would offer 50 Ohms at the center feed point would that not be more desireable? Thx,
Fred K4XXK

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