Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Designing a Mobile Whip Antenna at 30MHZ

Status
Not open for further replies.

ZunairaF

Newbie
Joined
May 28, 2021
Messages
1
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
7
Hi all. I am preparing for a job test, and I came across the question to determine the length of the mobile whip antenna at 30MHz frequency. As per my calculations, the answer should be 2.5m. The one stated in the answer book is 0.45m. I will be grateful if anyone can help.
 

betwixt

Super Moderator
Staff member
Joined
Jul 4, 2009
Messages
15,731
Helped
5,069
Reputation
10,163
Reaction score
4,924
Trophy points
1,393
Location
Aberdyfi, West Wales, UK
Activity points
133,219
30MHz = 10m
So a quarter wave vertical above a ground plane would be 10m / 4 = 2.5m.

That makes you correct using theory alone but in practice 2.5m would be too long for handheld or vehicle mounted antennas. Consider driving under bridges for example. Most whips are made shorter by adding a 'loading coil' near the base to make them physically shorter while still having the same electrical length.

Brian.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top