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  Topic: free space impedence matching?
E Kafeman

Replies: 8
Views: 15885

PostForum: Questions Related to Antenna Theory   Posted: Mon Jan 22, 2018 5:30 pm   Subject: free space impedence matching?
Antenna radiation resistance (part of total impedance) is a value which is depending on its environment. In free space should measured antenna resistance ideally be same as its feeding cable impedance ...
  Topic: Disabling mobile phone antennas
E Kafeman

Replies: 3
Views: 10667

PostForum: Questions Related to Antenna Theory   Posted: Wed Aug 12, 2015 10:53 am   Subject: Disabling mobile phone antennas
Removing GSM antennas will increase local radiation in active, non flight mode.
The phone adjust its output TX power level between few microWatt up to 2 Watt peak depending on how well base station i ...
  Topic: Disabling mobile phone antennas
E Kafeman

Replies: 3
Views: 10667

PostForum: Questions Related to Antenna Theory   Posted: Tue Aug 11, 2015 3:59 am   Subject: Disabling mobile phone antennas
1. EM radiation is emitted from your phone. It is same kind of radiation that is also emitted from an electric bulb. Main part of radiation that reaches us from the sun are also of same kind of radiat ...
  Topic: Incorporating non-dipole elements into directional antenna
E Kafeman

Replies: 1
Views: 7008

PostForum: Questions Related to Antenna Theory   Posted: Sat Jul 25, 2015 5:06 am   Subject: Incorporating non-dipole elements into directional antenna
A cellphone GSM antenna is often designed as a misshaped dipole antenna with less well defined polarization. It is a dipole, created by the the internal antenna as one pole and its internal ground as ...
  Topic: Dual band folded dipole (even lambdas)
E Kafeman

Replies: 3
Views: 12257

PostForum: Questions Related to Antenna Theory   Posted: Fri Mar 13, 2015 7:16 am   Subject: Dual band folded dipole (even lambdas)
Dipole which is resonant for both lambda 0.5 and 1 is possible.
It can be done several ways but most common is with serial coils in the middle of each monopole. Compare cellphone monopole antennas mo ...
  Topic: 22Hz receiver antenna design
E Kafeman

Replies: 1
Views: 8770

PostForum: Questions Related to Antenna Theory   Posted: Sun Dec 07, 2014 3:19 pm   Subject: 22Hz receiver antenna design
An effective loop antenna wire length should be in the range one wave length which at 22 Hz is 13000 km. A lot of copper wire.
It is however possible to make the antenna much smaller at cost of effec ...
  Topic: External Antenna design for smart phones
E Kafeman

Replies: 6
Views: 17951

PostForum: Questions Related to Antenna Theory   Posted: Sun Nov 30, 2014 1:05 am   Subject: External Antenna design for smart phones
Sorry but details will be your part to handle, or you can pay me, as I do such things for living.
Designing a coupler is much as any antenna developing process:
Optimize for lowest possible system l ...
  Topic: External Antenna design for smart phones
E Kafeman

Replies: 6
Views: 17951

PostForum: Questions Related to Antenna Theory   Posted: Fri Nov 21, 2014 6:34 pm   Subject: External Antenna design for smart phones
Very Happy
  Topic: External Antenna design for smart phones
E Kafeman

Replies: 6
Views: 17951

PostForum: Questions Related to Antenna Theory   Posted: Thu Nov 20, 2014 11:56 pm   Subject: External Antenna design for smart phones
External antenna coupler is possible but it cost transmission loss between coupler and internal antenna. Well designed will typical loss be 3-6 dB.
Possible but not any real boost.
This type of coup ...
  Topic: Changing my PCB Antenna to a whip antenna
E Kafeman

Replies: 1
Views: 6858

PostForum: Questions Related to Antenna Theory   Posted: Thu Nov 20, 2014 11:48 pm   Subject: Changing my PCB Antenna to a whip antenna
If there already is an internal antenna, do it most likely also have some kind of impedance matching circuit at PCB.
That circuit must be modified to fit your external antenna impedance.
For a whip ...
  Topic: limiting coverage area of 2.4 GHz data transmitter/receiver
E Kafeman

Replies: 5
Views: 12020

PostForum: Questions Related to Antenna Theory   Posted: Wed Oct 29, 2014 5:35 pm   Subject: limiting coverage area of 2.4 GHz data transmitter/receiver
Yes, cut away any other antennas as result else will be hard to predict.
An end terminator with same characteristics as the leaky coaxial cable can be used but is often omitted. An end cap is recomme ...
  Topic: limiting coverage area of 2.4 GHz data transmitter/receiver
E Kafeman

Replies: 5
Views: 12020

PostForum: Questions Related to Antenna Theory   Posted: Wed Oct 29, 2014 12:28 am   Subject: limiting coverage area of 2.4 GHz data transmitter/receiver
please do not write me about addressing techniques & ...
Software addressing techniques are not relevant in terms of coverage or field strength.
Addressing with aid of antenna polarization is ve ...
  Topic: limiting coverage area of 2.4 GHz data transmitter/receiver
E Kafeman

Replies: 5
Views: 12020

PostForum: Questions Related to Antenna Theory   Posted: Tue Oct 28, 2014 5:42 am   Subject: limiting coverage area of 2.4 GHz data transmitter/receiver
RF waves emitting from an omnidirectional antenna coverage behaves a bit as light emitted from an naked electrical lamp bulb.
As for the bulb can antenna have an reflector, resulting in a more direct ...
  Topic: Antenna calibration/tuning in smartphones
E Kafeman

Replies: 6
Views: 12952

PostForum: Questions Related to Antenna Theory   Posted: Mon Sep 15, 2014 4:34 am   Subject: Antenna calibration/tuning in smartphones
It can be a numerous reasons that affects power consumption.
For any cellular phone, if network coverage is less good must phone use more TX power to keep in contact with base-station.
Depending on ...
  Topic: Feeder SWR & power loss
E Kafeman

Replies: 22
Views: 48448

PostForum: Questions Related to Antenna Theory   Posted: Sat Jul 26, 2014 1:35 pm   Subject: Feeder SWR & power loss
Transistor-based class C stages, most simple schematics do usually include a trim-able PI network for most possible power delivered to antenna. Did build a few such in my youth. Small stages, maybe as ...
 
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