Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [swr-meter]

The SWR meter or VSWR (voltage standing wave ratio) meter measures the standing wave ratio in a transmission line. The meter can be used to indicate the degree of mismatch between a transmission line and its load (usually a radio antenna), or evaluate the effectiveness of impedance matching efforts.

The SWR meter or VSWR (voltage standing wave ratio) meter measures the standing wave ratio in a transmission line. The meter can be used to indicate the degree of mismatch between a transmission line and its load (usually a radio antenna), or evaluate the effectiveness of impedance matching efforts.

19 questions
11
votes
1 answer

Looking for criticisms for a VNA-like meter I am designing

I would like some help from anyone who could let me know any flaws or improvements in my design they can find and help me reconsider any last minute design fixes before I send my new project off to be mass produced. This is the second version of the…
Jeffrey Phillips Freeman
  • 1,233
  • 8
  • 24
5
votes
1 answer

Modify SWR meter

I am trying to modify a SWR meter (http://www.mondoplast.ro/Reflectometru-powermetru-Performer-DF2469-pg_ft-3597) and add a new scale (now it has 200W/50W and 20W/5W) for 2W/0.5W. I have made some measurements and it does not work exactly how I…
Bogdan-Ioan BRUDIU
  • 59
  • 1
  • 3
4
votes
1 answer

Explain differences in SWR meter circuits

I am trying to understand the detailed operation of a VSWR meter, and found an excellent account in the article "An Inside Picture of Directional Wattmeters" by Warren B. Bruene W0TTK in QST for April 1959. However there is an unexplained difference…
Harry Weston
  • 2,170
  • 3
  • 24
  • 28
4
votes
3 answers

How does an swr meter directional coupler work?

How does the directional coupler in an swr meter work? How are the forward and reflected waves separated out from the standing wave on the feeder? I would like an answer in terms of sine (or cosine) waves, phasors and complex numbers, as well as a…
Harry Weston
  • 2,170
  • 3
  • 24
  • 28
2
votes
1 answer

How can i create a SWR meter that works for 0dBm sources @ 2.4Ghz?

I've stumbled upon this, but it only works for outputs between 15db and 20dBm. How can I modify it to work for 0dBm sources? I'm planning to use this to roughly tune my matching circuit for the interface between a RF transmitter and a chip antenna.
cksa361
  • 3,814
  • 7
  • 33
  • 49
2
votes
3 answers

What does SWR and reflected power mean in terms of power actually dissipated in a load?

I'm struggling to understand the "meaning" of VSWR in the context of power delivered to a load. Say I have a transmitter operating at 10MHz, a short (~1m) piece of assumed-lossless transmission line, and a load whose impedance is not well-matched to…
Dan
  • 21
  • 1
2
votes
2 answers

Determining Power in a VSWR Bridge

I have recently been trying to build an Arduino based VSWR bridge. The final goal is to make it feature rich but right now im having trouble calculating the forward and reverse voltage from the ADC inputs (or even from the raw voltages measured with…
Jeffrey Phillips Freeman
  • 1,233
  • 8
  • 24
2
votes
1 answer

How to automatically switch RF path to external antenna

I'm designing a circuit that has 2 antenna options for one transceiver @ 1.6 GHz. One antenna is internal and is the default RF load. Another antenna is external - to be attached by the user if desired. If and when the external antenna is…
Kane Anderson
  • 335
  • 2
  • 11
2
votes
3 answers

Shortening the coax on UHF CB antenna caused SWR to get worse, why?

I shortened the coax cable on my car's 477MHz CB antenna because the braid was frayed at the transciever connector end, and a metre or so of spare coax was coiled up behind the dash. I thought if I cut the coax shorter, I would remove a little cable…
blueshift
  • 162
  • 1
  • 7
1
vote
1 answer

Voltage along transmission line with scattering parameters and VSWR given

A transmitter is connected to an antenna with a coaxial cable with length \$l=1.5 \:\text{m}\$. The characteristic impedance of the cable is \$Z_0 = 75 \: \Omega\$ and the scattering parameters are \$\textbf{S} = \Bigg[ \begin{matrix} 0 & e^{-j27}…
Carl
  • 3,646
  • 1
  • 14
  • 33
1
vote
2 answers

What are the reasons to use SWR instead of the reflection coefficient?

It seems that using SWR is a tradition (historical legacy). But even in the history of electronics I can't find why SWR was considered more useful compared with the reflection coefficient. What are/were the reasons to use SWR?
Arseniy
  • 2,150
  • 11
  • 29
1
vote
1 answer

Standing Wave Ratio(SWR) Measurement

I'm trying to find a way to measure SWR digitally. Generally SWR is measured with analogue equipments and it is not practical on self designed PCB. I did not find so much resource on how to do it digital way. I have 10 Mhz hcmos oscillator which is…
cheour
  • 105
  • 2
  • 10
0
votes
1 answer

VSWR measuring, directional coupler

I may need to measure reflected power from some PA at 868 MHz with a maximum power of 5W and there are readily available SMD directional couplers to buy. However, I found only 90 deg. couplers on immediate stock and I wonder if can I measure vswr…
user2274696
  • 51
  • 3
0
votes
0 answers

A DIY SWR bridge and some problems (toroids, diodes, etc.)

First of all, I've been a licensed radio amateur for 2-3 months. I want to make an SWR bridge myself that will work in the HF band. I want to use the MFJ 945E SWR bridge circuit as I don't have enough knowledge but I have a few problems. I cannot…
Asena Güven
  • 1
0
votes
1 answer

Is current direction always opposing when signals are reflected on a transmission line

Having read Dave Tweeds excellent description of reflections in electrical transmission lines, I thought I was one step closer to a full understanding of SWR. However, later I was watching w2aew's description of how a directional coupler works and…
Buck8pe
  • 1,674
  • 18
  • 44
1
2