SWR Variability Question

[WSKF472]

Hello Everyone.

First of all thank you for everyone's continued input and suggestions, it is very much appreciated.

I finally have gotten everything for my base station here in NE florida and as im setting everything up, i decided to test my Ed Fong GMRS Antenna With my Wouxon 1000+ with 50' of Coax (LMR400).

When i was holding the antenna with a Surecom SWR meter in the middle, i was getting varying SWR levels of a gratuitous nature.

When i Tx'd at channel 1 at 5watt it was a perfect 1.0 SWR.

As i moved up to the 50 watt channels (Chn 16), i noticed that my SWR fluxuated significantly (1.0 to 2.1) depending on how and where i was holding the antenna.

Im looking for any root cause for this, potentially the cheap extension cable between the SWR meter and the antenna.

Any advice for a rookie?

 

WSKF472

 

[SteveShannon]

11 minutes ago, WSKF472 said:

Hello Everyone.

First of all thank you for everyone's continued input and suggestions, it is very much appreciated.

I finally have gotten everything for my base station here in NE florida and as im setting everything up, i decided to test my Ed Fong GMRS Antenna With my Wouxon 1000+ with 50' of Coax (LMR400).

When i was holding the antenna with a Surecom SWR meter in the middle, i was getting varying SWR levels of a gratuitous nature.

When i Tx'd at channel 1 at 5watt it was a perfect 1.0 SWR.

As i moved up to the 50 watt channels (Chn 16), i noticed that my SWR fluxuated significantly (1.0 to 2.1) depending on how and where i was holding the antenna.

Im looking for any root cause for this, potentially the cheap extension cable between the SWR meter and the antenna.

Any advice for a rookie?

 

WSKF472

 

When it comes to antennas and SWR everything affects everything: the height above ground, the quality of the coax, the angle of the antenna, how you hold it, your bodily fat content, etc.

Not only that but changing frequencies can have a huge effect on SWR especially on some kinds of antennas. 

My recommendation is to place the antenna on some kind of fixed mount as high as you can get it and leave it alone while you do your tests. 
Second 2.0:1 SWR isn’t really terrible and perfect 1.0:1 is unusual. Don’t get too wrapped up in SWR readings.Far more important is the performance and SWR is just one aspect of that. 

[OffRoaderX]

1 hour ago, WSKF472 said:

i noticed that my SWR fluxuated significantly (1.0 to 2.1) depending on how and where i was holding the antenna.

As my esteemed colleague Mr Shannon (H.E.R.D.) has already pointed out, a slightly fluctuating SWR is normal and an SWR of 2.1 is perfectly fine. Stop fussing and trying to over-complicate everything and just enjoy your radio. 

[WSKF472]

Thank you both. Engineer by education and profession.  Regularly get caught up in the minutia.  

 

Appreciate everyone for the advice. routing the coax this weekend.

 

Regards,

 

WSKF472

[SteveShannon]

1 hour ago, WSKF472 said:

Thank you both. Engineer by education and profession.  Regularly get caught up in the minutia.  

 

Appreciate everyone for the advice. routing the coax this weekend.

 

Regards,

 

WSKF472

I’m a retired PE as well.  I absolutely understand the need to understand as much as possible.  Welcome to the forum!

[AdmiralCochrane]

Not even an engineer and I concur with the need to understand as much as possible.

 

Today I learned that photovoltaic cells are just heavily doped diodes operating in reverse.

[WRTC928]

Just now, AdmiralCochrane said:

Not even an engineer and I concur with the need to understand as much as possible.

 

Today I learned that photovoltaic cells are just heavily doped diodes operating in reverse.

I remember having read a lot about that a few years ago, and I thought, "Huh! Well, that's interesting" but until now I hadn't remembered it.

[WRUE951]

15 hours ago, AdmiralCochrane said:

Not even an engineer and I concur with the need to understand as much as possible.

 

Today I learned that photovoltaic cells are just heavily doped diodes operating in reverse.

now that's 'dope'

[WSKN763]

When you are holding an antenna, you are part of the antenna, even when you are just touching the PVC tube that the actual antenna is in. If the 50 feet of coax was coiled up laying on the ground, that affects the performance. Once you get it installed, you will probably find that the SWR is stable. 

 

FFor anyone else that reads this, be careful if you use an HT to check SWR. When you hold an HT in your hand, you are the counter-poise/ground plane. Lay the HT on a table or the floor and use a speaker mic to key the radio.

[LeoG]

On 12/6/2025 at 5:52 PM, AdmiralCochrane said:

Not even an engineer and I concur with the need to understand as much as possible.

 

Today I learned that photovoltaic cells are just heavily doped diodes operating in reverse.

I've used photo receptive diodes for alarms and such.  Same difference.  When you shine a light on the diode it's properties change and so does the signal so you can tell when light is or is not shining on it.  I wouldn't exactly call a solar cell a diode even though it exhibits those same properties.  But it does only conduct electricity in one direction and that's what a diode does too.

[LeoG]

9 hours ago, WSKN763 said:

When you are holding an antenna, you are part of the antenna, even when you are just touching the PVC tube that the actual antenna is in. If the 50 feet of coax was coiled up laying on the ground, that affects the performance. Once you get it installed, you will probably find that the SWR is stable. 

 

FFor anyone else that reads this, be careful if you use an HT to check SWR. When you hold an HT in your hand, you are the counter-poise/ground plane. Lay the HT on a table or the floor and use a speaker mic to key the radio.

Wouldn't you want to hold the radio while testing the SWR since that's the way you will be using it?

[Northcutt114]

On 12/4/2025 at 9:40 PM, OffRoaderX said:

As my esteemed colleague Mr Shannon (H.E.R.D.) has already pointed out

I've spent the last five minutes on the google machine and can't seem to figure out what "H.E.R.D." means. Care to enlighten the troglodytes in the room?

 

Also, to OP's question - and as others have already said - get it installed first, then check SWR. Also, a 1.0 SWR may be unusual...for any other antenna than an Ed Fong. My GMRS tuned j-pole from him also sports a clean 1.0 SWR. 

[SteveShannon]

48 minutes ago, Northcutt114 said:

I've spent the last five minutes on the google machine and can't seem to figure out what "H.E.R.D." means. Care to enlighten the troglodytes in the room?

 

 

[AdmiralCochrane]

Really, REALLY, glad I missed that thread.