100 feet of RG-58A/U SWR effects shown visually.

[Lil'Yeshua]

Yours is cheaper than this one
MFJ Enterprises Inc.

 

[Mudfoot]

In addition to quick band changes, it does continuous tuning. 11 meters is covered. It covers the entire HF spectrum up to 35 mHz.

 

[Captain Kilowatt]

I use the MFJ-269. There are better units but this one works for me.

MFJ Enterprises Inc.

 

[towerdog]

excessive cable length is not a cause of high VSWR. Any coax will have some cable loss, power lost in the form of heat but outside the world of UHF and microwaves its pretty negligible. For every 3dB in loss, your power is cut in half.
High VSWR is from reflections in the line, caused by impedance mismatch, which is in turn caused by crushed coax, broken and poorly done connectors, bad or wrong freq antennas, buzzards, water intrusion and about 5 dozen other things.

I THINK...at HF frequencies if the length of the line matches some multiple of a wavelength, then the line COULD dissipate some of the reflected power therfore giving you a lower reading of reflected power on your SWR meter. Is not how shit works on the UHF/SHF shit at work. Wavelengths are too small to radiate all the strange things HF does. It does strange things but different, like internal passive intermodulation from tiny things, like specks of copper crap in the line, poor connectors or rusted shit near the antenna acting like a diode mixing 2 freq to produce a third nasty freq jamming the RX band or worse.

Point being, 100 feet or 5000 feet, dont matter, matched impedance matters and VSWR aint everything if your signal dissipates in the line or your antenna radiates like a dummy load (hasta la vista says the terminator)

 

[RADIOOMAN]

excessive cable length is not a cause of high VSWR. Any coax will have some cable loss, power lost in the form of heat but outside the world of UHF and microwaves its pretty negligible. For every 3dB in loss, your power is cut in half.
High VSWR is from reflections in the line, caused by impedance mismatch, which is in turn caused by crushed coax, broken and poorly done connectors, bad or wrong freq antennas, buzzards, water intrusion and about 5 dozen other things.

I THINK...at HF frequencies if the length of the line matches some multiple of a wavelength, then the line COULD dissipate some of the reflected power therfore giving you a lower reading of reflected power on your SWR meter. Is not how shit works on the UHF/SHF shit at work. Wavelengths are too small to radiate all the strange things HF does. It does strange things but different, like internal passive intermodulation from tiny things, like specks of copper crap in the line, poor connectors or rusted shit near the antenna acting like a diode mixing 2 freq to produce a third nasty freq jamming the RX band or worse.

Point being, 100 feet or 5000 feet, dont matter, matched impedance matters and VSWR aint everything if your signal dissipates in the line or your antenna radiates like a dummy load (hasta la vista says the terminator)

I am curious about the buzzards; That's a new one on me.
Just trying to learn what I can here.
Also, if you don't mind, I am curious about the 5 dozen other things.

 

[northern35s]

Another analyser to consider is th Youkits FG01, I believe there's a company in Canada that supplies them, a couple of people this side of the pond have bought them and get some very good results with them, I'm considering buying one as part of my portable kit due to it's diminutive size, it wouldn't take up much space in my lightweight kit.
I currently use an MFJ269, I have an old MFJ249 and have on order a miniVNA PRO with bluetooth, I'm also bidding on an AIM 4170C on ebay so with a little look I'll have all I want (more than I need though ), I'll probably wait until an FG01 comes up on ebay rather than buy new.

I have a 60' tower going up this Spring and have some plans to make a number of home brew antennas for home so the analysers will be put to use here, I make my own mobile antennas and find the analyser is indespensible here too, it's important to know when an antenna is at resonance as most of my home built mobile antennas require shunt loading to lower the VSWR, so VSWR alone would be of no use

 

[RADIOOMAN]

Another analyser to consider is th Youkits FG01, I believe there's a company in Canada that supplies them, a couple of people this side of the pond have bought them and get some very good results with them, I'm considering buying one as part of my portable kit due to it's diminutive size, it wouldn't take up much space in my lightweight kit.
I currently use an MFJ269, I have an old MFJ249 and have on order a miniVNA PRO with bluetooth, I'm also bidding on an AIM 4170C on ebay so with a little look I'll have all I want (more than I need though ), I'll probably wait until an FG01 comes up on ebay rather than buy new.

I have a 60' tower going up this Spring and have some plans to make a number of home brew antennas for home so the analysers will be put to use here, I make my own mobile antennas and find the analyser is indespensible here too, it's important to know when an antenna is at resonance as most of my home built mobile antennas require shunt loading to lower the VSWR, so VSWR alone would be of no use

Good luck with the tower.
Are you gonna make it 'frequent visitor friendly?'
Am interested in your plans and ideas about your planned tower install.

 

[northern35s]

Good luck with the tower.
Are you gonna make it 'frequent visitor friendly?'
Am interested in your plans and ideas about your planned tower install.

You're welcome to pop round anytime, it's a bit of a drive though

I already have the tower, it's a four section 60' Strumech, the only downside with the UK is that I have to apply for planning permission from the local planning authority, fortunately enough I live in an area where there are no HOA issues or where it will spoil the neighbourhood, but I do have problem neighbours, one in particular took exception to my 45' portable mast and took it upon himself to vandalise my property, the local police resolved this issue

As for the planning permission, I'll install the tower first, and then apply if I get any complaints, I suspect I will

 

[BJ radionut]

[QUOTE
As for the planning permission, I'll install the tower first, and then apply if I get any complaints, I suspect I will [/QUOTE]

Always better to ask forgiveness....than ask permission!

I did the same....poured the base/installed 54ft of tower/tri-bander/twin 2 meter beams and 5/8w GP for 10m...it was 83ft tall overall....
Then applied for the permit(got permit and notified the council 24 hours later work was complete!)....Only thing they questioned was....
"Was the concrete even set when you installed tower?"....
All the Best
BJ

 

[Captain Kilowatt]

Is not how shit works on the UHF/SHF shit at work. Wavelengths are too small to radiate all the strange things HF does. It does strange things but different, like internal passive intermodulation from tiny things, like specks of copper crap in the line, poor connectors or rusted shit near the antenna acting like a diode mixing 2 freq to produce a third nasty freq jamming the RX band or worse.

I have actually heard of cases where copper filings from cutting hardline (not heliax) with a hacksaw and not clearing the line has caused holes to be worn in the line over time from the pieces vibrating and wearing a hole in the main transmission line. We were very carefull to make sure we cleared all filings and cuttings from the line when we installed the 3 inch hardline and fittings at our FM site.

 

[Captain Kilowatt]

[QUOTE
As for the planning permission, I'll install the tower first, and then apply if I get any complaints, I suspect I will

Always better to ask forgiveness....than ask permission!

I did the same....poured the base/installed 54ft of tower/tri-bander/twin 2 meter beams and 5/8w GP for 10m...it was 83ft tall overall....
Then applied for the permit(got permit and notified the council 24 hours later work was complete!)....Only thing they questioned was....
"Was the concrete even set when you installed tower?"....
All the Best
BJ[/QUOTE]


You should have told them no. You built it from the top down so as to give the concrete time to cure. :laugh:

 

[towerdog]

I have actually heard of cases where copper filings from cutting hardline (not heliax) with a hacksaw and not clearing the line has caused holes to be worn in the line over time from the pieces vibrating and wearing a hole in the main transmission line. We were very carefull to make sure we cleared all filings and cuttings from the line when we installed the 3 inch hardline and fittings at our FM site.

I also seen where the copper crap would short out under power, but not show up on a line sweep. GRRRRR fun when you got TMAs, bias-t, diplexers/combiners/etc all in the path as well.

 

[HomerBB]

"My Feedline Tunes My Antenna"
Byron Goodman, W1DX