Marconi, in a word - yes to both questions... I do this nearly every day to help those that need a good tuning or to resurrect an older antenna to let the family keep in touch on their trip...
ADDENDUM:
Marconi, you are in a separate plot twist looking for a VID - when you can supply that link I'll be more than happy to view it. But as of this moment - I'm referring to the 3-vids discussed in your initial original Post...
Yes, I viewed these vids...
In the 1st Video, they discuss, in a classroom setting - the basic principles of using Antenna Analyzers as well as Baluns to help the Amateur use longwire antennas in the various environments of backyards and emergency "I need to use this now" scenarios. They use Baluns and demonstrate their use in making connections between the Coax and the Longwire.
Not much of the vid can help the CB user so I can only say that it does show the different Analyzers but not much else except to use "baluns" when you use longwire...
That's the takeaway from that Vid...
Number 2 discusses the issues of Inverted V antennas - and also make a good reference to RESONATE antennas when hooked up to the coax you need for your radios SO-239 - referring to 50 ohm versus BNC of closer to 72~75 ohm impedance - they / He references "a multiple of the wavelength" - say 3.9 (+80m) and then double it 7.8(+40m) then double that 15.6 (above 20m). - and the issue of coax, it's types, and the lengths to use - came up.
What was not discussed is the issue of non-resonate frequency selection - and how you match that in...Well, they "claim" coax can provide the feedline matching - again the suggestion of Feedline as a Balun...per the simple description of non-resonate and now we have this high SWR condition - ok - do this...but the issue of RESONATE he seemed to skip over the definition of the Feedpoint Impedance of a Resonate antenna - that ohmic value - changes when to change the position of the radial "arms" - so you can make the antenna appear as a 75 ohm, 100 ohm or any ohmic value you choose - but if you wish to connect this to a 50 ohm coax, you need to make the feedpoint impedance EQUAL to the coax otherwise your coax becomes your feedline and Balun (the song "Reflections of my life - Marmalade" comes to mind...)
Didn't want to go into #3, because the first two is not helping the case of the defense side of why these myths even exist. Ok, at around the 3:45~3:50 mark he was discussing Common Mode Currents - and he says "the energy goes up to the antenna and something in magic occurs and comes back down" - Man! I don't have time for explanation to a police office investigating a complaint - "Magic"? Yikes! - Houston, we have a problem. Losses? It's in there - near the end...
What I can tell you, per your question, is to change the SWR by changing the length of the coax, you're not changing SWR at the feedpoint where the antenna meets the coax - what appears we're doing is now an impedance transformation of using the coax as a feedline and hence the transferring of Resonance to more of an Impedance Transformation. We now have multiple points of "matching" at given multiples of length along the coax - that is now our feedline acting as a balun.
How to prove this?
Go buy a Lil wil mag-mount and try to find a low SWR location on the roof of your vehicle - doesn't matter what vehicle - just use it and any simple CB radio you know and trust. Just put in the whip, note the length of how much adjustment you have for the whip, and set it to mid-point of your adjustment - you be checking your SWR at the end of their supplied coax.
A separate 3-foot patch cord - and barrel connector...and a Field Strength Meter...
Now I know for fairness, the SWR meter requires it's own patch cord, that's fine - use it on the TX side as needed to meet the radio - a Lil' Wil' has enough coax to reach the radio even if it's sitting on a seat inside the vehicle. KEEP the SWR Meters PATCH CORD - it is a set parameter - you'll need the 3-foot patch ford as a separate parameter.
Also locate a Field Strength meter a known set distance - just put it some distance away from the vehicle - say on a picnic bench - and just have someone observe the readings as you find points on the vehicle whiel you locate the lower SWR readings on the vehicle...
Install the SWR meter with it's own patch cord to the radios TX side and the Lil' Wil' to the ANT side...
Firstly - find the lowest SWR the antenna is set for. Don't re-tune the whip, keep it at mid-point, try different spots and check for lowest SWR per LOCATION...on the vehicle - why? That is how you find the best point for your counterpoise (the vehicle) to be made RESONATE (yes - it is the other missing half - so it too has to be made to couple it's surface to the energy wave (radiation) the antenna produces) The more acceptance it (counterpoise) has (per location on the vehicle) - gives you lower SWR due to the appearance of the shift in SWR (feedpoint impedance transformation in the feedline / coax) to offer better tolerance or lower SWR because the radiator and the counterpoise are provide a working circuit...
Secondly, a barrel end connector and a 3-foot coax patch cord of the same type - RG-58 - and then re-check SWR at the END of all that length...
Check the Field Strength too...
See a difference?
Some do, most don't - but the SWR has not changed - remove the barrel connector and install the SWR meter again there - where you originally measured - but keep the coax length added on, and the barrel connector and add this to the TX side of the meter and re-check SWR - it will still be the same as already found when you located the lowest SWR on your vehicle...
Why would Field Strength change? Well, for some radios - they don't like poor loading or high-SWR and so their internal matching network will tend to limit their output power and dissipate energy in the radios output network instead - appearing to fold back power - as a means to prevent or reduce transmitter damage incurred by poor SWR.
IF the SWR were to go lower, or by appearance - to be closer to 1:1, the radio "thinks" you have a better SWR and raises it's power - this is a dangerous realm here - for in some instances a poor SWR that has been covered up by a coax patching to make the SWR appear lower - is borrowing time - for the mis-match FIX is VERY sensitive to frequency and coupling - so a small variance in the whips position or proximity to other objects - the SWR will skyrocket and possibly damage the radio. This simply due to the FEEDPOINT impedance (at the antenna to mount location, is changing from the initial set tune - - forcing the "balun" inside the mount to appear different in impedance to the feedline. Which - when you think about it - is why you have to change that length of coax. Again, the Urban myths strike...
How to prevent most of the above problems are to avoid temptations and risks. Locate the antenna for it's benefit, not for your location to think it's cool. Some vehicles you have little choice - tree-whacker or hand me my whip please - it's right there off on the side of the road...
Ok, I'd love to do a Vid or two on this but XYL keeps that concept nixed for now, but I've done installs using the two meters versus a single MFJ antenna analyzer - the two meters provide separate verification and MFJ can only do so much in single antenna applications...
Either way, the MFJ would help you find the best locations for the install simply by the tool itself - no radios needed. However, the Field Strength is more of the tell-tale final answer as to what you're getting, for all the effort you're putting into it...
Can't buy a lil' Wil? No Problemo - use the above to help you in installing your own Hi-Po miracle of an antenna - provide for it, and it will provide for you ok?
ADDENDUM:
Marconi, you are in a separate plot twist looking for a VID - when you can supply that link I'll be more than happy to view it. But as of this moment - I'm referring to the 3-vids discussed in your initial original Post...
Yes, I viewed these vids...
In the 1st Video, they discuss, in a classroom setting - the basic principles of using Antenna Analyzers as well as Baluns to help the Amateur use longwire antennas in the various environments of backyards and emergency "I need to use this now" scenarios. They use Baluns and demonstrate their use in making connections between the Coax and the Longwire.
Not much of the vid can help the CB user so I can only say that it does show the different Analyzers but not much else except to use "baluns" when you use longwire...
That's the takeaway from that Vid...
Number 2 discusses the issues of Inverted V antennas - and also make a good reference to RESONATE antennas when hooked up to the coax you need for your radios SO-239 - referring to 50 ohm versus BNC of closer to 72~75 ohm impedance - they / He references "a multiple of the wavelength" - say 3.9 (+80m) and then double it 7.8(+40m) then double that 15.6 (above 20m). - and the issue of coax, it's types, and the lengths to use - came up.
What was not discussed is the issue of non-resonate frequency selection - and how you match that in...Well, they "claim" coax can provide the feedline matching - again the suggestion of Feedline as a Balun...per the simple description of non-resonate and now we have this high SWR condition - ok - do this...but the issue of RESONATE he seemed to skip over the definition of the Feedpoint Impedance of a Resonate antenna - that ohmic value - changes when to change the position of the radial "arms" - so you can make the antenna appear as a 75 ohm, 100 ohm or any ohmic value you choose - but if you wish to connect this to a 50 ohm coax, you need to make the feedpoint impedance EQUAL to the coax otherwise your coax becomes your feedline and Balun (the song "Reflections of my life - Marmalade" comes to mind...)
Didn't want to go into #3, because the first two is not helping the case of the defense side of why these myths even exist. Ok, at around the 3:45~3:50 mark he was discussing Common Mode Currents - and he says "the energy goes up to the antenna and something in magic occurs and comes back down" - Man! I don't have time for explanation to a police office investigating a complaint - "Magic"? Yikes! - Houston, we have a problem. Losses? It's in there - near the end...
What I can tell you, per your question, is to change the SWR by changing the length of the coax, you're not changing SWR at the feedpoint where the antenna meets the coax - what appears we're doing is now an impedance transformation of using the coax as a feedline and hence the transferring of Resonance to more of an Impedance Transformation. We now have multiple points of "matching" at given multiples of length along the coax - that is now our feedline acting as a balun.
How to prove this?
Go buy a Lil wil mag-mount and try to find a low SWR location on the roof of your vehicle - doesn't matter what vehicle - just use it and any simple CB radio you know and trust. Just put in the whip, note the length of how much adjustment you have for the whip, and set it to mid-point of your adjustment - you be checking your SWR at the end of their supplied coax.
A separate 3-foot patch cord - and barrel connector...and a Field Strength Meter...
Now I know for fairness, the SWR meter requires it's own patch cord, that's fine - use it on the TX side as needed to meet the radio - a Lil' Wil' has enough coax to reach the radio even if it's sitting on a seat inside the vehicle. KEEP the SWR Meters PATCH CORD - it is a set parameter - you'll need the 3-foot patch ford as a separate parameter.
Also locate a Field Strength meter a known set distance - just put it some distance away from the vehicle - say on a picnic bench - and just have someone observe the readings as you find points on the vehicle whiel you locate the lower SWR readings on the vehicle...
Install the SWR meter with it's own patch cord to the radios TX side and the Lil' Wil' to the ANT side...
Firstly - find the lowest SWR the antenna is set for. Don't re-tune the whip, keep it at mid-point, try different spots and check for lowest SWR per LOCATION...on the vehicle - why? That is how you find the best point for your counterpoise (the vehicle) to be made RESONATE (yes - it is the other missing half - so it too has to be made to couple it's surface to the energy wave (radiation) the antenna produces) The more acceptance it (counterpoise) has (per location on the vehicle) - gives you lower SWR due to the appearance of the shift in SWR (feedpoint impedance transformation in the feedline / coax) to offer better tolerance or lower SWR because the radiator and the counterpoise are provide a working circuit...
Secondly, a barrel end connector and a 3-foot coax patch cord of the same type - RG-58 - and then re-check SWR at the END of all that length...
Check the Field Strength too...
See a difference?
Some do, most don't - but the SWR has not changed - remove the barrel connector and install the SWR meter again there - where you originally measured - but keep the coax length added on, and the barrel connector and add this to the TX side of the meter and re-check SWR - it will still be the same as already found when you located the lowest SWR on your vehicle...
Why would Field Strength change? Well, for some radios - they don't like poor loading or high-SWR and so their internal matching network will tend to limit their output power and dissipate energy in the radios output network instead - appearing to fold back power - as a means to prevent or reduce transmitter damage incurred by poor SWR.
IF the SWR were to go lower, or by appearance - to be closer to 1:1, the radio "thinks" you have a better SWR and raises it's power - this is a dangerous realm here - for in some instances a poor SWR that has been covered up by a coax patching to make the SWR appear lower - is borrowing time - for the mis-match FIX is VERY sensitive to frequency and coupling - so a small variance in the whips position or proximity to other objects - the SWR will skyrocket and possibly damage the radio. This simply due to the FEEDPOINT impedance (at the antenna to mount location, is changing from the initial set tune - - forcing the "balun" inside the mount to appear different in impedance to the feedline. Which - when you think about it - is why you have to change that length of coax. Again, the Urban myths strike...
How to prevent most of the above problems are to avoid temptations and risks. Locate the antenna for it's benefit, not for your location to think it's cool. Some vehicles you have little choice - tree-whacker or hand me my whip please - it's right there off on the side of the road...
Ok, I'd love to do a Vid or two on this but XYL keeps that concept nixed for now, but I've done installs using the two meters versus a single MFJ antenna analyzer - the two meters provide separate verification and MFJ can only do so much in single antenna applications...
Either way, the MFJ would help you find the best locations for the install simply by the tool itself - no radios needed. However, the Field Strength is more of the tell-tale final answer as to what you're getting, for all the effort you're putting into it...
Can't buy a lil' Wil? No Problemo - use the above to help you in installing your own Hi-Po miracle of an antenna - provide for it, and it will provide for you ok?
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