Base Maco V58 model

[Marconi]

look what happens to the s-meter when s6 is reduced to s5

A very interesting video Bob.

I think a long time ago I tried to remind you of a conversation we had where I recall you talking about some similar ideas for a fix for CB radios that could help the RF meter respond better to signals. Bob, this is just a recollection however and the conversation could have been with someone else...but I can't imagine anyone but you talking with such knowledge at that time. As I said, I also think more recently I asked you if you recalled such a conversation...and I believe you said no.

Are you confident this swizzradios fellow is a reliable source? He looks very well informed and competent in my eyes, but I know very little about the technical work he is doing. Thanks, this kind of information could be more helpful for me to imagine what you guys see on your meters.

 

[bob85]

I don't know swizzradios,
i can't vouch for his calibration but that is the effect you get with uniden based rigs,
back in the day that was 95+% of all cb's in this area.

its not technical if you understand how diodes work, the same applies to vswr/power meters using detector diodes,
its the reason vswr seems to rise with increased power
and why you should change range on a tellewave or change slug on a bird to avoid measurements that fall in the lower 1/3rd or so of the meter scale for best accuracy.

 

[bob85]

Many years ago I made the same mistake DB,
I imagined moving along the wave nodes caused picket fencing,
i observed the meter and it just made sense in my head,

At one time I thought that meant I had to test with one pole, use coax cut to electrical 1/2waves, wear one green and one brown sock, roll up one sleeve and look at the s-meter through a mirror,

Then I met my mentor Earnie Ashby RIP ( a proper RADIO amateur ) who cleared it all up, I was about 15 years old,

on FM such effects are far more apparent than when using AM or SSB,
you can see and hear multipath when there is significant phase shift.

 

[Marconi]

I don't know swizzradios,
i can't vouch for his calibration but that is the effect you get with uniden based rigs,
back in the day that was 95+% of all cb's in this area.

Bob, your explanation sounds similar to mine after I posted the video earlier where Penn was using FM mode rather than side band. I also posted my explanation because I saw effects that for me were minimal. My contentions here are based on my models, my videos, and my personal experiences when testing, and I thought his video confirmed pretty much what I see on my radio meters.

its not technical if you understand how diodes work, the same applies to vswr/power meters using detector diodes,

For me, I consider the use of diodes in these radios as technical. I used the word to make the distinction that the work done and tools used in Swizzradios' video were likely not typical for CB operators.

Bob, I have an idea to model the two A99's at 36' feet apart 1st setting one antenna with an active feed point and then the other and compare effects.

I will then model numerous other objects in the far field at random locations around these two A99 antennas. That should be interesting to see what effects there are from each antenna as I switch the feed point from one to the other.

I could be wrong, but I expect the models to show some skewing, however I'll be surprised if I see a big difference, or a difference that I could detect just using my radio...whether there are large objects in the far field or not. It won't be duplicating a real world location, but it will have reflective objects nearby within 100's of feet just as an example.

 

[Marconi]

Here are my models.

1st file shows an A99 alone vs. two side by side 36' feet apart without any environment around.

2nd file shows two A99 as noted above in a field of 7 randomly placed reflective masts 36' feet x 20" inches in diameter and are 100' feet or more away from the antennas.

3rd file shows the overlays for the patterns generated for the 2 A99's side by side as noted in the 1st file above and the two models in the field of random masts...with 1st one then the other active element being made hot to better note skewing effects.

4th file is the wires current distribution showing magnitude and phase per segment per wire.

I checked the currents on the mast wires. Wires 15, 16,17, 20 were out of phase with the radiator currents. Wire 18,19, 21 were in phase. All far field random mast wires showed current values lower then the open tip segment of the active radiator. The wires on the inactive antenna showed modest to very low currents as well.

 

[Needle Bender]

Many years ago I made the same mistake DB,
I imagined moving along the wave nodes caused picket fencing,
i observed the meter and it just made sense in my head,

At one time I thought that meant I had to test with one pole, use coax cut to electrical 1/2waves, wear one green and one brown sock, roll up one sleeve and look at the s-meter through a mirror,

Then I met my mentor Earnie Ashby RIP ( a proper RADIO amateur ) who cleared it all up, I was about 15 years old,

on FM such effects are far more apparent than when using AM or SSB,
you can see and hear multipath when there is significant phase shift.

Well then I understand your post, at 15 we're all a bit naive & easy prey for misinformation.

I once erected an A99 on a 3/8 wave offset pole mounted on a rotor to prove my theory in the real world.
I could rotate the A99 through a total of a 3/4 wave circle and found the sweet spot & nulls on everyone were exactly 1/4 wave apart.
Now remember, this was only a real world experience, not book theory or elmer misinformation, so it's obviously worthless info.

I can't wait to hear all the nay-sayers tell me how it either never happened or was all coincidence.

PS: Quads are better!

 

[The DB]

I once erected an A99 on a 3/8 wave offset pole mounted on a rotor to prove my theory in the real world.
I could rotate the A99 through a total of a 3/4 wave circle and found the sweet spot & nulls on everyone were exactly 1/4 wave apart.
Now remember, this was only a real world experience, not book theory or elmer misinformation, so it's obviously worthless info.

Now their is a rotor involved? And an antenna on a 3/8 wavelength offset pole? That strikes me as an odd offset to use...

OK, I'm still trying to get a handle on exactly what it is you are saying you did, but if your saying what I think your saying it can easily be confirmed/denied with a mobile setup with a rubber band over the mic, a vacant lot, and a field strength meter...

Speaking from someone who uses a field strength meter as their primary antenna tuning device, I can't say I ever noticed the signal strength going up as I move it directly away from the antenna, ever, but admittedly I haven't specifically payed attention to the field strength meter while moving out to its measurement point either... When using said meter, both the meter and antenna are at fixed points, which is required to properly tune said antenna for maximum radiation.

I have used it in other ways, mainly using a thin rope (string) to maintain a given distance (at least as close to a given distance as I reasonably can) from the antenna as I move around it looking for directional peaks and nulls on my mobile installation to see how that compared to the modeling I've done (ultimately prompting me to make a more accurate model). This wouldn't be any harder to do than that, actually, it would be far easier... Next time I am tuning a mobile antenna I will test for your postulate as well...

I can't wait to hear all the nay-sayers tell me how it either never happened or was all coincidence.

With all due respect, that word doesn't mean what you seem to think it means.

And when it comes to the rest of this quote, its like the pot calling the kettle black...


The DB

 

[bob85]

NB. I don't doubt you observed the change in signal strength and i don't think its coincidental,
on the other hand I can't agree with your theory on what caused the effect you observed,

signal strength or power density reduces at an inverse square law rate as you move away from a transmitter in free space without obstructions or ground effects not up & down like a fiddlers elbow,

what you observed with the offset pole as you rotated it was imho likely multipath plus small pattern distortion caused by the support structure.

 

[Needle Bender]

Now their is a rotor involved? And an antenna on a 3/8 wavelength offset pole? That strikes me as an odd offset to use...

OK, I'm still trying to get a handle on exactly what it is you are saying you did, but if your saying what I think your saying it can easily be confirmed/denied with a mobile setup with a rubber band over the mic, a vacant lot, and a field strength meter...

Speaking from someone who uses a field strength meter as their primary antenna tuning device, I can't say I ever noticed the signal strength going up as I move it directly away from the antenna, ever, but admittedly I haven't specifically payed attention to the field strength meter while moving out to its measurement point either... When using said meter, both the meter and antenna are at fixed points, which is required to properly tune said antenna for maximum radiation.

I have used it in other ways, mainly using a thin rope (string) to maintain a given distance (at least as close to a given distance as I reasonably can) from the antenna as I move around it looking for directional peaks and nulls on my mobile installation to see how that compared to the modeling I've done (ultimately prompting me to make a more accurate model). This wouldn't be any harder to do than that, actually, it would be far easier... Next time I am tuning a mobile antenna I will test for your postulate as well...



With all due respect, that word doesn't mean what you seem to think it means.

And when it comes to the rest of this quote, its like the pot calling the kettle black...


The DB

But that's what I've been telling you, the Kettle IS black! - you "nay-sayer" you...

When I moved my A99 from one side of the cabin to the other, I noticed some locals read higher and others lower and only 1 remained the same, the one exactly perpendicular from the line one would draw between the 2 different placements. This got me thinking, and since we had switched to cable, I now had a rotor to play with.

I figured it might have something to do with the high/low current nodes within the sine waves hitting my antenna, and the distance of change in wavelengths or parts of a wavelength between us after moving the antenna which might be causing the change in signal strengths.

I had a bunch of old waterpipe laying around so I assembled it into a Z-bar about 14' long and mounted one end into the rotor and mounted the A99 to the other end.
It was an old Alliance bell type AR-30 or something like that (too many years ago) and made a nasty noise when I turned it because it was rather heavily tilted off balance due to the leverage so I added 6' out the other way with a nylon sack of rocks to counterweight it.
Dad said it was the ugliest thing he'd ever seen and didn't want it up there for too long - lol.

14' gave me enough of a circle that I could go about three 1/4-waves in a circle from anyone in any direction so if it was just past a peak but headed toward the full null, I could go past the null more than a full 1/4 wave and always find the high current node.

I knew from playing with home theater woofer placement & speaker building that it had worked with low frequency audio, finding the sweet spot for the favored low frequencies, so I figured RF might play similarly.

Admittedly, it mattered less & less - the farther away the received station was, due, I believe, to a lessening difference in strength between the direct path and those of the reflections.

I always wanted to try it at home with the P500 but never did, built a Quad shortly thereafter and no longer felt a need to put a lot of time & effort into maximizing the omni performance.

...and the Pot is usually green, not black, until after you "exhale".

 

[Needle Bender]

NB. I don't doubt you observed the change in signal strength and i don't think its coincidental,
on the other hand I can't agree with your theory on what caused the effect you observed,

signal strength or power density reduces at an inverse square law rate as you move away from a transmitter in free space without obstructions or ground effects not up & down like a fiddlers elbow,

what you observed with the offset pole as you rotated it was imho likely multipath plus small pattern distortion caused by the support structure.

That also sounds correct, the inverse square law, similar to dropping octaves in audio,
(4 x the power per octave) but as I see the

it's additional to your explanation. Seen it and measured it too many times to ignore it.

.

 

[bob85]

"When I moved my A99 from one side of the cabin to the other, I noticed some locals read higher and others lower and only 1 remained the same,"

i have seen the same sort of thing myself NB, made me realise you can't compare antennas on two different masts,

"I figured it might have something to do with the high/low current nodes within the sine waves hitting my antenna,"

i agree its currents,
more than one current arriving at the at the antenna , moving the antenna causes phase delay between the two or more signals to shift, you could get summing or cancellation,

"I knew from playing with home theater woofer placement & speaker building that it had worked with low frequency audio, finding the sweet spot for the favored low frequencies, so I figured RF might play similarly."

it does play similarly to hifi in a room with regrds to summing and cancelling,

speaker placement is critical,
you have the direct wave and all the multipath reflections arriving delayed in phase,
its the delay in all the reflections arriving at your ears spaced on either side of your head that your brain uses to determine what size shape & texture room your in,
we hear and use multipath every day, its why your living room sounds different to your bathroom,

"I believe, to a lessening difference in strength between the direct path and those of the reflections"

you just said reflections

 

[HomerBB]

A rotor? does this mean you put your vertical on a long arm and rotated it to a different position, say on a 9' arm from the center mast and swung it through an 18' arc so you could test the same mast and coax within mere seconds of being in each position?
I see inherently potential problems with same mast/coax testing of various antennas due to the time lag between raising and lowering of the different antennas and the time it takes to do it. Even leaving each antenna up for several days at a time so as to "average out" results doesn't guarantee exact duplication of conditions for each antenna.
This is why I have tried to always be careful to note that my results with various antennas was true to what I experienced at my location when I tested each one.
This is why I entered debates over antenna performances stubbornly. I realized my input was anecdotal, and subjective at best. I have refused to denounce my experiences in favor of arguments, but I always have appreciated the studied, scientific analysis of those who know more about the science through the tools they have at hand.
Then again, I think my horizontal beams do better in the Spring than any other season. It's all the bird poop on the elements . . .

 

[Marconi]

Homer, this most recent discussion about the pitfalls of antenna comparisons has taken on a whole new and different angle than I've ever heard before. I sense this maybe a more in-depth idea for what was done...suggesting how the revelations developed years ago when Bob and NB'r were very young. Revelations that made them aware and feel they could determine the peaks and nulls on a radio signal from another operator...just by checking out the meter on their radios.

IMO, just because I never experienced any similar and specific revelations...doesn't make my experiences totally invalid either in my opinion. I'm just not convinced I would ever see what they observed even if I was able to fix my radios meter like has been suggested in a video Bob posted for a fix on a lazy meter.

I also realize it is often times hard to consider valid, the words of other's that are totally opposed to our own thinking.

I don't what to put words in you mouth, but I think I agree with your thinking about the time element involved in doing signal reports when installing, comparing, reinstalling, comparing, rather than just simply installing two antennas and doing A/B comparisons if the antennas are relatively far apart considering a wavelength.

I'm also not suggesting A/B testing is perfect either, a lot of considerations from others on this forum have shed light on ideas I never thought about...when I set out to do videos and try and show a little of what I was doing that supported my words.

Do I recall correctly that you once had a vertical yagi element up and working that was attached on a <>3' foot offset from the mast?

I don't know if you had a rotor, but did you ever turn that setup and do anything near what is being discussed here between Bob and NB back in their early days in radio?

Did you ever sense a beam like effect at any point in your work with this setup?

I would think if you did rotate and had to go out and twist your mast a little and then retest...the effort would be dubious at best if you were thinking you could detect the peaks and nulls for any signal. Over time I had some poor working rotors and later some that worked fairly smoothly on the dial. However when I went outside with the beam rotating...it was not as smooth as I thought. With this said...I could not tell if I was detecting any notable rise and fall of the signals. Instead what I saw was a progressive rise and fall of a single on the rotor dial.

In my later years I got pretty good at changing antennas, but even with very thoughtful preparation I was unable to lower and replace an antenna within a short time period (less than an hour) where I felt good that no change in conditions was occurring before my very eyes. Of course I tried to recognize when conditions were a mess and then I just stopped...I knew further efforts were fruitless.

Did you or your neighbor ever figure out what was going on with your neighbors A99 a few blocks away that could not copy the local signals you were easily communicating with? Or do you think it was just the difference in antennas?

 

[bob85]

Its not too difficult to swap antennas in 2 or 3 minutes,
it can be done on a 36ft scaffold pole in under 1 minute using slot in stub masts & push on connector two swivel clamps,
if you have somebody helping even faster but there's no need to race to swap antennas,

FM signals don't usually change in a short period of time apart from the odd multipath flutter that you can hear and see,
all that up and down nonsense in Eddies videos is how and when he's testing, I don't engage in such tomfoolery,

when we used to foxhunt, the fox was not allowed to change signal strength or move his vehicle at all, doing either was seen as cheating,
you had to inform everybody if you wanted to start or stop the car engine because the folk sat on homebases watching for the fox cheating would see the change in signal from starting the car and phones started ringing,

Eddie do you have anything that says two masts is OK for comparing antennas from respected sources ?

I never said I could detect the peaks & troughs, that was NB, I don't think they exist unless you have multipath,

fixing the meter as seen in the video makes the meter more generous but it reduces the ability to see small changes in signal strength, its not a mod I would do, its for meterbaters & cybernetics,
the video shows cb s-meters are far from 6db/s-unit,

pay attenuation Eddie

 

[Marconi]

Now their is a rotor involved? And an antenna on a 3/8 wavelength offset pole? That strikes me as an odd offset to use...

Without more of an explanation I also thought NBr's idea a bit odd. NB, what was going on in your thinking at the time that gave you this idea you needed to answer by the experiment you site here? It would seem to me that the shear presence of the offset itself...would have an effect on the A99 pattern in all directions that would vary in magnitude.

When using said meter, both the meter and antenna are at fixed points, which is required to properly tune said antenna for maximum radiation.

I started out using a signal strength meter that in operation responded very well with its small add-on antenna. I soon found out however there was not much range beyond a few feet, even when set to the highest sensitivity.

So, I made a random 1/4 wave length of shorted coax at the far end and attached that to the meter. Then I could get out further, at least as far as I could still see the meter with binoculars and record the settings maybe 40' feet at best.

I found out that the height of this meter relative to the antenna field was and important considerations as well. I also found the polarity of the coaxial field strength antenna was an issue as well. At some point I attached this coaxial antenna to a length of PVC so I could handle it better. That said however, I found that relative height of both antennas was a big issue in such comparison testing.

I also found out that both the source and receiving antennas had to be absolutely stationary or the magnitude of signals were all over the place. I always set the sensitivity near the middle of the meter. I used an insulated ladder to set up the meter at various elevations as necessary, and one rung of the ladder, up or down, made a noticeable difference in results. If I moved that test antenna in any way...the tests was fruitless. In fact many of the tests were fruitless as to my final conclusion, and I often wondered if signals beyond my test area were sometimes causing some interference.

I was never satisfied with my field strength testing. Maybe I should have made my coaxial antenna not resonant.