Base CTE Saoliut LW 150 GPA

[Marconi]

Here is the Larry 150 an old idea that was similar to the Avanti Sigma 4.

1.. image of the manual with my guesstimate for dimensions.

2. is the model over Real Earth at 36' feet. This model is not tuned and therefore will likely show the gain to be overstated to say the least. The gain at 5.73 dbi @ 10* degrees is trending toward what the manual reports at 6.50 db gain.

Use the PDF Zoom feature and maybe this will help you see this old manual.

 

[DoctorAudio]

I remember an antenna from the 80's called "The Larry" that was similar to the Sigma 4. Over the years I could never find any info on the NET about it and if I asked anyone about it they didn't remember the antenna. Here it is!!!
Thanks a bunch for posting this up Marconi. I knew I wasn't dreaming that it once existed...

 

[Marconi]

DoctorAudio, it was real alright.

I had a neighbor that had several in disrepair and he gave them to me to see if I could make one. Too much was missing, but I was able to glean some dimensions, and Wilbur gave me copies of his antenna file with several ideas for dimensions among the images. I used these to get my guesstimates for the dimensions I used here. That said, still don't think the model is to specs yet and it sure won't respond to my matching and tuning efforts if the radiator is as long as the kit allows.

 

[Marconi]

I remember selling what I thought were Sigma 4 antennas to some local buds some years ago soon after I got my S4 made by Antenna Specialists and started working that monster.

I ordered 3 from a CB shop in Missouri City, Texas and had them shipped direct to these guys. Two guys were mad...saying this antenna had no ears. The models below of this antenna and my Sigma4 compared...suggest maybe why 2 of these 3 guys got it wrong.

I talked to all three, and I asked them if they paid any attention when I cautioned them these antennas were cut and tune-able for 10.11.12 meters, and that they would have to tune accordingly. 2 guys did not heed my warning...and they never got their new antennas to work.

Tex was the most vocal about all this and when I asked him if he adjusted the length for 11 meters...he said he made that thing as long as it would go...and that if it had a gamma match...then he could tune it. I told him I tended to doubt that, but he just wouldn't listen.

The instructions show under "settings" there is nearly 48" inches of difference from 10 to 12 meters that two of these guys paid no mind to consider.

I told them this antennas was built to work 10,11,12 MHz and if they could not get it to work, bring it back to me and I would give them their money back.

As we see in the instructions above...the manual is lacking details. So, two of these guys built their new antenna extended as long as it would go and now we understand maybe why they got it wrong.

Below is a model of the Larry 150 and maybe you can see why it likely had no ears.

Reminds me of the epoch threads about the Sigma4 and the Vector 4K when guys were claiming that they could tune these antennas at 30' and more and they work better.

See what happens when the 1/2 wave radiating part of these 3/4 wave antennas, the 1/2 wave radiating portion of these type antenns, the S4/V4k, are too far above the top of the radial loop, and all the power is push up and that skewing the pattern making very high angles, and this leaves little current to flow in the top 1/2 wave part of the radiator.

 

[bob85]

Eddie,
The cte lw150 was the same antenna as the early longer vector 4000, 9.5mtr 31ft+ long with 4 radials 2.275mtr about 89.5"

they perform better when you shorten them but they will tune with a vswr meter even longer than the factory settings.

 

[Marconi]

Eddie,
The cte lw150 was the same antenna as the early longer vector 4000, 9.5mtr 31ft+ long with 4 radials 2.275mtr about 89.5"

they perform better when you shorten them but they will tune with a vswr meter even longer than the factory settings.

Here is my Larry 150 model at 372" - 31' with 90.6276" radials. The model shows a modest mismatch as the gamma is set on its model with the radiator at 3/4 wavelength. The model at 31' doesn't look bad here, so I think maybe I can get it matched.

BTW, the gamma is 41" from feed point to dog bone, which is 5" at the top and 2" at the bottom. The capacitor is about 18" above the feed point.

I will try and tune this one and see what happens.

 

[Marconi]

Here are both models. The pattern still looks bad.

Bob, I can't be sure about the experience I had long ago. I never saw those antennas and I never owned one.

But, based on that account, and looking at the pathetic patterns my model produces...it sure sounds to me like what those guys experienced, NO Ears, with their new Larry 150 antennas...poke all the way out to the full length at 31' was no-way-no on receive.

At least that was their complaints.

 

[bob85]

Eddie
your buddies probably had them set longer than 31ft, the original vector had plenty of tuning tip left inside when set to factory length,
you could extend them to 32ft+ but performance goes down,

your buddies would have had better results removing the tuning tip.

 

[Marconi]

That said, still don't think the model is to specs yet and it sure won't respond to my matching and tuning efforts if the radiator is as long as the kit allows.

The reason I say this Bob, is because when I set the tuned model to Free Space, the match goes bad, and if I tune the FS model and the set the model over Real Earth, again the match produces bad results.

This tells me, if I don't see the match on these two models produce a fairly close match...the model has issues. This is where I see the section, above the loop and extending up and out of phase with the top 1/2 wave portion...as being a problem if the radiator is extended out to its full length or about 372" inches, consisting of wire #2 = 331" inches and wire #1, the gamma section, at 41" inches for a total length of 372" inches = 31' feet. And all the while the high angle pattern changes very little.

 

[Marconi]

Eddie
your buddies probably had them set longer than 31ft, the original vector had plenty of tuning tip left inside when set to factory length,
you could extend them to 32ft+ but performance goes down,

your buddies would have had better results removing the tuning tip.

Could be Bob. But if I have a model in Free Space with no losses in the model, and I set that model over Real Earth...adding the losses back to the model, and the match goes away...then something about the model is wrong. Remember I'm guessing at some of these dimensions. Do you have the dimensions for the gamma?

I have 3 sets of different dimensions for this Larry 150.

In the Free Space model below, I started with the Tuned model I posted in #7. All I did to the Real Earth model was remove the mast, and set the Ground Type to "Free Space", set the Wire Loss to "ZERO", and set the antenna Plot to "3D". This removed the losses from the model.

Correcting the understated gain for this model might appear confusing. So, if the FS model AG test results shows a (-) sign, the gain for the model reported is understated and needs to be added back to the reported gain...which is -0.37 in this case.

Corrected gain for this FS model should be 3.36 db @ 27.205 MHz.

 

[Marconi]

Bob consider this, if I set this Larry 150 at 3/4 wavelength, the model works fine in FS and over Real Earth. This is what I find in other models I post when I check the FS AG test. If the model does not work this way, again I figure I've done something wrong.

In that case however, the bottom of the 1/2 wave radiator pattern sits very close to the top of the radial loop, and there is little to no problem with currents flowing in that area that are out of phase.

Again IMO, this area is what appears to me to be skewing the pattern... similar to what we see with the model set at 31' feet.

How sure are you of what you saw back in the day...with this old Larry or the older Vector?

 

[bob85]

Eddie
i am 99% sure they are the same antenna,
same length weight & section count as the old style vector 4000, from memory the hubs are the same as the old vector,

lw150's were around many years ago, before we got sirio antennas here,

im 100% sure that the original at 31ft+ was too long, going shorter improves signals & going longer makes them worse,

i don't remember the details of gamma settings but you can get a low vswr over a wide range of monopole lengths from shorter than a sigma4 to longer than the old vector.

 

[Marconi]

Bob, here is a video for the Tagra BT-104 and it is claimed to be 7/8 wave like the older antennas of this type you described. It must work, but the resonance is close to <>28.7 MHz. This give clues to the dimensions. I will try this too.

 

[Marconi]

OK, the Tagra BT-104 is next.

 

[bob85]

Tagra BT104 was about the same 31ft+ length as the old vector, it has 3 radials like the sigma4.