How are the two helices fed? Do they do the old trick where one is slightly oversized and capacitive and the other is undersized and inductive or do they do something clever with the strip lines on the circuit board?
They'd either be in parallel, or a power splitter (not sure, I think the former). Edit to add: Looks to be in simple parallel. All four elements would definitely 'supposed to' be the same size and symmetrical.
You sure? Internet says "The Vaisala RS92 radiosonde's frequency can be set between 400-406 MHz." This antenna is for 1.6 GHz; says so right on the PCB. And it's also really obvious by the size that it's not for 400 MHz. Somehow I knew that radiosondes are not normally found on 1.6 GHz, so I looked it up to see. Cheers.
@@JxH In the US there are two bands used for radiosondes. One is that 400-406 band, and the other is much higher - up around 1600 MHz, if I remember correctly!
You'd want to make sure you ended-up with the correct polarization. I believe that RHCP is the goal for most applications. Hopefully the PCB design steers the assembler in one direction. Beware if you plan to add a reflecting dish, as that would flip things.
Back in the day took me a while to understand how it works. Mind twisting 😸
You made my day! Antennas rock!
Antenna of the day !
Never seen you use SDR
Devises and show their new advantages and disadvantages to RF design.
Great content and projects, happy new year all.
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How are the two helices fed? Do they do the old trick where one is slightly oversized and capacitive and the other is undersized and inductive or do they do something clever with the strip lines on the circuit board?
They'd either be in parallel, or a power splitter (not sure, I think the former). Edit to add: Looks to be in simple parallel.
All four elements would definitely 'supposed to' be the same size and symmetrical.
Actually this antenna is for reception of radiosondes (meteorological balloons) like the Vaisala RS92.
You sure? Internet says "The Vaisala RS92 radiosonde's frequency can be set between 400-406 MHz."
This antenna is for 1.6 GHz; says so right on the PCB. And it's also really obvious by the size that it's not for 400 MHz.
Somehow I knew that radiosondes are not normally found on 1.6 GHz, so I looked it up to see. Cheers.
@@JxH In the US there are two bands used for radiosondes. One is that 400-406 band, and the other is much higher - up around 1600 MHz, if I remember correctly!
@@flapjack9495 Okay, so *unlike* the Vaisala RS92, which is ~400 MHz. Thanks.
I had a professor that kept calling these Helicoils. 🤦♂️
Helicoils are for spark plugs Pravin!!!
guess he never took shop class
I think a 3D printed bending rig is a good helper for it or?
Anyone with good CAD skills please send help 😅
Normal şartlarda çalışır
Some call this an Egg Beater antenna.
You'd want to make sure you ended-up with the correct polarization. I believe that RHCP is the goal for most applications. Hopefully the PCB design steers the assembler in one direction.
Beware if you plan to add a reflecting dish, as that would flip things.