[amsat-bb] 70cm foldable paper antenna test via Ao40

["William Leijenaar" <pe1rah@xxxxxxxxxxx>]

Hi AMSATs,

Today I have finally tested my new ultra ligth 70cm paper antenna on AO40 
haha.
I made two QSO's with it, with very strong downlink signals, and with only 
10W PEP putting in it.

The antenna is a very funny construction and is actually been made just for 
fun.
What I have done is taken some long piece of paper and aluminium tape that 
is used for heat isolation behind heat radiators.
The aluminium tape I have cut in 6mm slices with the length of the 70cm 
elements, and I have sticked them on the paper at the right distances to 
each other.

The radiating element was a little bit tricky and it took me some time to 
find a good 50E matching solution. What I wanted to have is a gamma match so 
I can make the 50E matching optimal. A trimmer was a little to thick and not 
original :-)
What I have done is stick the outer (teflon) coax with the aluminium tape to 
the middle of the radiating element. At some 2cm from the middle of the 
radiating element I made a (gamma match) tap with aluminium tape. Over this 
aluminium tape I stick some plastic tape and ove the plastic tape again 
aluminium tape. This construction is the tunning capacitor .-)
The top aluminium tape I connected with the inner conductor of the coax.
The tunning of the capacitor I have done by slightly removing some aluminium 
tape of the top tape.

This antenna was just for testing, but it seemed to be very effectif !!!!
I never tought that it would work so good. This antenna is really extreem 
low cost and extreem easy to construct. Today I proofed that it even can be 
used for AO40 uplink, and now I am already working on a more profesional 
version of it.

It is the ultimate portable 70cm yagi antenna, in practical and financial 
way :-)

73 de PE1RAH, William
---








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