Handy SPIDER - No Soldering, No Connector

ab cd

Senior Member
Handy SPIDER - No Soldering Required, No SO239 Connector Required

Maximum Range Curve By VRS

Hardware Used for Range Curve Plotting:
Handy Spider >> 12 ft / 4 m RG6 Coax >> Generic DVB-T (black) >> Orange Pi PC

Quick-Spider+Generic-DVB-T_VRS-R.png




Trial Run - Indoor Near Large Window
coax-only spider step-7_800x1066px.jpg






HOW TO MAKE

Please see these posts also for previous Versions:

(1) May 2015

(2) September 2016




STEP 1 - Stuff Required
coax-only spider step-1_800x800px.jpg





STEP 2 - Cut Coax Into Required Pieces
coax-only spider step-2_800x800px.jpg





STEP 3 - Remove braid & Insulation
coax-only spider step-3_800x800px.jpg





STEP 4 - Bend Wires
coax-only spider step-4_800x800px.jpg





STEP 5 - Assemble Radials
coax-only spider step-5_800x800px.jpg






STEP 6 - Bend Down Radials 45 Degrees
coax-only spider step-6_800x912px.jpg




.
 
Last edited:

ab cd

Senior Member
ENHANCEMENT FOR OUTDOOR USE

1) Apply a rapid setting (5 minutes) sealant like 2-part epoxy, or silicone, or hot melt glue, or similar at the point where radials enter the outer jacket of coax.

2) After installation. wrap the F-connector in tape to prevent moisture ingress. You may also use outdoor type F connector which are water resistant


coax-only-spider-step-6_800x912px_OUTDOOR.jpg

 
Last edited:

ab cd

Senior Member
Testing of Quick Spider by Antenna Analyzer

VSWR=1.2, R=59Ω, X=5Ω, and S11=-20 @1090 MHz

Handy Spider VSWR R X.jpg




Plot of VSWR vs Frequency 137.5 Mhz ~ 2700 MHz.
Marker at 1090 MHz, minimum SWR at marker

Handy Spider VSWR-Frequency Plot.jpg
 

ab cd

Senior Member
If I don't have a VNA, is there any way I can find out the sweet spot in a coax?
If there is a way without VNA, it is trial and error. Start with a longer than calculated length, then keep trimming little bit at a time to improve performance, till performance starts to drop instead of improving. Stop there and go back a step or two.
 

ab cd

Senior Member
What are the tell-tale signs from looking at @weidehopf's graphs1090 program?
SNR? ADS-B rate?
"ADS-B Message Rate" is the prime graph to consider. SNR comes next.

On "ADS-B Message Rate" graph if, "Messages > - 3 dBFS":
- Is less than 5%, no need to reduce gain.
- Is more than 5%, reduce the gain in steps of say 2 or 3 dB, then wait for an hour or more, then check "Messages > - 3 dBFS" on the "last hour" graph

2854



.

LAST HOUR GRAPH
2855
 
Last edited:

AnirbanSen

New Member
"ADS-B Message Rate" is the prime graph to consider. SNR comes next.

On "ADS-B Message Rate" graph if, "Messages > - 3 dBFS":
- Is less than 5%, no need to reduce gain.
- Is more than 5%, reduce the gain in steps of say 2 or 3 dB, then wait for an hour or more, then check "Messages > - 3 dBFS" on the "last hour" graph
2857


2856


This is my current. Coax spider. Radials somewhat mangled due to a hate crime.

Will be testing a similar thing on the roof, a SO239 4-legged spider (the other 4 legs - soldering did not stick despite several attempts) and also a PCB 3dbi gain antenna. There's also a bandpass filter. The LNA materials have still not arrived.
 
Top