Scanner antenna ohm question

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Xourque

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Nov 2, 2011
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Oregon
Hello!

I am using the following equipment:
- Icom IC-PCR100 scanner radio
http://www.icomcanada.com/pdf_manual/receiver/ic-pcr100.pdf

- Antenna Craft ST2 scanner antenna
http://www.antennacraft.net/Manuals/ST2_Manual_.pdf

The ST2 antenna has a 300 to 75 ohm matching transformer and about 50 feet of RG6 coax. According to the icom manual for the PCR100, the receiver is best matched with a 50 ohm antenna: "Select antenna(s), such as a well-matched 50 Ω antenna and feedline. 1.5:1 of Voltage Standing Wave Ratio (VSWR) is recommended for a desired band. Of course, the antenna line should be a coaxial cable"

My question for all of you experts is if this is an "OK" setup. Meaning, will the 75 ohms result in "poor" receiving performance if Icom suggests 50 ohms? Would it be beneficial for me to find a 300 ohm to 50 ohm transformer instead (which I have not been able to find...)? What would the real-world difference(s) be between the two?

Thank you all in advance!

Tony
Portland, OR
 

Xourque

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Nov 2, 2011
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Oregon
I found my answer. It won't make much of a difference for receiving. It seems to only be crucial for transmitting.
 

SCPD

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Virginia
Match game

I found my answer. It won't make much of a difference for receiving. It seems to only be crucial for transmitting.
You are correct.
Even on transmit, using 75 ohm antenna and feedline with a 50 ohm radio will result in a 1:1.5 match.
Perfectly acceptable.
 

datainmotion

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Jan 9, 2001
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2,268
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Colorado
I found my answer. It won't make much of a difference for receiving. It seems to only be crucial for transmitting.
FWIW - I run RG-6 from a 300-75ohm balun on my home-made dipole to two PCR-100s and a Pro-2006, all monitoring civil aircraft.

Airport Detail: KDEN | LiveATC.net

Works great for me. Some purists will frown on it, but what matters is whether you are satisfied with the results. :wink:
 
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