[Antennaware] Checking Hy-Gain TH7 Traps

Guy Olinger, K2AV olinger at bellsouth.net
Thu Oct 11 22:14:13 EDT 2007

You can use an MFJ269x analyzer or equivalent.

Put a 50 ohm non-reactive resistor in parallel with the trap and use the frequency button to scan 
it. Look for the zero reactance points. This will be fairly broad, but will show you where the 
resonance is.

If you have a higher end analyzer like the AIM 4170, which can measure higher values more 
accurately, use a 450 ohm resistor, run a scan over the 20-10 bands and watch the reactance 
crossovers, which should be at the peak R points.

73, Guy.

----- Original Message ----- 
From: "Eric - VE3GSI" <ve3gsi at sympatico.ca>
To: <antennaware at contesting.com>
Sent: Thursday, October 11, 2007 11:39 AM
Subject: [Antennaware] Checking Hy-Gain TH7 Traps

| Is there a way to test the traps used on the Hy-Gain TH series antennas for
| resonance before assembly or even with the traps on the elements? I have
| tried my dipper but could not find a way to couple it to the traps.
| Yes I know the traps are simple to check with an ohmmeter and visual
| inspection, but curiosity got the best of me and I wanted to see if I could
| excite them somehow before putting the antenna up the tower.
| Eric - VE3GSI
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