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I did not intend to use a dummy load as an attenuator, I was thinking that it would be possible to connect the "final bypassed, tamed down" radio to a dummy load via a path that goes through a coax switch, then taking my test signal from the unused (shorted) port of the coax switch. In effect, using the cross talk between the active port and shorted port as an attenuator. It offers 60dB of isolation from the active port, figured it made for a ready-made attenuator is all.

This is a MacGyver-type project I am referring to. The goal is to create a 27.205MHz ±1kHz CW source with a 50ohm output impedance having an adjustable signal level between -110dBm and -130dBm (we're talking microvolts here). The same device needs to have a second mode, via toggle switch, where a 27.205MHz signal of the same output impedance and microvolt level has 30% AM modulation at 1kHz, and to do all of this with scrap parts while preventing rf leakage getting from the source to the test radio. If the signal generator can be detected by the radio under test without being connected via coax, or if connecting via coax provides so much signal that it can be detected regardless of receiver slug adjustments, I have failed in achieving my goal. I want the signal low enough to hear the adjustment with my ear, and I want the overall setup relaible. I need a signal source that represents a signal so weak I can barely hear it...

<blockquote data-quote="brandon7861" data-source="post: 781958" data-attributes="member: 53724">I did not intend to use a dummy load as an attenuator, I was thinking that it would be possible to connect the &quot;final bypassed, tamed down&quot; radio to a dummy load via a path that goes through a coax switch, then taking my test signal from the unused (shorted) port of the coax switch. In effect, using the cross talk between the active port and shorted port as an attenuator. It offers 60dB of isolation from the active port, figured it made for a ready-made attenuator is all. This is a MacGyver-type project I am referring to. The goal is to create a 27.205MHz ±1kHz CW source with a 50ohm output impedance having an adjustable signal level between -110dBm and -130dBm (we&#039;re talking microvolts here). The same device needs to have a second mode, via toggle switch, where a 27.205MHz signal of the same output impedance and microvolt level has 30% AM modulation at 1kHz, and to do all of this with scrap parts while preventing rf leakage getting from the source to the test radio. If the signal generator can be detected by the radio under test without being connected via coax, or if connecting via coax provides so much signal that it can be detected regardless of receiver slug adjustments, I have failed in achieving my goal.&nbsp; I want the signal low enough to hear the adjustment with my ear, and I want the overall setup relaible. I need a signal source that represents a signal so weak I can barely hear it...</blockquote>

[QUOTE="brandon7861, post: 781958, member: 53724"] I did not intend to use a dummy load as an attenuator, I was thinking that it would be possible to connect the "final bypassed, tamed down" radio to a dummy load via a path that goes through a coax switch, then taking my test signal from the unused (shorted) port of the coax switch. In effect, using the cross talk between the active port and shorted port as an attenuator. It offers 60dB of isolation from the active port, figured it made for a ready-made attenuator is all. This is a MacGyver-type project I am referring to. The goal is to create a 27.205MHz ±1kHz CW source with a 50ohm output impedance having an adjustable signal level between -110dBm and -130dBm (we're talking microvolts here). The same device needs to have a second mode, via toggle switch, where a 27.205MHz signal of the same output impedance and microvolt level has 30% AM modulation at 1kHz, and to do all of this with scrap parts while preventing rf leakage getting from the source to the test radio. If the signal generator can be detected by the radio under test without being connected via coax, or if connecting via coax provides so much signal that it can be detected regardless of receiver slug adjustments, I have failed in achieving my goal. I want the signal low enough to hear the adjustment with my ear, and I want the overall setup relaible. I need a signal source that represents a signal so weak I can barely hear it... [/QUOTE]

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