I am looking to terminate a line with the below characteristics and having a hard time locating an RF coax terminator. Can anyone help?

I have an FPGA HW that is feeding multiple receivers. The input feeding the FPGA circuit is connected in a way to feed multiple output receivers. I need to terminate one of the outputs of that FPGA because one of receivers is no longer needed. The below information is the load and line impedances information of that output line previously that now needs to be terminated since it is no longer connected.

The output line needing to be terminated operated in the UHF frequency.

Characteristic line Impedance: 93 ohm coax

Load Impedance: 300-2200 ohm

Coax Type: RG180/U | Connector Type: TNC

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    $\begingroup$ What is the frequency range? The RF power level? $\endgroup$
    – tomnexus
    Commented Mar 6 at 19:22
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    $\begingroup$ So, are you looking for 93-Ohm Coax Connectors? What coax type, RG63? There is not much call for 93-ohm circuits anymore. $\endgroup$
    – Dereck
    Commented Mar 7 at 1:08
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    $\begingroup$ would love if you’d share the use case that has this configuration! $\endgroup$
    – webmarc
    Commented Mar 7 at 1:09
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    $\begingroup$ The edit timer cut me off. We can help, but we need more information. You said 93-Ohm coax. So, the first thing we need to know is the coax type, like RG62. The second thing is the connector type like BNC, TNC, N, or UHF. I have no idea what to make of the load impedance other than an antenna like an end fed. What is the application? More data please. $\endgroup$
    – Dereck
    Commented Mar 7 at 1:21
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    $\begingroup$ I have updated the main post to include more information and the requested added information from the responses. Thank you all for your time. $\endgroup$
    – Newb
    Commented Mar 8 at 16:47

1 Answer 1


First of all, I'm not sure you need a termination.
Is there a problem with the system as it is? With 91 ohm coax, a load of 300 ohms is already a large reflection, and a load of 2000 ohms is as good as an open circuit, almost all the power is reflected anyway. So if the system requires between 300 and 2000 ohms on (each?) TNC connector, it should work with no load too.

You won't be able to buy a 300 ohm TNC load, but you could make one with a connector and two resistors. This is how I make 50 ohm loads, good to a few GHz:
enter image description here
I don't think you get TNC connectors with a solderable flange like this, so use an SMA and an adapter. You could use three 1k 1206-size resistors. These are all parts you will find on Digikey etc.
If you have spare cables with TNC connectors on them, you could cut one and solder a resistor to it, then protect it with some heat shrink tubing.

  • $\begingroup$ Thank you much for your response. $\endgroup$
    – Newb
    Commented Mar 12 at 14:11

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