SDRPlay connection with Yaesu FT5000

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Re: SDRPlay connection with Yaesu FT5000

Post by » Sun Oct 28, 2018 5:57 pm

IK2RGT wrote:Little update about this post.............

Yesterday we have configured the RSP to work as a panadapter with my friend's FT5000

In order to obtain this, without using the IF OUT , we placed a bnc-tee on the RX ANT OUT on the rear panel of the rig
The 2 exit of this tee are connected like this:
- one goes to the RSP through a bnc-sma cable
- the other goes to the RX ANT IN of the FT5000 through a bnc-uhf male cable

In this way , by pressing the RX-ANT button on the front panel , you can share the RF signal between the FT5000 and the RSP

The complete setup looks like this, sorry for my ability with Paint :lol:

Hope this helps, Emanuel, IK2RGT
I know this is an old thread but this post was very helpful. However, what is confusing is "WHY" does one need the BNC-T connector.

Well it turns out that when you push the RCV button, the selected ANT (1-4) is routed out the RCV OUT connector to a Pre-Amp (or something similar) and the FT5000 expects the output of the Pre-Amp to be connected back into the RCV IN SO239 connector. Initially, I thought I could just connect straight to the RCV Out BNC and then push the RCV button on the FT5000. That does not work. (The documentation in the FT-5000 manual is a bit weak and confusing about this.) Therefore, one MUST use the BNC-T connector to route the RCV OUT signal back in to the RCV ANT so that the FT5000 continues to receive signals from the selected ANT (1-4) while taping off the signal to go to the RSP-1A.

Once I installed the BNC-T connector as Emanuel shows, it worked great! Thank you.
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Re: SDRPlay connection with Yaesu FT5000

Post by KK6QMS » Sun Oct 28, 2018 6:42 pm

Thanks for the clarification!
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Re: SDRPlay connection with Yaesu FT5000

Post by Roger » Sun Oct 28, 2018 11:06 pm

Just a comment on the use of a T connector. A T connector is a poor way to parallel two receiver inputs together. Doing it this way can lead to a number of problems including:

- The input impedances of the two receivers may not be 50 ohms and the signal will not be split equally between the receivers. If they are both 50 ohms there will be a 3 dB drop in signal power into each. If one is 50 ohms and the other is less than 50 ohms the lower one will get more power and the 50 ohm input receiver will have more than 3 dB loss.

- When both receivers are 50 ohm input impedance they are 25 ohms in parallel and this will result in a mismatch with the circuit or antenna providing the input signal and result in less than maximum signal power transfer.

- Spurious signals present on the antenna input port of one receiver (like local oscillator feedthrough) will directly couple into the other receiver and degrade it's performance.

- If the bias-t port is used (only choice on an RSP1A) and the bias T is accidentally enabled approximately 5 volts will be injected into the front end of an expensive ham transceiver. This can cause considerable damage if it does not have DC blocking at the antenna input.

The best approach is to use an RF splitter to split the signal between the receivers. This is a passive device which has about 3.8 dB of power loss and at least 20 dB of isolation between ports. This loss is not significant because the signal and noise are both lowered by the same amount so the SNR stays the same. There are several low cost splitter options. You can buy a amateur radio product like a Diamond SS500, a commercial device from Mini-Circuits or use a top quality CATV splitter that goes down to 5 or so MHz.


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