Loosing RX while Transmitting

Hello All,

i am looking for an help that i cannot find the solution.

I have made two cases, In one ( Picture on the right side ) i have just two PSU

one 36v set to 28V to power the SG-Labs 20W Power Amplifier for 2.4GHz and the Big PA by F4VSG.

In the Other case ( Picture on the left ) i have the two PA, one RX filter, the CN0417, one 12V to 5V converter to power the CN0417

and a Bias Tee.

My Problem: is While i am RXing the QO-100 signal, as soon i go in TX also without giving power, the RX signal drops

down until i do not pass again in RX.

If i try to use an external 12V power supply powering with it just the Bias Tee, the problem does not pop up.

I am struggling from several weeks without getting the solution.

Please anybody can help me to eliminate the problem?

Any help will be really appreciated.

If you need more info, please do not hesitate to ask me.

Thanks in advance for any help or suggestion.

73's de Enzo IK8OZV

Quote from DL3ED

Thanks for the reply. I will check this setting, but if it could be this setting, apologies, why if i use in external PSU, i do not have the issue. I think that if it is this setting, i had to have the problem even if i feed the Bias Tee with the external PSU.

Please can you confirm?
Thanks

Enzo

Quote from on4kvi

Hello Enzo,

I had the same problem with the bias tee injector you use !!!

My 2 cents...

Apologies what you mean????

Quote from on4kvi

Enzo,

I had the same problem , loose of rx when transmitting.

The culprit, in my situation, was the DC injector ; i used the same model as on your picture.

So i changed this DC injector with another model and bingo....continuous RX.

Renauld

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Renauld,

Thanks for your description of the problem but what i cannot understand is why the issues does not pop up also

when i use an external PSU?

Please can you tell me with which one you have substitute it maybe also with a photo of it?

Thanks a lot

Enzo

Quote from PY1SAN

Hi Enzo.

You probably have some RF feedback on the power supply line at its T Bias. When you use external power supply you isolate this way. In the Bias T +12 VDC try:

- Use some ferrite (bead, core or choke).

- Use some capacitors for RF decoupling (or feedthrough capacitor).

- A shielded cable for power supply.

73 de PY1SAN

GG77SN

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Quote from PY1SAN

Hi Enzo.

You probably have some RF feedback on the power supply line at its T Bias. When you use external power supply you isolate this way. In the Bias T +12 VDC try:

- Use some ferrite (bead, core or choke).

- Use some capacitors for RF decoupling (or feedthrough capacitor).

- A shielded cable for power supply.

73 de PY1SAN

GG77SN

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Renauld please can you post a picture of the Bias Tee you using that do not cause anymore the problem?
Thanks

Enzo

Quote from on4kvi

Enzo,

I had the same problem , loose of rx when transmitting.

The culprit, in my situation, was the DC injector ; i used the same model as on your picture.

So i changed this DC injector with another model and bingo....continuous RX.

Renauld

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Renauld please can you post a picture of the Bias Tee you using that do not cause anymore the problem?

Thanks

Enzo

Quote from S57NML

I'm using 2-way splitter for satellite TV.

Common IN to LNB one way to receiver and second +12V DC.

Please any picture?

Thanks

Quote from S57NML

I have this one. Is it the same??????
If yes please will you tell me how to connect??
Thanks

73's de Enzo IK8OZV

Quote from S57NML

Please how you feed the 12V where i put the black arrow?

with an antenna cable?

And what if you want to do DATV?

Take the cable with the 12V OFF and put the cable with the 18V????

Thanks. 73's de Enzo IK8OZV