Use SDR while transmitting

Post information or questions regarding SDRplay products here
IZ2TWX
Posts: 3
Joined: Wed Oct 12, 2016 1:42 am

Use SDR while transmitting

Postby IZ2TWX » Sat Oct 15, 2016 11:37 am

Hello everyone, I want to know if I can use sdrplay while I transmit with to other radios nearby. Thank you
Last edited by IZ2TWX on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
Reason: No reason

dsalomon
Posts: 51
Joined: Sat Oct 10, 2015 1:50 pm

Re: Use SDR while transmitting

Postby dsalomon » Sat Oct 15, 2016 3:49 pm

That really depends on your definition of Nearby, how close the transmitting antenna is from the RSP receiving antenna, and the amount of power being transmitted.

In general it is a VERY BAD IDEA to have a receiving antenna attached to any energized radio when a transmitting is nearby. Many companies sell RX/TX switches that automatically switch the radio out of line when transmitting so the radio is not damaged. It is also very easy to build such a switch. Google it and you will find LOTS of answers.

There are several approaches to protecting your precious RSP (or any receiver, for that matter). There is also a very wide range of costs associated with these approaches. Once such exaxmple is the DX Engineering RTR-1A: https://www.dxengineering.com/parts/dxe-rtr-1a. This device has a number of useful functions, none of which I will discuss here except the one that addresses your concern. It has a circuit that limits the input to a safe level, which allows you to continue to use the attached receiver safely while transmitting. This protection does not come cheap: $170 USD. Read their documentation to find out all the details: https://static.dxengineering.com/global ... rtr-1a.pdf. This is the best of the best when it comes to protection (IMHO). There are many much less expensive alternatives. Here are a few examples:

Yet Another Front End Saver (yep, that is actually the name): http://www.ok1rr.com/index.php/technica ... -end-saver. This site details instructions for a homebrew switch

AY Technologies RIP-1: http://www.aytechnologies.com/TechData/RIP-1.pdf. This is a simple XMIT/RCV switch.

DX Engineering Receiver Guard: https://www.dxengineering.com/parts/dxe-rg-5000

These are just a few examples. Google for lots more.

Bottom line - you MUST have some protection for your RSP if you're going to use it near a transmitter. Even ONE test without some protection can damage the front end of the RSP.

73 - David, AG4F

Reason: No reason

IZ2TWX
Posts: 3
Joined: Wed Oct 12, 2016 1:42 am

Re: Use SDR while transmitting

Postby IZ2TWX » Sat Oct 15, 2016 4:08 pm

David, Thanks for the reply, I can use a simple manual antenna switch?
Last edited by IZ2TWX on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
Reason: No reason

dsalomon
Posts: 51
Joined: Sat Oct 10, 2015 1:50 pm

Re: Use SDR while transmitting

Postby dsalomon » Sun Oct 16, 2016 7:44 pm

Sure you can, as long as you remember to switch it EVERY TIME you transmit. It only takes one mistake to let the magic smoke out. :-)

Reason: No reason

CU3AA
Posts: 2
Joined: Sat Oct 22, 2016 9:30 pm

Re: Use SDR while transmitting

Postby CU3AA » Sat Oct 22, 2016 9:38 pm

I'm waiting for my SDRPlay and I've been reading here and there about it and how to use it with my Yaesu FT-1000MP. Found an article that mentions that using a splitter/combiner, connected to the ant rf in/rf out, I may use it without any problems as transmitting is concerned. Anyone has any thoughts or comments about this? Appreciate any help. CU3AA, Joao
Last edited by CU3AA on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
Reason: No reason

dsalomon
Posts: 51
Joined: Sat Oct 10, 2015 1:50 pm

Re: Use SDR while transmitting

Postby dsalomon » Sun Oct 23, 2016 1:12 pm

If by the rf in / rf out you mean a connection on the transceiver that switches that rf line out of the chain when you transmit, then you should be ok. One way or another, you need to switch the RSP out of line when you transmit, or you will blow it up. That's not really something you want to test to see it it's ok without taking it out of line, because it only takes once to blow it up.

73 - David, AG4F

Reason: No reason

IZ2TWX
Posts: 3
Joined: Wed Oct 12, 2016 1:42 am

Re: Use SDR while transmitting

Postby IZ2TWX » Sun Oct 23, 2016 9:58 pm

When I transmit with my radio I unplug sdrplay because when they are in the HF my output power is about 500 watts and I'm afraid of burning it. I think it is the best solution

Antonio IZ2TWX
Last edited by IZ2TWX on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
Reason: No reason

CU3AA
Posts: 2
Joined: Sat Oct 22, 2016 9:30 pm

Re: Use SDR while transmitting

Postby CU3AA » Sun Oct 23, 2016 10:24 pm

Hi David, thanks for your reply.
As far as I understand, the SDRPlay is connected to the RX ant and when I transmit the circuit jumps to antenna A or B and (I guess) closes RX input. I send you the scheme so hope it helps to understand better the situation Hi Hi.
73 de CU3AA, Joao
Attachments
SPLITTER SDRPLAY.JPG
SPLITTER SDRPLAY.JPG (37.33 KiB) Viewed 3082 times
Last edited by CU3AA on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
Reason: No reason

vk4dcm
Posts: 2
Joined: Sat Jan 14, 2017 12:20 am

Re: Use SDR while transmitting

Postby vk4dcm » Sat Jan 14, 2017 2:57 am

I have a dead SDR I didnt Tx into it but there is a 400 Mhz Tx at the end of my street that has a big siginal into my antenna I think they should have built some input protection into it If I ever get another one I will be putting a amp in front of it to protect it against RF
The disign seems so sensative that if a Taxi puled up in your drive way and his Tx keyed up it would blow it up.
Seems poor idea to me.
Last edited by vk4dcm on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
Reason: No reason

Tech_Support
Posts: 196
Joined: Mon Jun 01, 2015 7:00 pm

Re: Use SDR while transmitting

Postby Tech_Support » Sat Jan 14, 2017 9:26 am

The RSP can sustain continuous power of 0 dBm (1mW) or +10 dBm (10mW) for short durations. It is extremely unlikely that a local 400MHz transmitter would damage your RSP.

Sincerely

SDRplay Tech_Support

Reason: No reason


Return to “SDRplay related”

Who is online

Users browsing this forum: No registered users and 1 guest