RSP2 front-end protection?

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Ian G3NRW
Posts: 3
Joined: Wed Jan 18, 2017 8:32 pm

RSP2 front-end protection?

Postby Ian G3NRW » Wed Jan 18, 2017 8:53 pm

I plan to buy an RSP2 for use with a TS-590SG, probably using Simon's SDR Console. I would welcome users' experiences of a similar configuration, particularly with regard to protecting the front end of the RSP2 when transmitting 100 watts of RF on the HF bands.

Previously I had an SDR-IQ, with an Elad antenna changeover switch box. Details here:

http://ts590family.zs2ez.co.za/HOWTO_TS ... SDR_IQ.pdf

The Elad box provided sufficient front-end protection, and I never had any problem.

However, knowing that the RSP2 is more sensitive than the SDR-IQ, I'm not sure if the Elad box protection will be good enough.

Also, I understand the RSP2 is housed in a plastic box with metal screening on the inside. Would it be preferable to spend a little more and buy the RSP2 Pro with its metal box?

Comments anyone?

--
73
Ian, G3NRW
g3nrw@g3nrw.net
Last edited by Ian G3NRW on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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g1hbe
Posts: 216
Joined: Sat Jan 17, 2015 3:28 pm
Location: Cheshire

Re: RSP2 front-end protection?

Postby g1hbe » Wed Jan 18, 2017 11:07 pm

Hi Ian

The internal screening of the RSP2's plastic box is continuous as far as I know and forms a closed screen around the circuit board. It is grounded to the 0v of the electronics. I doubt the 'pro' version is any better.
As for protection, I think it uses the usual back-to-back diodes and according to SDRPlay it can stand 0dBm (1mW) power at its input indefinitely and +10dBm for limited periods. It's hard to quantify this in any given setup though. All I can say is that I transmit with a PEP of 30w on Topband with the receive loop of my RSP just a few feet away. So far (touch wood) no fires!

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Andy

lauchlin
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Joined: Sat Dec 17, 2016 2:28 pm

Re: RSP2 front-end protection?

Postby lauchlin » Thu Jan 19, 2017 12:17 am

I use the elad box and just bought the mfj Switch box and have not had a problem at 1000 watts with the RSP-2 ..

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VE7SHM

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Harry
Posts: 35
Joined: Mon Nov 02, 2015 9:47 pm

Re: RSP2 front-end protection?

Postby Harry » Thu Jan 19, 2017 1:19 pm

Ian,

I don't think you're going to need the switch box.

With the TS-590S a switch box was required if you connected an SDR via the method described in the instructions. There is an alternative method that I used allowing a direct connection to the transceiver via a simple cable to the CN101 (attenuator jumper). This method requires no surgery to the rig, is easily reversible and has the SDR in the transceiver's receive path. When transmitting the K101 relay cuts off the receive path and hence protects the SDR. Mine has been set up this way for quite some time and works well. Using this arrangement there is no need for external boxes, etc. Less clutter, less expense. Details can be found here:

http://www.crystalradio.us/projects/ts-590s-rx-mod.htm

With that said, if you are using a TS-590SG then I believe Kenwood designed into that transceiver sufficient isolation of the RX Ant port where a switch box is unnecessary. Check out the TS-590 Yahoo Group as a number of ops have done the same.

Harry WE1X

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n2ic
Posts: 12
Joined: Sat May 28, 2016 7:26 pm

Re: RSP2 front-end protection?

Postby n2ic » Fri Jan 20, 2017 3:37 pm

Hi Ian,

I'm sure you know that the TS-590SG has an RX-output (shared with the low power DRV output). I have been using the RSP1 since June with the TS-590SG RX-output. I run 1500 watts, with monobanders, high duty-cycle, in contests. No problems with the RSP1.

Steve

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Ian G3NRW
Posts: 3
Joined: Wed Jan 18, 2017 8:32 pm

Re: RSP2 front-end protection?

Postby Ian G3NRW » Fri Jan 20, 2017 8:02 pm

To everyone above

Many thanks for your comments. Plenty of food for thought.

My preference is to not delve inside the TS-590 box (50+ years ago I wouldn't have given it a second thought, but today my eyes and hands are not up to the job). Using the SG DRV/RX port is simpler, provided I can get sufficient isolation.

Steve, fine on using 1500 watts, but I guess the real question is how much RF power the 590 is supplying to the amp, not the output of the amp itself. If you only need 10 watts from the 590, say, to drive the amp, then there shouldn't be any problem with front-end protection of the SDR. I am talking about 100 watts output from the 590, which would be a much different matter.

--
73
Ian, G3NRW
g3nrw@g3nrw.net
Last edited by Ian G3NRW on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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n2ic
Posts: 12
Joined: Sat May 28, 2016 7:26 pm

Re: RSP2 front-end protection?

Postby n2ic » Sun Jan 22, 2017 9:02 pm

Ian,

I run a full 100 watts from the 590SG to the amp. Soft tubes in the amp !

73,
Steve

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kg0ew
Posts: 2
Joined: Wed Feb 01, 2017 5:01 am

Re: RSP2 front-end protection?

Postby kg0ew » Wed Feb 01, 2017 5:08 am

Harry wrote:
With the TS-590S a switch box was required if you connected an SDR via the method described in the instructions. There is an alternative method that I used allowing a direct connection to the transceiver via a simple cable to the CN101 (attenuator jumper). This method requires no surgery to the rig, is easily reversible and has the SDR in the transceiver's receive path. When transmitting the K101 relay cuts off the receive path and hence protects the SDR. Mine has been set up this way for quite some time and works well. Using this arrangement there is no need for external boxes, etc. Less clutter, less expense. Details can be found here: http://www.crystalradio.us/projects/ts-590s-rx-mod.htm

I've seen several references to using a buffer amp when connecting to a radio's IF signal path, but the approach Harry described taps into the radio at RF; with the RSP1, is there a benefit to installing a buffer amp between the SDR and the TS-590S?
Thanks,
~ David, KG0EW
Last edited by kg0ew on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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