question about safe antenna distance from transmitter antenna

[JA37Participant]

I just got my RSP1A today, and I notice there is a warning about proximity to a transmitter antenna.

What is a SAFE distance from my Base Station Antenna to the RSP1A Antenna?

My output might never be over 200 watts, at least not in the near future.

I do want to use this in conjunction with my transmitters.

I use SSB AM FM and CW.

I wonder also if their is an IF limiter available?

Thanks for any help…

[diysdrParticipant]

since I’m using the same antennas for rsp and my ham rigs I made a small switch box with a relay in it. If I key the xmtr it not only switches the antenna but also gnds the input to the rsp1 just to be safe(r). the exact answer to your question is going to be “it depends” on so many things. It would be nice if rsp had some kind of input high voltage detecetion device like a relay or neon bulb but it would probably reduce sensitivity.

[merlinmaxwellParticipant]

I asked a similar question of Wellbrook (of the loop fame), it has an active front end like the RSPs, his answer was “anything more than a few metres will be fine”. I don’t know if the RSPs have any specific overload protection, there are some rather good ESD protection devices for USB signals (up to 100s of MHz) that would do a good job, better than a couple of back to back 1N4148s (the Wellbrook uses 1N4148s).

Easy to build with a scrap of Veroboard and a couple of pcb SMA connectors, you can get those for silly cheap from eBay (I bought 10 for a couple of quid), they are on a 0.1″ pitch and therefore fit Vero nicely.

I am growing to like the SMA connector it is just the right size for modern stuff, BNC also good but not used much in amateur radio gear, N, very good big and waterproof, I use them for outdoor stuff. The SO239 (PL239) is horrible in all aspects both electrically and mechanically, why is it still here????

[JA37Participant]

Thanks, I appreciate the replies, sounds good, I know there is no protection in the rsp1a and they stress it,,, I did find an rf guard for just under $100 on the dx website, and as for pl259 and so239 I still have a couple new cables not opened and spools of OLD milspec wire and so today I made the 10 meter long wire antenna, I have everything I need to seal out moisture, I just need to decide which trees to suspend it between seal the connectors and go… I’ve been hooking it up to my sirio gpe 5/8 and I get nice am and fm broadcast band signals, but for hf I only heard a couple guys about 1100 and 1400 miles away I have run into problems trying to find signals and had restart the program, it suddenly start to jump 500kc or more when trying to tune and/or wont let me click on a peak to select or click the waterfall to select, so I think I’m touching some option somewhere and not catching it..

I’m still hoping to find out what safe antenna distance is for 200 watts and below to know whether to get the rf guard or just longer coax…

I need to watch a few videos I guess to see what actually does what… I sold my shop and all my equipment and got out of radio over 30 years ago, and just saw this waterfall stuff, so I had to have it, its like waking up from long long coma into a whole new world….

And again, Thanks for the info… Enjoy…

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