Two antennas on my Kiwi SDR
edited December 2020 in Installation, Antennas and Interference
Presently, I'm using a president Himalaya vertical on my Kiwi SDR. The vertical works really well down to around 20 m. However, it's not so great on 40 and below. I have got a disc cone antenna on my AOR 8600 communications receiver and that receives very well right down to 80 m. So recently I purchased a diamond antenna splitter with the plan of putting both receivers onto the one antenna. However, what would happen if I put two antennas onto the Kiwi SDR? Would the radio not be able to differentially between the two, or would it favour one particular antenna depending on the band?
You'd get phase cancellation on some signals and end up weaking on those.
OK to start off the discone at lower than it's designed frequency is probably not working in a particularly well controlled mode, I.E. it might not work that same on the Kiwi. It is probably acting as a vertical using the feed so will be hard to tame on the Kiwi (IMHO).
I'd try to make a proper HF antenna. Long wire, end fed or (assuming UK level of noise) an active loop.
Then if you really want to combine the two and just want to test for a few quid, just stick the Himalaya behind a Satellite splitter then to a plain T-Piece on the Kiwi.
Satellite splitters The most common types in the UK anyway) pass only above about 7MHz in my experience (the ones that say good for 5MHz and above).
I'm not saying that is a long term solution but I learnt a fair bit by doing just that with HF + 11/10m antennas.
This is the antenna splitter I have purchased. I've made sure that it is a wideband receiving splitter so it should work for all the frequencies the Kiwi covers.
I did purchase a high end fed SWR antenna a few months ago that works very well. However, it wasn't so good on 10 m if people wanted to test the CB and 10 m frequencies locally. I've actually gained quite a lot of people locally who like to use my Kiwi SDR as a means of testing the signal. So I want to keep my vertical working on the Kiwi.
As Jim says you can't reliably just add two antennas with a splitter covering the same frequencies.
The reason I said use a satellite splitter in there to to specifically avoid feeding the lower end of the HF spectrum from the vertical (including the noise), ideally you want to do the opposite with the HF here I found it had so little signal from the HF it worked OK (little signal to conflict).
Here I use a Kiwi for the vertical and share the HF antenna between other Kiwi and one other device using just resistive dividers.
Okay, so I may be better off purchasing a second Kiwi that is just dedicated to 10/11 & 10 m? Since the president Himalaya is a tri-band vertical covering these bands. I'm assuming that you can program the Kiwi so that when people open it up they only have a choice of these three bands?
I have a kiwi per antenna and don't try to limit the coverage other than by advising users of the best range.
see http://www.jimlill.com:8073 and http://www.jimlill.com:8075
at the moment 8075 is on the same antenna as its own antenna is under maintenance.
If you can afford another one I'd definitely go that route.
I gave up sharing my CB vertical because I have only a limited number of users in the day and when I had the CB up (on a different port) they would seemingly select whatever Kiwi was last listed (I assume from the Map?), so I'd see people trying LW, MW, 160 and 80m on the CB vertical before leaving and no activity on the one that actually could get reception there. I tried all sorts of things like calling it CB Vertical.. but still people don't read the name, frequency cover or description.
You are coming in from the other way, users expect to be able go get to the vertical so would at least still get some reception if they got the sdr wrong.
It would be great to have a pop up like "for this frequency try http://this-sdr-but-other-port"
See my systems... look at top of screen