2m and 70cm Range Testing

Today I got all excited and thought about seeing what kind of range of usable range i could muster by connecting a small amp to the DMR hotspot and connecting it to the outdoors antenna. I was putting about 0.5w out into a slim jim about 3m off the ground. I could still hear the kerchunkers about 1km away. Nothing stellar but you really could not expect to much giving the setup.

So after that I got all excited and connected the Hackrf to the same little amp and again to the outdoor antenna and fired it up in FM CW beacon mode and got an ultimate range of about 3Km. Again nothing stellar but considering everything, not to bad either.

So the moral of the story here is I really need to get the antenna much higher into the air if I want to be able to turn this into something a little more usable without resorting to much higher power.

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I Can Do QRP, ME

I got excited last night and grabbed some of the piles of junk out of the piles of junk draw to give a go and see if i could do anything with them. First off the ranks was the Pixie, its god awful but works. I did not manage a contact with it last night but was spotted by the guy up the road on RBN.

This morning I sent a mate in Sydney a message and got him to listen out for me and after he opened his filters up to find where I was, we made the exchange. Brisbane to Sydney with a Pixie, 750km or there abouts, so that was SUCCESS.

Next I busted out the Frog Sounds, I dont know why but its not working on receive, but it transmits just fine and is making 1/2 to 1 w. So i called CQ a few times just to see if I could make some RBN spots and low and behold i got a spot in New Zealand. 2600km. So that was a success also.

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100w Amp Repairs

So when i initially powered this up it was transmitting into a dead short. Obvious not a good thing, but on a good note, one bank of fets actually survived because I did not turn the bias way up on it by mistake LOL.

Anyway, this was way easier to pull apart than I was expecting it to be. Now i just need to run down the shops and get some solder wick to clean up the pads and drop in 4 new fets and then power it back up again. You will notice now there is a wire bridging the pads where the output relay is. Yeah this time it will be dumping rf into a dummy load. LOL

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HackRF One as a Transmitter

So a number of what we all call SDR receivers are capable of transmitting. The output power in the case of the HackRF one is about 250mV p-p, in other words a very small signal, 0.15mW. This is not much good for transmitting further than the end of the street, but with some amplification you can get that up some. I added the QRPLabs 10w TX to it and was getting close to 0.8W and was being heard over 800km away.

Anyway, my plan for a while has been to use the HackRF as a receiver and make a couple of low power CW transmitters to go with it. By low power i am talking in the 10w kind of range. But this has gotten me thinking, with some VHF and UHF amplification, this might be a really cheap and easy way into SSB and CW on those bands for field day here in VK. It would require a 2nd SDR to act as the receiver, because the HackRF is only half duplex and there is no software out there that can so the switching currently, and it can be locked to a reference signal so it might be somewhat useful.

 

 

 

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