ESP Extended Range

(Derryn Harvie) #1

I’ve been building and testing a number of different antenna styles on ESP-07’s.

One very simple and successful antenna I’ve tried so far has been making a tin can wave-guide, also known as a “Cantenna”. I’ve build two and set one up as an AP with a TCP server that just loops back.

Today I set one up pointing at Mt Taylor out a window, and walked up Mt Taylor with the other and laptop. Results were pretty awesome. This is a 2km distance with direct line of sight. From the top of the hill I had a -74db RSSI to the AP ESP, which has some more distance in it.

Perhaps we should look at mounting some weather stations on hills around Canberra and feed weather underground (with appropriate permissions of course.)

(Paul Harvey) #2

Cantennas are great! We could ask @CarlosPeco if he can Bring the ZVB along one night in case you were interested in plots of how close you are to 2.4GHz. I’m actually considering running a cantenna & tape-measure Yagi workshop for the BSidesCBR conference, in which MHV is helping with the hardware hacking village - but I only have a VHF antenna analyser myself.

It’d be great to do a small trial run of the workshop on a Tuesday or Wednesday night soon, what do you think?

(Carlos Peco-Berrocal) #3

Hi Paul,

It is a ZVM.

Moving houses in a week, but you can come home and pick it up whenever you


(Derryn Harvie) #4

I think the workshop is a great idea. Most folks working on electronics projects at the space have some sort of RF interface now.

I’m currently self-teaching myself the basics of RF and it’s quite amazing the results you can get with easily available and cheap hardware (the cantenna’s above were a $2 thing from Aldi and about 50mm of wire.)

I have one of these:
It’s only a relatively cheap tool, but can get ball park measurements for tuning.

(Carlos Peco-Berrocal) #5

That analyzer looks great. The ZVM is a pain to move around, and I don’t see myself working above 3 GHz.

Looking forward to see your toy in action one of these days


(Derryn Harvie) #6

I can bring it into the space any time. Would actually be very interesting to compare the performance to you ZVM if you were able to bring it in some time?

I actually got it a while ago for a job where I needed to tune a 13.6MHz RFID loop and impedance matching circuit, worked a treat for that. My experiences up in the 2.4GHz band have been a little more hit and miss, but that’s more likely due to setup.

(Carlos Peco-Berrocal) #7

Hi Derryn,
The ZVM is not mine, it was a demo/lease unit that came back from Air Services because they got a better instrument/deal. So they took it out the books and let me move it to Canberra.

My problem is the calibration kit: I use a load from Huber+Suhner, a short from Rohde&Schwarz, but I don’t have a proper open. When I have some “important” thingie to measure I use one of the calibration kits from the demo pool in Sydney, but after a couple of weeks I have to take it back.

I just moved from Kaleen to Evatt (MHV space is almost LOS form my place) but once I sort out the mess I have at home I can take it to the space one of these Tuesdays/Wednesdays.