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Forum Index : Microcontroller and PC projects : RF meter and a scanner radio...
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9081 |
Recently, I bought a couple of cheap toys from AliExpress, and they are actually rather good, so I thought I would link to them here for anyone interested in RF stuff perhaps looking for some cheap test gear. The first is a dual-band scanner radio. This will also transmit on either band, but I really only wanted it for receiving. 128 channels, dual-band, 136-174MHz VHF band, and 400-520MHz UHF band. This is useful for me, as it allows me to listen to pager transmitter messages on either the 160MHz VHF band or the 434MHz UHF paging band here in New Zealand. It's UHF band also covers any RF data modules I have here that I might want to listen to. Naturally, this only gives you an audible confirmation of transmission, but this is still handy to have in many situations. This thing also has an LED light, and charging cradle and FM radio in it too. ;) Only US$27 a piece! $27 dual-band scanner radio The next thing is a digital RF power/SWR meter. This unit supports 100-520MHz range, 120W capability, frequency counter, SWR meter, transmission efficiency, forward and reverse power displays, and built-in rechargeable battery(charge via mini-USB). Many parameters can be changed in the built-in menu. US$48.50 Surecom digital RF/SWR meter Here is a photo of my using it to measure the output of a paging transmitter(into a dummy-load):  Smoke makes things work. When the smoke gets out, it stops! |
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CaptainBoing Guru  Joined: 07/09/2016 Location: United KingdomPosts: 1994 |
hmmm... Grogster has a new Txciever and then I read this ... Anything you wanna confess before the assembled?   |
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| robert.rozee Guru Joined: 31/12/2012 Location: New ZealandPosts: 2294 |
that couldn't be grogster - like myself, he lives on the mainland. nz is spread across three major islands: - the mainland (also called the south island) is where all the productive new zealanders live. it contains, mountains, fiords, and much farmland. it is a land of sunshine and plenty. - below the mainland is stewart island. this is much smaller, and where the hardiest of new zealanders live. while the weather there is wild, it too is a place of great beauty, and situated right next to the bountiful southern fishing reserves. - then there is the north island, where the abovementioned prankster is 'oinking' at the local constabulary. no one much cares for that island, and it is reserved for yuppies, jafas (https://en.wikipedia.org/wiki/Jafa ) and is where all our politicians are banished to. cheers, rob :-) |
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| CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 1994 |
can we banish our politicians to the North Island too? I know it is a bit close for comfort for you but it is fine for us, and it would be a particularly nice gesture on your part  |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9081 |
That article is hilarious!  I can happily confirm that this is NOT me. I actually have respect for the police and what they do for our safety and community. I also have ethics, so would never dream of transmitting into police, ambulance or fire-service radio bands.  As the article mentions though, via simple triangulation they should be able to find him without too much trouble. It does depend on how long he is on-air though. Triangulation of a 100% duty-cycle such as an FM transmitter is easy. Triangulation of a sporadic transmission is much, much harder, as the signal has to remain there for triangulation to work. A year in the clink - he's playing dangerously there, really, and most inconsiderate of the fact that the band may well be needed for the cops to talk about something that could be life-critical - not very smart, and he's a very naughty boy.  Smoke makes things work. When the smoke gets out, it stops! |
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| ajkw Senior Member  Joined: 29/06/2011 Location: AustraliaPosts: 290 |
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| HankR Senior Member Joined: 02/01/2015 Location: United StatesPosts: 209 |
The radio is a world wide phenomenon and has made impressive sales figures to amateur radio operators who can operate one or both of these bands in almost any country. Similar products (distinct designs, not copies) are made by Wouxun. I have had a predecessor radio (UV5R) for about 2 years. I think they've been around for roughly 5 years. The power meter has received a technically rigorous, unfavorable review to which I'll post a link later. It's also demonstrated on youtube (driven by a Wouxun). If it were more like $25 or $30 I might be tempted to buy because in addition to power it has a not bad little frequency counter built-in. Very portable. Curious, Grogs, if you've been able to compare its power reading with a calibrated instrument. |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9081 |
The screenshot shows exactly the right information compared to my analog SWR meter, but that is not a calibrated instrument. The frequency as stated on the LCD is close enough - 160.3875MHz was the transmit frequency. The figure of 160.388 could be an 'Error' or could simply be the unit rounding up. Output power is actually off a little when I do a comparison. 4W FWD, but the unit is about 400mW out. I guess that depends on how specific you want to be, and bearing in mind what it does for the price, I don't think you can expect NASA standards on this thing - more of a ballpark indicator of what is going on, which is still useful. A 400mW power reading error is too high IMHO, and would possibly make the unit useless depending on how accurate you wanted to be. There is updated firmware for these, but you have to send it back to China for them to program it - probably not worth the effort.Smoke makes things work. When the smoke gets out, it stops! |
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