Friday, April 10, 2020

Fun project - remote magloop tuner

I was inspired by the MW1CFN remote controlled magloop tuner and decided to purchase all the ingredients needed for this handy device. John does not give many details on what the costs and the particulair parts are. For instance I never seen or heard from the flex couplers he used but it seems to be a very good solution. John seems to have a 6:1 planetary unit to drive the capacitor but it is not really needed as the PWM gives you very good control over the speed. You can purchase all the parts on Ebay but since I think AliExpress is more populair here in the Netherlands and it is easy to purchase there. So with the help of the description and photos from John I searched for the parts, of course the cheapest I could get. But when you take a bit more time to search on you can find it probabely for lower prices. So far I spend about  €21 in total for this project. Variable capacitor 12-365pF €10,48, PWM 12VDC motorcontroller €5,48, 2x flexcoupler 4x5 and 5x5mm €2,60, 12VDC 3RPM motor €2,10.

However, if you want it on the cheap you have to prepare for some things. First of all it will cost you time, 6 weeks or more to have the goods delivered. Second, the packages are not always that good. My first PWM controller was severely damaged and the seller sent another one that was packed well. The 12V motor got a defect as well, turning only left and not right. After a short surgery the contacts on the rotor were dirty and a few drops of contact cleaner and some compressed air did the trick.

So why this project in the first place. At first I wanted to make a rotatable magloop for receive on the low bands and especially 60m since there was a lot of radar QRM there lately. Not a wideband loop with a rx amplifier like widely used by radio amateurs. I want to make as selective as possible. You probabely noticed the variable capacitor I use is not really good for transmission but good enough for receive. But time is always my enemy. So I just developed it as fun experiment...
I might use it in a magloop project in the future.


2 comments:

Photon said...

Despite my lack of detail, you produced something pretty identical! Very nice! The only comment: probably an idea to increase the distance between the flex connectors. The most important take-home is that this dirt cheap solution is a good reminder of how much we are being ripped off by commercial magloops and their tuning units that need specialised knowledge and parts to repair.

PE4BAS, Bas said...

Hello John, it is a prototype. I've thought about the connectors afterwards. I don't like the housing either. But haven't find a nice plastic box to fit the tuner in. Well....time is a issue. 73, Bas