/diy/ - Do It Yourself

I bought this to transmit FM
it says it has 10 meters of range, i want to extend that to several kilometers.

Also bought this one to test which of the two works best.
Link to this one:
http://www.amazon.co.uk/gp/product/B00L0X07QI

link to previous one:
http://www.amazon.co.uk/gp/product/B000R5NJCE

https://en.wikipedia.org/wiki/Parabolic_antenna
Just read up about pic related.
Does anyone know of anyway of making a parabolic antenna?

>>751781
use a scrap sattelite tv dish.

also why would you want to tx radio over several kliks?

>>751814
It's just a project, trying to see if i ever needed it in emergency situations, i'd have it.
Also, if i want to track where someone is sending an fm transmission, what would be the easiest way to do it? In other words, can i get in trouble for using this device? I really hope not

>>751814
Also, how would I wire the fm transmitter to use the sat dish as an antenna, and the receiver as well?? Wouldn't they interfere with each other?

>>751818

For the frequency those car transmitters are on you can be in quite some trouble. As in 5000 euro fine trouble.

They got to catch you though so if you only send for like a few minutes a day they wont have the time to find you.

>>751820

Read the OP again, and if you are just interested in some long range walkie talkies you'd better be off with a baofeng uv-5r handheld radio. you can get one for 30 bucks shipped and can be set up for a range of 20 kliks with a good external antenna on frequencies where there isnt much activity.

>>751829
Fm frequencies as well?

>>751825
How the hell do they know where I am???

>>752145
Google "radio fox hunting".

>>752118
No. 137-174 + 400-520MHz, which covers FRS, MURS, PMR, business radio and amateur bands. A "DIY walkie talkie", especially in the FM broadcast band, WILL get your stupid ass chucked in jail. Your voice will make it even easier to track you down.

Source: I do radio DF for Ofcom spectrum enforcement in the UK with a £40k Anritsu service monitor.

>>752199
Very interesting anon. Thanks for the info

>>752199
Can RDF be used to track a moving transmitter in real time? Would be interesting

>RDF

>>752199
With your advice and With everything I have I think it would be very interesting to make a distress beacon (402 mHz or around there). Thinking about connecting all of this to pic related. Thoughts?
Arietta g25, much smaller than arduino uno + debian wheezy

>>752208
Yes. We use Doppler RDF which uses 8 verticals in a circular pattern and small differences in phase with some nifty custom software to direction-find. AFAIK the FCC use the same method.

Protip: if you're going to run an illegal transmitter, do it in the middle of nowhere. Lack of roads make it much harder.

Really what you need to be doing, though, is getting an amateur radio licence. I don't know what country you're in but generally, unless you're in North Korea or some other assbackwards third world shithole they are not expensive or difficult to get. Then you can do it legally, on known frequencies, where people are going to be listening, and you'll learn a bit about antennas/transmitters/etc. into the deal. You might want to look into things like "emcomm" and APRS, then you can do much more with the G25 on the air.

>>752299
Interesting to hear from someone doing work for OFCOM, do you guys bother looking much for small pirate users (illegal cb etc) or just big dangerously interfering (aka profitable to fine) stuff? Also, I'm a radio amateur in NI, not a pirate.

>>752299
How does ofcom deal with people that bring transmitters to places, turn them on to jam fm, then turn it off and leave??

>>751773
>I bought this to transmit FM
>it says it has 10 meters of range, i want to extend that to several kilometers

>inb4 OP gets v&

>>752199
This. And broadcasting in the FM broadcast band is also difficult, as you are easily overpowered by the commercial stations. Get a Baofeng and a license.

>>752426
Ham in Scotland here. It's great because I can do my own NoVs and licence upgrades by just dialling the licensing office.

We used to go after the small fry, before I started working there, but nowadays we only go after reported pirates, we don't have the time or resources to go after some kid fucking about.

I'm with a Scottish enforcement office and Mad George on 27.555 is a big thorn in our side, but he's about the only "CB" user we've gone after in some time. Licensing is currently trying to revoke his ham licence for his motormouth on 11m. We get a lot of reports of interference on PMR despite it being an open band but we find eventually a lot of folk using Baofengs at full tilt.

Also inteference reports from paid users (broadcast, SL, LMR and so on) get priority, obviously.

>>752451
Not a great deal. Generally you need to have been going for a week or two constantly before we actually get on your case.

Although if someone records the interference you're pretty fucked because many jammers and/or transmitters have certain telltale signs and we can get a police warrant to go through eBay/Amazon/... purchases to see who purchased a matching transmitter/jammer. Homebrew we can't really trace due to the variation in output signal characteristics.

I'm an EE major with a good theoretical background but little practical experience. Anyone here have experience with long range telemetry (50+ miles)? I'm trying to figure out how to transmit sensor data from a rocket using either an arduino or a beaglebone. I have my amateur radio license but I haven't done anything with it yet, so I'm not familiar at all with the commercial equipment out there. What kind of receiver set up would you recommend and would I have to design a preamp, LNA, and maybe some DSP to go along with it? Or is this stuff standard in the commercial equipment out there? Also, are there any questions I should be asking?

>>753296
Dorji DRA818V (google it). Stick a TNC on the BB and have it transmit APRS packets. Use an RTL-SDR as the ground station.

>>753305
Thanks!

TNC on the BB?

>>753310
>>753305
Terminal node controller on the beaglebone?

>>753312
Yep, like http://www.george-smart.co.uk/wiki/AX25_Soundmodem

so, whaat happened boss

>>754254
> this post definitly required the use of a tripcode