Re: [Discuss-gnuradio] Computer controllable antenna tuner

[Jeff Scaparra]

Sorry didn't finish my email for hitting send. 

Marcus there are some things you need to be aware of. First the bandwidth of a small magnetic loop, like your describing is really small (2-6 KHz) for the frequency range that your describing. Assuming that is ok I don't know of a commercial solution. You can use this calculator to get a general idea http://www.66pacific.com/calculators/small_tx_loop_calc.aspx .I am currently planning on building one of these loops for the 40-20 meter bands using heliax 1 5/8 inch for the outer loop and a vacuum variable for the tuning capacitor controlled by either a arduino or rasp pi. I am still working on my plans but if your intent on utilizing one of these antennas I suggest you check out the group at www.magloop.com. If you not planning on transmitting a PA0RDT may be better. It is smaller. It is an active antenna and does require power but the websdr guys are getting good results with it. I would like to build one in the future as well. See google for more references but it is suppose to work well from 10KHz to 30MHz.

73 Jeff N6SDR

On Mon, May 13, 2013 at 11:14 PM, Jeff Scaparra <address@hidden> wrote:

Marcus there are some things you need to be aware of. First the bandwidth of a small magnetic loop, like your describing is really small 

On Mon, May 13, 2013 at 11:20 AM, Marcus Müller <address@hidden> wrote:

As for not talking about hardware on the GNU Radio mailing list - I find
that a little silly.  While GNU Radio is more about a framework for
processing baseband signals, there's also the real need to interface to
the outside world.  Dynamic range, gain, and all the little hardware
bits in the radio front end are all valid discussion points and
completely on topic, in my opinion.

Brian

Hi Brian, Hi Juha,
I didn't mean to stifle hardware discussions at all - it just stroke me as a little bit odd to ask gr-discuss a question that, although being technically related to software defined radio, asks for something that is kind of like "an antenna tuner buying guide"; it's only logical to ask a question like "hey, I'd like to get medium wave audio broadcast transmissions, what do you guys use for a tuner" here. It's less logical to ask "I'd like to buy a 1-20MHz tuner", without adding a little more specs than "computer controllable".
Yes, we are software radio users. But we are not the right point to start looking for an antenna tuner, impedance matcher etc. in my opinion. That being said, I think Juha has asked a valid question, and I'd totally like to see him use that antenna / tuner / system with GR,
and therefore I'd actually hope someone helps him choose a good component.

Sorry that I came around arrogantly, I didn't mean to.

Greetings
Marcus

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