On Sat, 13 Feb 2016 11:02:07 EST, rickman wrote:
On 2/12/2016 4:13 PM, Howard Lester wrote:
"rickman" wrote
So who here is using a loop antenna?
I just a couple days ago set up my MFJ Hi-Q Loop (30 - 10 m) to compare
it to my 140' somewhat-inverted V up 30'.
Are you taking a poll, or do you have a specific question or two?
I got into loop antenna design to construct a WWVB receiver with a
"large" loop (compared to a ferrite stick) to maximize the voltage
output. This is not typical because the SNR is the actual limitation in
that band so that you can use an amplifier with the weak signal from the
stick antenna and get a good signal. But I wanted to try doing it
without an amp and directly sample the signal with a 1 bit ADC at 240
kHz. Then use signal processing to pull the 1 bps signal out of the dirt.
It would be easier and more interesting if you demodulated the
relatively new BPSK enhanced format instead of the older AM/PWM
format. However, don't get any ideas about selling a WWVB product
that uses BPSK as it's locked up in patents held by a company that
seems unwilling to manufacture the promised chips.
There was an article on a WWVB receiver that did BPSK a few months
ago. Googling...
"A Frequency Standard for Today’s WWVB"
http://www.arrl.org/files/file/QEX_Next_Issue/2015/Nov-Dec_2015/Magliacane.pdf
Never got that project off the ground mostly because I got distracted by
the antenna design. While digging around with that I learned about the
complexities of transmitting loops and now I am thinking of getting a
license and setting up a loop antenna for ham use.
Just do it. Getting a ham license is fairly painless.
I've always been a gear-head liking the details of a design more than
the use. lol
So how does your loop compare to the other antenna? I understand the
loops often have a better SNR.
I know I've seen the name MFJ, but what
does it stand for again?
Martin F. Jue.
http://www.mfjenterprises.com/about_mfj.php
https://en.wikipedia.org/wiki/MFJ_Enterprises
Like all companies, the product quality, engineering, service, and
politics vary depending on the specific product and situation. I'll
spare you my opinion.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558