geekhack
geekhack Community => Other Geeky Stuff => Topic started by: keyb_gr on Wed, 23 December 2009, 16:07:43
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I got one of these today:
(http://www.fmuser.com/uploadfile/200812/6/547577939.jpg)
(not my pic)
It's a Tecsun AN-200 tuned mediumwave loop. (For reference: 9" / 23 cm diameter.) So far I like it, looks nice and works well. I did already have a homebrew loop before, but at almost 1 m square it was just too big and cumbersome. This one is a much better match for my portables and still gives a nice boost when used via inductive coupling. The price was right, too (about 20€ - it was a bundle deal together with the latest issue of Sender & Frequenzen, normally you can also pay twice that).
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A tuned loop for FM? Apart from the usual "folded dipole", loops are quite uncommon up there. Honestly, that sounds more like an AM loop.
I also have a big homebrew one, square and a good 3 x 3 ft, uses one half of a 2x 500pF mechanical varicap. Big signal, but very cumbersome. The Tecsun is much better suited for my purposes really. Mine can still be peaked all over 160m, too - that gives some nice reception there on the ICF-SW7600G with half-inserted antenna jack trick (same should apply for DE1103/E5 which use the ferrite rod up to 3 MHz). That is, provided all the local QRM sources are off (quality energy-saving bulbs tend to be OK at some distance, conventional fluorescents are worse, and TVs are just EVIL).
One of these days I should build a tuned loop with preamp for the low shortwave ranges. The AN-LP1 is only useful from about 3.5 MHz up, and the Sony sets use a broad band filter after the ferrite rod so that's not too much use beyond 2 MHz. Not good for 120m or 90m.
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Almost remember building a 10.8 foot-per-side trapeoid antenna for fine tuning a station at circa 102 FM. I have no idea where I got my math. Does that sound remotely on target?
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I've got an old Sangean ATS-803A with a military spec 0.1 - 30 Mhz Datong signal amplifier with a 40 foot longwire plugged into it.
Shame I hardly use it these days as I listen to National and local DAB on a Pure Oasis and I have a brilliant little Roberts R757 3-band in the kitchen next to the deep fat fryer!
It can pick up continental AM at night and over 200 Countries on Shortwave.
I've got logs for over 60000 stations over 15 years.
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All the best for Chrimbo Ripster - I'm not travelling this season because the weather here in Manchester is appaling so I'm not seeing my family and friends who live hundreds or thousands of miles away.
Yeah Sangean are good little radios Ripster - they badge engineer radios for Roberts and a few other companies - they're reliable - my 22 year old big desktop model is still working great.
I don't need a pocket radio anymore because I have an FM RDS tuner on my Samsung mobby.
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Sangean - I've got one of their older versions of this. Rarely used these days since I can normally live with my Sansa Clip tuner.
Funny you'd mention it - I consider my Clip to be pretty deaf. I suspect a change in AGC handling at about firmware 30 - people used to complain that the Clip would drain the battery quickly in radio mode, while afterwards there were reports of seemingly reduced sensitivity. Anyway, I wasn't really content with the FM performance of the iAudio G3 already (the stereo threshold was sorta high, and strong-signal handling not very exciting), which ultimately led me to vintage pocket radios. Selectivity on these was only middle of the road, but sensitivity and strong signal handling much better in spite of simple frontend circuitry, and the Toshibas I had weren't too bad in terms of hiss either.
Ultimately I ended up with a DE1102 (http://www.radiointel.com/review-degende1102.htm) for a portable FM radio. In comparison to the Clip it's huge, but with good sensitivity and unmatched in selectivity and strong signal handling for such a small set at that time. The MW/SW part isn't bad either, and the headphone out is pretty much hiss-free. Today I might look at a Grundig G8 or other little DSP sets (Tecsun PL-310, whatever), although none of these are officially imported into Europe yet.
EDIT: Yay, 1111 posts :D