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My six dollar ebay xmitter arrived in the mail.


frascati

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Arrived well packaged in bubble wrap three days ahead of estimate. Unit itself surprisingly well built with crimped metal clasps joining the halves of the case. Installed driver and plugged in unit. Selected an empty space on the dial of an fm radio, opened my last.fm scrobbler and typed in Steve Earle, and it worked just beautifully. Truly plug-n-play for the novice.

Slight ambient hum noticeable between songs that was eliminated simply by touching the metal side clasps with fingertips. Range sufficent for one large room.

I removed side clasps and split the case. 3.5 inch antenna wire was doubled over and bare end of it was simply tucked behind the metal side clip. Guess they were using the side clip as part of the antenna element. No solder. Must have been the source of the spotty ground and subsequent hum.

Ran xmitter as bare board with antenna wire extended and range improved to the other end of the house very clearly. Never owned a xmitter to compare but I"m pretty impressed.

Does not, however, reach the back yard or garage. That is my goal actually to have web broadcast music available while wrenching the motorcycles or gardening in the back, or sitting around the fire with a cheap radio. High fidelity is not a premium for me but the quality so far compared to actual stations on the dial is quite good.

So can anyone help me with a couple of questions that have been discussed in these forums, but specific to this little unit?

Is a 1/4 wave ground plane antenna, built according to this calculator,

http://www.fmuser.com/uploadfile/201004/8/2349199801.png

inherently balanced and therefore SWR (which I have no means to measure) not a concern for me?

Are the tiny SMA connectors and associated tiny coax common to wifi applications compatible with FM frequencies? I'd like to use these connectors and coax to fab the antenna.

I've read that varying "skin effects" between different element choices can affect the length calculation. Copper, alum, steel.... different diameters of wire... insulated or bare....

Is this correct? It is supposedly sufficient to require adjustment of length by as much as an inch on a 30 inch element? I'm planning on using 3/32 steel tig welding filler rod for the elements on the antenna. Any advice here?

Ebay Link

http://www.ebay.com/itm/USB2-0-FM-Audio-transmitter-Wireless-adapter-/230669438036?pt=Other_MP3_Player_Accessories&hash=item35b4f84c54

GUI

http://images52.fotki.com/v1551/photos/8/1799248/10530209/FM1-vi.gif

GUI

http://images15.fotki.com/v588/photos/8/1799248/10530209/FM2-vi.gif

Package Contents

http://i802.photobucket.com/albums/yy303/svejkovat/SDC14265.jpg

Antenna was tucked under metal side clasp

http://i802.photobucket.com/albums/yy303/svejkovat/SDC14268.jpg

Bare wire end was simply clasped behind the metal side clip. I noted during operation that

minor hum was eliminated simply by grounding the metal clip with my fingers.

Top of board

http://i802.photobucket.com/albums/yy303/svejkovat/SDC14269.jpg

Bottom of board

http://i802.photobucket.com/albums/yy303/svejkovat/SDC14270.jpg

Bottom closeup left

http://i802.photobucket.com/albums/yy303/svejkovat/SDC14280.jpg

Bottom closeup right

http://i802.photobucket.com/albums/yy303/svejkovat/SDC14279.jpg

Top closeup right

http://i802.photobucket.com/albums/yy303/svejkovat/SDC14277.jpg

Top closeup left

http://i802.photobucket.com/albums/yy303/svejkovat/SDC14275.jpg

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Since I'm anticipating the lead going to the antenna being 10ft of USB and there is only two inches or less of coax linking the xmitter to the antenna, do I need to be concerned with swr/baluns? What if should later decide to build a half wave dipole with the same arrangement of xmitter linked by two inches or less of coax?

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After a bit more reading I'm just going to guess that eliminating the need for coax by connecting the transmitter directly to the antenna negates the concern for a balun.

I may be overthinking this. I just took a pair of rabbit ears, extended them fully, hung them vertically from a rafter, connected the antenna wire to the top element (the flat twin lead coming out of the base) and then connected the bottom element lead to the usb's shield (easiest ground to access on the card for the sake of my trial) The xmitter is now connected directly at the joint between the ears. A usb extension leads down to my laptop.

I got perfect high quality reception out to the corners of my yard. In the workshop, all rooms in the house, the detached garage, garden, and firepit. I'll look up dipole calculations to see how close I am with the rabbit ears extended and perhaps make some adjustments for my frequency.

So USB xmitter seven dollars free ship. Rabbit ears $1.50 at Goodwill. Will need to get a 15ft USB extension from monoprice for two dollars. In spite of the obsessing over details this was childsplay to set up and less than 15 dollars total. And I've got GUI PC connectivity to boot.

A few of you worried that I was trying to sell these things. I read the posts over a couple of times and just couldn't imagine that. I even offered the mods to delete any references to the product itself or links to its vendor. Guess I'll always be a bit puzzled by the cold shoulder I got here generally. MY very first post was a LITTLE aggressively stated, but you'd call that (please do read it) sufficient for shunning a new member?

Frankly I'd be just as happy if the mods would just take down this entire thread. I feel silly offering this crowd such an effective bargain basement option for your hobby interests.

And relax, I won't darken your doorstep again.

Edited by frascati
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I was the one who initially flagged your message for review. I absolutely detest spam, and when I see it I take care of it. In this case, I flagged it for review since I wasn't 100% sure if it was or not.

Spammers have become much more sophisticated -- making posts that appear relevant but which are actually thinly disguised ads. Since I wasn't sure about your message, I flagged it, (I assume) the admin got in contact with you, and everything verified.

I'm sorry you felt singled out, as that was not my intention. I'm happy that you are not a spammer.

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Guest wbottomley
I feel silly offering this crowd such an effective bargain basement option for your hobby interests.

And relax, I won't darken your doorstep again.

OK.

Maybe this will help.

5689609.jpg

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Seeing you posted, several times in one day trying to get some type of response, Jeff's got it right, we're busy, living Life, and working on our own stuff. And at THIS point in the year, we've gone way beyond the radio to use.. Chill, relax, wait for someone to reply. God, Grant Me Patience, But Do It Right Now!! Really?

If you had taken the time to look thru other threads here re: transmitters, you might have seen posts, numerous in fact, about modding antennas or power, preventing visits from guys in dark suits, wearing sunglasses, with no sense of humor, driving dark panel vans with gov't plates and lots of antennas. One point, if you had bothered to read thru those posts, is any type of USB stick radio wont be heard outside the room its in. But you didnt. Good luck with what you got there, bud.. Hope it works for ya.

Edited by TJ Hvasta
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