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FM transmitter group buy on EDM LCD ends 10/31/08


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rbar,

EDM got your transmitter and tested it out. No problems were found. They were able to field test it on 100mW and had ~1 mile range.

I would be willing to further test your transmitter at my home, if you would like. EDM can either refund your purchase, have you send the unit to me for a 2nd opinion testing or send it back to you. There would be no additional cost to you either way.

If the unit works at my location, then there would be something unique about your location that is causing the unit to not work properly.

Let EDM know how you would like to proceed.

Best regards,

Scott

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Scott,

Received my transmitter yesterday and followed the instructions.

Needless to say LCD screen wont light up so I'm somewhat at a loss. (wont light up but displays a bunch of squares where I assume text would be) I ensured the chip was in the right orientation and the solder joints were done correctly.

Is there an off/on switch here or something? Direction didnt mention it but I'm a lil disappointed at the moment.

Please holler,

Tom

Edited by bcdmahn
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EDM tested the unit and says it is fine.

I will try connecting coax to the antenna instead of the 1/8 inch headphone cable. Nothing I did withe antenna connected to the headphone cable had any impact on the reception.

I got some absurdly complex antenna advice from the Yahoo "support group." I can't call this support because I have no way of knowing if the advice offered is good or bad.

I am counting on the reception improving using coax to the antenna.

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Rbar,

if I can suggest...not only do you want to use coax, but be sure to get "RG58" coax which has 50 ohm impedence that will match the output of the EDM.

(not RG59 or RG6, used for TV... it is 75 ohm)

It is available at Frye's electronics if you have one near for a reasonable price. (it is in computer networking area...go figure), or also at Radio shack.

The adaptors to go from BNC or whatever (on antenna) to RCA (on Transmttr) are available there also.

Hope this helps... just picked these items up today for another setup myself! ;)

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Terry,

50 ohms? I've had specific instructions from others (non-EDM) to get 75 ohm coax. That would explain why the antenna doesn't work when attached to my coax. Why wouldn't EDM support tell me that? Their support is incomplete and has varied between insightful and scolding. I'm sure that once I send them a specific question (50 vs 75ohms) I'll get an accurate, courteous reply. But that would be the 3rd cable I've bought in this ongoing misery; I've told them what I'm doing every step of the way. Today EDM advised me to buy an antenna; that would do no good if I'm using the wrong cable.

Btw, we have a great local electronics & cable store and I would never go to Frys or a big-box know-nothing chain store for this stuff. I'd have bought any transmitter than my local specialty store recommended, but they don't carry them. :-(

I have found EDM's email and Yahoo style fend-for-yourself support to be frustrating.

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rbar, to be fair, I know they (EDM) are trying very hard to help you. I have even offered to call you, but then you don't reply. Communications is a two way street. Your technical level seems to be low ... and unfortunately, you are in a somewhat technical problem you are trying to solve. I'm sure it is VERY frustrating to you also ... but how about spending more time working with EDM or calling me up (I'll PM you my phone number, ok?) and spend less time posting complaints on these threads? Don't shoot your helpers, ok? We are trying to help you ...

You mis-represent their support as poor, when your are unclear or take long periods to respond yourself about your problem and situation. Yes, it is internet / email support ... but where else do they actually answer questions on the weekends and late at night? In my mind, EDM support is amazing ... I've had questions on the yahoo board answered around midnight.

When I asked for pictures of your location, your hookups, your wire ... you never responded. In over 125 of these sold, your situation is unique. People are trying to help you, but you need to do your part as well. You are getting confused and need a clear plan of how to proceed from here. I think they got you on the complicated plan of antenna building, when I'm not convinced the hookups and cabling are correct yet. Do you have ANY members nearby that could help you? You don't state a specific location in your profile.

I still doubt that you need an antenna at all. I think the wire antenna should work fine for you. I think the problem is in your hookup between the source (a computer? a dvd player) and the transmitter and/or the cabling used. I would focus on that and provide pictures of what you current have and what is hooked into what and using what cables (be specific, thats why pictures help so much). If you need help getting pictures, then ask us for help ... we can and will help you.

re: the antenna ohms

50 ohms is ideal (but pricier), 75 ohms is what is cheap and readily available. EDM gave you instructions for an antenna which included a hame-made balun to handle the 75 to 50 ohm. You can use RG8 which is 50ohm to start with (which is better) ... either should work. If you use the RG8, then you don't need the balun part of the plan EDM sent you.

Please don't take any of this as an attack ... I'm just trying to help you.

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Terry,

Btw, we have a great local electronics & cable store and I would never go to Frys or a big-box know-nothing chain store for this stuff. I'd have bought any transmitter than my local specialty store recommended, but they don't carry them. :-(

RBar,

I am surprised you didn't have this up and working by now with a good local specialty store to help you out. ;)

I was trying to suggest the most efficient cable that could be found easily and cheaply... I don't disagree that you will not get good tech advice from these stores... but that is what you have friends on PC for.

I helped another PC member construct a simple antenna using these same items from these same sources and the total cost was under $20... cable and adaptor and and his EDM went from just getting to the edge of his property (small city lot) to way more range than he could ever possibly need... and his situation was kind of unique also.

RF can be very confusing, but I was able to help him without getting him too confused with the tech and design aspects of it all, just cut it this length, 3 to 4 coils here, hang it and forget it.

Problem fixed in a day. :)

There are so many ways to do an antenna is why you have gotten so many different answers... Pick one and try it!

(make sure your audio is making it to the unit first of course)

Maybe you have a source of high amounts of negative energy at your location... could be a problem too! :cool:

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Terry,

EDM told me to join their message boards; the first advice I got was absurdly complex instructions to build an antenna using 75 ohm cable.

Then they advised me to buy a 60" antenna that was clearly overkill.

If you have simple instructions for an antenna I'm all "ears."

My experience with this unit is at odds with all the praise I've read about it (unless I stay in the driveway).

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rbar,

the fact that your only getting range of '1 car length' tells me something else is wrong, other than the antenna.

If you were trying to go 1 mile vs. 1 block ... then we need to talk antennas.

You should easily make it to the bottom of the hill, even with test antenna.

The only other thing I think of is ... is your home located on a mineral deposit or do your live next to high powered ham operator, radio tower ... or anything?

Check the output (volume) levels from your source. I would like you to try using a simple am/fm walkman (or cd player, or ipod/mp3 player) where you can vary the output levels .... generally, full volume is too high, many need to turn it down to the middle of the volume range.

If you are still using the dvd player as the source, I would try something else.

I gave you my phone# and email if you want to talk this over and get it resolved.

Scott

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transmitter whose signal I cannot

pickup except in a very narrow useless range using the test antenna.

No matter where I've put the test antenna (vertically positioned) I can

only get good reception in a small area of my carport.

I live on a hill and I get trivial reception above or below the level I

place the transmitter / antenna on. I have a street to street lot and

the reception is very very weak on the uphill street and non-existent

on the street below. This is a 1/4 acre lot.

The transmitter has been tested by EDM as working.

I would appreciate any comments on placement of the test antenna or

what type of antenna I could test with for improved transmission.

I have extended the reach of the antenna with a 1/8 headphone wire with

adapters for rca connection to the receiver. No placement of the test

antenna has made significant improvement

I would do away with the 1/8 headphone wire (single wire??) ... I'm not confident that your using the right thing.

Just try a simple 1/8 to RCA cord from a reliable source, like a walkman (portable is key) ... then plug in the transmitter somewhere outside (ideally) and the portable audio source ... and try that. If that works, then you know you either have a bad audio input or bad cable or connector. You should only need the test antenna for this ... and your range should be several hundred feet, unless you hills are super steep. I'm still waiting for a picture (or two) that would help me (and other members) understand your situation better.

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Here is an even simpler one: coax only

I suggest looping the coax 3 to 4 times in a coil right at the bottom of the stripped length to help act as a balun to prevent radiation further down the length of the cable. You can even clip the braid off if you have trouble keeping it in one piece and it will not make a HUGE difference.;)

There are a couple of variations on this design and they all seem to work fairly well.

The ground plane taybrynn posted above is also a very good proven design! :)

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This is one of the most simple antennas I know of and can be made for $10 or less.

Some folks use the welding rods, other probably have used coat hangers or other things.

See pic attachment below.

I built this one. Get a solid 2-3 blocks and have range up to 1/2 mile in some areas. Using the EDM set at 10mw.

Remember, obstructions will decrease your range in that direction.

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the first advice I got was absurdly complex instructions to build an antenna
EDMdipole1.gif

Instructions from EDM support:

Construction.

The easiest option is probably to make the antenna from the coax. To do this, you will need to strip away the outer casing of the coax to half the length (32") of the complete dipole - making the braid visible. You then push some of the braiding apart near the part where the outer insulation is still on, and pull the inner wire (with its insulation on) through that hole. Insulate the end of the coax, so water does not get in, fit a coax connector on the other end of the coax, and it is ready to mount.

Another option is to cut two lengths of wire, each half the dipole length. You then strip the insulation from the end of some coax, and solder these wires to the end. The connections should be well insulated, so that water does not get in.

If you are feeling adventurous, you could make the dipole from tubing. As with the wire dipole, you will need two lengths, each half the dipole length. You could make each half out of two pieces, which slot inside each other. This way, the antenna length can be adjustable.

You will need something as a base, which the tubing and coax will go into to make the connections. It will need to be non-conductive (possibly plastic) and you will need some way of fixing it to a wall, gutter, etc.

When cutting lengths, remember to be cautious - the wire dipole should be cut slightly longer than you expect, as you could trim it when tuning. With the coax dipole, it may be possible to strip back a bit further to lengthen the dipole when tuning. The tubing is best done with sections as suggested, and made slightly long so that it can be tuned by sliding the sections inside each other.

Mounting.

Wire dipoles can be dangled from objects, tied to bamboo type sticks, mounted on walls, etc. It should be remembered that nearby objects affect the signal, so open space is best.

Tubing types can be mounted from a wall or pole.

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So, the problem was "just" the antenna hook up/Antenna?

I just started reading this thread today and have had some experience with FM transmitters. Was gonna spew out some suggestions but if its working.

:-)

So, is anyone having any trouble with stereo on these? I know that when transmitting stereo the mixer can't have any content above 15khz or the channels don't separate correctly. I run a PCI max and have some trouble with stereo mode and just wondering how your new transmitters do with stereo separation vs mono??

The coax ony solution sounds great.

50 ohms that is.

Thank you Scott.

Rbar

Edited by kb9nvh
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I know your on a hill, and it sounds steep on either side. But do you have lots of trees? Trees (or a thick forest) can eat up signal like crazy.

I know 50 ohm is still preferrable to 75 ohm ... but either should work. Don't go cheap on the cable.

I've asked 3-4 times already, but a picture of your location would be worth 1000 words ... can you post one, or email one to me to post here (for you) ?

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Okay, so I've gotten over half of the downhill reception I wanted with the whip antenna hanging from direct attachment to the transmitter atop a stack of paint cans on the back deck railing. When the reception is good, it is good. In the rain, in the dark that was enough for today.

I will attach the antenna to my 75 ohm coax and experiment with different placements.

At a minimum, I will be know where to park to enjoy my synchronized lights and music.

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