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Author Topic: My incomplete report on FM part 15  (Read 279 times)
Rev. Robert P. Chrysafis
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« Reply #10 on: September 23, 2005, 10:46:54 PM »

try here....

http://www.geocities.com/Area51/Nebula/3736/

Thanks,






> > quality is the same as the FM100b as it uses the same
> > BH1415f Stereo chip. uses the same basic design as the 25b
>
> > and uses a custom silicon for a PLL. Range on the 100mw
> unit
> > is about 1500ft to a Walkman using the Tx at ground level
> > indoors. it's a decent plug n' play unit if you aren't
> handy
> > with a iron. Stability and harmonics are excellent.
>
> Where can I find more detailed published technical specs on
> the Ramsey stuff?
> Searched their homepage but found nothing. I want to compare
> apples with apples.
> >
>

______________
Rev. Robert P. Chrysafis
Universal Life Ministries (ULC)

http://www.freecycle.org
Join the FreeCycle Revolution

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radiooke
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« Reply #11 on: September 23, 2005, 10:58:56 PM »

> try here....
>
> http://www.geocities.com/Area51/Nebula/3736/
>
> Thanks,
>
  Looks like I am stuck. This is what I found here on the 100 (not 100b) from the reviewer
A REPORT ON A RAMSEY FM100 KIT
From:         xxxxx@sweden.hp.com (John)

"
After assembly, here are basic observations of my particular kit:

  As far a the specs are concerned,  the FM100 is 'ok' for the price ,however,
in my opinion it isn't a "PROFESSIONAL FM Transmitter" as is emblazoned on the
front panel and printed within the manual.

  My freshly built FM100 works in that it will go to the desired frequency
and has an OK kind of stereo like signal.... all the buttons and knobs do
what they say.  But for me, the FM100 has a way to go to really be a
'PROFESSIONAL' FM stereo exciter/transmitter."

"  Since Ramsey chose not to publish specs on separation, signal to noise
ratio and frequency response, I won't either."

"I have to clarify that, yes I did assemble the FM100 correctly and yes I did
use high quality HP test equipment and a top of the line Pioneer tuner to
check things out."
----------------------------------------------

This is all I could find on the 25B as far as noise and audio

Ramsey FM25B Review by FM Guy:

"Overall, it sounds like a somewhat weak FM station even when the
receiver is right next to the FM25B.  You get some "fuzz" and odd stereo
artifacts at times.  If you overdrive the audio input, it causes most
receivers to drop in and out of stereo in step with the music (it's also
well into audible distortion while it's doing this).

The frequency response seems quite good.  I haven't measured it yet (I
might later, along with actual THD and S/N ratios).  Likewise, the
stereo separation is also OK.  For an all-in-one FM chip, the BH1415F
used in the FM25B does a decent job.

Ok, so enough technical stuff, how does it sound?  Well... I guess that
depends on how fussy you are.  As others have reported, there's some
buzz and hum that's audible during quieter passages and between songs.
It seems to be due to RF leakage back into the circuitry.

The FM25B sounds reasonably good but far from great.  It won't put your
favorite FM station to shame as Ramsey claims unless your favorite
station is a hundred miles away.  The distortion steadily rises with
increasing deviation (audio level) and at low audio levels the signal
gets buried in assorted forms of noise.  So you're between a rock and
hard place when setting levels."


Update:
He-He This is funny, or sad! Just read the rest in the EDM FAQ document

"How does your unit compare to X,Y and Z product?
We provide detailed specifications resulting from our test results, using random test units to sample data. These figures are there in black and white to read, not like the vague "Excellent", "Professional Grade", "High Quality", "Low Noise" statements you get from many other competitors. Ask yourself: "How long is a piece of string?" To compare, ask for their figures. You will be very lucky if they know what you are talking about, and even luckier to get it from them. They may have something to hide from you, we don't!"

Maybe some employee from Ramsey that (surely must be) reading these boards can provide more information for us?


>
> >
> > Where can I find more detailed published technical specs
> on
> > the Ramsey stuff?
> > Searched their homepage but found nothing. I want to
> compare
> > apples with apples.
> > >
> >
>
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Steve
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I have been involved in broadcasting since I was 8 as anyone knows radio gets into your blood (Before Clear Channel). Occupation: Broadcasting Hobbies: Broadcasting, Building radio stations and transmitters.


« Reply #12 on: September 23, 2005, 11:19:14 PM »

I’m not going to do an AM & FM comparison, the main difference you will notice is the noise level as in hiss. The EDM uses an external switching power supply. The DC input is well filtered preventing any ingress of external EMI or RFI. The carrier is very quite when compared to the Ramsey 100B. Ramsey crams too many noise causing things into a small case including the power supply.
EDM is designed and manufactured by a well-qualified RF engineer in South Africa. Ramsey could never produce a product like the EDM without the FCC blowing a fuse. Most of those who own an EDM will agree it’s in a class by itself when it comes to design performance and workmanship. The case is so sturdy you could almost drive over it with a car with little or mo damage.
My main beef with Ramsey is the high rate of component failure, most likely a result of poor design. Case in point: If an IC fails in the 25B it will also take out another IC as well as two voltage regulators. I also think Ramsey products are grossly over priced for what you get. The price of the 25B could be brought down to $75 and Ramsey would still make a good profit. Compare the Ramsey 25B to the EDM or Wavemach 100 milliwatt unit. These are not kits; they are ready to go transmitters produced by individuals with a passion for excellences. Both transmitters can be had for about the price of a 25B kit.
A fairer comparison would be the Ramsey AM transmitter vs. the Sstran AM both sell for about the same price We are comparing the difference between a Yugo and a Mercedes in quality and design.
One last thing between the Ramsey and the EDM: because of the lowerer noise floor of the EDM you will end up with increased range as well as a cleaner sound.

Remember professional equipment never says its professional, only low quality products attempting to fool the purchaser into thinking it is do, as is the case with most Ramsey products.  I think the case of Hobbytron with the FCC proves that out.

Note: I started typing this right after your post but one glitch after glitch with PC delayed my post.
I read the Rev. post with regard to EDM. Even when I helped toast my first transmitter the guy only charged $15 to correct the problem it would have been free if I had not decided to play doctor first. The RF amp failed it happens, it's an easy fix. The transmitter has been on 24/7 since it got back here over 4 weeks ago here on the test bench.
One tip: Go easy on the antenna connector. {Don't press down on it to hard}
I'm sure Carl will agree EDM responds pretty fast to e-mails in detail.
I also have to check with EDM to see what kind of high SWR the RF amp can withstand. I will post the answer here.

Steve
www.RadioBrandy,com

> >I recommend the EDM FM transmitter
>
> How does this compare against the Ramsey 100B?
> Sound quality wise etc.
>
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radiooke
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« Reply #13 on: September 23, 2005, 11:32:02 PM »

Compare the Ramsey 25B to the EDM
> or Wavemach 100 milliwatt unit. These are not kits;
 
When last have you looked? The EDM seems to be a kit now, at least a simple one that is http://home.global.co.za/~edm1/operation.htm
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rkchicago
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« Reply #14 on: September 23, 2005, 11:46:54 PM »

Is the link below the correct unit?

http://www.edmdesign.com/orders.htm
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radiooke
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« Reply #15 on: September 24, 2005, 12:35:34 AM »

> Is the link below the correct unit?
>
> http://www.edmdesign.com/orders.htm

YES
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Steve
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I have been involved in broadcasting since I was 8 as anyone knows radio gets into your blood (Before Clear Channel). Occupation: Broadcasting Hobbies: Broadcasting, Building radio stations and transmitters.


« Reply #16 on: September 24, 2005, 03:30:28 PM »

That has just been added to the site, EDM has recieved way to much publicity
lately on this and other boards. EDM is protecting itself from the intrusive goverment, You need to go over the entire site. I think EDM was trying to keep a low profile, being from South Africa EDM may have not realized how much Americans desired a high quality low power transmitter at a fair price.
Note how you did not point out the Wavemach.

Steve
Radio Brandy

> Compare the Ramsey 25B to the EDM
> > or Wavemach 100 milliwatt unit. These are not kits;
>  
> When last have you looked? The EDM seems to be a kit now, at
> least a simple one that is
> http://home.global.co.za/~edm1/operation.htm
>
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radiooke
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« Reply #17 on: September 24, 2005, 04:32:02 PM »

> That has just been added to the site, EDM has recieved way
> to much publicity
> lately on this and other boards. EDM is protecting itself
> from the intrusive goverment, You need to go over the entire
> site. I think EDM was trying to keep a low profile, being
> from South Africa EDM may have not realized how much
> Americans desired a high quality low power transmitter at a
> fair price.
> Note how you did not point out the Wavemach.
>
> Steve
> Radio Brandy
>
> >
 What is classified as a kit and what not? The official stance on this
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radiooke
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« Reply #18 on: September 24, 2005, 05:54:11 PM »

> Note how you did not point out the Wavemach.

Do they have a 100mW stereo kit as well? I just looked there http://www.fmamplifiers.com/Kits.htm and the only kits i see is a 350mW and 2 Watt amplifier
>
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radiooke
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« Reply #19 on: September 29, 2005, 08:47:01 PM »

> I also have to check with EDM to see what kind of high SWR
> the RF amp can withstand. I will post the answer here.
>
> Steve
> www.RadioBrandy,com

Any answer on this Steve?
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