[slinkelist] Ramsey FM-10A and FM-25

[Alan Freeman]

Dear Slinke-list,

Being a broadcast engineer and Ham, I can shed a little light on the Ramsey
FM transmitter kits.  By the way, they are alive an well at the Ramsey site,
addressed below.
http://www.ramseyelectronics.com.  I am not connected with Ramsey in anyway,
so my review below is based on my experimentation with their products only.

The FM10A uses unsynthesized tuning, so it's frequency drifts; annoyingly.
The price begins at $35, but I wouldn't bother to buy it because of the FM
drift.  You get what you pay for however, and it's ok for just a short while
you mow the grass or something with your headphones on.  The power output is
enough for a city block; depending on the lack of obstructions such as large
buildings.

The FM25 uses a synthesized tuning method that uses dip switches to set the
frequency.  It is very stable and a very good unit.  You can find it on
their site for $130.  The case, a whip antenna, and a power supply comes
with it.  It is a raw kit and requires a few hours to assemble. You need a
fine tip soldering pencil/iron.  I soldering gun will not do:

http://www.ramseyelectronics.com/cgi-bin/commerce.exe?preadd=action&key=FM25

I will review just the FM25; since I know most folks that bother with it,
would want a solid and stable signal.

I assembled and tested a FM-25 in about 2-3 hours.  It has a strap option
for high power within it that says basically that you shouldn't strap it
unless you're outside of the USA federal jurisdiction.  The FM-25 has an
external antenna connect (RCA type).

With the strap unconnected, you can get out a city block (500') using the
attached antenna.  You can put a switch on the strap so you can enable and
disable it at will.  This is handy for use with the LPA1 Ramsey Linear Power
Booster kit mentioned below.

Using an external 'tuned' antenna (I tried a home built vertically mounted
yagi) you can get out about 2 city blocks (1000') at least.  This is illegal
in the US.  Ramsey also sells a great J-Pole antenna called the 'Tru-Match
100' for about $40.

http://www.ramseyelectronics.com/cgi-bin/commerce.exe?preadd=action&key=TM10
0

With the strap and an external antenna, you can get out about a half mile at
least.  This is illegal in the US.

Ramsey sells the above mentioned broadband amplifier, the LPA1 Ramsey Linear
Power Booster kit for about $50, which can be connected to the unit for an
extended transmission range.  IMPORTANT:  If you try this, be sure to set
the FM-25 to low power (unstrapped), or you will fry the input on the LPA1.
With the FM-25 in low power mode and the amplifier attached, you get about 1
watt of FM stereo power.  In this configuration with an external tuned
antenna will get you out about 4-5 miles; depending on terrain and building
obstructions.  This is illegal in the US.

http://www.ramseyelectronics.com/cgi-bin/commerce.exe?preadd=action&key=LPA1

Not to insult anyone's intelligence but worthy of mention here is to keep in
mind that the FCC (Federal Communication Commission) allows low power
transmission the FM band with kits such as this, as long as you do not
exceed the maximum field strength reading suggested with the literature that
comes with the transmitter kit.  This legal limit is easily obtainable to do
using the low-power mode with the included whip antenna; which is how Ramsey
suggests that you do it.

Either addition of an external antenna or strapping to high-power mode, or
both, will put you in violation of the allowed federally regulated legal
power specifications.  Transmitting which would cover up another local or
distant stations licensed to a FM channel or interfering with an authorized
pattern, as-well-as obscenity are also major no-no's.  There is little
tolerance within the FCC regulations for bending those three rules.

A few final words:

1.  The FM-25 is a bit touchy on input will squawk if you overload the
inputs.  I highly recommend a good cheap compressor/limiter like the Alesis
3630 available at
http://www.americanmusical.com/cgi-bin/sgin0101.exe?UID=2000120409183322&T1=
ALE+3630&UREQA=3&UREQB=5&FNM=00 for about
$170) to keep your levels constant, or Ramsey's STC1 Stereo Transmitter
Companion
http://www.ramseyelectronics.com/cgi-bin/commerce.exe?preadd=action&key=STC1
($60 as a kit or $99 assembled) to polish up your input signals for best
possible FM transmission.

2.  If you are not in a major market or local FM station saturated location,
you might check with the FCC's new LPFM (Low Power FM) licensing regulation
with actually allows you to have an FM station of 100 watts or less for your
community.  You can search their site for info at www.fcc.gov using LPFM as
your keywords.

 >(©¿©)<
Best regards, Alan Freeman
e-Mail: alan@cdcontrol.com
Web URL: www.cdcontrol.com