|
More info on the FM- 10 transmitter
NOTICE: TO ALL CONCERNED Certain text files and messages contained on this site deal with activities and devices which would be in violation of various Federal, State, and local laws if actually carried out or constructed. The webmasters of this site do not advocate the breaking of any law. Our text files and message bases are for informational purposes only. We recommend that you contact your local law enforcement officials before undertaking any project based upon any information obtained from this or any other web site. We do not guarantee that any of the information contained on this system is correct, workable, or factual. We are not responsible for, nor do we assume any liability for, damages resulting from the use of any information on this site.
From [email protected] Tue Jun 1 12:14:06 1993
Received: from ES.COM by dg-rtp.dg.com (5.4.1/dg-rtp-proto)
id AA20111; Tue, 1 Jun 1993 12:14:06 -0400
Received: from sim.ES.COM ([130.187.170.219]) by orca.es.com (4.1/SMI-4.1)
id AA13056; Tue, 1 Jun 93 10:13:59 MDT
Received: by sim.ES.COM (4.1/esunix-ver1.7/SMI-4.1/esunix)
id AA26831; Tue, 1 Jun 93 10:07:37 MDT
From: [email protected] (Clint Dimick)
Message-Id: <[email protected]>
Subject: Progress...
To: [email protected]
Date: Tue, 1 Jun 1993 10:07:37 -0600 (MDT)
X-Mailer: ELM [version 2.4 PL21]
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Content-Length: 1169
Thanks to those of you who sent suggestions on the AC hum problem I was
experiencing. I went all out and visited a local Smack Shack and bought a
decent 13volt, 3amp CB power supply. The hum has been eliminated and I got
an additional 300' or so of broadcasting coverage to boot!
Now on to the signal amplification projects... (sigh) I received my PA-1
last week so I went to work on the simple 70mw amp first to drive the Ramsey
kit. Everything, I swear, looks right but all I end up doing is decreasing
my coverage when the pre-amp and PA-1 are powered-up. I have reason to believe
that the pre-amp isn't functioning, simply because I tend to doubt my schematic
reading abilities before I'd knock the configuration of Ramsey's documentation.
I don't know where the problem lies, however, until I buy an SWR/power meter.
I think I'll go for the 800mw project since it includes the circuit board lay-
out. Has anyone bothered with either of these two hacks Mycal has included in
the FAQ? Tips for the PA-1? (Yeah, I did remember to wind L1 and L2 the
additional turns.)
Who else is out there broadcasting on a semi-regular basis?
Thanks,
- Clint
From [email protected] Thu Jun 3 14:44:21 1993
Received: from silver.ucs.indiana.edu by dg-rtp.dg.com (5.4.1/dg-rtp-proto)
id AA15069; Thu, 3 Jun 1993 14:44:21 -0400
Message-Id: <[email protected]>
Received: by silver.ucs.indiana.edu
(5.65c+/10jsm) id AA17305; Thu, 3 Jun 1993 13:44:19 -0500
Date: Thu, 3 Jun 1993 13:44:19 -0500
From: david jerome adams <[email protected]>
To: [email protected]
Subject: newbie info
I just ordered my fm-10 kit today. Ergo, any particularly
successfully amp/antenna/filter designs you folks have would be
greatly appreciated.
Dave
From dbrillha@dave.mis.semi.harris.com Sun Jun 6 15:49:34 1993
Received: from dave.mis.semi.harris.com by dg-rtp.dg.com (5.4.1/dg-rtp-proto)
id AA01756; Sun, 6 Jun 1993 15:49:34 -0400
Received: by dave.mis.semi.harris.com (5.65/DEC-Ultrix/4.3)
id AA20815; Sun, 6 Jun 1993 15:49:13 -0400
From: dbrillha@dave.mis.semi.harris.com (Dave Brillhart)
Message-Id: <9306061949.AA20815@dave.mis.semi.harris.com>
Subject: FM10 current draw
To: [email protected]
Date: Sun, 6 Jun 93 15:49:13 EDT
X-Mailer: ELM [version 2.3 PL11]
--
Dave Brillhart
UNIX Systems Group
(407) 729-5430
[email protected]
__________________________________________________________________________
/=========================================================================/|
| The highest reward for man's toil is | Dave Brillhart (407)729-5430 ||
| not what he gets for it, but what he | Harris Semiconductor ||
| becomes by it. - Ruskin | Mail Stop 62A-024 ||
|----------------------------------------| P.O. Box 883 ||
| Internet: [email protected] | Melbourne, FL 32902-0883 ||
+_________________________________________________________________________+/
From [email protected] Sun Jun 6 22:22:27 1993
Received: from UUCP-GW.CC.UH.EDU by dg-rtp.dg.com (5.4.1/dg-rtp-proto)
id AA05640; Sun, 6 Jun 1993 22:22:27 -0400
Received: from Limbic.SSDL.COM by UUCP-GW.CC.UH.EDU with UUCP id AA20196
(5.67a/IDA-1.5 for [email protected]); Sun, 6 Jun 1993 20:54:11 -0500
Received: by limbic.ssdl.com id AA08488
(5.65c/IDA-1.4.4 for [email protected]); Sun, 6 Jun 1993 20:18:45 -0500
From: "Gil Kloepfer Jr." <[email protected]>
Message-Id: <[email protected]>
Subject: Substitute for welding rods?
To: [email protected] (FM-10 Mailing List)
Date: Sun, 6 Jun 93 20:18:42 CDT
X-Mailer: ELM [version 2.3 PL11]
In the FAQ, Mycal describes a ground-plane antenna design which uses
welding rods as the radiators. I have used #12 solid copper
wire stripped from a piece of regular Romex-type house wire. Will
this work as well? Has anyone tried this yet and had any success?
FYI- I have not had much success trying any new antenna designs. The
best antenna I have used was a big piece of wire strung across my
apartment. Now that I'm no longer in an apartment, I have tried putting
the transmitter in the attic with very disappointing results. I don't
have any large trees to place the antenna, and climbing on the roof
and putting it there doesn't have a lot of appeal.
When I first posted to this mailing list (when, for some reason, I wasn't
receiving it!) I got some messages from some kind broadcasters who wanted
to strike-up a conversation. My apologies to you for not being more
friendly and responding. It was right about that time that I started
looking for a house, and I neglected a lot of things!
Just some of my own experience which I'd like to pass along .. I
constructed my FM-10 in a metal box. This seems to keep a lot of the
drift under control since the box keeps away stray capacitance from
your hands or other objects. My last antenna (which I was hoping would
be fantastic) was a piece of #12 solid copper wire soldered directly
to the hole in the FM-10 PC board (the wire of was of the "correct"
size), and the unit placed in the attic. This thing has homed my
property line like a surveyor's instrument! I hardly could get the
signal outside my (tiny) piece of property! I am thinking about putting
back the little amplifier addition mentioned in the FAQ to see if that
helps. I built a small bench power supply a while ago which I used for
powering the FM-10. Basically, the power supply is equivalent to a
12V 2A transformer powering a bridge rectifier and a 12V three-terminal
regulator IC. I put 1000uF capacitors on both sides. This supply seems
to produce a nice clean output (although EE-types out there may have a
better or cheaper design).
I'd enjoy hearing stories about uses of the transmitter. My original
intent was to share my musical tastes with the neighbors (without causing
their doors to vibrate, like the hoodlums across the street like to do
with their gazillion-watt stereo in a jeep!) as well as have some fun
playing DJ! (a nobile idea for a 30-year-old loner) Obviously, not being
able to radiate a signal beyond the confines of my yard has hampered those
efforts!
Gil.
From [email protected] Mon Jun 7 13:40:35 1993
Received: from relay.tek.com by dg-rtp.dg.com (5.4.1/dg-rtp-proto)
id AA28192; Mon, 7 Jun 1993 13:40:35 -0400
Received: by relay.tek.com id <[email protected]>; Mon, 7 Jun 93 10:31:59 -0700
Received: from soul.tv.tek.com by tektronix.TEK.COM (4.1/8.0)
id AA19273; Mon, 7 Jun 93 10:29:41 PDT
Received: from thd.tv.tek.com ([128.181.58.237]) by soul.tv.tek.com with SMTP id AA11221
(5.65c.tv/IDA-1.4.4); Mon, 7 Jun 1993 10:03:02 -0700
Received: by thd.tv.tek.com (4.1/SMI-4.1(tv.tek.com))
id AA06212; Mon, 7 Jun 93 09:58:30 PDT
Message-Id: <[email protected]>
To: "Gil Kloepfer Jr." <[email protected]>
Cc: [email protected]
Subject: Re: Substitute for welding rods?
In-Reply-To: Your message of Sun, 06 Jun 93 20:18:42 -0500.
<[email protected]>
Date: Mon, 07 Jun 93 09:55:25 -0700
From: Bill McFadden <[email protected]>
>In the FAQ, Mycal describes a ground-plane antenna design which uses
>welding rods as the radiators. I have used #12 solid copper
>wire stripped from a piece of regular Romex-type house wire. Will
>this work as well? Has anyone tried this yet and had any success?
I don't think copper would be stiff enough to use for a ground plane
antenna. I used wire coat hangers for mine.
--
Bill McFadden Tektronix, Inc. P.O. Box 500 MS 58-639 Beaverton, OR 97077
[email protected], ...!tektronix!tv.tv.tek.com!bill Phone: (503) 627-6920
From [email protected] Mon Jun 7 15:13:37 1993
Received: from netmail.microsoft.com by dg-rtp.dg.com (5.4.1/dg-rtp-proto)
id AA12424; Mon, 7 Jun 1993 15:13:37 -0400
Received: by netmail.microsoft.com (5.65/25-eef)
id AB01148; Mon, 7 Jun 93 12:11:55 -0700
Message-Id: <[email protected]>
X-Msmail-Message-Id: 96B9B150
X-Msmail-Conversation-Id: 96B9B150
From: Bruce Hale <[email protected]>
To: [email protected]
Date: Mon, 7 Jun 93 12:12:07 PDT
Subject: RE: Substitute for welding rods?
Any conductor will work. #12 wire is a bit soft, but if the antenna is
not outside, it doesn't matter. If you mount the antenna outside, you
do want something stiffer, like welding or brazing rod.
Coat hangers work, but they rust.
From [email protected] Mon Jun 7 17:04:39 1993
Received: from relay.tek.com by dg-rtp.dg.com (5.4.1/dg-rtp-proto)
id AA29135; Mon, 7 Jun 1993 17:04:39 -0400
Received: by relay.tek.com id <[email protected]>; Mon, 7 Jun 93 13:53:09 -0700
Received: from soul.tv.tek.com by tektronix.TEK.COM (4.1/8.0)
id AA28494; Mon, 7 Jun 93 13:50:51 PDT
Received: from thd.tv.tek.com by soul.tv.tek.com with SMTP id AA19369
(5.65c.tv/IDA-1.4.4 for <[email protected]>); Mon, 7 Jun 1993 13:52:16 -0700
Received: by thd.tv.tek.com (4.1/SMI-4.1(tv.tek.com))
id AA06813; Mon, 7 Jun 93 13:52:14 PDT
Message-Id: <[email protected]>
To: [email protected]
Subject: Re: Substitute for welding rods?
In-Reply-To: Your message of Mon, 07 Jun 93 12:12:07 -0700.
<[email protected]>
Date: Mon, 07 Jun 93 13:52:12 -0700
From: Bill McFadden <[email protected]>
>Coat hangers work, but they rust.
Mine didn't rust, but I had spray painted it.
--
Bill McFadden Tektronix, Inc. P.O. Box 500 MS 58-639 Beaverton, OR 97077
[email protected], ...!tektronix!tv.tv.tek.com!bill Phone: (503) 627-6920
How can I prove I am not crazy to people who are?
From [email protected] Thu Jun 10 13:36:10 1993
Received: from silver.ucs.indiana.edu by dg-rtp.dg.com (5.4.1/dg-rtp-proto)
id AA23979; Thu, 10 Jun 1993 13:36:10 -0400
Message-Id: <[email protected]>
Received: by silver.ucs.indiana.edu
(5.65c+/10jsm) id AA26390; Thu, 10 Jun 1993 12:35:28 -0500
Date: Thu, 10 Jun 1993 12:35:28 -0500
From: david jerome adams <[email protected]>
To: [email protected]
Subject: Crystal mod
Before I do the crystal mod, I noticed from the FAQ that either
a 10pf cap was used or 2 22pf caps in parallel. Is any one setup
superior to the other, or is it a case of whatever is on hand?
Dave
From miller@robin Thu Jun 10 14:17:17 1993
Received: from robin.rtp.dg.com by dg-rtp.dg.com (5.4.1/dg-rtp-proto)
id AA00936; Thu, 10 Jun 1993 14:17:17 -0400
Received: by robin (5.4.2/rtp-s04)
id AA12826; Thu, 10 Jun 1993 14:17:15 -0400
From: [email protected] (Mark T. Miller)
Message-Id: <9306101817.AA12826@robin>
Subject: Re: Crystal mod
To: [email protected] (david jerome adams)
Date: Thu, 10 Jun 93 14:17:15 EDT
Cc: [email protected]
In-Reply-To: <[email protected]>; from "david jerome adams" at Jun 10, 93 12:35 pm
X-Mailer: ELM [version 2.3 PL11]
>
> Before I do the crystal mod, I noticed from the FAQ that either
> a 10pf cap was used or 2 22pf caps in parallel. Is any one setup
> superior to the other, or is it a case of whatever is on hand?
I don't believe on is superior to the other. In fact depending
on the manufacturing and assembly tolerances of your board, you
may not even need the parallel caps! I have one board that
needs 'em and one that doesn't. If you try it without the caps
and the xtal doesn't oscillate, then you need the caps.
Regards,
Mark M.
>
> Dave
>
--
Mark T. Miller [email protected]
...uunet!xyzzy!miller
From [email protected] Sun Jun 13 19:11:25 1993
Received: from raid.dell.com by dg-rtp.dg.com (5.4.1/dg-rtp-proto)
id AA03763; Sun, 13 Jun 1993 19:11:25 -0400
Received: from uudell.dell.com by raid.dell.com (5.67/jrv-1.2i) with SMTP
id AA14555; Sun, 13 Jun 93 23:08:46 GMT
Received: by uudell.dell.com (5.61/smail2.5b)
id AA08456 (for [email protected]); Sun, 13 Jun 93 18:08:48 -0500
Received: by sooner.ctci.com (4.1/SMI-4.1)
id AA25135; Sun, 13 Jun 93 18:01:23 CDT
From: [email protected] (Dewey Coffman)
Message-Id: <[email protected]>
Subject: Rainbow Kits?
To: [email protected] (fm-10 Mailing list)
Date: Sun, 13 Jun 93 18:01:21 CDT
Reply-To: [email protected]
X-Mailer: ELM [version 2.3 PL11]
Hello world.
I'm new to list and have yet to purchase a FM-10 kit. I noticed
that there is company that advertises in Radio Electronics a FM
Stereo transmitter for $29.95 with a optional $8.95 metal enclosure.
Has anyone bought this? It's sounds like the Ramsey kit being
resold. Part # is FMST-100
Electronic Rainbow
6254 LaPas Trail
Indiannapolis, In 46268
1-317-291-7262
--
Dewey Coffman [email protected] [email protected]
CTC, Texas Inc. All opinions expressed are unrelated to reality.
"If you fail to plan, plan to fail" "One Dollar, One Vote"
"A fart is the cry of an imprisoned turd." [email protected](Murray Chapman)
From [email protected] Mon Jun 14 15:04:58 1993
Received: from nntp.crl.com by dg-rtp.dg.com (5.4.1/dg-rtp-proto)
id AA02096; Mon, 14 Jun 1993 15:04:58 -0400
Received: from acsys.UUCP by nntp.crl.com with UUCP id AA14800
(5.65c/IDA-1.5 for [email protected]); Mon, 14 Jun 1993 12:05:37 -0700
Received: by NetAcsys.com (UUPC/extended 1.11v);
Mon, 14 Jun 1993 10:14:27 PDT
Date: Mon, 14 Jun 1993 10:14:26 PDT
From: "Mycal" <[email protected]>
Message-Id: <[email protected]>
Organization: ACSYS, Inc.
To: [email protected]
Subject: check this out
I just got a package from Ramsey electronics. It contained a shirt, base
ball cap, two kits, and bucks for the info packet. Seems John Ramsey got a
hold of a old version of my FAQ. Seems he liked some of the modifications
and would like to incorporate some of them in the FM-10 kit. Pritty cool,
eh.
If someone would like to forward this to alt.radio.pirate, that would be
cool. Seems all my posts there have been going to /dev/null. I don't
know if its technical problems or if someone doesn't like me, but all my
posts to "alt" groups die when they hit the internet. Local and one hop
up there fine.
thanx,
mycal
--
---------------------------------------------------------------------------
PGP key on request. [email protected]
\ //
"..unfortunately we can't control the actions // \
of everyone." President Clinton 04/20/93 No Risk, No Rush
From [email protected] Mon Jun 14 15:24:41 1993
Received: from ES.COM by dg-rtp.dg.com (5.4.1/dg-rtp-proto)
id AA04581; Mon, 14 Jun 1993 15:24:41 -0400
Received: from sim.ES.COM ([130.187.170.219]) by orca.es.com (4.1/SMI-4.1)
id AA20402; Mon, 14 Jun 93 13:24:36 MDT
Received: by sim.ES.COM (4.1/esunix-ver1.7/SMI-4.1/esunix)
id AA24743; Mon, 14 Jun 93 13:16:53 MDT
From: [email protected] (Clint Dimick)
Message-Id: <[email protected]>
Subject: FWD'd list msg.
To: [email protected]
Date: Mon, 14 Jun 1993 13:16:53 -0600 (MDT)
X-Mailer: ELM [version 2.4 PL21]
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Content-Length: 145
Mycal,
Glad to see you ARE out there! I'll go ahead and post your pirate-mailing-
list msg. is someone else doesn't jump the gun.
- Clint
From [email protected] Mon Jun 14 19:32:31 1993
Received: from thor.INS.CWRU.Edu by dg-rtp.dg.com (5.4.1/dg-rtp-proto)
id AA12324; Mon, 14 Jun 1993 19:32:31 -0400
Received: by thor.INS.CWRU.Edu (5.65b+ida+/CWRU-1.5.3-freenet)
id AA01302; Mon, 14 Jun 93 19:32:27 -0400 (from dxk10 for [email protected])
Message-Id: <[email protected]>
Date: Mon, 14 Jun 93 19:32:27 -0400
From: [email protected] (David Kazdan Md)
To: [email protected]
Subject: Re: Rainbow Kits?
Reply-To: [email protected] (David Kazdan Md)
>
>
> Hello world.
> I'm new to list and have yet to purchase a FM-10 kit. I noticed
> that there is company that advertises in Radio Electronics a FM
> Stereo transmitter for $29.95 with a optional $8.95 metal enclosure.
>
> Has anyone bought this? It's sounds like the Ramsey kit being
> resold. Part # is FMST-100
>
> Electronic Rainbow
> 6254 LaPas Trail
> Indiannapolis, In 46268
> 1-317-291-7262
>--
>Dewey Coffman [email protected] [email protected]
>CTC, Texas Inc. All opinions expressed are unrelated to reality.
>"If you fail to plan, plan to fail" "One Dollar, One Vote"
>"A fart is the cry of an imprisoned turd." [email protected](Murray Chapman)
>
>
I bought one of these at the Dayton Hamvention. It's not the Ramsey kit;
it has the 38 KHz crystal included, has input levels, and a nice PC-board
layout. All of these kits are hard to get on frequency, though. I am not
sure what is wrong with mine--it puts out a good right-side channel but not
left. Probably one bad part in the audio chain.
Personally, I recommend this kit or the D-C electronics one.
--David
--
David Kazdan, M.D., Ph.D [email protected]
Department of Anesthesiology, University Hospitals of Cleveland, Ohio
Amateur Radio: AD8Y
From dbrillha@dave.mis.semi.harris.com Mon Jun 14 20:27:23 1993
Received: from dave.mis.semi.harris.com by dg-rtp.dg.com (5.4.1/dg-rtp-proto)
id AA29401; Mon, 14 Jun 1993 20:27:23 -0400
Received: by dave.mis.semi.harris.com (5.65/DEC-Ultrix/4.3)
id AA08114; Mon, 14 Jun 1993 20:26:59 -0400
From: dbrillha@dave.mis.semi.harris.com (Dave Brillhart)
Message-Id: <9306150026.AA08114@dave.mis.semi.harris.com>
Subject: Audio Front-End for FM-10
To: [email protected]
Date: Mon, 14 Jun 93 20:26:58 EDT
X-Mailer: ELM [version 2.3 PL11]
I need a simple (read: cheap) circuit that will take a range of audio
signal levels and adjust them to a particular level. The caveat is
that it needs to *somewhat* preserve the dynamic range of music.
The application is:
I built an FM stereo transmitter (FM-10). It takes "line-level"
signals and broadcasts them (around the house). The problem is that if
the volume is too loud, the signal distorts. Also if I attach a mike,
I need to shout into it to be heard.
Is a circuit possible that does not destroy the sound quality of say
classical music which depends on long "soft" passages followed by
sudden loud passages. I would guess the circuit would need some type
of hysteresis so that as long as the "RMS" of the signal was centered,
the dynamics would not be smushed???
Thanks to all you audio design experts out there!!
-- Dave
From [email protected] Tue Jun 15 04:19:15 1993
Received: from lirmm.lirmm.fr by dg-rtp.dg.com (5.4.1/dg-rtp-proto)
id AA01533; Tue, 15 Jun 1993 04:19:15 -0400
Received: from roseau (roseau.lirmm.fr) by lirmm.lirmm.fr, Tue, 15 Jun 1993 10:24:33 +0200
Received: from localhost by roseau, Tue, 15 Jun 93 10:21:50 +0200
Message-Id: <9306150821.AA05826@roseau>
To: [email protected]
Subject: add [email protected]
Date: Tue, 15 Jun 93 10:21:48 +0200
From: Michel Jacquot <[email protected]>
add [email protected]
Thanks,
Michel
Note : Au fait, le telephone a change, 41 au lieu de 14.
-----------------------------------
Michel Jacquot [email protected]
LIRMM
161 rue ADA
34392 Montpellier Cedex 5 FRANCE
Tel (33) 67 41 85 94
Fax (33) 67 41 85 00
-----------------------------------
From [email protected] Fri Jun 25 18:33:43 1993
Received: from nntp.crl.com by dg-rtp.dg.com (5.4.1/dg-rtp-proto)
id AA26569; Fri, 25 Jun 1993 18:33:43 -0400
Received: from acsys.UUCP by nntp.crl.com with UUCP id AA27556
(5.65c/IDA-1.5 for [email protected]); Fri, 25 Jun 1993 15:33:17 -0700
Received: by NetAcsys.com (UUPC/extended 1.11v);
Fri, 25 Jun 1993 12:14:13 PDT
Date: Fri, 25 Jun 1993 12:14:09 PDT
From: "mycal's fc email account" <[email protected]>
Message-Id: <[email protected]>
Organization: FutureIsNow
To: [email protected]
Subject: Version 8 or FAQ
Ok, version 8 is here. Not much has changed, but some of the spelling and
grammer has changed. Note also that the info packets have gone up in price.
This reflects the increase in information contained.
Please post this to alt.radio.pirate, since we still haven't sorted out
our posting to 'alt.' group problem yet.
thanx,
mycal
----cut----
Ramsey FM-10 Info
by
[email protected]
8th Edition
-----------
Here is a rough compilation of information about the Ramsey FM-10, and
other BA1404 Stereo FM broadcasters. Some of the modifications may make
your BA1404 based broadcaster illegal to use on the open airwaves in the
US and Canada. Also it has been brought up that the stock Ramsey FM-10
kit may exceed FCC power limits when used with a proper antenna.
The information contained in the file is in no way complete, nor do I
take any responsibility for its accuracy. With that in mind, along
with the above paragraph I must say :
"This file for informational purposes only."
About This File
---------------
When I first started hacking on my FM-10, a few of us on alt.radio.pirate
were exchanging information on mods to improve the range, stability and
audio quality of the FM-10. After a couple of posts about filters and
amps, my mailbox was swamped with requests for copies of previously posted
information and other questions about the FM-10. So rather than drive
myself crazy with sending a piece of info here and there, I decided to
dig through my mailbox an notes and compile this file. I hope it helps.
Also if anyone has more information about the FM-10 or FM transmitters,
antennas, mixing equipment, programming information, stories about pirates,
or anything else that falls into this realm, please send it to
[email protected]. I will try to update this file as new information
becomes available.
Also I am working on a some Postscript files that will contain instructions
on how to build some equipment that is to complex for ASCII art. You
might want to check the FTPable archives every month or so.
I would like to say thanx to all the people that contributed to the
information in this file. The list has grown quite long, and some
of the contributors would like to remain anonymous. So for now I am
going to forgo all the names, if this is not up to your liking please
let me know.
FM-10 Mailing List
------------------
First Things First. There is now a mailing list that deals with the topic
of the Ramsey FM-10 and other BA1404 based FM Stereo Transmitters. Feel
free to join up and contribute.
To send a message to the mailing list, send your question, reply, comment,
or contribution to :
[email protected]
To add or delete yourself from the list, send a short message with
the function (add/delete/change address) along with the relevant e-mail
address to:
[email protected]
If you have any questions I can be reached at [email protected].
FM-10 Archives
--------------
Yes it is finally here, message archives of the FM10 mailing list and a
place to put/find schematics, reviews, stories, etc. related to the FM-10
and other BA1404 based FM transmitters. Currently a 350mw amp plan and
the BA1404 spec sheet are located there.
People can FTP into dg-rtp.dg.com with user "anonymous" and password
"<your EMail address>". In the fm10 directory you'll currently
find two sub-directories:
incoming
This is writable by everyone and this is where people should
upload new stuff.
msg-archives
This directory will have files named according to the date they
were last "sealed". The file "Current" is a running log of
all EMail messages from the last "seal" date of the archives.
I want to thank Ed Savage and the guys at Data General, NC for
making the list and the archive possible.
Snail Mail Info Packet (or Pirates Guide to FM Stereo)
------------------------------------------------------
The info packet has evolved yet again, it is now 24 pages. It includes
plans for 4 amps, a 200mw, 350mw, 800mw, and 5watt. Instructions for
modifying the Ramsey PA-1 for FM broadcast band operation. A section
on how to design and build your own antenna. Plans for a power meter,
regulated power supply, and dummy load. A block diagram showing a
typical station. Spec sheet for the BA1404. FM-10 modifications.
Sources for parts and info. And a more up to date design of my digitally
synthesized transmitter. Loaded with schematics, board-layouts and diagrams.
The price for this packet is $4 in the US and $7 overseas.
Address to send the $$ to is:
mycal
PO Box 750381
Petaluma, CA 94975-0381
You can also use this address to send me any info that would be hard
to send by email. I will trade info packets for hard copy information,
email me for details.
Note : this packet is in a constant state of change, more info could be
added at any time.
Other Places to Look
--------------------
alt.radio.pirate is another good forum to find or post information on FM
radio transmitter. Although you may not have pirate aspirations, many of
the things talked about can benefit everyone.
Other places to scan, sci.electronics and the amateur radio groups.
Recommended Test Equipment
--------------------------
An SWR/Power meter is a giant help, a CB to 2 meter one will suffice.
Power readings will not be accurate, but can be useful for peaking.
The most important part is the SWR meter, this is very important when
making an antenna.
A note on power meters. I recommeded the above power meters because they
are inexpensive and most people that are interested in hacking a FM-10
have very limited funds. These are by no means accurate, but they will
give you some idea what is going on. If you can spend the money you
can get an accurate power meter that is designed for this band, but the
cost is 10-15 times more.
A 50ohm non inductive load is also very helpful, for low power applications
a 50ohm 1/4 or 1/2 watt carbon resistor works well. This can be used to
tune up your kit and amp without interfearing with anyone. Also note that
you can run as much power you want, legally, as long is it doesn't radiate.
A VOM is also very helpful. I would put out the extra bucks and
buy one with a freq counter (if you shop around, about $60-$70). Buy
the one that covers audio to 20MHz(or more). If you are serious about
electronics you need one of these!
Dummy load
----------
Dummy loads are great for testing, without radiating a signal. In fact
you can run as much power as you want into one of these things legally!
Basically you want to create a non-inductive 50-ohm load. This can be
done with regular carbon resistors, or by buying pre built Amateur or
CB radio loads. For low power ( <.5 watt ) an ethernet terminator works
well (check temp when using if it gets very hot lower input power, if it
is still cool you may be able to go up to .75 watt.)
Most CB loads use a 2-watt carbon 50-ohm resistor.
You can build your own, as wimpy or as studly as you want by running
resistors in parallel to create 50-ohms. ie, 2 100 ohm 1/4 watt resistors
will create a 1/2 watt 50 ohm load...
Do not use 50 ohm wire wound resistors, they are not 50 ohms at radio
frequencies.
-----
---------\ Sample Dummy Load where -****- = 50 ohm
---|--****-- / mounted in UHF connector. carbon
--------- resistor
-----
Ramsey's Address
----------------
If your looking to purchase a FM-10 kit and can't find one locally try :
Ramsey Electronics, Inc.
793 Canning Parkway
Victor, New York 14564
Phone (716) 924-4560
FAX (716) 924-4555
Ramsey FM-10 70mw output amplifier
----------------------------------
Provides almost 9db gain to bring the output power of the Ramsey FM-10 Stereo
transmitter from 8mw to 70mw. Not the best design, but all parts can be
found at Radio Shack! Much better designs are available at the archive
site.
+12v
|
/
\ R1 *220 ohms(1/2 watt)
/
\
R2 9k | C2
-/\/\/\/-----------||-----> output
| /
| /
| | /
C1 | |/ <----------MPS2222A (276-2009)
in --||------|\ -or- 2N4401
^ | -> --
| |
| GND
currently on board
* you can also use 2 440 ohm 1/4 watt resistors run in parallel
I built this thing right on the underside of the FM-10 kit, C1 is the
cap that currently goes to the RCA ant jack, the 9k and the 220 ohm
resistor have to be bought, note that if you cannot find 220 ohms you
can make one by using 2 440 ohm resistors in parallel, and that a 10k
will work in place of the 9k but yields poorer performance (-5%).
The MPS2222A is from Radio Shack part number 276-2009, use this part! if
you substitute it for a 2N2222A you will get only half the gain. Be
very careful to get the leads in the correct orientation!
I have found that a 2N4401 can be used in place of the MPS2222A with a
little better performance, about 5mw more. I think the 2N4401 can be
found at Radio Shack too.
C2 is of the same value of C1, I took the one that goes to the on board
antenna pad.
Important! the value for R1 that seems to be optimal is 220 ohms, but it
is very close to the sat point, If the amp. seems noisy (interferes with the
TV etc.) back this value off to 240 ohms. If you lower this value below 205
ohms the power meter may read higher power but this will not be true, the
transistor will be spewing all kinds of junk and the power meter will
mistake this for higher output (in reality the signal we want will drop
considerably.)
Well that's it, effective range with a good antenna should be a little
over double.
Ramsey PA-1 2-meter to 3-meter conversion mod
---------------------------------------------
The Ramsey 2-meter amp (PA-1) can be converted for use on the FM broadcast
band. The inductors L1 and L2 need to be changed to the following:
L1 - Should be replaced with a 1-turn 1/4" diameter coil, Identical to
the stock L2 shown in the PA-1 manual.
L2 - Should be replaced with a 2 turn 1/4" diameter coil, one more turn
than the above coil.
Tune up should be the same as in the PA-1 Manual. Note that a FM-10 kit
cannot be used to drive a PA-1 kit alone. The FM-10 kit doesn't put out
enough power to turn on the PA-1 kit running class-c. So you have two
options. One, you can do the "biased on" (newer kits may call this class-b)
modification shown in the PA-1 manual. Doing this you can drive the PA-1
with a stock FM-10, yielding about 200-300mw of output power. Or two, you
can drive the PA-1 with the output of the 70mw amp shown above and get close
to a watt of output power.
It should be noted here that running the PA-1 "biased on" (or class-b)
produces a much cleaner output signal than running the PA-1 class-c. Also
that you can run the PA-1 "biased on" while driving it with the 70mw amp,
but you will show slightly less gain than in class-c.
ANTENNAS -- read, read, read, read, most important!
--------
Also Do you have a good antenna? I think that is the most important
thing that you can do for extended range. I built a 1/4 wave ground plane
using a UHF connector and 5 lengths of copper plated brazing rod (found at
the local welding shop). Works great and only cost $3 dollars to make.
Remember good antenna will improve you range much further than a good amp
into a bad antenna. So this should be your 1st project to increase your
range.
use the formulas out of your FM-10 manual 234/freq=length of rod.
Example : 234/88Mhz = 2.66 feet * 12 in/feet = 31.9" -or-
234/108Mhz= 2.17 feet * 12 in/feet = 26"
insert the 4 ground plane rods in the 4 holes of the UHF connector, stick
them through about 1/4 inch and solder. Solder the radiator in the top
of the UHF connector (you may have to grind it a bit to fit.) Then bend
the ground plane rods to a 45 degree angle to the radiator. There you
have it a very effective antenna, just connect with a 50 ohm CB cable
to your amplified Ramsey, stick the antenna in a tree or in another high
place and you should have 1 miles of solid coverage (when using the
above amp.).
Also If you have an SWR meter you can cut the rods a little longer and start
clipping the ends off a little until you get the best SWR reading.
|
| | | = brazing rod
| | |
| |
----- ----- ----- = UHF connector
| - | / - \ -
| | / \
| | / \
The final antenna should look like this:
| ^
| |
// \\ sky ground --horizon--
|
v
That is 1 radiator pointing strait up and 4 ground plane
radials. (sorry for this extreme description, but there
has been some confusion.)
Be careful when you bend the brazing rod, don't break the connector. Grab
the rod right below the connector with a pair of vice-grips (or the likes)
and bend the brazing rod at that point.
Try not to have anything metal near the radiator, this will effect
the radiation pattern. The radiation pattern should look a lot like
a doughnut surrounding the radiator, though deformed a bit.
I have been told that you can shorten the radiator and make the ground
radials longer to lower your radiation angle, but I haven't tried this, nor
do I know what this would do to the antenna impedance.
On The Road
-----------
Old magnet mount CB antennas can make great mobile antennas, just take all
of the base load out of them and cut the radiator to 1/4 wave length.
If you need a longer radiator than the one that comes with the antenna
use the above mentioned brazing rod.
I've tried this antenna and it works great! It is better than my di-pole at
home and you can drive to a high, optimal location for your broadcasts (and
you can see the vans coming for miles ;'). Also with this setup you need
very little coax cable. Line loss using RU-58u can be killer @ 100MHz.
You could also try a 5/8 wave length antenna, this would give you 2+db gain,
or almost 2x power gain on transmit.
Filter design for FM Radio Transmitters.
----------------------------------------
It is very important to have a clean signal, the way 99% of all people
who get busted for illegal transmitting is that the people that live
around them complain about interference. Most of this interference
is caused by harmonics. Filters cut down these nasties. So don't
draw attention to yourself, keep everyone happy, including yourself,
be clean, use a filter.
When you amplify a signal, you get unwanted byproducts these are called
harmonics. The show up at multiples of your starting frequency. For
example if you amplify a 50MHz signal you may get echo's on 100MHz, 150MHz
200MHz, 250MHz... If you interfear with your neighbors TV, the local fire
department, or anyone else, you are just asking for trouble. If you are only
on the FM Band, you will hardly be noticed.
...
Filter Designs
--------------
(basically scaled from the charts in the ARRL handbook).
Filter Design: 7 element Chebyshev
I run @ 88.1 so my 1st harmonic is 176.2
This filter seems ideal.
Fc 3db 20db 40db
85.8MHz 95.9MHz 116MHz 148MHz
.132uh .150uh .132uh
-----()()()-----()()()-----()()()-----
| | | |
<-50ohm - 33pF - 68pF - 68pF - 33pF 50ohm->
- - - -
| | | |
--------------------------------------
|
---
-
lowering the 33pF caps to 30pF and the 68pF caps to 62pF would make
this filter sutible for higher frequencies like 100MHz.
Filter Design: 5 element Chebyshev
Not as good as above, but thrown in anyway.
Fc 3db 20db 40db
81.8MHz 105MHz 147MHz 222MHz
.128uh .128uh
-----()()()-----()()()-----
| | |
<-50ohm - 30pF - 62pF - 30pF 50ohm->
- - -
| | |
---------------------------
|
---
-
The tuff part in the above is winding the coils. 3t of #12 wire 1/2" diam
should be about .12 uh. 4t is .17 uh. (but ugh, #12 wire is big stuff).
You could just use molded inductors, I have found these work well. Try
to use fixed value caps, or fixed value with small 5pF trimmers. The
latter works well when you have a spectrum analizer to tune there babies.
I just pulled a program of a BBS that tells you how to wind inductors.
Give it the value and wire size you have and it will tell you how many turns
and what size. Way cool. More on this later.
Very simple Chebyshev filter.
------------------------------
.15uH
from FM10 >------()()()------> to antenna
| |
- c1 - c2
- -
| |
--- ---
- -
88MHz 102MHz 107MHz
c1 62pF 54pF 50pF
c2 62pF 54pF 50pF
It won't knock the harmonics down as much as the other two designs but
the good thing about this one is that it uses standard off the shelf
parts. The inductor is one of those molded jobbies that looks like
a resistor so you can make this very small. You may stack these things
to make a better filter. Each stage will knock the 1st harmonic down
about 15db.
Use the above cap values depending on which freq range you want to operate
at. ie. if you run 87-90 use the 88MHz vals, 90-103 use 102MHz vals,
and above that use 107MHz vals.
Try to use fixed value parts!
[Also of interest is that the FM-10 puts out about 8-9mw and the 2nd harmonic
is -25db off the fundamental (frequency we are broadcasting on). The FM-4
Kit by Ramsey puts out 130mw and the 2nd harmonic is only -12db off the
fundamental, which means the 2nd harmonic of the FM-4 is about as
powerful as the FM-10. db is log10, ie 3db is 2 times 6db is 4 times...]
FM-10 Myths
-----------
There have been several myths about the FM-10 kit, the most prevalent are :
1) The FM-10 puts out 100mw of power. This is not true, or at least not
true for the Ramsey FM-10's that I have tested. They put out between
8 and 12mw when driven with a 12volt supply. (note: there has been several
revisions of the FM-10, it is possible that the original version put out
more power, but I find even that highly unlikely since it would require
another amplifier stage.) Also the FM-10 is the only low cost kit, that
I have seen, with an amplifier stage. Most others have power outputs
in the fraction of a mw area.
2) The FM-10's output can be cranked up by reducing the value of R9. This
like the above is not true. R9 and R10 are optimized for maximum output
and greatest harmonic suppression at 12volts. There are much better ways
of getting more output power than to mess with this output stage. Lowering
the value of R9 will most likely degrade the FM-10's performance and cause
lots of interference.
=============================================================================
FM-10 Improvements -
--------------------
(Some from ACE magazine.)
Stereo Pilot Mod
----------------
One of the first problems experienced with the FM-10 is difficulty
in getting the stereo pilot to operate correctly. One solution is to
replace C7 and C8 with a 38KHz crystal, this works the best and is
recommended. If you cannot find a 38KHz crystal, you can make your life
a whole lot easier with a couple part changes. As indicated on the
Ramsey schematic, about 110pF is necessary to tune the oscillator. The
components supplied to achieve this are a small fixed value capacitor (C7)
and a slightly larger value trimmer (C8). Since proper setting of the
trimmer occurs within a very small 'window' (about 5% of the trimmers
range), it can bet difficult or impossible to adjust the pilot to 19KHz
and have it stay put. This can be cured by increasing the value of c7 to
100pF and replacing c8 with a 6-50pF trimmer (Radio Shack #272-1340);
a 5-30pF trimmer will do the trick. The RS trimmer will not fit the holes
in the pc board; one needs to cut the leads off a spare resistor and
solder them to the legs of the trimmer (just use bits of wire) to mount
it on the component side of the board.
On a 2nd note: I replaced c7 with a 68pF cap and found it much easyer to
tune a rock solid 19KHz at the test point.
Crystal Mod
-----------
old set up new setup
c8 c1 xtl where c1=10pF and xtl=38KHz
|-||-| |-||-|\|-|
| c7 | | | v8=var cap
|-||-| | | c7=cap
| | | |
Remove C7 and C8, replace with 38KHz crystal and 10pF cap. Note that
the 10pF cap and the crystal are running series and the old cap setup
is running in parallel.
Note: there have been good and bad reports on using the Epson crystal
from digi-key. From what I have heard the crystal is quite delicate,
and in at least one case the experimenter destroyed the crystal.
In one of the positive case C1's 10pF cap was replaced by 2 22pF caps
run in parallel, this yielded a rock solid stereo.
Treble Boost Mod
----------------
Treble boost (pre-emphasis) improvement. The FM-10 appears to have
been designed by someone outside the United States since it operates
at the European audio standard of 50 microseconds. Receivers in the
US are set up for 75 microsecond de-emphasis. R3 and R6 determine the
time constant for the pre-emphasis curve. Replacing them with 75K ohm
resistors (standard value 68K ohm is close enough) will result in
improved audio response.
A much better pre-emphasis/input circuit is shown in the July 1992 issue
of "Radio Electronics". Not only do they use 75K ohm resisters in there
pre-emphasis, but they filter stray RF signals by inserting a .001 cap
between pin 1 (of the BA1404) and ground, and pin 18 and ground.
It has been noted that the above mod may actually cause distortion on
cheaper stereo receivers, since they were mass produced for the world market,
they were designed for the European audio standard, which Japan and other
Asian nations use too. Try it out, let me know what works for you.
Anti-Drift Mod
--------------
There has been quite a bit of discussion on the FM-10's frequency stability.
Complaints that digital receivers cannot lock onto the FM-10's signal for
any great length of time. I have used the below mod with good results
(I used an N750 negative temperature compensated disc), but I have been
told that Mylar or Polystyrene caps are even better.
The FM-10 was designed to be inexpensive and cost-saving measures with
components are inevitable. Disc ceramic capacitors are less expensive than
silver-mica caps, and also much less stable. Simply replace c16 with a
silver-mica, tantalum or negative temperature compensated disc (say anywhere
from N150 to N750) cap of the same value.
============================================================================
Sources
-------
The following is a list of sources for items used for modifications,
replacement parts, or other kits and equipment used in FM radio
transmitting:
--
BA1404s and other FM Broadcaster kits can be found at :
D.C. Electronics
phone: 1-800-467-7736 & 1-800-423-0070
fax:1-602-994-1707
They sell BA1404s for $2 a piece, seems to be the best deal going.
Also they Sell 38KHz crystals for $5.99, which is also a fair deal, the
crystals are tiny ones like the digi-key ones, but a different brand and
work without problems or the Digi-Key ones.
--
--
38KHz Crystals can be obtained by calling :
Digi-Key at 1-800-DIGI-KEY.
38.000 KHz by Epson America, Digi-Key part No. is SE3314
(see notes on crystal mod on using this crystal, also note that
this is a cylinder type crystal and kinda delicate. you are probably
better off getting the 38KHz crystals from D.C. Electronics.)
--
--
Panaxis Productions makes some very high quality FM transmitters. The
last word in Transmitting, tons of kits.
Panaxis Productions
PO Box 130 (right next to my old place of study
Paradise, CA 95967-0130. Chico State! )
(916)534-0417
Catalogs are $2, well worth it, a must have item.
A little taste of there catalog :
MMC1 Macromod Compander for 2:1 compression
Plans $12, PCB $18, P+P 26.50, Full kit $87
SG High performance stereo generator
Plans $15, PCB $13.5, P+P 26.50, Full kit $105
FME PLL FM exciter
Plans $17.5, PCB $15, P+P 24.50, Full kit $129
More expensive than a FM-10 but much higher performance.
--
--
A company called Progressive Concepts sells plans for a 88MHz to 108MHz
amp. The power curves show that 12mw in will yield 2.5 watts, but can
be driven harder for up to 12 watts.
Plans only in U.S., $16 (a bit spendy, ouch!)
Progressive Concepts
1313 N. Grand Ave. #291
Walnut, CA. 91789
--
--
If your looking to purchase a FM-10 kit (or a PA-1 kit) and can't find one
locally try :
Ramsey Electronics, Inc.
793 Canning Parkway
Victor, New York 14564
Phone (716) 924-4560
FAX (716) 924-4555
Should be $29
--
--
The makers of the infamous BA1404 :
Rohm Corporation
Rohm Electronics Division
3034 Owen DR
Jackson Business Park
Antioch, TN 37013
PH: (615)-641-2020 (ask for someone who deals with the BA1404)
FAX: (615)-641-2022
Also they have:
PO Box 1399
Antioch, TN 37011-1399
=============================================================================
--
============== ==============
============== Other Raw Info ==============
============== ==============
the 2SC2570 is supposedly replaceable with an ECG10. Also I have used
an MRF901 for a replacement, though tough to mount, try bottom of the
pc board and connecting the whip antenna pad to ground plane. MPS901s
seem to replace the 2SC2570 directly, same case too, check the pinouts
though. I have also been told that MPS918s work well also.
The MRF239 can be used as direct replacement for the Ramsey 2 meter PA-1
kit. Cost is around $14 bucks.
Newark also has the 38KHz crystals for $2.90 ( I don't know Newark's address,
this was sent to me in the mail, will try to find it though.)
------------------cut-----------------
Once more If you have any info, I stress "ANY", about this subject please
drop me a byte or two.
have fun,
[email protected]
my public key is as follows:
-----BEGIN PGP MESSAGE-----
Version: 2.1
owEBmABn/4kAlQIFACsiwof0ygCBjeci2QEB3XkEALLCAgpRyo9jEfq6TmyNr3q/
13k6+OEBEMWh70HzS6cyTXyD2EpUWlNLIndQN9fDNC5HZq8YgES2vrxpiZBiLiv4
ZaqFE1REtDvAHO0owW75mcZW0dczngzI2tzqaANL/05DrWezeMLGGRLzeQNeaaK0
VSxyQYX0xE736qRo3SEh
=J2FX
-----END PGP MESSAGE-----
From [email protected] Tue Jun 29 16:27:17 1993
Received: from gw.PacBell.COM by dg-rtp.dg.com (5.4.1/dg-rtp-proto)
id AA14090; Tue, 29 Jun 1993 16:27:17 -0400
Received: from pacbell.UUCP by gw.PacBell.COM (4.1/PacBell-06/23/93)
id AA05625; Tue, 29 Jun 93 13:27:14 PDT
Received: by boo.uucp (/\==/\ Smail3.1.25.1 #25.17)
id <[email protected]>; Tue, 29 Jun 93 13:13 PDT
Received: by drc.UUCP (1.65/waf)
via UUCP; Tue, 29 Jun 93 13:12:33 PDT
for [email protected]
To: [email protected]
Subject: Newbie... And I have a feq questions...
From: [email protected] (SiD ViCioUs)
Message-Id: <[email protected]>
Date: Tue, 29 Jun 93 13:02:15 PDT
Organization: BLa Bla Bla Bla Bla BLa BLa Concord,Ca
Sorry.. Im a newbie. And I have no clue..
Aprox. how much dose the FM-10 cost? Plans and parts..
Am I mistaken or is the FM-10 (Without mods) transmit with 8mw of power?
What would be a avrage distance that 8mw trasmit with fair clairity(sp?)?
I'm intrested in legal transmision with transmiting far as I can..
-SiD
\|///
|O O|
___________nnn|_^_|nnn____________________________________________________
| [email protected] || "Cool Hu Hu Hu Uh Hu Hu" |
| sid%[email protected] || Butt-Head (Beavis and Butt-Head) |
| root%[email protected] || |
|
|
