Sirius listening on vintage radio

[Dan Starnes]

I love my sirius radio, drive tons of miles a year. Mostly listen to old radio shows and the Sinatra channel. I have a home kit which is attached to my bose. I dont have any FM radios of vintage and would love to listen on my 47 Emerson or my 31 Crosley Playboy. Anyone done anything like this? I was thinking of finding an old fm converter like I used to use back in the 70's and 80's on old cars.

[jr_tech]

Why not build a simple Ramsey kit AM transmitter:
http://www.ramseyelectronics.com/hk/
Or a vacuum tube model such as the one described by Phil N :
http://www.antiqueradio.org/transmitter.htm
There are even some AM stereo kits that might be still available (Chris Cuff sold the Alfredo "lite" transmitter on his AM stereo site, but I am not sure it is still active):
http://mysite.verizon.net/tekel/amstereo/ccuff.htm

jr

[fifties]

This is what I use;

http://sales.talkinghouse.com/shop/item.asp?itemid=71

And it works bitchen! It has a digital readout and it's transmit freq can easily be changed all over the AM dial. The transmit range is about 75 feet or so.

I set it up so that it's input connects to my stereo receiver, which receives both wireless from my Sirius Starmate, and wired from my desktop, for internet oldies stations. I can walk around my house or yard with one of my many portable tube or transistor radios, listening to oldies, or with an AA5 in another room.

The big advantage is that it's professionally made, and there is no drift. The transmitter actually calibrates itself every once in awhile, to stay on the frequency it's set to.

[dano]

I've done something like this before too, only for me I have some old time radio shows on tape. Because I have collected some old test equipment over the years, one thing I did was use my signal generator as a transmitter:

http://www.antiqueradio.org/eico01.htm

Also, I tend to like radios with phono inputs for just this type of thing (or connecting my old record players).

[fifties]

You can connect any analog audio source to any AM radio receiver, tube or transistor, by simply attaching the hot lead from the source to the center wiper contact of the receiver's volume control, and running a lead between the grounds of both sets.

For line-powered tube radios, an electrolytic cap between the source hot lead and the receiver's volume control would be a good precaution, if the source is also line-powered.

I have used this method as a quick and dirty way to check the audio stages of mal-functioning receivers as well, to isolate the problem between the RF/IF and audio stages.

[bandersen]

I've been considering the SSTRAN low power AM transmitter kit: http://www.sstran.com/

[radiotvnut]

I've also been considering the SSTRAN. I've read some nice things about it and maybe I'll get my priorities (and $) in line and order one.

My ultimate goal would be to create a vintage looking radio broadcast studio, using ex-radio station equipment, to drive the transmitter. The only problem is space limitations and the fact that radio station equipment can get expensive. I do have a couple of old radio station turntables; but, still need a mixing board, cart machines, etc.

[Dan Starnes]

Originally Posted by fifties

This is what I use;

http://sales.talkinghouse.com/shop/item.asp?itemid=71

And it works bitchen! It has a digital readout and it's transmit freq can easily be changed all over the AM dial. The transmit range is about 75 feet or so.

I set it up so that it's input connects to my stereo receiver, which receives both wireless from my Sirius Starmate, and wired from my desktop, for internet oldies stations. I can walk around my house or yard with one of my many portable tube or transistor radios, listening to oldies, or with an AA5 in another room.

The big advantage is that it's professionally made, and there is no drift. The transmitter actually calibrates itself every once in awhile, to stay on the frequency it's set to.

I got the one above for Christmas to myself. I need to figure out how I am going to make it all work. I play my starmate sirius thru a bose wave radio which is direct plug in. But looks like a real nice setup. Thanks for the heads up!

[fifties]

Originally Posted by Dan Starnes

I got the one above for Christmas to myself. I need to figure out how I am going to make it all work. I play my starmate sirius thru a bose wave radio which is direct plug in. But looks like a real nice setup. Thanks for the heads up!

Easy as pie;

if the Wave Radio doesn't have a "line out", simply make one by running leads from each of the two speaker lugs (from one speaker if it uses multiple) to an audio mono jack that you would mount on the back panel, then run a double mono plug cable between that and the line input of the transmitter.

This setup is strictly mono, BTW; but of course for AM radio ya don't need anything beyond that.

[darklife]

I wouldn't recommend the talking house transmitter since it's audio quality is poor and the frequency seems to wobble with modulation causing annoying heterodyning with any other station on the same frequency.

The sstran seems to get a good thumbs up from most people I know over at part15.us. The ramsey AM1C cost around 30$ but it works on a VFO oscillator so it will drift a bit until warmed up. The AM25 for around 100$ uses a PLL so it won't drift and it's audio is decent.

Very few of these kits modulate at 100% but still will give you good results. With a 10 foot wire antenna and no aerial grounding you can theoretically broadcast up to 1/4 mile under good conditions legally without the need for a license. However you should review the Part 15 rules to make sure you are within specifications. The general rule is 100milliwatts into the last amplifier stage with no longer than a 3 meter (10 foot) antenna, which includes length of ground lead.

Check out part15.us for lots of links and reviews on kits and fully built AM transmitters.
If you have a bit of electronics know how it is also very easy to build your own from scratch.
With a legal full length antenna your whole neighborhood could tune in

[fifties]

Originally Posted by darklife

I wouldn't recommend the talking house transmitter since it's audio quality is poor and the frequency seems to wobble with modulation causing annoying heterodyning with any other station on the same frequency.

I wouldn't have recommended it if I had found that to be the case. My experience is as I posted above. Mine is set to 540 Kilocycles, and although on the same freq as a somewhat distant station, provides completely clear reception.

Are you speaking from your own experience with it, or just relaying what you have heard?

[darklife]

Originally Posted by fifties

I wouldn't have recommended it if I had found that to be the case. My experience is as I posted above. Mine is set to 540 Kilocycles, and although on the same freq as a somewhat distant station, provides completely clear reception.

Are you speaking from your own experience with it, or just relaying what you have heard?

This comes from both my experience using it and from hearing others using it for the legitimate talking house sign advertising.
After moving away from the transmitter far enough to hear it start to fade and mix with other stations on the same channel I clearly hear a bit of FM in the signal.
Maybe with the newer models they fixed this?

[fifties]

Originally Posted by darklife

This comes from both my experience using it and from hearing others using it for the legitimate talking house sign advertising.
After moving away from the transmitter far enough to hear it start to fade and mix with other stations on the same channel I clearly hear a bit of FM in the signal.
Maybe with the newer models they fixed this?

After moving far enough away from any AM transmitter the signal will fade, and in some instances heterodyne with one or more stations on the same frequency.

I have never heard, however, of an FM transmission being reproduced on an AM receiver; it's just not possible.

[darklife]

Originally Posted by fifties

After moving far enough away from any AM transmitter the signal will fade, and in some instances heterodyne with one or more stations on the same frequency.

I have never heard, however, of an FM transmission being reproduced on an AM receiver; it's just not possible.

FM stands for frequency modulation remind you. When the modulated audio of the talking house transmitter is excited it tends to drag the frequency of the oscillator with it thus causing FM. I know it's built on PLL circuitry but for some reason it still seems to drift with its own modulation. Though it's only a few tens to hundred hertz it's noticeable enough to cause a wobbling sound in the audio program material when hetrodyning with another locked carrier that is solid on frequency.
I believe this is caused by the lack of good power supply capacitors in the talking house transmitter, or just an inadequate power supply.
When pushing an AM transmitter to it's fullest modulation it causes a large power spike on the positive amplitudes because of the required output power to the RF stages. If a power supply is not used to support this varying power fluctuation it can cause FM to ride the AM signal which is what I have heard numerous times in these transmitters.
I believe in the professional world of AM transmitters they call this undesirable effect "carrier shift".
Most tiny part 15 transmitters tend to be built with underrated power supplies causing this effect.
In reality it won't matter for the average person who wants to just hear audio a few hundred feet away from the transmitter. OTOH if trying to hear their signal outside of the perimeter of the average range they will notice the effect especially at night when the AM dial becomes cluttered with distant stations.
Hope what I am getting at makes more sense now.

[fifties]

Originally Posted by darklife

FM stands for frequency modulation remind you. When the modulated audio of the talking house transmitter is excited it tends to drag the frequency of the oscillator with it thus causing FM. I know it's built on PLL circuitry but for some reason it still seems to drift with its own modulation. Though it's only a few tens to hundred hertz it's noticeable enough to cause a wobbling sound in the audio program material when hetrodyning with another locked carrier that is solid on frequency.
I believe this is caused by the lack of good power supply capacitors in the talking house transmitter, or just an inadequate power supply.
When pushing an AM transmitter to it's fullest modulation it causes a large power spike on the positive amplitudes because of the required output power to the RF stages. If a power supply is not used to support this varying power fluctuation it can cause FM to ride the AM signal which is what I have heard numerous times in these transmitters.
I believe in the professional world of AM transmitters they call this undesirable effect "carrier shift".
Most tiny part 15 transmitters tend to be built with underrated power supplies causing this effect.
In reality it won't matter for the average person who wants to just hear audio a few hundred feet away from the transmitter. OTOH if trying to hear their signal outside of the perimeter of the average range they will notice the effect especially at night when the AM dial becomes cluttered with distant stations.
Hope what I am getting at makes more sense now.

I still don't believe that you can hear an FM station -or any carrier at the FM frequency of 88-108 Megacycles- on an AM radio receiver that -at it's best moment- won't tune above 1.7 Megacycles, and can only reproduce modulation varied by amplitude rather than by a frequency.

Aside from that, however, the unit does what it's supposed to; it provides good usable signal for a distance of about 75 feet or so, using the eight foot wire that comes with it for an antenna.