Wireless re-broadcasters?

[WQ9E]

Anyone have suggestions on a decent one of these so I can provide decent source material for some of my vintage receivers?  I have acquired and restored a number of nice 1930's era receivers but the background crackle from Christmas tree lights is about as compelling as most of the modern programs available.  I have plenty of reel to reel tapes, MP-3 files and the old time radio channel on XM available for use.

I have the schematic and instructions for the Knight Kit unit and I am thinking about building it (except with a power transformer instead of AC/DC) but I am curious what others might be using.

Rodger WQ9E

[K5WLF]

Rodger,

I haven't used any of these, but I've heard good reports about some of Ramsey's other products.

http://tinyurl.com/6kntv

ldb
K5WLF

[DMOD]

I used to have the AM88 and liked it very much for transmitting Christmas music all over the house:

http://www.northcountryradio.com/Kitpages/am88.htm

It will do LF FM and AM up to 75 meters.

DMOD

[k4kyv]

Why not just build up a simple little heising modulated low power AM transmitter.  Something  running a watt or two into a short piece of wire should do the job.  Use xtal control if you can find a suitable xtal for a blank channel, or build a tunable oscillator with an intermediate stage between oscillator and final.

Before I was even licensed as a ham I built several of those out of old broadcast receivers. You probably wouldn't want to destroy a repairable vintage tube type BC set to-day for the purpose, but you could salvage parts from a basket case, or from junk box parts on hand. Some of mine were AC/DC, but my best one used a transformer, and would generate enough rf to burn out a #47 pilot lamp.

I used to fire mine up and re-broadcast another BC station, or put on an LP, and take my little Hitachi AM transistor radio (somewhat of a novelty back then in the late 50s) on my bicycle and see how far I could ride and still pick up the signal. Best DX was about 2 miles. Later I built one for a wannabe DJ, and his was audible for almost 10 miles.  He quit using it when he became afraid a nailing by the FCC. But I mostly used those little transmitters to transmit a signal around the house. I once tried to do a spoof newscast on top of the local radio station that someone had bombed the bus station just moments after my mother's bus home from a shopping trip had departed, but she knew right away it was me.

Those "wireless broadcasters" from the 30s, 40s and 50s were pieces of crap.  Usually modulated oscillators with plenty of FM and incapable of anything close to 100% modulation, and piss-poor audio to boot. You could easily homebrew something that would be at least as good quality as the receiver you will be using to pick it up.

My experience with a Ramsey kit was that I had to do some substantial revisions after I built it before it would work to published specs.  Mine was a broad-band rf power amplifier to bring the output of my DDS VFO up to a useful signal level.  Although it was supposed to be essentially flat from something like 150 kc to 100 mc, I had to rewind one of the toroidal rf transformers and use a much larger rf choke before it would work on 160m, and I never even tried it out on VHF.

[K4TLJ]

Solid state but http://www.sstran.com/ is about the best transmitter around. I have one and it works FB.

[WQ9E]

Thanks to everyone for the suggestions!  Some of those commercial units look very tempting and given my backlog of projects make the most sense.  I should have ordered something in time for this Christmas.

Don,  the Knight Kit unit does use a separate Heising modulator (a 12AX7 preamp stage with a 50C5 modulator heising choke coupled to another 50C5) and was the style I was thinking of building.  These Knight units go for stupid amounts on ebay with multiple bidders.  According to the original Popular Electronics article it is capable of near 100% modulation and is supposed to sound very good.  Maybe this is why the unit sells for so much but I definitely won't pay ebay prices for something I can build myself out of parts I already have around.  You certainly had fun with your radio experiments. 

[Opcom]

I don't remember where this was found on the www but it's a small tube AM BC TX for that purpose.

http://www.bunkerofdoom.com/lit/hmbcam1/index.html

[WA5VGO]

I agree with Terry. The SSTRAN is the only way to go.

Darrell, WA5VGO

[k4kyv]

I don't remember where this was found on the www but it's a small tube AM BC TX for that purpose.

http://www.bunkerofdoom.com/lit/hmbcam1/index.html

That one is just exactly what I described.  A modulated oscillator. You can't modulate it close to 100% because the oscillator would quit on negative modulation peaks.  Would make a nice SBE though, if followed by a couple of stages of leen-yar.