Am I looking for something that doesn't exist: Coax to spade converter

[chucky2]

Skip to End for question...

So I have an older receiver, Pioneer SX-828 (that markthefixer did a great job on!), and we've moved houses. What used to work for FM, the cheap plastic 300 ohm dipole antenna, just isn't cutting it any longer as the receiver is in the full basement. The SX-828 has both 75 and 300 ohm hookups.

I looked around and saw the Stellar Labs 30-2435 had pretty good reviews and was cheap, and to go with it I ordered a Channel Master CM-3203 balun/matching transformer. With some Menards pre-terminated RG6, I figured I'd be all set. Turns out, I was wrong...

First I tried hooking it up with the spade connectors on the CM to the 300 ohm on the receiver. That got me basically nothing, even worse than the dipole. So I tried hooking the spade connectors up to the 75 ohm on the receiver and got almost nothing, and nothing real clear at all. Then I actually read the sheet that cam with the Stellar, and low and behold, it says right on there: Output: 75 ohm.

Looking at the CM balun, it's designed to take 300 ohm antenna and convert it to 75 ohm for the coax homerun/end equipement. Doh!

So really all I need is a coax to spade converter, which I thought would be plentiful. After 15 minutes of google searching, all I can find are 300 ohm to 75 ohm baluns like I already have. I realize I can cut the coax end off and use the shield as a ground and the inner conductor as my feed, but I was hoping for a more finished install here.

End: Does anyone know if there exists a coax to spade converter that will allow me to screw the coax in (normal F connector) and output to spade, which is what the receiver needs? There must be something like this for older receivers, right?

Chuck

 

[goodolpg]

Like this?
https://www.parts-express.com/rca-v...campaign=pla&gclid=CImducfw2uICFUjWwAod9qcDug

 

[chucky2]

Something that connector-wise does exactly that (which is what my Channel Master balun does), but, doesn't actually do any ohm conversion. The Stellar is already outputting 75 ohm (I thought it'd be 300 ohm), so I just need to get from coax homerun to spade type termination on the back of the receiver.

 

[hjames]

Like this?
https://www.parts-express.com/rca-v...campaign=pla&gclid=CImducfw2uICFUjWwAod9qcDug

Thats a Balun (Balanced to Unblanced transformer) - looks like exactly what he needs inside IF he decides to convert back to 300 ohm - which is what the spde terminals are on hs receiver.
There are no adapters that do not have a 75/300 transformer function ... the twinlead screws ARE 300 ohm, the Coaxial connector IS 75 ohm.

But every connector is a point of signal loss - the less connectors and adapters the better.

Looks like the Stellar Labs 30-2435 has a 75 ohm coaxial connector on the crossbeam.
So, put that antenna up on top of your roof, (they generally won't work very well in the attic) screw on a piece of coax with fittings on each end, run coaxial down the side of the house and into the basement, then connect the coax to your coax fitting on your receiver.
I taught folks to install antennas for a living years back - thats the basics ...

The other question is - what are the signals like in your area ? If you have weak radio,
you may need a directional antenna with more gain than the omnidirectional loop you bought.

Another possibility is to put a line powered FM amplifier up on your antenna to boost the signals.
Down in the basement, you plug in a power supply adapter (comes with the amp) to feed juice up the coax to your amp.
But - the amp can only boost what it sees - if there are few stations where you live,
the amp could just boost noise and not have much value to you.

 

[knockbill]

If it is 75R,, just put a spade on the center conductor, and another on teh ground shield.. use heatshink or other insulator between the conductors...

 

[JDub]

First I tried hooking it up with the spade connectors on the CM to the 300 ohm on the receiver.

I'm pretty sure you had it right the first time - 75 ohm coax antenna output connected via the balun to the 300 ohm receiver input. Why it didn't work, though, I have no idea. All I can suggest is check your upstream connections. Maybe check continuity on the coax cable?

 

[chucky2]

OK, I went back and tried the 300 ohm. I can in fact get some stations depending on how I walk around the basement (got about 8' of cable to do that with) and if I move the antenna closer to the ceiling or more mid level. So there is in fact some kind of signal getting through the balun in a reverse manner. Looking at FMFool, I may just be screwed having this antenna in the basement: Setting the height of antenna from 1 (the lowest FMFool will go, I'm really at 0 or -1 to -2', or lower if I hold it waist high) vs setting it to 15' gives a much different chance of picking up stations on the map.

The other weird thing is I'm missing a lot of stations that should be there given I can pull one particular one in pretty strong where I have the antenna (many are Chicago based). Then I've got one station that completely spans a range of space. Bizarre...

 

[chucky2]

I wonder what the difference would be chopping the end off this cable and going straight 75 ohm all the way through. Anyone have opinions on that?

 

[JDub]

I may just be screwed having this antenna in the basement: .

I suspect you just hit the nail on the head right there. Having the antenna in the basement pretty much defeats the purpose - get a long enough length of coax to reach a bedroom or a window in the attic and evaluate. Then nail it up on the roof, on a pole in the back yard, or somewhere it can see a signal.

 

[chucky2]

I suspect you just hit the nail on the head right there. Having the antenna in the basement pretty much defeats the purpose - get a long enough length of coax to reach a bedroom or a window in the attic and evaluate. Then nail it up on the roof, on a pole in the back yard, or somewhere it can see a signal.

That's a good idea, I will do that. The sad thing is, when I moved, I cleaned out/recycled/gave away a bunch of stuff I had sitting around unused. Since I have U-verse for TV I really have no need for coax...so I gave 50' of pre-terminated coax away. This is why I need to be a hoarder...