Vintage Radio Gound Connections - Videokarma.org TV - Video

Charlie · #1 06-02-2005, 10:54 PM

Quote:

Originally Posted by Chad Hauris

This may be the case for the 1920's sets...they are so robust with very few components and if you supply the proper power supply voltages and an antenna and ground they will likely work (they won't do anything without antenna and be very weak without ground)...

The above quote came from another thread and sparked me to start this one.

I've often wondered... the ground connection on old radios... does this really make a difference or in some way improve performance? I've got some sets with the ground connection... 2 from the 30's, 2 from the 40's, and even one from the 50's. I've never tried connecting a true ground to these sets, but often wondered if doing so would make a difference in reception?

BTW... the above mentioned sets seem to play just fine without the ground connection.

I would suspect that the earliest radios... for instance sets from the 20's... depend on the external ground moreso than the later sets. Or am I completely incorrect in making this assumption?

Fisherdude · #2 06-03-2005, 09:35 AM

It's been my (somewhat limited) experience that connecting a true earth ground does make a small difference. First, these older radios were designed with the assumption that it would be connected to a ground, so there is also a safety factor involved.

It seems that the noise level drops a bit. The radio seems a little less "staticy" with the ground connected. I'm assuming the ground drains off some of the power line interference, etc.

Then again, maybe it's the coffee! Sandy G, chime in with your thoughts!

Chad Hauris · #3 06-03-2005, 10:23 AM

When we were working with the arborphone 1927 radio we could barely get anything at all without the ground, even with an antenna wire connected...connecting the "ground" terminal to the water pipe enabled us to get all the local stations clearly. Have not found the ground connection to be nearly so important on any other type of set.

Telecolor 3007 · #4 06-03-2005, 10:44 AM

It's making a differnce. I've tryed and with the ground antena connected the sound have less parazites.

Morden2004 · #5 06-03-2005, 11:38 AM

Digging way back into my EE courses and with experience as a kid with 20's and 30's sets, I believe that most of them were designed such that the AM antenna circuit was not complete (as a tuned circuit) until a ground was connected. That is not to say that you wouldn't receive some RF without a ground.

In those days A/C service was ungrounded, giving rise to the need to add a earth ground to the chassis (circuit). AM transmissions were usually done with a horizontal transmission line(s) and those transmission lines used earth ground as part of the transmitter's tuned circuit.

[Trivia Alert] BTW, it was soon discovered that stations along the seaboard put out more radiated power than, say, those in the desert - guess why?

I think this is true for most pre-war receivers.

Paul

bgadow · #6 06-03-2005, 12:01 PM

On sets from the 30s & up I have seen little difference & have even noticed on some sets that it will work WORSE with ground connected. Recently I've had fun experimenting with a homebrew 3 tube set from the mid-20s that works quite well (given it's limitations). It will work without the ground but not nearly as well. The better the ground, the better it worked. I had it set up outside & at first connected it to the clothesline pole, where it worked very well. Connected to just a pipe I drove in the ground a couple feet, it worked but not quite as well.

I think it was my grandfather who told me how when reception was bad (I think he was talking about TV) they would go out a pour a bucket of water at the base of the pipe holding the antenna & it would come in clear. Water certainly helps. As a kid we used to fish a lot in the river & I loved carrying my old radio out there & listening to the am station just downriver. Their transmitter was (is) right on the banks & they come BOOMING in when you are out there!

Charlie · #7 06-13-2005, 01:08 AM

Guys,

Thanks for your comments on this. I am going to make an effort to try a true ground in the next few days with a few different sets and see what kind of difference (if any) takes place.

I certainly want to try a true ground with the 1935 Philco cathedral I recently bought. It has fresh electrolytics and caps in it, but still produces a noticeable hum. It makes me curious if the ground being connected would take away some of the hum.