Quick dipole antenna question

Status
Not open for further replies.

fredg

Member
Premium Subscriber
Joined
Dec 23, 2007
Messages
107
Location
East Central Kansas
I am using an old baby monitor as a "repeater" for my Pro-2006 connected to my outside antenna.

I used these instructions for my baby monitor just FYI:

Convert the Fisher-Price Baby Monitor into a Repeater This works quite well and the old Fisher-Price model 157 monitors are available on ebay.

What I want to do is make a simple 1/4 wave dipole antenna for the baby monitor. Currently the monitor has a rubber duck style antenna attached to the board with a screw.

So if I make a simple dipole to run up the wall I would connect the lead going up the wall to the place on the board where the duck antenna was..

The question is where do I connect the wire running down the wall? It's an all plastic case and runs on 110 volts.

I assume there is a ground somewhere on the board which would make sense to connect the down wire to.

Oh and don't worry, I will be VERY careful to not have a hot 110 volt wire running up my wall. LOL
 
Last edited:

majoco

Member
Joined
Dec 25, 2008
Messages
3,726
Location
New Zealand
It's going to be a pretty large dipole - the blurb says the frequency is about 50MHz - one wavelength = 6 metres - quarter wavelength 1.5 metres = 5 feet per leg, 10 feet overall.

So if I make a simple dipole to run up the wall I would connect the lead going up the wall to the place on the board where the duck antenna was..
Yes, one leg to the "ground" and the other leg to the ducky centre. The "ground" is where your 110v problem may come in, although I noticed in the article that no mention was made of isolation so I guess there's a transformer in there.
 

fredg

Member
Premium Subscriber
Joined
Dec 23, 2007
Messages
107
Location
East Central Kansas
It's going to be a pretty large dipole - the blurb says the frequency is about 50MHz - one wavelength = 6 metres - quarter wavelength 1.5 metres = 5 feet per leg, 10 feet overall.

Yes, one leg to the "ground" and the other leg to the ducky centre. The "ground" is where your 110v problem may come in, although I noticed in the article that no mention was made of isolation so I guess there's a transformer in there.
Yep 49.845MHz, 56" each leg. The bottom wire will have to angle under the desk for the last couple of feet, or I could just make it shorter, it's not like this is super critical, I just want to be able to receive it when walking around outside in the yard. I can receive it now but want to make the reception stronger.

Yes there is a transformer inside the monitor.... I think... I will have to check.... thinking about it now it may not have a transformer.

If that's the case how does that effect where I hook the ground?

Thanks for the info!!
 
Last edited:

fredg

Member
Premium Subscriber
Joined
Dec 23, 2007
Messages
107
Location
East Central Kansas
Ok it has a transformer...

The plug is not polarized so I do not want to ground to it.

How about grounding (the down leg of the dipole) to the metal case around the transformer?
 
Status
Not open for further replies.
Top