PCS Electronics PCS Electronics - home page PCS Electronics  
RegisterSearchFAQAM & FM Radio transmitters shop UsergroupsLog in
300 Ohm Dipole FM Antenna to 75 Ohm input on rcvr

 
Reply to topic    PCS-Electronics Forum Index » Antennas View previous topic
View next topic
300 Ohm Dipole FM Antenna to 75 Ohm input on rcvr
Author Message
e_identity
New registered user
New registered user


Joined: 15 Sep 2005
Posts: 2

Post 300 Ohm Dipole FM Antenna to 75 Ohm input on rcvr Reply with quote
I have a cheapie 300 Ohm dipole FM antenna. I live in an urban area and don't need much more. I want to connect the antenna to my receiver, but my receiver has only a 75 Ohm F Connector input for the antenna. All my reading indicates I need a "BALUN." I have found BALUNs for converting a 75 Ohm coax cable to a 300 Ohm input. I do not know if these will work in reverse or if I need something else. I don't really want to spend much money on this, but w/o the antenna, I am not getting any reception. I tried to find my answer in this forum b/f posting, but w/o luck. Thanks for your help! Michael
Thu Sep 15, 2005 8:17 pm View user's profile Send private message
FLORIN_MX
New registered user
New registered user


Joined: 16 Sep 2005
Posts: 1

Post Reply with quote
HELLO!!
IT IS POSIBLE TO CONECT YOUR ANTENA TO THAT RECEIVER TROUGH THAT BALUN OR SOMETHING EASIER USE ONE TV ANTENA (WICH COMES WITH TV SET) IT HAVE THE SAME ADAPTOR FROM OPEN DIPOL TO TV INPUT 75 Ohms. Dancing
Fri Sep 16, 2005 1:15 am View user's profile Send private message
pcs
Site master
Site master


Joined: 18 Jan 2002
Posts: 3063
Location: Radio Land

Post Reply with quote
Yes, you can use 4:1 balun. For receiving purpose it is ok.
For transmitting, however, you are limited by power handling
rating of the ferrite inside the balun. I doubt it can carry more
than about 4W.

If you take the one from FM antenna, make sure it is a VHF
antenna, you stand a better chance its the right "iron" in the balun.
UHF type might be more suitable for higher frequencies and less
so for radio band.

_________________
Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Fri Sep 16, 2005 7:21 am View user's profile Send private message Visit poster's website
e_identity
New registered user
New registered user


Joined: 15 Sep 2005
Posts: 2

Post Reply with quote
Thanks for your help!

1) to answer my own question, it appears that at least some BALUNs are reversible (see description of RS unit below).

2) Radio Shack hides it well, but does sell such a device called an "Indoor/Outdoor Matching Transformer" Brand: RadioShack; Catalog#: 15-1140; Model: 15-1140. Description: "Matches 300-ohm screw terminals on antenna to 75-ohm (round) coax cable downlead. Reversible." No specific reference to VHF frequencies unfortunately. Cost: $4.00 USD (plus shipping). Don't look for it under "antennas" since it's not there.

3) Followup: I purchased the RS transformer, soldered the twin lead wires to to my antenna wires, covered w/ heat shrink tube, connected it to the back of my receiver using a cable leftover from my VCR install, and it worked fine. The only caution is to make sure you have a cable that will connect to the back of your receiver-I didn't see anything like the cable I used for sale anywhere. The connector on the back of my receiver was similar to the coax F connector on the end of the RS BALUN (I'm not sure which is male/female since f connectors seem hermaphrodidic to me), except that the exterior had no threads. The cable I used was push on at both ends. I don't know whether a standard screw on f connector would have worked.

e_identity
Mon Sep 19, 2005 6:50 pm View user's profile Send private message
Display posts from previous:    
Reply to topic    PCS-Electronics Forum Index » Antennas All times are GMT + 1 Hour
Page 1 of 1

 
Jump to: 
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group