DIY FM antenna to tuner connection question

[streetwise]

I built a folded dipole out of copper pipe awhile back using an online calculator and design. from the antenna I have a radioshack 75ohm to 300ohm balun, going into a roughly 30' run of RG6. At the receiver end my receiver Fisher 400 only has the old 300ohm screw terminals with local or distant selection so I have another 75ohm-300ohm balun connecting to receiver. Is this optimal? anybody with antenna expertise?

 

[rcs16]

Each balun has a small bit of loss. 300 ohm twin lead might be less lossy

 

[rmp]

Compared to twin lead and no baluns, your setup loses some signal strength. However, it's worth the loss, if the cable comes very close to metal.

 

[John Ess]

The issue with open wire feedline isn't as crazy as it's made out to be. As long as the metal isn't touching and parallel for some distance, not really an issue. I transmit through 450 and 300 ohm all the time. This 300 ohm stuff is much better than basic twinlead...https://www.dxengineering.com/parts/dxe-ll300-1c

 

[gadget73]

Old outdoor TV antennas used to run the 300 ohm twin lead down the tower or post using stand-offs to keep the wire 6" or so away from the metal bits. Seemed to work OK. This was back when no TV sets had 75 ohm coax inputs so flat lead was just what you used.

 

[Lavane]

I remember my dad running bare copper wire 300 ohm ladder wire from an antenna high up in a huge oak tree. You s t see that ladder wire much anymore.

 

[streetwise]

interesting I saw some people do the cable loop/and or ferrite chokes at the antenna end. Not sure how much of a difference that makes. Maybe I should go to 300 ohm twin lead. That wasn't what I was expecting seeing that most antenna installation use coax now

 

[Bob@FM]

Here's my opinion -
You are better off first playing with the location and orientation of the dipole antenna to increase the signal strength of the stations - versus trying to optimize the cable / balun. Try the antenna horizontal, vertical, 45 degrees, etc and also try moving it as high as possible, facing (broadside to) the desired stations when horizontal. Find out where the transmitters are with FMFOOL or MIT Radiolocator - many times they are all close together - and makes sure the antenna is positioned correctly to optimally receive them. Even if you go to all 300 ohm cable, I doubt you will see a big change or improvement. Unless you have a bad cable or balun.

Bob

 

[John Ess]

I would probably try avoiding baluns unless I had one that was built better than what's available. I just don't trust them. I run a full wave loop which has a fairly close match impedance wise to 75 ohm RG-6. I should try tweaking the loop with my nanoVNA and dial it in better...just busy with other aluminum and wire.