Wait a minute, there was another analysis done where the Phillips balun was very close to the CM one. I think the moral may be, it depends on the individual unit. The CM one may have better quality control at the factory.

I bought a Source balun, not sure of the name...but I guess the best bet is the CM.

More than likely, but dont throw the other away. Test and compare it to the CM one.

I'm really lamenting the fact that none of the pre-amps that I can find have 300 ohm inputs. I found the circuit layout for one in a 1977 IEEE Transactions on Broadcasting
(Advanced Antenna Design and an Ultralow-Noise Preamplifier Extend UHF Viewing Area : ieeexplore.ieee.org/iel5/11/4044035/04044041.pdf but you need an IEEE account or access to an institution that has one... Thanks, local college!)

But that is beyond my current insanity level here.

firimari:

What's the basis for your statement that the balun might be hampering your signal - are you experiencing reception difficulties????cause now you have me doubting...

Balm: I am in a quest to get a PBS station that is just out of reach. I built a gapless jed GH10 (http://www.digitalhome.ca/forum/showthread.php?t=103535) and it was much better than the Antennas Direct DB4 I had before. I can now watch it snowy on Analog, but can't get a lock in digital (channel 24 vs 25, so frequency differences in the antenna are not much of an issue). I'm just trying to wring as much signal out of the antenna without building a double bay GH10

I'm really lamenting the fact that none of the pre-amps that I can find have 300 ohm inputs.
The Channel Master 0264 (mine) and I believe the CM 0064 has. And they are pretty low noise and reasonably priced.

The Channel Master 0264 (mine) and I believe the CM 0064 has. And they are pretty low noise and reasonably priced

*sigh* My Google-fu is weak, I guess. I saw the 0064 was no longer available and didn't see the new model.
I have a Antennas Direct PA-18, but I also have a tower a few degrees off the signal I'm trying to get, which is much closer and higher power. Add pre-amp, get only that channel. Luckily the FCC says they're moving for the June 12 switchover. (behind my antenna, but I already get the other channel being broadcast at that location.)

I'm really lamenting the fact that none of the pre-amps that I can find have 300 ohm inputs.
The 300 ohm pre-amps have an "internal" balun, so you should do just as well with a 75 ohm input pre-amp.

firimari, no need for google-fu! You'll find a ton of info in the parent forum! :)

Start at the top of this site's OTA Forum: http://www.digitalhome.ca/forum/forumdisplay.php?f=81 where threads exist for general OTA topics like preamps, etc etc and you'll see that the Antenna R&D forum actually is a sub-forum of it for the really experimental and theoretical stuff like in this thread.

Ah, but I bought the PA-18 before I found this place. But yeah, there is a wealth of knowledge here and I am eternally grateful.
(he says before finding some advertisers to click on and peruse)

About three years ago a member here tore down a Zenith Silver Sensor and posted photos to this site. Sadly those photos disappeared due to that online hosting site that was used, so they're not available anymore and the member hasn't been heard from in quite a long time.

The key feature that really intrigued me was the feed point design, which appeared to me to be a Hall Effect transducer:

http://www.digitalhome.ca/forum/showpost.php?p=531442&postcount=110

http://en.wikipedia.org/wiki/Hall_effect

Since this seems to have been already done in the OTA antenna field Is this of interest to anyone looking to get out of our reliance on Baluns, with their inherent losses?

I have been trying to research alternatives to the Baluns we're currently using, with my current reading being into wideband planar log baluns:
A new wide-band planar balun on a single-layer PCB (http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1435442)
Wideband, planar, log-periodic balun (http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=705107), and the author's free copy: http://palgong.kyungpook.ac.kr/~ysyoon/Pdf/weif_03.pdf

The hall effect transducer would be another interesting area to look into.

I want royalties if you invent and patent a Hall Effect transducer for balun replacement! :)

I'm really lamenting the fact that none of the pre-amps that I can find have 300 ohm inputs.

Channel Master 3041DSB has one 300 ohm in and a 75 ohm out. Fry's has them in stock for $50 each.

They may be discontinued, but I bought one last week at Fry's.

Hope this helps.

Mike

PS: I just sent CM an email letting them know what serious mistakes they are making eliminating the CM4228A and the 3041DSB pre-amps.

Probably wont do much good. Percentage wise, not that many Chinese in China read English all that well, heh. :p

Found a decent BALUN at Fry's a moment ago. Name of it is Philmore and the model is No. MT74. Looks exactly like the one CM uses. They were like $2 US each.

What really ticked me off is they have a CM4228A mounted in the middle of their TV display area. It isn't for sale. It is the one they use for their demos! I told them to hold on to it because they won't be any more like it!

Of course they had none in the store as well!

While I was at it, I picked up a couple more of those CM 3041 DSB 300 ohm in 75 ohm out pre-amps!

HTH.

Mike

I have searched and still can't seem to find an answer!

Would there be less loss by attaching 2 baluns to antenna compared to using a splitter? It is also asked here:

http://www.digitalhome.ca/forum/showpost.php?p=866319&postcount=392

with no answer, that I can find.

Would there be less loss by attaching 2 baluns to antenna compared to using a splitter?
Eh? That question make sense not. :)

The usual way, is to use two baluns and a splitter. Not one or the other.

???

This is the scenario Grand Audio is asking about:
Plan A
balun 1 ---> to TV 1
/
antenna feed points
\
balun 2 ---> to TV 2

...

Plan B
to TV 1
/
antenna feed points ---> balun ---> splitter
\
to TV 2
...Electronically, Plan A would cause the 300ohm antenna feed impedance to be cut in half due to the baluns being in parallel. This means that the normal 300:75 transformation would instead be 150ohm impedance stepped down 4 times to 37.5 ohms at the TV, which would probably ruin everything.

If the baluns in Plan A were connected in series the 300ohm-to-75ohm step down would be proper but the voltage would be dropped to likely an unsustainable level except in the case of the very strongest signals.