STL, How did you arrive at 83% for the v.o.p of your Addison copper-braid RG-59 ??? The 23" you use is quite a departure of ~18" that comes from 66% that is the default of the K7MEM calculator.

"Philips Outdoor 300:75-ohm Balun was measured to have 0.5 dB Loss from VHF thru UHF"

Any idea where to get these?


Of course, nowhere to be found in this province, Quebec, as usual!

Wall-Mart DOES NOT carry these, they carry RCA only...

kkoceski:

It is really RG6 and not RG59. I found the spec online using an identical RG6 with 95% copper braid shield and no foil. These features affect the capacitance and the v.o.p.

83:66 and 23:18 are the same ratios. So the computation is good.

I guess this is a reminder to find the true v.o.p. of a coax because it affects the length of loop so much...

Will proceed with install today. Can't wait to find out if it works for me!

STL

Philips Outdoor 300:75-ohm Balun was measured to have 0.5 dB Loss from VHF thru UHF.
I have yet to see any better measurements posted...
holl_ands - is this a different balun than the one you reported a loss of 3.0 to 4.7 dB (the PM61009)? If so, can you provide the model # for us? I just want to make sure I'm looking for the right one...

Thx. See below for an extract of your post in a different forum...

"BALUN TRANSFORMER LOSS MEASUREMENTS:

RMS, CA-2100B, Indoor fm CATV Co, Typ 1.2 dB, Max 1.5 dB
SEGA, "SEGA", Indoor fm SEGA, Typ 1.2 dB, Max 2.2 dB

C-M, 3075, Outdoor fm outpost.com, Typ 1.7 dB, Max 2.2 dB
RCA, VH101, Outdoor fm HomeDepot, Typ 2.5 dB, Max 4.2 dB
Philips, PM61009, Outdoor fm Lowes, Typ 3.0 dB, Max 4.7 dB
Radio Shack, 15-1230 Goldstar, Outdoor fm R-S, Typ 3.5 db, Max 6.2 dB
Radio Shack, 15-1140B, Outdoor fm R-S, Typ 4.5 dB, Max 6.2 dB"

Thanks for your tip mlord. The 300-ohm feeds on the 10Y13s are about 3" apart and I connect the coax loop directly to the feeds without using any 300-ohm cable.

I built and tested a 23" loop and I had zero reception for WVNY. kkoceski was probably right that I used a wrong v.o.p. So I trimmed the loop down to 20" and reception was recovered. I trimmed it further to 19" and reception was more or less the same.

All in all, I would believe that the coax balun has saved about 1-2 dB of signal but it is hard to tell because today's weather variations affect the signal by more than that.

Reception of WVNY was at 70% at its best, but that was holding the antenna by hand off the mast. Back on the mast, the best signal was probably 50-55% using a 8 ft. span of RG6 to an Insignia STB on the roof.

When I hoooked the antenna back up to the CM 7777, reception was below locking on the TV's inside the house. I'll only know if the coax balun helped when the weather recovers and I measure reception levels over a few weather cycles.

STL

What is the advantage of using RG6 over RG59 for the loop, calculated or real life. Less loss, if so by how much?

holl_ands - is this a different balun than the one you reported a loss of 3.0 to 4.7 dB (the PM61009)? If so, can you provide the model # for us? I just want to make sure I'm looking for the right one...

Thx. See below for an extract of your post in a different forum...

"BALUN TRANSFORMER LOSS MEASUREMENTS:

RMS, CA-2100B, Indoor fm CATV Co, Typ 1.2 dB, Max 1.5 dB
SEGA, "SEGA", Indoor fm SEGA, Typ 1.2 dB, Max 2.2 dB

C-M, 3075, Outdoor fm outpost.com, Typ 1.7 dB, Max 2.2 dB
RCA, VH101, Outdoor fm HomeDepot, Typ 2.5 dB, Max 4.2 dB
Philips, PM61009, Outdoor fm Lowes, Typ 3.0 dB, Max 4.7 dB
Radio Shack, 15-1230 Goldstar, Outdoor fm R-S, Typ 3.5 db, Max 6.2 dB
Radio Shack, 15-1140B, Outdoor fm R-S, Typ 4.5 dB, Max 6.2 dB"
I did the above UHF Balun Loss measurements at the end of 2004.
I found about 0.5 dB loss at VHF for all Baluns tested.

It is possible that some have updated their products since then.

And now you know EVERYTHING I know re "Philips Outdoor Balun":
http://www.avsforum.com/avs-vb/showthread.php?p=15851345
Suggest you ask Johnrmckee directly....

PS: I've checked several times and have yet to find them in stock in
local stores so I could retest. Lowes is now carrying RCA instead....
So on-line order seems the only way to do it....

Of course, someone might volunteer to best some additional Baluns....

distox you can see the change in values between RG59 and RG6 using the calculator at the bottom of this page:

http://www.k7mem.150m.com/Electronic_Notebook/antennas/yagi_vhf_feed.html

...And now you know EVERYTHING I know re "Philips Outdoor Balun":

PS: I've checked several times and have yet to find them in stock in
local stores so I could retest.

Thanks - lol! So my search for the elusive Holy Grail for my deep fringe reception continues...

I made the coax loop balun last night and am going to test it on my 4228 tonight, as well as a new CM balun and 2 other cheapies...

distox you can see the change in values between RG59 and RG6 using the calculator at the bottom of this page:

http://www.k7mem.150m.com/Electronic_Notebook/antennas/yagi_vhf_feed.html

Other than length and ease of bending, I do not see any other differences mentioned between the two. I was looking for performance differences i.e. would the RG6 one have more or less loss than the RG59 or perhaps different band width, if both were built the using the same method and were cut to the correct length.

RG6 has a thicker centre conductor (MUCH thicker), and better shielding than RG59. This makes RG6 less lossy (lower loss) than RG59. On very short lengths (like a UHF balun) it really shouldn't matter much.

Cheers

... So my search for the elusive Holy Grail for my deep fringe reception continues...

I made the coax loop balun last night and am going to test it on my 4228 tonight, as well as a new CM balun and 2 other cheapies...

Well the results are in and not surprisingly, the coax loop balun wins.

I tested 2 CM baluns, a Philips Indoor Balun a Home Depot Outdoor Balun and a homemade coax loop balun optimized for channel 45. The test was using an original CM 4228 mounted 6' above the peak of the roof, receiving three 2-edge digital stations broadcasting from the approximate same location (a few hundred meters apart) 48 miles from my location.

The channels were:

22 - My most stable/ steady signal
33 - rarely locks (transmits with the power of a hair dryer...)
58 - occasional picture, depends on time of day

I won't go into too much detail, but I will mention that I tested within a half hour period and used a reference balun after 15 minutes to confirm that the reception was the same as when I started. I'll also mention that I get a steady picture at 35-40% with my TV (Panasonic PX80) and that the measurement is signal strerngth, not signal quality.

My observations:

Philips Indoor balun - 0 % on all three channels (may have been a dud). I cut it up to reuse the twinlead and connections, since I don't have any more.

Home Depot Outdoor Balun - Channel 22 - 20%, Channel 33 and Channel 58 - 0%.

Channel Master Baluns - both pretty good and about the same. Channel 22 - 55 -60 %, Channel 33 - 1 -2 %, Channel 58 - 5-10%.

Homemade Coax Loop Balun - Channel 22 - 70-75%, Channel 33 - 5-10 %, Channel 58 - 30-35%.

As a side note, I used channels 33 and 58 because they broadcast from the same location and are extremely tough for me to pick up - I wanted to get the best balun I could so I could use that to at least remove that variable from my setup to continue my quest to get them. Now I can focus on changing some other things using my coax balun (making more of them optimized for those specific channels rather making the one optimized for the half way point).

It may have been mentioned in an earlier post, but I did notice two additional notable things with the coax loop balun - it appears that I get a stable picture now at a lower signal strength - with the other baluns a non dropout/ steady picture came at about 40%. With the coax loop balun, I am getting the non dropout picture between 30-33% (go figure). I also noticed that with both channels 33 and 58 (my problem channels), with the other baluns the signal strength bounced around from 0 to their peak levels and back to 0 over a period of a minute or two, while with the coax balun, the signal strength remained fairly constant. Not sure why this would be...

Anyway, this has been long winded enough. Suffice it all to say that I will sticking with making/ refining my own baluns from now on...

Thanks for that, zapperman, you deserve a nice day of fishing now! :D

Thanks for that, zapperman, you deserve a nice day of fishing now! :D
...don't mind if I do...legs are a little stiff though from walking up and down the ladder so many times! Neighbours probably think I've lost it...

It may have been mentioned in an earlier post, but I did notice two additional notable things with the coax loop balun - it appears that I get a stable picture now at a lower signal strength - with the other baluns a non dropout/ steady picture came at about 40%. With the coax loop balun, I am getting the non dropout picture between 30-33% (go figure). I also noticed that with both channels 33 and 58 (my problem channels), with the other baluns the signal strength bounced around from 0 to their peak levels and back to 0 over a period of a minute or two, while with the coax balun, the signal strength remained fairly constant. Not sure why this would be...

It may be because the coax loop balun also acts like a filter. You are tuned to channel 45, anything below and above that starts to get attenuated . That also includes any interference from other unwanted signals therefore allowing the AGC in your tuner to pull in more signal. Just a thought.

The real-world measurements from earlier in this very thread, show no more than about 0.5 dB loss across the UHF band for a coax-loop balun. So it's not much of a notch filter, just simply a better (and simpler) balun than most others.

Earlier posts here also suggest adding 1:1 current balun functionality to the coax downfeed from the loop (voltage) balun, which can be done just about as simply as the original.

With both types of balun functionality (voltage and current) used together, it should really be unbeatable. That's what I'll be doing here for my dual PR8800 array, hopefully within the next couple of weeks.

Cheers

Hey,

I picked up a old antenna, and I believe it is a Delhi C101.

I wanted to redo the wiring, and upon taking apart the screws were so rusted I did some damage to the balun.

Can I make a new one myself?

Is there anywhere I can buy one?

The balun is a 4:1 i believe. does it have to be a 4:1?

I cannot find a replacement.

thanks

http://www.digitalhome.ca/forum/picture.php?albumid=269&pictureid=1214

http://www.digitalhome.ca/forum/picture.php?albumid=269&pictureid=1215

With both types of balun functionality (voltage and current) used together This is also the same concept that Andrew Roos suggested to do with 1:1 and 4:1 transformers. Has anyone run a simulation of the equivalent combo coax balun optimized for the UHF band for Ottawa (Channel 14 to 67) and calculated the losses for the VHF band using the same balun as would be needed for a GH with NARODS? (Maybe I should get up to speed with Microcap again - it's been a while....)

ClgShaft, unfortunately those photos of the balun are very dark so I can't really speculate on their condition. My suggestion is to just ditch that old box and use either a modern 4:1 store-bought balun or make your own CLB (Coax Loop Balun) as described in this thread.

The balun looks in bad shape, very dirty, and a couple broken wires.

I found the calculator for building one, and I am looking at getting vhf low.

I found the one post pertaining to the 4:1 coax balun, and it showed the connection points inside the box.

The antenna I have the points were outside the bx and spread apart by about 18".

thanks