|Topic Review (Newest First)|
|2017-05-12 03:09 PM|
Both my CM94444's are less than 2 years old and one hasn't ever been used beyond a couple days trying to make the dual ganged ff4 work (too unwieldy). I tried the unused one and it matches the one I've had on for a year and a bit, no difference.
I bought the new pair only because The source no longer carries the CM94444's and these Chinese ones looked the same. I guess those CM94444's were a bad batch.]
|2017-05-12 02:57 PM|
I measured lots of different Indoor & Outdoor BALUNS....they all had significantly LOWER Loss in FM Band than UHF.
In the four BALUN's that ADTech measures (incl CM94444) Loss in Hi-VHF Band was UNDER 0.5 dB.
So your old CM94444's have probably been degraded due to Absorbed Moisture and/or Static Electricity Breakdown....or perhaps the oxidization on the coax connectors was disturbed when you first changed Baluns (in which case you might find the CM94444's NOW work the SAME???).
|2017-05-12 02:12 PM|
I recently ordered 2 very cheap baluns off ebay that I intend to use on a pair of ganged VHF antennas. They looked exactly like my CM94444's that I bought through radio shack/the source. When I got them they were different, it's obvious they are hollow in comparison to the CM94444's which seem solid. I tested both out on my FF4 antenna and they were MUCH better than the CM94444's on VHF with no discernable difference in UHF.
Normally CFTO Toronto comes in around 50-60% ss with the CM94444's, these "knockoffs" gave a reading of 86-90%, when I tried pulling in WICU (rf12), which is tropo only for me, I got nothing, not even a "poor signal strength", switched to the cheap Chinese Balun and low and behold it gave me a nice picture at 40%ss, switched back nothing.
Since Sunday night I've been getting WICU every night in good quality BEFORE I get WJET (which is my true tropo from Erie), this NEVER happens using the CM94444's, WICU is always the more difficult to get and more often than not unless tropo is really strong out of Erie I don't get it.
From what I've read this doesn't make a lot of sense unless CM had a run of bad product and both my others are part of that bad batch.
P.S. The Source in Canada no longer carries them, that was why I ordered off flea bay.
P.P.S. I got a pair with weather boots for less than $3 delivered.
|2016-05-19 10:08 PM|
|rabbit73||Good; thank you.|
|2016-05-19 09:36 PM|
|goforit||I got it from Summit Source. I did eventually get the boot off with a lot of tugging...|
|2016-05-19 09:21 PM|
Very odd. Who makes that balun?
It looks a lot like this one:
If it is, the boot has been forced on too far.
|2016-05-19 09:08 PM|
Installing Coax Cable to Balun with Weather Boot
I'm trying to connect a coax cable to a balun (see pics), but it has this heavy duty weather boot; not sure how to connect.
Slice the weather boot to increase the hole, pull the boot off the balun (tried but doesn't want to come off), or...?
|2015-12-07 10:03 PM|
Because when you connect the two halfwave coaxial baluns in parallel they present an impedance of 150 ohms to the feed point of the antenna for a 2:1 SWR mismatch. And then you have two lengths of 75 ohm coax hanging down to connect to the coax feed line. How are you going to do that?
Please draw a diagram of what you want to do, so that I understand your plan.
Or better yet, why don't you make two baluns and connect them to your antenna and tell us what happens.
|2015-12-07 02:06 AM|
Why wouldn't it work?
|2015-12-06 07:10 PM|
No, it wouldn't work, and it isn't necessary. A half wave coaxial balun will cover the UHF band with loss that is less than a ferrite core balun.
The major problem you will have is how to waterproof it.
|2015-12-06 05:58 PM|
Is it possible to run 2 Co-ax type baluns, in parallel, tuned for different parts of the UHF band?
That way, the losses away from the ideal tuned frequency, would be minimized.
|2015-04-01 06:23 PM|
|ProjectSHO89||If it's Belden's cable, go to their website and look up the data sheet. No guesswork involved.|
|2015-04-01 11:04 AM|
Ok, thanks, plus Hollands has a link on the previous page as well.
So, with my Belden RG11 it is Gas-injected FPE - Foam Polyethylene. Therefore I use the velocity factor of .80?
So via Bouval for 1/2 wavelength that is 22.17" and Hollands 1/2 wave link above it is at 22.16"
Looks like spec say..."Nominal Velocity of Propagation: 83 % " So I can tweak that. Hmmm... if I do change via Bouvals - comes in right on 23" now.
Ok, that gives me something to work with. I'll have to work with aluminum instead of copper, but I can work around that.
|2015-04-01 12:02 AM|
_____________ Coax Balun Calculator
|2015-03-31 11:44 PM|
Would someone be so kind as to point me to the formula for cutting a coax balun? VHF only Ch 8 & 13 is my targets. 13 is the weakest, so I'll shoot for that. Tried the search of this mega thread and did not find what I was looking for. I know it is here, from reading it all a year ago. Seems like the loop was 26". But no guessing allowed.
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