This is Blowin my Mind!

[prcguy]

KMA log periodics are a lot of antenna for the money compared to other brands, very rugged and they will last a long time. If you look at the Create 50-1300MHz log specs, boom length and amount of elements you can see the hyped up Create advertising compared to the KMA 4113, which has many more elements and a boom nearly twice as long. Create claims 2 to 4 dB more gain over the KMA, which is bogus. The KMA Rover is a great choice for VHF/UHF scanning as it covers 88 to 1300MHz in a 6ft boom. I can show you how to effectively rear mount a Rover for vertical operation with no mast interaction if you get one.
prcguy

 

[JackTV]

I have also had the Create LPA(50-1300mhz model)That was also a very good antenna.
Kinda frustrating to put together & a little expensive but still a good antenna.
What kind of pre-amp are you using?

Jack

 

[Gilligan]

What kind of preamp are you using?

 

[mancow]

How much is the KMA4113? The guy's site it slow as heck and most of the pages wouldn't load for me.

 

[jonny290]

you do have this vertically polarized (elements pointing up and down) right?

 

[LeeBarnes]

WOW, I just spent about one hour searching for some info on the antenna and company and I found NOTHING!.

well, the only i found was a couple sites that listed it's manual. at least i think so...

http://www.radioera.com/m-manuals.htm
http://www.agtannenbaum.com/m_cat.html

look for 1604, and the each list shows military antenna. gotta be it.


definitely an odd find.

 

[tonsoffun]

well, the only i found was a couple sites that listed it's manual. at least i think so...

http://www.radioera.com/m-manuals.htm
http://www.agtannenbaum.com/m_cat.html

look for 1604, and the each list shows military antenna. gotta be it.


definitely an odd find.

Good find LeeBarnes. Interesting to see it cost $17.00! LOL
Take Care

 

[zguy1243]

I got another antenna like this last week new in the crate, unused. Was very expensive so i gotta sell my original one. Go get it guys, http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=190080336320

I will entertain offers too.

 

[kb2vxa]

Jody, you have discovered the ruggedized mil version of the Winegard log periodic TV antenna that's been around for the last 30 years. I can understand the thrill of discovery but frankly I'm unimpressed. Sorry to be the proverbial wet blanket but when the buzz wears off you'll discover it's shortcomings and understand. Maybe you can save some time by reading the specs published by sellers of mil surplus where the e-Bay guy got them from and told hype for truth.

Frank, looking at the KMA4113 I see more misleading hype. First off the gain is given in dBi which is a mathematical concept and not a figure in the real world. For years it's been used to jazz up the numbers so multiply by 0.8 to get dBd, the true representation. The most misleading part of it is no mention is made of what frequency it exhibits this gain figure on. With a log periodic the gain is nil at the lowest operating frequency and rises with the frequency because the beam narrows from nearly omnidirectional to only a few degrees. It's my educated opinion this figure represents the highest operating frequency where it has the most gain and directivity. Any ham who has operated on the centimeter bands knows that 8dBi is piss poor on 1300MHz so it's primary mission is to cover a wide range of frequencies and little else besides passing for a TV antenna to fool the neighbors.

Interestingly enough KMA4113 is an old CB callsign from the New York City area. (;->)

Now guys, climb down from the roof and do your homework, it's nearly bed time. MOVE IT, the old curmudgeon has SPOKEN!

 

[wa2ciq]

I got another antenna like this last week new in the crate, unused. Was very expensive so i gotta sell my original one. Go get it guys, http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=190080336320

I will entertain offers too.

ya made a nifty profit on that "$20" antenna

KCR7930 at your service

 

[prcguy]

dBi is a figure for measuring antenna gain and is used exclusively for very expensive and high performance antennas in the satellite and other critical use industries. Using dBi for antenna comparison is no different than using dBd as long as you know that a dipole in free space has 2.14dB gain over an isotropic radiator. Where does multiplying a dBi figure by .8 get you dBd? I have a KMA 4113 and it is a great antenna and a nice accessory for scanner or other wide band use. It is not nearly omni directional at the low end and this type antenna has a fairly constant gain across its entire range, although the low end does degrade a bit. Some hamsters get too caught up in long boom, super high gain mono band antenna BS and anything less is a waste of time to them. This is not so and the 6 or 8dBi gain of a KMA log periodic can bring weak signals out of the dirt just fine.
prcguy

Jody, you have discovered the ruggedized mil version of the Winegard log periodic TV antenna that's been around for the last 30 years. I can understand the thrill of discovery but frankly I'm unimpressed. Sorry to be the proverbial wet blanket but when the buzz wears off you'll discover it's shortcomings and understand. Maybe you can save some time by reading the specs published by sellers of mil surplus where the e-Bay guy got them from and told hype for truth.

Frank, looking at the KMA4113 I see more misleading hype. First off the gain is given in dBi which is a mathematical concept and not a figure in the real world. For years it's been used to jazz up the numbers so multiply by 0.8 to get dBd, the true representation. The most misleading part of it is no mention is made of what frequency it exhibits this gain figure on. With a log periodic the gain is nil at the lowest operating frequency and rises with the frequency because the beam narrows from nearly omnidirectional to only a few degrees. It's my educated opinion this figure represents the highest operating frequency where it has the most gain and directivity. Any ham who has operated on the centimeter bands knows that 8dBi is piss poor on 1300MHz so it's primary mission is to cover a wide range of frequencies and little else besides passing for a TV antenna to fool the neighbors.

Interestingly enough KMA4113 is an old CB callsign from the New York City area. (;->)

Now guys, climb down from the roof and do your homework, it's nearly bed time. MOVE IT, the old curmudgeon has SPOKEN!

 

[zguy1243]

Ok, with all this said...I know for fact that this antenna has outperfomed all 5 of my outdoor antennas for aircraft reception in the 118-136 band and the 225-400mhz band. I am VERY picky about connectors, coax and such. I have NO antennas that are in bad shape. This antenna will outperfom a vertically polorized tv antenna any day. I know this because I have modded MANY tv antennas for scanner antennas. As far as gain figures across the spectrum, I have no idea on this model. I can assure performance in the airbands though. If you think this antenna is very "unimpressive" Please point me to somthing better! Cause that would make my day!

Jody

Jody, you have discovered the ruggedized mil version of the Winegard log periodic TV antenna that's been around for the last 30 years. I can understand the thrill of discovery but frankly I'm unimpressed. Sorry to be the proverbial wet blanket but when the buzz wears off you'll discover it's shortcomings and understand. Maybe you can save some time by reading the specs published by sellers of mil surplus where the e-Bay guy got them from and told hype for truth.

Frank, looking at the KMA4113 I see more misleading hype. First off the gain is given in dBi which is a mathematical concept and not a figure in the real world. For years it's been used to jazz up the numbers so multiply by 0.8 to get dBd, the true representation. The most misleading part of it is no mention is made of what frequency it exhibits this gain figure on. With a log periodic the gain is nil at the lowest operating frequency and rises with the frequency because the beam narrows from nearly omnidirectional to only a few degrees. It's my educated opinion this figure represents the highest operating frequency where it has the most gain and directivity. Any ham who has operated on the centimeter bands knows that 8dBi is piss poor on 1300MHz so it's primary mission is to cover a wide range of frequencies and little else besides passing for a TV antenna to fool the neighbors.

Interestingly enough KMA4113 is an old CB callsign from the New York City area. (;->)

Now guys, climb down from the roof and do your homework, it's nearly bed time. MOVE IT, the old curmudgeon has SPOKEN!

 

[kb2vxa]

Look you guys, I'm not going to argue with those who don't read and understand what I'm saying, especially one who calls me a "hamster" unless you've seen my avatar on QRZ. I'll just tantalize you with a couple of tidbits to hopefully make you think.

"It is not nearly omni directional at the low end and this type antenna has a fairly constant gain across its entire range, although the low end does degrade a bit."

If it degrades at the bottom end it's quite obvious it does NOT have a "fairly constant gain" so go back and read WHY it performs the way it does.

"Some hamsters get too caught up in long boom, super high gain mono band antenna BS and anything less is a waste of time to them."

If you were doing EME and weak signal work over 300+ mile paths you'd know why we feel that way.

"I know for fact that this antenna has outperfomed all 5 of my outdoor antennas"

As compared to what? Without proper information I'm not prepared to debate the issue. OK, it works "wonders" on the aircraft bands, so what exactly did you think it was designed for? If I were on the battle field calling SAR and it saved my life I might be impressed but for scanning applications I'm not.

To quote myself, "Now guys, climb down from the roof and do your homework" and you just MIGHT learn something from the hamsters rather than trying to defend the indefensible and pointless argument. I invite you to come on over to some of the ham forums, we're happy to teach you if you lose the attitude and are willing to learn.

 

[prcguy]

Warren,
It’s not an indefinable and pointless argument just because you announce so, however it does appear you don’t understand every aspect of the subject and that’s your easy way out. I’m not an “antenna engineer” but have spent much of my career with research, design and testing of antennas, some of which you might even own. What’s your experience? Why do you assume others listed in your argument are not hamsters and possibly have more experience with weak signal modes and very large and very high gain antennas? You think I have an attitude? I suggest you read some of your past postings.
prcguy

Look you guys, I'm not going to argue with those who don't read and understand what I'm saying, especially one who calls me a "hamster" unless you've seen my avatar on QRZ. I'll just tantalize you with a couple of tidbits to hopefully make you think.

"It is not nearly omni directional at the low end and this type antenna has a fairly constant gain across its entire range, although the low end does degrade a bit."

If it degrades at the bottom end it's quite obvious it does NOT have a "fairly constant gain" so go back and read WHY it performs the way it does.

"Some hamsters get too caught up in long boom, super high gain mono band antenna BS and anything less is a waste of time to them."

If you were doing EME and weak signal work over 300+ mile paths you'd know why we feel that way.

"I know for fact that this antenna has outperfomed all 5 of my outdoor antennas"

As compared to what? Without proper information I'm not prepared to debate the issue. OK, it works "wonders" on the aircraft bands, so what exactly did you think it was designed for? If I were on the battle field calling SAR and it saved my life I might be impressed but for scanning applications I'm not.

To quote myself, "Now guys, climb down from the roof and do your homework" and you just MIGHT learn something from the hamsters rather than trying to defend the indefensible and pointless argument. I invite you to come on over to some of the ham forums, we're happy to teach you if you lose the attitude and are willing to learn.

 

[mtindor]

ROFL hamsters. That's beautiful. I'm a hamster, but I'm not offended [nor do I think hamsters have some sort of elite status]. That was better than a whole evening of watching my favorite comedian.

M

 

[zguy1243]

OK, I am using a Diamond Discone, a Scantenna, A 300mhz cut groundplane, a DPD Productions 225-400Mhz log periodic. All of these antennas are fed with Rg-11 or high grade LMR600 coax. They are weather proofed and checked up on alot. I am very picky. The mil surplus antenna will outperfrom these antennas in the airbands. Why is this so hard to believe? I do understand what you are are syaing about the coverage of the antenna, but I dont use it at 1300mhz man. If you hooked this thing to your receiver and played with it for a few minutes I think you may change your mind.




"I know for fact that this antenna has outperfomed all 5 of my outdoor antennas"

As compared to what? Without proper information I'm not prepared to debate the issue. OK, it works "wonders" on the aircraft bands, so what exactly did you think it was designed for? If I were on the battle field calling SAR and it saved my life I might be impressed but for scanning applications I'm not.

 

[zz0468]

My 2¢...

It's simply a log periodic antenna, nothing fancy. In fact, they're easy enough to build. For the purists, given a yagi and a log periodic of the same boom length, the yagi is going to win by a substantial margin. For those of you with antenna envy, consider turning a tv antenna on it's side for vertical polarization. It's not as pretty or exotic looking, but you'll get comparable performance.

All in all, a nice little antenna, though.

 

[zz0468]

dBi is a figure for measuring antenna gain and is used exclusively for very expensive and high performance antennas in the satellite and other critical use industries.

Huh? Dbi has nothing to do with the price of the antenna. It merely defines the fact that the power gain ratio is referenced to an isotropic antenna. That being said, in practice the opposite from what you say is true. Since a dipole has 2.4 db gain over an isotropic radiator, shady antenna manufacturers will specify gain referenced to the isotropic antenna - WITHOUT the dbi label to make their antennas show 2.4 db gain more than the competition who uses a dipole as a reference. CB and scanner antenna manufacturers are quick to use this trick. Surprised?

2¢ more, I guess. *shrug*

 

[prcguy]

Agreed that cheesy manufacturers will use the higher dBi figure and not reference to the “i”. However, dBi is still the reference used for EMI test antennas, commercial satellite and most other antennas outside the two-way radio and scanner world.
prcguy

Huh? Dbi has nothing to do with the price of the antenna. It merely defines the fact that the power gain ratio is referenced to an isotropic antenna. That being said, in practice the opposite from what you say is true. Since a dipole has 2.4 db gain over an isotropic radiator, shady antenna manufacturers will specify gain referenced to the isotropic antenna - WITHOUT the dbi label to make their antennas show 2.4 db gain more than the competition who uses a dipole as a reference. CB and scanner antenna manufacturers are quick to use this trick. Surprised?

2¢ more, I guess. *shrug*