Could anyone tell me what this antenna is used for?

[instrumentphilip]

I found this and though that I could use it for something since I Am getting into radio recently. I couldn't find any info on the antenna to look up to tell me what it was. I do know that it gets good receive on UHF but not so good on VHF. Some people have been telling me they think it is a external cellular antenna, and some people have been saying they think it is an external WiFi antenna. Does anybody have any clues what this could have been used for?

 

[fourthhorseman]

look up 12 element Yagi..youll get some more info on the style,,make up ect,,
theres 2 types,,passive,i think ,,and driven,,
looks like a nice clean homebrew..

nice score you lucky son of a gun,,

 

[instrumentphilip]

Ok I am googling that now and I am not getting to much that looks like it and has 12 elements. Some look like a 900mhz antenna and some look like a 2.4 ghz antenna. I wish there was a way to tell what it is made for. IT has a female pl-259 or SO 32 or what ever that is on it.

 

[AK9R]

It appears to be a Yagi antenna which is a type of directional antenna. In the traditional Yagi design, the feed line connects to the driven element through a matching network. The elements to one side of the driven element are longer than the driven element--these are the reflectors. The elements to the other side of the driven element are are shorter than the driven element--these are the directors. The greater the number of directors and reflectors, the more directional the antenna and the higher the gain.

The length of the driven element will give us a clue as to what frequency the antenna is designed for. Carefully measure the length of the driven element and let us know.

 

[Peter_K2XM]

what is the length of the driven element ( the one with the connector ) from the center of the boom to the end of the element

 

[prcguy]

From the size of the shoes in the picture its a UHF Yagi and it looks like a very early Maxrad. Its going to have about 20MHz of bandwidth so you would have to sweep it to see if its cut for 450-470, 470-490, etc. I think these were most often used in SCADA (low power point to point data) applications.
prcguy

 

[13riverking]

this is the best site ive found on Yagi's, you might be able to take some measurements and plug them in the antenna designer and see where it is tuned VHF/UHF Yagi Antenna Design by dxzone.com from there click on vhf/uhf yagi antenna design, and itll take you there.

 

[kruser]

From the size of the shoes in the picture its a UHF Yagi and it looks like a very early Maxrad. Its going to have about 20MHz of bandwidth so you would have to sweep it to see if its cut for 450-470, 470-490, etc. I think these were most often used in SCADA (low power point to point data) applications.
prcguy

I agree fully and the gamma match construction and hardware looks almost identical to the one on my old Maxrad 850 MHz yagi I posted about earlier today in another thread. Our power company has two of these mounted on equipment shacks at a sub-station I can see out my window. The one in the OP's picture appears to be the same physical size as the ones mounted at the sub. Those were licensed in the 460 range several years back but are unused these days. The coax is removed on both.
I'm positive one was used for telemetry back then and the other was possibly used for remote switching of loads but it is all done with a single antenna up around 950 MHz these days.

 

[instrumentphilip]

Sorry guys for the wait I have been really busy. I will be able to measure it tomorrow and put up the measurements for the boom and elements.

 

[instrumentphilip]

The Boom is 6 Feet, or 72 inches. The driven Element or the element with the connector is 1 foot, or 12 inches. What frequency do you think that this directional antenna is for?

 

[AK9R]

With a driven element roughly 12 inches long, I would guess the antenna is for the 440 MHz ham band or the 450-470 MHz commercial band.

 

[instrumentphilip]

Well that would be very nice if it was a 440 Mhz antenna as I am looking to get into the HAM Radio sometime. Is there some way to find out for sure, like a formula. I know that would work for a Vertical antenna but I do not know since it is a directional antenna and not an omni directional antenna.

 

[scanpprcn]

I think everyone's on the right path, but the one 'clue' in the OP's post that pushed me over the proverbial edge as to the antenna's use was the mention of the PL259/[SO239]. Above 300 MHz the impedance of these connectors becomes unstable. However, HAMs do typically use them on the 440 band. Therefore, I'm throwing in my hat for the 440 HAM band.

 

[kruser]

I think everyone's on the right path, but the one 'clue' in the OP's post that pushed me over the proverbial edge as to the antenna's use was the mention of the PL259/[SO239]. Above 300 MHz the impedance of these connectors becomes unstable. However, HAMs do typically use them on the 440 band. Therefore, I'm throwing in my hat for the 440 HAM band.

I wonder if the connector is really an "N" connector.

To the untrained eye, the two connector types can appear to be the normal SO239 that many are so familiar with.
If it is homebrew for the 440 amateur band then someone did a darn good job.
The construction appears to be an exact match when compared to my MaxRad 850 MHz 12 element yagi including the gamma match hardware that is visible in the OP’s pictures.
My Maxrad also has the chamfered ends on all the elements and the same looking machine screws that attach each element to the boom.
Same looking mounting hardware as well.

I think the only thing mine is missing is the silicone that appears to have sealed the OP’s fittings and coax

 

[12dbsinad]

I think everyone's on the right path, but the one 'clue' in the OP's post that pushed me over the proverbial edge as to the antenna's use was the mention of the PL259/[SO239]. Above 300 MHz the impedance of these connectors becomes unstable. However, HAMs do typically use them on the 440 band. Therefore, I'm throwing in my hat for the 440 HAM band.

PL259 connectors are very common on the UHF band. I have many commercial Larsen yagis in the 450-470 range that have SO239 connectors on them. Actually, current production Kenwood, Vertex Standard, Icom, Etc still use SO239's on there commercial UHF radios. Although i do believe type N or TNC should be used, there are everywhere and even in commerical equipment.

 

[kruser]

PL259 connectors are very common on the UHF band. I have many commercial Larsen yagis in the 450-470 range that have SO239 connectors on them. Actually, current production Kenwood, Vertex Standard, Icom, Etc still use SO239's on there commercial UHF radios. Although i do believe type N or TNC should be used, there are everywhere and even in commerical equipment.

That is a very good and true point. At the same time, I have several very old 450 MHz corner reflectors that used N connectors as well as a bunch of vertical VHF LMR and 2 Meter base antennas that also used N as the stock connector.
And as you stated, I do have some commercial base antennas designed for 450 MHz use that do indeed accept PL259's.

I myself prefer the N type for anything outdoor on a tower or mast. Nothing worse than installing your N connectors on your coax only to discover the antenna you just assembled takes a PL259. I now look first and assemble the fittings to the coax last!

 

[instrumentphilip]

Nope the connector is definitely a PL-259 / SO-239 Does anyone know what would be a good idea how to find out what it is tuned for?

 

[scanpprcn]

If you know a HAM or someone who has an SWR meter for the suspected UHF band and a low power transmitter they could check it for reflected power at various frequencies. The HAM would know what frequencies could be used by their license.

Of course, the professional way to do this is to sweep it with an instrument. You might try the local radio shop. They might do it for you for free if they're nice and it's for HAM radio (non-commercial) use.

 

[talkpair]

I'm guessing that it's for 440 amateur radio...........especially if it's home made

 

[instrumentphilip]

Thanks scanpprcn, I might be able to possibly do that with a handheld on low power or something like that you are saying? And ha I wish there was a local radio shop around here.I mean the closest one I can think of is Abel Electronics and I talked to the people there and it sounded like they wouldn't let me bring anything in and take a look at it. I thought that was very odd. Well if it is home made that would be weird because it has the "Beware of Electric Shock" Warning sticker that is on all antennas. But maybe it is.