Antenna question

[F350-6]

I have a Uniden 396XT and bought one of those metal extendable antenna's from Radio Shack. I then found out this was probably not the best idea after doing some reading and receiving advice here. I went back to Radio Shack and bought the flexible rubber antenna that is longer than the one that came with the radio. It was hanging on the rack next to the extendable one I had already bought.

The problem is, the flexible one did not fit. Sorry I don't know the name of the connections, but the antenna would start to fit on the adapter, but not seat down quite far enough to allow it to twist down into place in the fitting. Lucky for me I had the scanner with me and tried it in the parking lot. When I went back in, we tried all the rubber ones they had on the rack and none of them fit, but they fit fine on the Radio Shack scanners, as did my metal extendable one.

What am I missing here? Why does one Radio Shack antenna fit and not the other, yet both of them fit the Radio Shack scanner? Tolerance issue with my adapter by chance? Is there really a different style fitting that is so close it appears the same and the Radio Shack model can fit both of them?

Is there some other little gem of information I'm missing? I would like to have a better flexible antenna, but at this point am scared to order anything for fear it too won't fit. Any advice would be appreciated.

 

[DannB]

I have the same radio , you want a great antenna Diamond SRH77CA come's with the SMA connection. here is one place to purchace it,click below

Ham Radio Outlet | DIAMOND SRH77CA | SMA 2M/440 DUAL + WIDE BAND RX HT ANT 15 IN

 

[F350-6]

Thanks Dann. What do you consider makes it great in layman's terms? Are you referring to clarity or range? I'm guessing the terrain and distance I listen to is quite a bit different than you and it may have some affect on antenna comparisons.

I'm out in flat land in the corner of my country, so I listen to 3 different counties SO and Fire channels, as well as the local VFD's, PD's of half a dozen towns that I can pick up within 25 or so miles. I'm in the boonies, so even scanning all that doesn't keep the scanner making noise all the time.

Does your antenna still fit the bill? Any ideas why the radio shack antenna didn't fit? If my little adapter is bad, I'd like to get another one ordered at the same time I get an antenna just so I have it on hand since shipping on small stuff makes it wise to order multiple items at once.

 

[DannB]

just works well

Well "what makes it great" I just get signals from much further then with the stock antenna. It worked so well i bought a second to use on my handheld HAM radio and what a difference here when i transmit..Its just a quality antenna. All i can say is that im able to pull in signals that i know is a good shot away...And as far as your radio shack question i really cant comment cause i just dont buy there products, they never have what i need so i dont even go into the store anymore...Batteries, Phones and misc junk is what the stores over here in my area sell..

 

[mike_s104]

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You might want to figure out the bands you're monitoring or prefer to monitor and get an antenna for that band or bands. If you're mostly using it in the car, get a mobile antenna.

 

[derevs]

To be a little more specific in answering your question you probably got an antenna with a BNC connector from Radio Shack. I just looked at their website and there are no antennas listed with an SMA connector.

The 396 XT uses an SMA connector. So, being that a BNC connector is larger than an SMA connector, the BNC connector will fit over the SMA connector but not seat on the connector.

You will have to get an antenna with an SMA connector. Unless you can find a proper radio/scanner outlet in the area you live in. Barring that you will have to order by mail. Just remember one thing, make sure the antenna terminates in an SMA connector.

 

[OCO]

No need to buy a different antenna .. Get a SMA to BNC adaptor like this one from ScannerMaster. Got one with my HP1, works just fine with that same center loaded antenna from RS (I use a short BNC to BNC jumper with mine to keep the antenna from tipping the HP1 over..)

 

[garys]

From reading your post it seems that what you are experiencing is that the clearances are just a bit tight between the BNC adapter and the RS antenna. I've had that happen as well and the best way to avoid damage to the radio is to remove the adapter from the radio and then twist the antenna on to the adapter. Then put thread the adapter back onto the radio.

You can also try buying another adapter, I've found them on Ebay reasonably priced. You want to search BNC female to SMA male. I'd recommend against the one at Scanner Master as it leaves the connector unsupported.

 

[OCO]

garys
Can you show a link to a specific SMA male to BNC female adaptor that supports the SMA bulkhead connector on the radio? I assume you mean that somehow the outer shell of the SMA connector end of the adaptor has a flange that seats against the bulkhead to provide a more rigid connection? I can't find one like that but would be interested in seeing it.

The OP's first post really may be misleading, I don't think he's ever had an intermediary adaptor, I think he was trying to fit the male BNC on the bottom of the RS antenna directly to the SMA female on the radio, which would be a trick since one is push and twist and the other is threaded.. I have never had a problem with BNC connectors being so out of tolerance that you couldn't get 'em together (30+ years)..

 

[nanZor]

Uniden includes an sma-bnc adapter with the 396XT - probably the best one I've very seen as far as reducing stress goes. Look inside the nooks and crannies of your box.

The flexible antenna you picked up, is probably the old RS 2m/440 amateur dual-bander, which does as well as most amateur dual-banders do. If it has kind of a tapered bulge near the top, this is the one - and it really isn't that flexible. I got a few when they went on clearance, and do ok with window-clip mounts - their rigidity while mobile is pretty good.

Check your box for that adapter - and the RS dual-band duck isn't that bad.

 

[garys]

garys
Can you show a link to a specific SMA male to BNC female adaptor that supports the SMA bulkhead connector on the radio? I assume you mean that somehow the outer shell of the SMA connector end of the adaptor has a flange that seats against the bulkhead to provide a more rigid connection? I can't find one like that but would be interested in seeing it.

The OP's first post really may be misleading, I don't think he's ever had an intermediary adaptor, I think he was trying to fit the male BNC on the bottom of the RS antenna directly to the SMA female on the radio, which would be a trick since one is push and twist and the other is threaded.. I have never had a problem with BNC connectors being so out of tolerance that you couldn't get 'em together (30+ years)..

Right here. They were originally made for some of the Yaesu portable radios that use the same connector as the Unidens. Some people are a bit concerned because they don't have the "shoulder" of the Uniden parts, but a nylon washer fixes that.

From his original post and my experience I think that he's having a problem getting the BNC bayonet lugs to lock onto the antenna. I've run into that with the GRE swivel antenna, but not RS antenna. As a matter of fact, I have the same tight fit with the original Uniden adapter and the GRE antenna.

 

[John_S]

If you're shimming the BNC connector, be careful... it's very easy to go too far and put strain on the lugs or rip them right off. They're the weak link in that connector.

 

[OCO]

Thanks - I don't think I'll order just one right now - 99 cents all the way from China - the shipping might eat up any savings <grin>. I will keep on the lookout though. I do know that the connector I'm using would not stand up to harsh use - the one you are showing will, but at least I got away from the SMA antenna (using a BC100 duck on it when portable, better ears in the services I'm listening to than the stock HP1 guy). When using it in the house I use a BNC jumper between the ant and radio anyway.

Gerry

 

[F350-6]

Sorry if I was unclear, and again I apologize for not knowing the names of the fittings. Yes I did get the adapter in the box with my scanner and that is what I used to install the extendable antenna to begin with. And I did figure out the part about removing the adapter and trying to force the antenna onto the adapter so there was no additional stress on the expensive parts.

That still leaves my original question unanswered. Did I just get a bad adapter or why did none of the flexible antennas fit in my adapter when the extendable one just slid right in like it was no big deal?

I really don't want to order a new antenna until I figure out why the other one didn't fit. If I need to order another adapter, I'd rather order it with the new antenna to save on shipping.

 

[GTR8000]

The Uniden adapter is a pretty darn good quality part. Radio Shack's junk, on the other hand, not so much. Order a proper antenna with BNC connector and you'll be a lot better off. Stay away from the Radio Shack junk.

What frequencies are you trying to monitor anyway? You never mentioned. That Radio Shack rubber ducky is an 800 MHz antenna, which isn't going to do you much good if you're trying to pull in Low Band or VHF signals from 25+ miles away.

 

[F350-6]

What frequencies are you trying to monitor anyway? You never mentioned. That Radio Shack rubber ducky is an 800 MHz antenna, which isn't going to do you much good if you're trying to pull in Low Band or VHF signals from 25+ miles away.

Mostly in the 122 - 155 range so far, but as I learn more I'll venture out. Or as these old analog systems start getting phased out I'll be forced to follow the locals to wherever they end up.

 

[hiegtx]

Mostly in the 122 - 155 range so far, but as I learn more I'll venture out. Or as these old analog systems start getting phased out I'll be forced to follow the locals to wherever they end up.

Chris,
From where you are, in southeast Johnson County, the vast majority of what you monitor is going to be Vhf-high, probably for the next year or two. Johnson County, Ellis, Navarro, Hood, Hill, all of those, as well as most of the smaller in them, are all Vhf. The only 800Mhz in Ellis County, for now, is the ETMC site in Waxahachie, with Waxahachie & ETMC the only users. Waxahachie still simulcasts their fire & PD traffic on their old VHF frequencies, but you probably can hear that site. The Burleson trunked system is Uhf. In Hood County, Granbury is also Uhf (conventional, not trunked). Everything else close to you is Vhf-high, ~155Mhz range. So, of course, is Texas DPS.

There are, of course, other antennas out there. I'm sure you'll find more comments over in the Antenna forum as well.

While the R/S 800Mhz antenna is excellent for the 800 meg trunks in the Dallas/Tarrant metro area (Grand Prairie, Arlington, and Mansfield being among the closest to you), it's not the best choice for Vhf, which is where most of your listening is for now. It's ok for Uhf, but there are better choices.

What I use, when I head out of the metro area, is one of the Diamond antennas, like this. There are two versions on that page- The RH77CA has a BNC connector, and would require using the adapter. The other one, SRH77CA, has an SMA connector, and would screw directly onto the 396XT without the adapter. Using that antenna, out away from the city, I often get counties 50-60 miles away, or farther. (That, of course, depends on terrain between where I am, and the transmit site, as well transmitter power & antenna height.) I also use that same antenna on one of the 396XT's here at home. Besides the Vhf cities and surrounding counties on the southern side of the metro (I'm in S/W Dallas), I also get most of the trunked systems in Dallas County, as well as Arlington. So, while it's not as good as the R/S 800 on the trunks, it's not totally deaf either. I do pick up a couple more on the other XT, which I use with the R/S 800. That's also the scanner I carry on my commute, so I can hear the systems in the southern part of Collin County.

 

[fullmoon]

I also like the Diamond Antenna that was mentioned...

 

[John_S]

The SRH77CA is good and I own one, but there's another that I favor over this if you can tolerate a telescoping antenna. I bought a Smiley 270A Tri bander to go with the Yaesu VX-8R HT and tried both antennas on 2 meters, 220, and 440. The Smiley had better signals on all 3... not by a ton, but still. So I've been mentioning it to anyone looking for a good SMA antenna. It features a heat shrink covered spring at the base, so there's a bit of flex. $20 at AES.

 

[F350-6]

So still no ideas why the antenna wouldn't fit? I guess it's worth buying another adapter when I order a new antenna just to be on the safe side? From what I'm reading, it sounds as if the 800 mhz antenna should have fit my adapter with no trouble.

Chris,
From where you are, in southeast Johnson County, the vast majority of what you monitor is going to be Vhf-high, probably for the next year or two. Johnson County, Ellis, Navarro, Hood, Hill, all of those, as well as most of the smaller in them, are all Vhf. The only 800Mhz in Ellis County, for now, is the ETMC site in Waxahachie, with Waxahachie & ETMC the only users. Waxahachie still simulcasts their fire & PD traffic on their old VHF frequencies, but you probably can hear that site. The Burleson trunked system is Uhf. In Hood County, Granbury is also Uhf (conventional, not trunked). Everything else close to you is Vhf-high, ~155Mhz range. So, of course, is Texas DPS.

There are, of course, other antennas out there. I'm sure you'll find more comments over in the Antenna forum as well.

While the R/S 800Mhz antenna is excellent for the 800 meg trunks in the Dallas/Tarrant metro area (Grand Prairie, Arlington, and Mansfield being among the closest to you), it's not the best choice for Vhf, which is where most of your listening is for now. It's ok for Uhf, but there are better choices.

What I use, when I head out of the metro area, is one of the Diamond antennas, like this. There are two versions on that page- The RH77CA has a BNC connector, and would require using the adapter. The other one, SRH77CA, has an SMA connector, and would screw directly onto the 396XT without the adapter. Using that antenna, out away from the city, I often get counties 50-60 miles away, or farther. (That, of course, depends on terrain between where I am, and the transmit site, as well transmitter power & antenna height.) I also use that same antenna on one of the 396XT's here at home. Besides the Vhf cities and surrounding counties on the southern side of the metro (I'm in S/W Dallas), I also get most of the trunked systems in Dallas County, as well as Arlington. So, while it's not as good as the R/S 800 on the trunks, it's not totally deaf either. I do pick up a couple more on the other XT, which I use with the R/S 800. That's also the scanner I carry on my commute, so I can hear the systems in the southern part of Collin County.

Thanks Steve. I'm starting to get comfortable enough with the scanner that I was thinking of trying to program in some big city stuff and try and listen to the trunked stuff on one of my trips through DFW. The 800 mhz antenna seemed like a good one to get for taking the scanner with me while driving into town. Besides, I was under the impression if this was to become a serious hobby, I was supposed to have a drawer full of antennas, adapters and parts I didn't really need.

The SRH77CA is good and I own one, but there's another that I favor over this if you can tolerate a telescoping antenna. I bought a Smiley 270A Tri bander to go with the Yaesu VX-8R HT and tried both antennas on 2 meters, 220, and 440. The Smiley had better signals on all 3... not by a ton, but still. So I've been mentioning it to anyone looking for a good SMA antenna. It features a heat shrink covered spring at the base, so there's a bit of flex. $20 at AES.

Thanks for the tip. I'm not opposed to the telescoping antenna. I've just read they can be hard on the connection in the radio, so I was trying to play it safe. I guess it's "springy" enough to protect the radio internals?