Antenna Connector on Saber

billy7834 · Post by **billy7834** » Sat Feb 28, 2004 2:54 pm

What do you call the antenna connector type on a Saber? Is it SMA? I would like to occasionally connect an external antenna with a BNC connector using an adapter, just for monitoring purposes. Any problem with this?

RadioSouth · Post by **RadioSouth** » Sat Feb 28, 2004 3:15 pm

Yup, you wouldn't be getting a balanced load you need a RF adapter that
taps RF off the accessory connector.

Tom in D.C. · Post by **Tom in D.C.** » Sat Feb 28, 2004 4:12 pm

The round ring which is NEXT to the acc. block is where the RF comes out the back of the Saber when it's placed in an SVA. There is an automatic switching circuit in the radio which changes the output from the top to the back, and it IS balanced and proper and won't mess up your RF.

There is a connector/adapter which goes in the standard Motorola antenna connector, but they're really special and difficult to find. Someone will jump in here and give you information, I would hope.

jnglmassiv · Post by **jnglmassiv** » Sat Feb 28, 2004 5:57 pm

There's a Saber Accy-to-BNC cable available, too. Perfect for this. They don't, however, appear to be that common.

I do have one, tho and can confirm its existance. Its not really for sale, I'm afraid.

billy7834 · Post by **billy7834** » Sat Feb 28, 2004 6:21 pm

Ok....Maybe a dumb question......But.....Why wouldn't unscrewing the standard antenna and replacing it with an adapter (BNC to SMA) that leads to an external antenna work?

KG6EAQ · Post by **KG6EAQ** » Sat Feb 28, 2004 6:31 pm

Well on a regular saber it's not an SMA antenna, and plugging in an adapter to it will not catch the center pin. Or depending on the center pin will hit and so will the outer sheild, thus shorting the antenna

The radio has it's own ground which isn't on the top connector, it's only available via the back one. So when you just get something in there you won't have a ground connection to the antenna either.

billy7834 · Post by **billy7834** » Sat Feb 28, 2004 7:21 pm

Oh OK...So... it's not an SMA. So, the regular screw on antenna is made to get down into the accessory connection where it has to in order to work. Correct? And, there is no adapter that adapts a BNC connnector to that same type of screw-in connector?

giantcake · Post by **giantcake** » Sun Feb 29, 2004 5:56 am

I use an SMA with the extended nose that fits on an Astro Saber antenna port and then has a BNC connector.

I also have a screw stud to BNC connector that fits the standard Saber or MX radio.

I also use a Saber Accessory connector to BNC adaptor. The Saber (or Astro Saber) Service cable uses the Acc. port on the rear of the radio for testing.

The SMA or Stud > BNC test adaptor is really just for verifying power and signal thru the antenna connection on top.

The acc. port to BNC test cable for a regular Saber is on eBay at this time.
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... tegory=296

If your looking to put together a test cable or an external antenna cable, your alternative is a Public Service mic with the antenna on the mic itself.
You might be able to open up the cable or mic and put a connector on it.

-Steve

giantcake · Post by **giantcake** » Sun Feb 29, 2004 6:41 am

To early and did not have the magic of coffee inside me yet.

The Astro Saber has an actual SMA connector on it. I use an SMA with a deep nose to BNC adaptor to test the Astro Saber receive and transmit.
Recommend you do not use this for mobile or portable app, just for testing. Mobile or portable use; buy a Vehicular Adaptor (Convertacom)

The Astro Saber service cable (RKN4046) does not have the RF BNC connector on it.

The regular Saber test cable does have the RF BNC on it.

The regular Saber antenna hole is referred to as just a "stud" connection.

OK, back to work.

-Steve

billy7834 · Post by **billy7834** » Sun Feb 29, 2004 1:48 pm

Thanks to all....here's what I'm left with........The regular screw-in antenna is made to connect the way it should to function properly, however, there is no readily available adapter from BNC that will screw into the stud hole and work the same way. Is that correct??
If that is correct, is the cable on ebay described above, a good choice to do what I want to do (occasionally connect an external antenna just for monitoring purposes...no TX)? Thanks again to all.

giantcake · Post by **giantcake** » Sun Feb 29, 2004 7:03 pm

There is a stud to BNC adaptor. Try ebay, there seems to be a guy on there that sells several different types of BNC to antenna connector adaptors. Search on " motorola antenna adap* "

That RF test cable on ebay is a better idea though. Much better overall matching between the receiver and your antenna/feedline.

-Steve

billy7834 · Post by **billy7834** » Sun Feb 29, 2004 10:17 pm

Thanks Steve.....The ones I always see on ebay are BNC to SMA. Don't ever see BNC to stud. Have you actually seen them?

kc2dla · Post by **kc2dla** » Mon Mar 01, 2004 2:23 am

I have seen BNC to 'MX thread' aka stud adapters at hamfests and this may work for RX only. However, you aren't making electrical contact with the radio's ground which, believe it or not, is still important even for simply receiving. The threaded connector on the saber, MT1000/ genesis series, GP300 type radios and a few others are this standard MX thread. The adapter I have seen actually has a plastic spacer on it to work with certain radios (non-motorola) that have a ground 'ring' or other ground tap at the top of the MX thread connection.

Paul

KG6EAQ · Post by **KG6EAQ** » Mon Mar 01, 2004 4:05 am

All the stud to BNC connectors I've ever seen never tested out right. The stud would be to the ground ring of the BNC or it'd go to both, I never did find a GOOD one. Do it the fun way, get yourself a convertacom and then show us install pics

k4wtf · Post by **k4wtf** » Mon Mar 01, 2004 5:50 am

billy7834 wrote:Ok....Maybe a dumb question......But.....Why wouldn't unscrewing the standard antenna and replacing it with an adapter (BNC to SMA) that leads to an external antenna work?

Because it's not an SMA? The Saber doesn't have both "center conductor" and ground at the antenna connector. It's just "center conductor"...

John

billy7834 · Post by **billy7834** » Mon Mar 01, 2004 6:41 am

Given all of the above, how does the regular screw-in antenna work then? And why doesn't an adapter work the same way? Thanks again.

k4wtf · Post by **k4wtf** » Mon Mar 01, 2004 6:56 am

The regular antenna works the same way the whip on your mobile antenna works. It has an electrical connection to what would be the "center conductor" on a coaxial antenna connector. The groundplane is provided by the radio chassis (inside the case).

This is no different than the way a BNC duck or SMA duck works. The "duck" doesn't use the ground connection at all. The center pin is connected to the antenna element and the "shield" is used only for mechanical connection.

On the Saber stud connector, there is no "center pin".... The whole antenna connector is the "center pin".

Now, the reason this won't work for connecting an "external" antenna is because of the impedence bump (mountain in this case) you're going to take as a result of the shield of the coax not being connected to RF ground (the chassis).

When you use the connector on the BACK of the radio and tell the radio you're doing so (appropriate option selection on the accessory connector), the radio routes the RF to/from the port on the back of the radio rather than to the stud connector on the top.

As has already been posted, the appropriate adapter cable (to mate to the RF connector on the back of the radio and tell the radio to use that connection) is available on eBay.

I personally like using an SVA better. I have a few SVAs and would be willing to part with one if you want to go that route. I also have the appropriate Motorola RF amplifier (30W I think) to use for VHF amateur/MURS. I've also got a UHF amp but, it's for 416-430Mhz if I remember.

Anyway, like I said, I've got SVAs, brand new (unboxed) amplified SVA speakers, and both the display mics and non-display mics to get you set up with a complete, tested and working SVA solution if you're interested.

John

billy7834 · Post by **billy7834** » Mon Mar 01, 2004 10:16 pm

Thanks again all.......Believe it or not I'm not dense....just having difficulty understanding why there is not a screw- in adapter that incorporates the same properties as the screw-in antenna and would therefore work the same way. Guess there is not, right?

k4wtf · Post by **k4wtf** » Tue Mar 02, 2004 5:02 am

I give up. Don't get a Saber. The radio is not what you want. Go out and buy a kenwood or icom amateur rig. They have the antenna connector you want.

John

billy7834 · Post by **billy7834** » Tue Mar 02, 2004 4:40 pm

k4wtf.....Too late, already have two. Didn't mean to try your patience. Do appreciate your help. My last post was meant as a sort of confirmation.

jjbond · Post by **jjbond** » Fri Jun 10, 2005 12:03 am

Hi guys, I just found this thread and am curious... I have an MTS2000 with the SF connector I believe it's called. This does appear to have both a center and a shield connection and I currently have an SF to BNC adapter that I use. As I am not using and MX (groundless) antenna connector on the radio (I totally understand the whole no ground/impedence mismatch issue you were talking about) am I ok using this adapter and am I also ok using this on my Astro Saber as it uses the same type antenna connection (SF I believe)?

Thanks all
Jennifer

DJP126 · Post by **DJP126** » Fri Jun 10, 2005 4:07 am

am I ok using this adapter and am I also ok using this on my Astro Saber as it uses the same type antenna connection (SF I believe)?

Thanks all
Jennifer

You are ok in this case. The ASTRO Saber, the MTS2000 & the MT2000 all use a SMA connector at the antenna, BUT you want to be sure that your adaptor is physically LONG enough to make good RF contact (as noted in some of the earlier posts).

tvsjr · Post by **tvsjr** » Fri Jun 10, 2005 4:59 am

Yep, you've got it right with the SF. Just be careful about how much torque you're exerting on that antenna connector - there's a reason that Mother's antennas have a big sleeve that sits down against the plastic.

jjbond · Post by **jjbond** » Fri Jun 10, 2005 6:40 am

Thanks guys.... and Dave, your signature kinda hit home. I was the Installation Manager for Motorola Canada, in charge of the BC region back in the early 90's. There was a senior manager in our office a year shy of retirement they screwed over and laid off...... really put a bad taste in my mouth about a long term career with M in Canada.

Jen

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