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Author Topic: Bought wrong antenna  (Read 5912 times)

wildsky

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Bought wrong antenna
« on: April 06, 2013, 11:54:43 AM »
I'm playing with a Baofeng UV-5RA HT, and recently heard good things about this antenna:

http://www.amazon.com/gp/product/B0053QEJHG/ref=oh_details_o02_s00_i00?ie=UTF8&psc=1

But it's the wrong gender to use with my HT. So far, I can't find the same thing in the opposite gender. If I find a coupler, would that work ok or would it degrade performance?

gil

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Re: Bought wrong antenna
« Reply #1 on: April 06, 2013, 12:12:09 PM »
Hello Wildsky,

I don't think an adaptor would degrade performance in a way that could possibly be noticed.. I would be careful however about the mechanical sturdiness (or lack thereof). What connector do you have on your handheld, BNC? My Yaesu has an SMA connector, female part on the handheld, and that antenna would probably fit? I do prefer BNC though, it just seems stronger. A BNC to SMA adaptor would probably be OK, since in case of shock to the antenna, it would probably break at the antenna/adaptor junction, as opposed to the handheld/adaptor, which would be bad..

Gil.

cockpitbob

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Re: Bought wrong antenna
« Reply #2 on: April 06, 2013, 04:51:58 PM »
Hi Wild,
I agree with Gil.  An SMA adapter won't degrade performance, and I also agree about the sturdiness problem. 
 
I have the same radio and I wouldn't do it for mechanical reasons.  Note that the base of the antenna is much wider than the SMA connector and that wide base makes snug contact with the radio's housing.  Most of the bending forces go through that wide base leaving the SMA connector to mostly see pulling forces.  With the SMA adapter all the bending forces will go through the radio's connector.

I bought this cheap antenna thinking it would be better than the shorter stiffer Baofeng, but I don't think it's much better.  It's only advantage is it's more flexable so it's safer for the radio. 
 
Then again, I'm not sure how bad the Baofeng is.  I put both antennas on my antenna analyzer and both looked like respectable 50ohm loads on the 2M band.
 
The biggest thing you can do it put a rat tail on the radio.  I attached am 18.5" piece of 24AWG insulated wire to one of the belt clip screws.  This acts as a tuned counterpoins on the 2M band and dramatically improves the HT's performance.  Look in the HT Antennas thread for my before-after test write-up.
 
Here's the Baofeng and Yaesu with their rats.  For both I found a tiny ring lug and used it to attache the wire with the belt clip screw.
 
« Last Edit: April 06, 2013, 07:30:01 PM by cockpitbob »

Geek

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Re: Bought wrong antenna
« Reply #3 on: April 06, 2013, 06:44:05 PM »
I'd like to see some pictures of the rat tail set up.

gil

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Re: Bought wrong antenna
« Reply #4 on: April 06, 2013, 09:30:24 PM »
Yep, I added a rat tail to my Ft-270R after Bob's post back then and got three S-units more on the local repeater. Awesome!

Gil.

wildsky

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Re: Bought wrong antenna
« Reply #5 on: April 07, 2013, 01:15:47 PM »
Great stuff, thank you all!

So how would I measure the S-units that I am getting? I'd love to do a lot of before/after testing, but first need a benchmark to work against.

gil

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Re: Bought wrong antenna
« Reply #6 on: April 07, 2013, 01:35:30 PM »
Quote
So how would I measure the S-units that I am getting?

That would be printed on the screen while receiving, as a bar graph.

Gil.

KC9TNH

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Re: Bought wrong antenna
« Reply #7 on: April 07, 2013, 02:14:17 PM »
Use of an adapter isn't going to deduct as much as extending an antenna with degrading qualities of cable, e.g., opting for something smaller than RG-58, where at higher frequencies the losses really magnify.

Reliable source IME for various oddiments:
http://cablesandconnectors.com/31000-31.HTM

Gigaparts and DigiKey can also find this stuff.

The desire to give the structural integrity of these modern ht's at the connector when not using the duck has been covered above, good stuff; my Wouxun is no different. One thing to be deliberate about is when ordering something because the actual implementation of the SMA connector by the factory can be somewhat counter-intuitive to how we think of connector genders. The important thing to ascertain is where is the pin/center-conductor.  That's MALE.

Again, using my Wouxun KG as example, on initial viewing for a couple seconds one might assume that the connector at the end of the duck is male and the flush-mounted "socket" on the radio is female; not so. (I recently had to flesh this out in how I was going to implement a quick mag-mount antenna as it's sold in a variety of terminations, including the "reverse SMA for Wouxun.")  Having spread out the 817's field bag & looking through various adapters I owned, I could've ordered the antenna (Diamond MR77) in a variety of terminations. But I had adapters sufficient to order the SMA; the goal was to be able to terminate the thing in a right-angle BNC, both for structural relief when in the vehicle and when I simply may want the 817 to fill that role. (The Wouxun is handy, yet the one pretty much dedicated to a SKYWARN go-bag.) I know a compadre that has the same ht, with just the vehicle mounted antenna lead coming in an SMA right to the radio.  Works for him because the radio rides nicely how it is in the truck and he's able to take a bit of slack for strain relief before it gets to the point where it comes straight down into the radio. Just stuff to figure out.

Long way 'round the barn but if one is new to various implementations of SMA, when you find a source (whether it be HRO or just a specialty parts outlet), before ordering on the internet just call them and ask them to actually look at what you're contemplating. Most places enjoy that kind of call and are happy to do it.

All the above because I'm in the 'been there done that' column. :-[

Happy trails!
de kc9tnh . .

cockpitbob

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Re: Bought wrong antenna
« Reply #8 on: April 07, 2013, 02:31:24 PM »
So how would I measure the S-units that I am getting? I'd love to do a lot of before/after testing, but first need a benchmark to work against.
I did the before/after testing during a local sunday pm repeater net so I had a constant signal to listen to.  I picked a repeater net that was far enough away to give me a somewhat weak signal so improvments weren't hitting the S-meter's max.  Then I just kept changing antennas and looking at the S-meter.  Do it outside so you don't have the building mucking things up.

Geek

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Re: Bought wrong antenna
« Reply #9 on: April 07, 2013, 03:18:25 PM »
Should this be solid or stranded wire?

KC9TNH

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Re: Bought wrong antenna
« Reply #10 on: April 07, 2013, 05:01:03 PM »
Should this be solid or stranded wire?
Personally, I'd use stranded; more flexible, easily found, in a variety of sources, cheap, easily stowed in some fashion if you're wearing the radio for some reason.
:)

Edited to add: If you don't already have some speaker wire (18ga or thereabouts) laying around, get thee down to the nearest "dollar-type" store and keep 25-50 feet around; pull it apart, you've doubled the length you now own. All kinds of uses.
« Last Edit: April 07, 2013, 05:03:26 PM by KC9TNH »

whoppo

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Re: Bought wrong antenna
« Reply #11 on: April 07, 2013, 08:51:44 PM »
If you use a gender-changing barrel and there's space between the body of the radio and the base of the antenna you can get a hard rubber or plastic washer to go around the adapter that will allow you to snug it up and reduce the lateral stress on the radio's SMA connector. I picked a few up at the local hardware store to use with this very same antenna... it even looks good.

cockpitbob

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Re: Bought wrong antenna
« Reply #12 on: April 07, 2013, 09:33:35 PM »
Should this be solid or stranded wire?
As KC9TNH said, "stranded".  Actually it doesn't matter at all, except the limper the better.  Though not critical, it's best if with wire hangs straight down.  My wire it stranded but isn't very limp and still makes an amazing difference in performance.

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Re: Bought wrong antenna
« Reply #12 on: April 07, 2013, 09:33:35 PM »