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To increase the performance of my Saber 1 I installed a 1/4 wave UHF antenna on my vehicle. Instead of using the external antenna pins and biasing the radio, I simply used an adapter in place of the antenna. Performance is much less than with the original rubber ducky,
To verify the antenna installation I used a scanner programmed within the same range and had great performance. My question is, on this model is it not advisable to install an external antenna in this manner, is it maybe only tuned to handle the original rubber ducky uhf antenna.

This thread may answer your questions.

http://batboard.batlabs.com/viewtopic.php?t=29473

The search feature on the site works wonders.

Yes that helped. I new the antenna connector was not grounded, so I grounded the coax to the radio chassis ground. This wasn't suitable and it didn't actually make a difference between grounded or not ( for receive anyway). The adapters as described in the thread will not work since most incorporate the ground and this will short. The adapter I am using isolates the ground from the stud, but it does not seem to work anyway, it probably is an impedance thing. I will try the external antenna connection point, but the radio must be biased for that?
Thanks.

Stop horsing around and install a 5487 SVA, which is
designed to allow you to use an external antenna when
you're mobile. If you don't you'll eventually fry your
final amp in the Saber and then you'll REALLY have a
big problem.

SVA's are now relatively cheap, easy to install, and
very reliable. Just be sure to get a guarantee that the
one you buy is in working condition.

Tom is absolutely right here!

The RF is routed through the F.D.S(filter/detector/switch) and when the impedance changes between ports, the F.D.S senses this and routes the RF to the external port on the rear of the radio, any other toying around WILL blow the PA and the FDS as both were never intended to operate into a shorted condition for any length of time.

The SVA is the ONLY proper way to get the signal out from the inside of the vehicle.

The F.D.S also detects RF and forces the PA into a foldback condition if high SWR is detected, and of course, this also has a direct impact on the reception of the radio as well.

I'd hate to see you ruin a fine radio by taking short cuts.

Thanks for the advice, unfortunately I don't have the room for a vehicle adapter if this indeed was what your referring to. My antenna adapter didn't short the antenna stud since it was isolated from the ground, but needless to say your right and there is probably better ways to do it. My HT1000 worked great with an sma adapter and it also had the external antenna pins, and yes I know the antenna stud on the Saber does not incorporate a ground where as on the HT it does. In the Saber accessory connector description if pin 7 (opt sel) is grounded through a zener diode= 3.74 vdc.
Doesn't this mean the radio will transfer to the external antenna pins?This may be a good option for me in this situation.
Thanks for your help so far

Steve:

Running external OPT SEL pins externally is a far more difficult task to create and modify the accy. connections to do the task of the SVA, but you will have a large mess of easily shorted components hanging off the back of the radio.

The SVA performs the task properly and easily, plus gives you far more freedom of movement with external speaker output levels as well, making the paltry internal speaker use passe so to speak.

Not to mention, if you obtain the display mic, it's just like having the radio in your hand, with all the radio functions at your fingertips, aside from VOL/PWR and channel changes, but zones can be done from the mic.

The HT1000 not only had a direct connection, but that connection also has the disconnect once the accy is installed, disconnecting the internal antenna physically while not doing so electrically which the Sabers do.

The only drawback to the mechanical connection, is the wearing out of the antenna disconnect whereas the electrical method has no wear, but does suffer from shorts and external electrical discharges.

I never heard of an FDS switching RF paths.

But, I agree that the SVA is the way to go. They are cheap enough that there's really no excuse.

mancow wrote:I never heard of an FDS switching RF paths.

But, I agree that the SVA is the way to go. They are cheap enough that there's really no excuse.

That's only part of the 'job' it does.

The others are detecting RF power as well as filtering the RF signal, hence the term: F.D.S for Filter/Detector/Switch.

Actually, there is a pigtail available that connects to the accessory port of the Saber. It terminates in a BNC connector and will drive an external antenna just fine. This pigtail is a real part, and I have used mine with both VHF and UHF Sabers with great results. I'm sure that is is long NLA, and I don't have it in front of me to find the part number. But be on the alert for it at hamfests or if you find someone selling a pile of surplus equipment. Mine was included in a lot of parts that I bought for a completely different radio model. It looks exactly like what it is...a coax coming out of an accessory connector. It is not kludged together or made from something else, but for this purpose.

You cannot, unfortunately, use a Saber programmong and alignment cable for this purpose, since that cable reroutes the audio as well.

Good luck!

AEC wrote:

mancow wrote:I never heard of an FDS switching RF paths.

But, I agree that the SVA is the way to go. They are cheap enough that there's really no excuse.

That's only part of the 'job' it does.

The others are detecting RF power as well as filtering the RF signal, hence the term: F.D.S for Filter/Detector/Switch.

Oh, yea I guess so. I was reading it as if the FDS sensed the SWR and picked the path all on its own. I'm with you now.

Thanks for all the info. I was just offered a 5/8 wave 403-430 for my vehicle install but was warned that the impedance may not match the sabers impedance, could this be an issue? Right now, I have just the 1/4 wave spike installed. Is there a way of knowing if it is a good match? In the past, I would only check the swr and adjust as necessary.

Stevey

stevey wrote:Thanks for all the info. I was just offered a 5/8 wave 403-430 for my vehicle install but was warned that the impedance may not match the sabers impedance, could this be an issue? Right now, I have just the 1/4 wave spike installed. Is there a way of knowing if it is a good match? In the past, I would only check the swr and adjust as necessary.

Stevey

Stevey:

If you are going to use the 403-430 band, then yes, it should work fine for you, but if your needs are higher in the band, then no, the antenna will be out of resonance and will need to be replaced with the proper band split you will require.

You can always trim the antenna for use in your band of choice, but with any collinear, it's a little 'touchier as both the upper and lower sections of the antenna will require 'adjustment' due to length, and not just a lower section trimming will work, as the antenna's main radiating section will be longer at the lower frequencies than one that is tuned for say, the 440-450 band.

Check with the manufacturer on tuning directions, they are your best source here, and can supply you with the proper cutting charts should you choose to retune that antenna.