Do NOT use Diamond SRH77CA on SDS100
- Thread starter bob-k
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Uniden listens ? When was there an outcry for the next scanner to be water resistant ? And how many of us said okay to losing the use of 99% of our favorite SMA antennas that we've used for years with the 396XT and 436HP's?
Something is wrong when you have users modifying there $20-30 SMA antennas just so it will fit the SDS100.
Ubbe
Member
Remember that the SDR receiver chip in the SDS100 are designed to receive tv signals that are 5-10MHz wide, not 25KHz. The manufacturer Rafael recommends the chip for digital terrestial and cable tv.
My SDR usb sticks reacts to any strong signals withing a few MHz that'll raise the noise floor and burries the carrier signal in the noise and if it is set to AGC the received signal level jumps around like crazy.
The specification for the SDR chip says it's using an internal power detector to adjust the gain of its front end amplifier. Only the IF sections gain can be controlled from an external source.
I have no idea how Uniden have solved this to be able to only let the internal power detector see the signal level from a 25KHz bandwidth and not from adjacent frequencies within 5MHz. Maybe it's a hardware limitation and are unsolvable, lets hope not, and could be the reason why there are some strange signal level behaviour from this scanner.
/Ubbe
How soon we forget. Using SMA antennas has always been problematic. There has never been a standard for how far the SMA connector should protrude from the body of the radio, so some antennas fit OK, some antennas didn't make electrical contact because they couldn't screw on far enough, and still others bottomed out on the SMA connector before contacting the radio body, leaving a gap between the antenna base and the radio, looking like crap, and greatly increasing the risk of breaking the SMA connector, unless you could find a washer of the correct thickness. The SDS100 has simply changed the mix of SMA fitment issues encountered.
Using BNC antennas has always been faster and more convenient to change antennas (no cross-threading,1/4-turn of locking collar to attach or remove), standardizes base, mobile, and handheld antennas on a single connector, eliminates the SMA fitment issue (as long as the adapter matches the radio you're good), and reduces wear on the radio itself (the SMA connector only gets wear when you change adapters, not antennas).
Your comparison is only valid if you compare the same set of frequencies before and after. If the new antenna picks up additional freqs that the old one did not, then the new freqs will skew the average and make it look like the new antenna is performing poorly when the opposite is true.
I found these Antenna's to work very well i prefer band specific antenna's
I used a simple carpet knife and just cut some of the rubber molding off
this one pictured is 6'' 150-163 1/4 wave EXB150smi
Laird Technologies - EXB-150-SMI - 150-162 Portable Antenna, Icom IC-F250
Laird Tuf Duck Antenna
I used a simple carpet knife and just cut some of the rubber molding off
this one pictured is 6'' 150-163 1/4 wave EXB150smi
Laird Technologies - EXB-150-SMI - 150-162 Portable Antenna, Icom IC-F250
Laird Tuf Duck Antenna
Attachments
It was designed for 2M/70CM operation. It will not be optimal across the entire electromagnetic spectrum.
Then why does Uniden , Icom, Kenwood and Yaesu use SMA connectors if they are so "problematic"?
The problem is Uniden's design of the SDS100 to meet water resistant specs.
Jon, are you serious ? The BNC adapter that comes with the SDS100 make its more difficult and inconvenient to use. You even recommended someone to "Get a lathe!!!" so they can modify their SMA antennas.
Each manufacturer uses a different protrusion dimension, even from model to model (Uniden is not the only one guilty of this), which the antenna needs to match to fit properly. It's one way to "encourage" users to use the manufacturer's antenna, while still nominally adhering to a standard. Thank you for making my point for me.
The SDS100's SMA connector protrudes from the radio body less than other models. There is no standard that specifies how far it should stick out. See my first comment.
Absolutely. Some of the factory BNC adapters fit tightly. You just have to tighten the adapter on the SMA connector a wee bit tighter, so it doesn't unscrew when changing antennas.
As for the lathe comment, that was in reference to the guy who dremeled the base of his SMA antenna. Not exactly the best way to get the dimensions right for optimal fit, and not very aesthetic, either. If you're going to modify an antenna to get the fitment correct, a lathe is the right tool for the job, not a Dremel. But that is hardly the same as saying only SMA antennas should be used.
Oh Really?
What is what looks like a metal band? Being this is brand new I eat it if it is defective, yet I may try it as I prefer the tighter fit of SMA. So you modified yours instead of getting a same antenna w/BNC.
Phooey!
5 minutes with a Dremel and problem solved!
Sent from my SM-G935V using Tapatalk
What is what looks like a metal band? Being this is brand new I eat it if it is defective, yet I may try it as I prefer the tighter fit of SMA. So you modified yours instead of getting a same antenna w/BNC.
Yes. The metal band is the unpainted metal that I ground down so that the antenna will fit.
Sent from my SM-G935V using Tapatalk
Sent from my SM-G935V using Tapatalk
Valeriy
Member
On July 27, 2017, in the afternoon I saw the worst Summer shower ever, and I was out and about with my 436 in a belt case.
My 436 survived, but I definitely didn't like the risk to ruin it...
I think all the handheld devices such as scanners, transceivers, mobile phones, navigators, etc.
should be built to comply with military-grade specs.
seth21w
Member
It would have been much easier to make a bnc connection waterproof than the sma! And it would have been more durable. Should have went bnc to start with.
Valeriy
Member
I agree. I've never liked the weak SMA connector. BNC is more operational, so to speak.
SMBaugh2
Member
The problem is Uniden's design of the SDS100 to meet water resistant specs. I love my SDS-100 but this statement is what bothers me. The fact that now all of my SMA antennas will not work with my SDS-100. But I can use my BNC antennas. How ever I will say also that having my scanner somewhat weather proof and I don't have to worry about hiding it in the rain and worrying about it getting wet is nice to have too. So the moral of this story is you just cannot have everything.
Looks like RH77CA is worse for you. Where exactly are you located in the Seattle area? I live fairly close to the KCVC site and have much better RSSI numbers
slicerwizard
Member
No! ur doing it all wrogn!
Instead of dealing with the issue, you're supposed to fire off a multi-post rant-fest.
(Damn, can't even write *****fest here)
Instead of dealing with the issue, you're supposed to fire off a multi-post rant-fest.
(Damn, can't even write *****fest here)
Phooey!
5 minutes with a Dremel and problem solved!
Sent from my SM-G935V using Tapatalk
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