mic problems with ht1250

[habfirelt]

someone please give me some ideas to why my radio is doing this. if i dont use a shoulder mic i can transmit fine, but when i put any shoulder mic on my radio i can transmit but all you hear on the reciving end is feedback like i am holding my mic to close to another radio. it worsens on tac channels more than dispatch channels. if anyone has any ideas please let me know

[HLA]

does this only happen with your radio or just your speaker mic? try using another speaker mic on your radio and your speaker mic on somebody elses radio and see if the problem goes away anywhere?

[habfirelt]

mine was ok wiht a psm and witht he regular mic and the new rugged mic both motorola mics it sounds like i am in a bucket

[Grog]

mine was ok wiht a psm and witht he regular mic and the new rugged mic both motorola mics it sounds like i am in a bucket

Just making sure, you're not actually in a bucket, right?

[habfirelt]

not in a bucket. the psm doesnt get out great around here is the only problem

[Idahoht1250]

I joined this forum specifically for this issue. My public safety agency just switched to the HT1250. Without the shoulder mic it works great! With it, NOT so much. We are on VHF and are using the Public Safety Mic with the antenna on the top. I have spent 3 days with an engineer going over the mic. It is VERY directional many of the end users are having trouble getting out. I have experimented with the gain level in the programming and it has helped a little, but if you get it too high there is a very very annoying "hiss" from every transmission. If anyone can help please let me know. My dealer has contacted Motorola and they basically said "deal with it".

[Tom in D.C.]

To start with, are you certain that you're on VHF and not UHF? Reason I ask is that Motorola usually does NOT recommend use of the PS/antenna speaker/mics on VHF, only UHF. For one thing the antenna used must be a super-short VHF unit which really has bad transmit
characteristics, unless you use the longer "standard" VHF stubby antenna which is likely sooner than later to stick you in the eye.

[Idahoht1250]

Yes we are on VHF. I helped our local radio engineer with the programming. We are using the stubby antenna from Motorola. They say "Motorola VHF" on them. We are between 151 and 156 mhz on most of the channels. We put the radio and shoulder mic on a scope and tried various antennas. Stubby that came with them actually works good, according to the scope anyway and it does actually put out considerably more signal that using a standard shoulder mic. Our main problem seems to be that the mic is so directional that you just about have to unclip it from your should and talk into like a mobile (car) mic. When you do this they work well. The problem is that this is not practical for field personnel to unclip the mic from their shoulder everytime they want to talk on it. The radio engineer has filed some kind of research notice or something with Motorola. I am looking for someone out there who is using this setup successfully. I know that there has to be one out there somewhere. When the HT1250 is used without a shoulder mic it works GREAT. I have been really frustrated by this issue so any help that anyone could give me would really be appreciated.

[wx4cbh]

That mic was never really designed for VHF and they don't recommend it for use on VHF, so MotherMoto is probably not going to support using it for that. In fact, when looking at the way the antenna circuit is designed it's almost as if the radio wasn't designed with external antenna attachments in mind at all, and anything of that nature is an afterthought.

Without getting immersed in techno discussions, the way the antenna matching is done just isn't physically or electrically optimum for external microphones with antennas at any frequencies, but because of shorter wavelengths is "acceptable" in the UHF ranges (400 and 800). "Acceptable" doesn't mean it works as well as the standard configuration in those ranges, but it works in those urban systems where there is plenty of signal level and there are multiple receiver sites.

I've never been able to get one to work satisfactorily on VHF, even on systems with multiple receiver sites, and yes, I've tried at the request of customers, but to no avail. Guess that's the way it's gonna be.

[laramiecountyCERT]

We ran across the same problem with the PSM that we had for the HT1550's that we use and did away with the PS and went with a standard mic instead. The VHF PSM are not very good at getting good audio out of them and yes they are VERY directional as the mic sits back in a rubber gasket well behind the plastic cover which turns the mic port in to a tunnel thus reducing the effectiveness of the mic to begin with. I know you loose some signal on your belt with an HT and the antenna next to your body but then the audio on the PSM leaves a lot to be desired as well even with the mic gain set to max in the CPS it was still low. You might be better off just getting a standard mic and see if that doesn't work for you instead.

[escomm]

just so we're clear, which psm is being used? the hmn9057 that has been canceled or the current rmn5076?

[Idahoht1250]

The new one. Model # off the unit: RMN5076A.

[Karfield]

I do believe that new mic has the 3.5mm headset jack installed on them. If that's the case might I suggest getting the clip on mic for your lapel. That might help fix your audio issue and still allow you to get your added benefit of having the PSM on your shoulder. However I generally cringe when I see the Waris series PSM's (shiver)

[Idahoht1250]

Thanks to everyone for helping me with this question. After working with our local radio engineer and motorola here is the simple solution we came up with. The noise cancelling part of the mic is done through a small hole on the back of the shoulder mic that is supposed to help, in my field tests is DOES NOT help. To defeat this we simply put a piece of black electrical tape over the hole on the BACK of the mic. Just take off the clip, put the tape over the hole and then put the clip back on to hold the tape in place. This defeats the noise cancel problem and still gives you the antenna on your shoulder away from your body. We have been using the "CplK" modification for a week now and the results are amazing. It really works! Thanks again to everyone that responded and if you are using one of the Public Safety Mics try the CPLK mod and see if it works better for you.

[laramiecountyCERT]

Thanks for the tip I will have to try that with our mics here and see if that does not work to relieve the problem of low audio.

[Tom in D.C.]

Noise cancelling microphones work fine if you, first, need them and, second, use them properly. You use them in noisy environments, but the catch is that they must be "close talked" and close talking does not cover talking out of the side of your mouth to the unit which is on your shoulder. If you operate this way you should be using a mic with standard gain. Following these basic principles will avoid your having to use a mic with tape stuck to the back because someone who didn't know any better ordered the wrong mic.

[laramiecountyCERT]

Thanks tom, I was curious after dissecting one if the rubber holder for the mic had anything to do with it? I am just reaching here but we had all kinds of problems with ours and then decided to get rid of them for just a standard mic.

[Idahoht1250]

Your right Tom. Our issue was we wanted the antenna on top of the shoulder mic and our sales guy told me that Motorola only makes them in noise canceling. So we bought them with some grant funds and now we are stuck with them. Thanks again to everyone on the forum for the help.

[muggsy09]

Had the same issue with my HT1550XLS, brand new out of the box, would hiss crazy when transmitting. Drove me crazy. I paid like $900 for it new and it wasn't working right. So brought it to the shop I bought it from and they sent it out to Motorola. came back a week later with new firmware and one of the parts replaced, works perfect now. Clear as a bell. I looked for the depot slip but I can't find it and I can't remember exactly what part had to be replaced, but if you send it out Motorola should be able to fix the issue. Mine was under warranty so I paid $0.0