Most of this is true, but good noise blankers only operate on impulse noise. More to my point is that noise blankers were a big factor in my observation, therefore the dominant problem still appears to be impulse noise.
In a similar vein, many of the newer, inexpensive small wide band Low VHF radios have foregone noise blankers entirely. There is no question that there has been a rise in the urban noise floor at all frequencies. Computers and networks are a major contributor. But like any other radio source, path loss is a reality and when operating mobile other vehicles have the proximity advantage. The fact also remains that even if you presume that FE bandwidth is a factor, it's only likely a 15 or so dB factor with respect to broadband noise - and that's only. Adjacent vehicles on the road have a lot more impact than that, probably starting at 30+ dB. Oz On 8/30/2010 4:36 PM, Paul Plack wrote: > > > > > Noise blankers also target broadband noise. If some computer is > dumping right on your intended receive frequency, you're out of luck. > > 73, > Paul, AE4KR > > > ----- Original Message ----- > *From:* Chuck Kelsey <mailto:[email protected]> > *To:* [email protected] > <mailto:[email protected]> > *Sent:* Monday, August 30, 2010 3:10 PM > *Subject:* Re: [Repeater-Builder] DB212-3 > > > > > > The radio I'm using in the mobile is a GE Orion with a noise > blanker. However, a noise blanker is designed to help with > impulse-type noise. Microprocessor hash and similar noise sources > are continuous, so I doubt a blanker is very effective. The > problem, in my mind, is the huge increase in this type of noise > compared to 20 or 30 years ago. > > Chuck > WB2EDV > > ----- Original Message ----- > *From:* Oz-in-DFW <mailto:[email protected]> > *To:* [email protected] > <mailto:[email protected]> > *Sent:* Monday, August 30, 2010 5:00 PM > *Subject:* Re: [Repeater-Builder] DB212-3 > > > > On 8/30/2010 2:08 PM, Chuck Kelsey wrote: >> >> >> >> >> Doug, what were the State Police using for mobile radios back >> when you were involved? I'm finding that the newer, wider >> front end, radios don't hear as well as the old 0.5-1 MHz >> wide receivers did. I can hit my 6-meter repeater full >> quieting, yet sometimes can hardly hear it due to mobile >> environment noise that you can't avoid driving past >> (computers, LAN equipment, etc., etc.) >> >> Chuck >> WB2EDV > > I'll bet 99-44/100% of this is the lack of an effective noise > blanker. I was running a LB SyntorX 9000 at the peak of the > last cycle and it ran rings around everything else. It ran > FULL band 10 and 6. Bench sensitivity of all the radios were > pretty close, but the moto mobile noise blankers were a major > (>> 10 dB) advantage. I'll bet those 'old' radios have good > noise blankers. > > -- > mailto:[email protected] > Oz > POB 93167 > Southlake, TX 76092 (Near DFW Airport) > > > > -- mailto:[email protected] Oz POB 93167 Southlake, TX 76092 (Near DFW Airport)
