buy frequency scanner or ditch G2 system?

J

Josh Bass

Veteran
Hey guys. I believe this has been touched on in other threads but I really want to hit it hard this time.

So they last several times I have tried to use my G2s, I run into serious problems with (I believe) interference. Can't remember last time if it was static or just total dropouts, but today I was getting total dropouts, I could watch the receiver LED readout and see the mute come on and the RF light go out in time with the dropouts. When I had the receiver and trans right near each other (like a few feet away), it was fine. 10 feet away, dropout city.

Yes, I am aware of the scanning function, and I am aware also of the sennheiser freq chart that shows what's good in what cities. According to both of those, I should have been in the clear (full RF bars on Receiver or trans, whichever shows that meter, scanning returned 4 channels available in each bank I tried). Still, dropout city.

It seems like every time I use this thing, I would have to manually go through all 32 channels to see which (if any) were REALLY clear, since the system can't seem to accurately tell me.

So, question is, should I get one of the $129 frequency scanners and use THAT to find what's really available in my location, or ditch the system.

I've heard the G3s are better with interference, but on the other hand, used Lectros, some of them, can be found on ebay for around $1000 or less. That's only a few hundred dollars difference and likely a substantial quality upgrade.

I know everyone says learn to find good frequencies, etc., but I've used a client/colleagues lectros a lot and you know what? We never tweak the frequency pots, and those things work all the time every time everywhere with no issues. They just work.

So, wondering your thoughts. Thanks.
 
Houston shouldn't be that bad, freq wise so you should be able to find clear channels. One difference with the Lectros is that the transmitter has quite a bit more power. If I remember correctly that is because Lectro make a US model and the others are making just one and a number of places have a lower legal limit on transmission power. I was doing a test the other day and I got a solid clear signal from the back of the basement to the receiver on the second floor at the other end of the house. So 100-150 feet through two floors and a brick wall. I expected some dropouts or static but nothing. And this is 100 series non diversity.

I have to say though that I also did a walk and talk test with a G2 system a Fantasy records and we got solid coverage almost all the way around the building, at the worst location it was going through 10 -15 offices diagonally through the building so?

Don't discount a faulty unit.
 
Unless it's recently become faulty, not a faulty unit. I've had it since 2004 or so and don't use it real often, I don't think I abuse it. Lately it only seems to work when the TX and RX are right on top of each other. I was in a med center building today having problems, last time was at the Jung center (art gallery). I wouldn't think an art gallery would have much flyin' around. . .maybe some computer wifi? I pretty much can't trust it at this point. As I said, without manually testing each of the 32 programmed channels, I have no way to know what's REALLY safe, 'cause it tells me everything's good and RF meter is full up, even as I'm watching/hearing the dropouts happen. No way to know if it's the unit without sending into Sennheiser. . .I can't recall if that's a free service or not, to have it looked at. That $800 for some lectros sounds real tempting.

Forgot to mention, no, it's not in the 700 mhz block. It's in the 500s. 518-529 or something.
 
I was going to ask about the 700 mhz so that is one thing off the table.

Are you setting them up correctly? For one thing though there are 32 presets the user bank of four presets can be set to any of the 1440 frequencies available in the range of your system.

You want the RF to show no activity at all with the transmitter off. If your getting any RF activity with your transmitter off that is not a good frequency to use. That would explain your problems and the strong RF with "drop outs" they would actually not be your TX dropping out but your Frq. getting stepped on.

Medical places are full of RF noise. I'm actually surprised they let you use a wireless mic, many don't want you even using a cel phone.

I would revisit the manual and make sure you are setting it up correctly. Having a strong signal when both are on doesn't tell you that you have a clear freq., just that you are over powering the interference. That will change with distance. If I remember correctly there is a clear freq. scan feature on the G2 receiver. You also should check the squelch setting to make sure it's not too high.
 
Yes, tested a few freqs with tx off, saw no rf activity, though that might be a clever way to check for interference in the future. Played with squelch settings too. High, med, low, no difference. This was in a tv studio in med center so yes, wireless allowed down there.

I dont know what could be set up wrong? I do a scan every time i go somewhere new. On each bank i was getting "4 channels free". Then i try any of those channels and rf city.

Thats why i had the idea for the freq scanner...instead of screwing around with the g2s, scan for whats AVAILABLE wherever i am and set g2 to THAT. however im worried g2s are going bad or things have gotten so bad in rf land in the last few years that the unit's pretty useless now.
 
Well I think you have gone past my experience/ expertise. I've only played with a friends G2 and used the Lectro's a bit. Most of my wireless experience was with VHF units in theatrical venues back when UHF was just coming in. Now those were a PITA and single freq. so if it doesn't work you are SOL.

Hopefully someone with more G2 experience will chime in.

The only other thing from the past that was a classic of problems was not using fresh batteries, or using rechargeables. Weak batteries were killers. I'm assuming you were using fresh, plus units are more forgiving now, but you may want to stick them on a tester. I have found "new" batteries now and then that were not in great shape. Usually it's because they were bought awhile ago and they just sat too long on the shelf.
 
My experience with the unit is that batteries are good for about 8 hours, and dont cause problems til they die.
 
If you really want to see what is going on - try one of these.
http://micro.arocholl.com
Very handy for seeing what channels are active.

I suspect, though, that your problem is either with the receiver or transmitter. In the absence of another set to swap, find yourself an empty space, set the transmitter up, and then walk away from it with the receiver, watching the RF display. With any of the Sennheisers, you should, with clear line of sight, not see much change in the RF level on the receiver until you get a fair way away - at least 50m. After this it will start to get fluttery and then die. If there is a problem with either unit, then the RF level will drop quickly. If this happens, give the rubber mount where the aerial joins the body a firm wiggle - if the RF jumps up, then a simple dry joint on the PCB could be the fault, and a fairly easy cure. Co-channel interference has a pretty characteristic sound, so if it is interference, then if you turn off the transmitter, the receiver display and possibly audio output should reveal something. My money's on a fault.
 
Any chance you're using NiMH rechargeables in your Sennheiser units?

Perhaps totally coincidental, but an audio engineer on a shot this year said Sennheiser G's can have more interference issues when using rechargeables due to their slightly lower max voltage output (not sure how that works). I have had fewer noticeable interference problems since going alkaline-only in my G2's, and I work a lot in DC (possibly one of the messiest RF landscapes)
 
Thanks for the troubleshooting test idea. No, just regular batteries. Kroger, duracell, etc. Will try that out today if I can. Also emailed sennheiser. Looking hard at used lectro 210 or 211s.
 
The reason that rechargeables are problematic is that the "cell" of a rechargable is 1.2 volts rather than the standard 1.5. All batteries are a multiple of their cell size so 9V is six cells (6 X 1.5 = 9) and a 9V rechargeable is 7.2V (6 X 1.2 = 7.2V). So with units that use a 9V battery the hit is pretty big. Not quite so bad if you are on a couple of AA's. Also the older chemistry in rechargeables tended to fade and of course the older chemistry didn't like partial recharges. NiMh and the new "rechargeable Alkaline" do better on the fade and partial recharge but they are still lover voltages. That is why on devices where you can use NiMh there is usually a setting so that the device knows it's on a rechargeable and gives a more accurate battery reading.
 
Josh Bass said:
Thanks for the troubleshooting test idea. No, just regular batteries. Kroger, duracell, etc. Will try that out today if I can. Also emailed sennheiser. Looking hard at used lectro 210 or 211s.
Click to expand...

From a tool I use for finding 'available TV channels', it seems that Houston has 2 UHF band channels for 'mics', TV channel 33, 584-590 MHz, and channel 40, 626-632 MHz. In the hubub on 'whitespace', the FCC came up with a requirement that there be channels made available for radio mics. For every location, one needs to find out what those channels are.

For your indicated frequency range, 518-529 MHz, there is a broadcaster operating on TV Channel 22, 518-524 Mhz, KUVM-LD, and likewise for channel 23, 524-530 MHz, KLTJ. Don't know why if you went to the 'free frequency' page that it would give you 'free' frequencies in those ranges.

I don't know if the G2 you are using can access those channels...

The rest of the Houston spectrum appears to be 'filled' with licensed broadcasters, or channels that may have interference from adjacent channels.

Locations may have more or less interference which varies throughout the day or from day to day... locations because of their 'RF' characteristics may also lead to 'move a short distance and reduced signal'...

And of course, there's always the ever occurring fault of the connection to the antenna, cabling, etc.
 
I may not have the frequency numbers exactly right but its in that neighborhood (dont have unit in front if me right now).
 
Josh Bass said:
I may not have the frequency numbers exactly right but its in that neighborhood (dont have unit in front if me right now).
Click to expand...

Here's a Lectrosonic's PDF of a frequency map for 13 'major markets', Houston included... oddly my 'source' indicated the Houston mic channels were 33, and 40... this PDF lists channel 49... so mileage may still vary... but at least it has 'nice' TV channels to MHz chart and for the lectrosonic devices what the corresponding mic channel blocks are.

Frequency Allocation Map for 13 Major markets
 
Ok i see what you meant. I bought taht system back in 2004 locally, didnt know anything about available frequency ranges etc. at the time, the question didnt even come up; that was the set/block the local vendor sold me.
 
Ok, so tried your test, put Trans on a table, walked away with receiver, watching RF meter on receiver. It didn't drop at all 'til I was way out (maybe about the distance you stated). Left my house and got to the edge of the street, only had dropped a few bars. Set to same frequencies that we last tried it on that shoot before abandoning it (529.850).

I guess it only likes to not work when I need it.
 
If buying another system be aware that the fcc is selling off some more spectrum/channels in a year. They were going to sell them off january 2014 but pushed most of the auction for a year.
 
Yes, a local sound guy told me the same. Im hoping trew audio or lectro can advise me on which blocks are relatively future proof.
 
It always makes me warm and fuzzy when the public property get sold to private companies. Ah well, they keep trying to eliminate amature radio also, the only folks who have consistently been able establish communications after a disaster.

Sorry OT kind of. Any idea which freq. they are going to sell?
 
Noiz2 said:
It always makes me warm and fuzzy when the public property get sold to private companies. Ah well, they keep trying to eliminate amature radio also, the only folks who have consistently been able establish communications after a disaster.

Sorry OT kind of. Any idea which freq. they are going to sell?
Click to expand...

I recently read that the FCC is 'encouraging' experimentation by TV broadcasters to combine several stations to use the same channel... This may be 'reasonable' for very small stations... but really it is so FCC can sell off the vacated spectrum in the 'below 700 MHz' region to LTE carriers... as if auctioning off the above 700 MHz several years ago wasn't enough... in any case it will be region dependent and most likely involve 'unused' (or recently vacated...) channels.

But I don't think the '2 mic reserved' channels will be part of the auction... but who knows...
 
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