Azden 325 system

[Chris Harding]

Hi Randy

Mine is dual channel and not diversity!! Now I went back to the older 200ULT Dual receiver and guess what it's also not diversity either..with diversity you need two antennas so when they make the dual channel unit the diversity system goes out the window!!!

It seems like it's better to have two single channel systems and then strap the two receivers together on the back of the camera and then both are true diversity!!!

I have a single channel set so I think I'll put the dual one on ebay and use two singles rather and get good audio. My single channel diversity set has been running close on 5 years now and not ever a drop out!!!!

Chris

[Randy Johnson]

I am using mine this weekend I will let you know.

[Randy Johnson]

o.k. I got my 310 today. I didnt give it a full test but what I did seemed VERY promising. I set the body pack with a lav up in my garage I have a 2 story house. I walked with the camera out of the garage down the steps and into the basement. I didnt see or hear as much as a hicup it was rock solid. 2 things I noted about my camera that you may already know. 1. If I am in ALC and I hit the external shotgun mic on my AG-hmc 150 it clips my primary channel also (weird shouldnt do that) 2. the input level that works best is -50 in the menus -60 is too much. i'll report again in Friday after my wedding.

[Randy Johnson]

Well I took it on a job, its hard to tell if all is well because the job was so small. It was outdoors with only 100 people so I was like 20 feet from the groom although when I saw the groom approaching he was up to 100 feet away and the signal was fine. It did however drop out at 50 feet indoors but I was walking around from room to room. I dont have any more jobs until December but I when I do I will report. for now I will keep the 310 series.

[Chris Harding]

Hey Randy

Did a wedding tonight (it's Saturday here) with the 330 and I was never more than 20' from the groom in the Church so it was fine. However while he was still outside it was breaking up like crazy. I find that people not walls cause the chaos!!!

I have bought another 100ULT system from the USA via my buddy Chip so it's going from Georgia to Wisconsin and then to Australia!!! My current 100ULT punches thru anything so I'll make a bracket for the two 100UPR receivers on the camera (so I have a dual system) and then put the 330 system on eBay!!

The problem is definately in the receivers!! The transmitters work great with the 100upr receiver!!!

My 330 works great at home I can go outside so the signal needs to go thru maybe 4 walls of the house plus twists and turns and furniture and works fine!! Put it in a Church with 100 people and it dies!!!

I certainly hope your 310 works out fine!!!

Chris

[Randy Johnson]

Its a shame how that works, you test like crazy at home but once you go into the field it all turns to crap. As I do more work I will send more updates. BTW here in the states we had a law making digital signals the law and when they did they changed our frequencies are the systems in your country the same frequencies as ares? I didnt start having issues until the new ones kicked in.

[Randy Johnson]

Just to follow up I did a wedding in real world conditions last week and the 310 worked fine I was in a small greek orthodox church it was about 18 pews I went to the back and out the front door and went about 50 feet further before I started getting dropout. So I can definatly say there is something wrong with the 325 series.

[Roger Van Duyn]

This is an interesting thread, especially the part about "diversity" reception. I have the Azden 325 system too, and have experienced intermittent dropouts with it. This thread got me started reading. It looks like not being a true diversity receiver is the source of the problem, not the transmitters at all.

So, not wanting to waste money, what receivers should I consider to work with my current three transmiters? I have two 35BT Body Pack transmitters with lavalier mics, and one 35XT Plug In transmitter that I use with various hand held microphones.

Randy, how's your 310 receiver holding up?

Has anyone tried a Sony URX-P2 receiver from the Sony UHF system with the Azden transmitters. Specs say it runs on channels 30/32 like the Azdens? Is is easy to set them to the same frequency? I have a chart that shows frequency vs. channel number. Azdens display channel number. If sony shows frequency instead of channel numbers, just use the chart?

[Greg Miller]

To address some comments about antenna length, a 1/4 wavelength antenna at 800 MHz would be quite close to 3.5" in length.

At that frequency, you will get significant RF attenuation from human bodies. It might be helpful to have the antennas elevated above floor level, so the signal has a relatively clear shot from transmitter to receiver. Doing that would require proper low-loss coax cable, and also an antenna with some sort of ground plane... you can't just put a "stick" antenna on the end of the coax, as a 1/4 wave is only half of a dipole and you need some ground plane elements to mirror the other half.

You will also get plenty of reflections inside a building, and when the distances are just right (or actually just wrong) you will get destructive cancellation between the direct and reflected signals, causing a big null in the RF signal level at the receiver. That's when it's really useful to have a diversity system, ideally with the antennas separated by many wavelengths.

Of course with a true diversity receiver, you would want the two antennas in different physical orientation... typically one leaning 45° to the right of vertical, and one leaning 45° to the left. That's because the receive antenna should be parallel to the transmit antenna, and as the transmitter moves around, the "talent" assumes different postures and positions, that antenna polarization will be constantly changing.

[Chris Harding]

Hey Roger

If you look at the specs the dual receivers are not true diversity one antenna is for one receiver and the other for the second. My solution was to get two 100ult receivers and mount then side by side..they span the same frequency range as the 325 and 330 but each are true diversity!! They also seem to have a lot more output!!!

The 35 series transmitters are great with no issues at all.....don't fall for the dual 200 series receiver either!! That's not true diversity and only has two antennas. You could check and see if the 300 series single receiver has two antennas and then find two of them!!

I did tons of tests between the 325 and 100 swopping receivers and transmitters and the 35 transmitters are perfect..you just need true diversity receivers to work in tough situations....the attenuation was far greater with the 325 compared with the 100 diversity when the signal had to go thru glass but was the worst by far when the area between TX and RX was filled with people!!! In a Church when the groom was at the door and I was up front at a wedding the signal was almost zero!!!

Chris

[Roger Van Duyn]

Thanks Greg and Chris. I absolutely NEED to get a true diversity receiver. But my present transmitters might be okay. At the least, if I get a new system, I'd like to be able to use my present transmitters, lavs, and handheld transmitter as spares. They should work with another Azden receiver, and I won't fall for the twin antennas on a dual receiver looking like a diversity receiver. I'll make sure to buy a "true diversity" model this time.

What I'm wondering about though, is mixing and matching with different manufacturers? The Sony model is attractively priced right now and seems to work on the same frequencies as my present Azden 325 system. The current special on the Sony comes with one transmitter too, and it's the same price as buying just the Sony receiver, or an Azden 310, receiver only. And the Sony say's "true diversity."

IF I had plenty of money now, I'd buy two Sony systems. I still might try to scrape up the cash. But other business expenses are looming, taxes etc.

Opinions?

[Greg Miller]

Chris:
I'm surprised you mention glass. Glass should provide no attenuation to RF signals, since it is non-conductive. However, if it's a tinted glass with a metalized layer, or metal film adhered to one face, then it could indeed provide some attenuation. (Of course metal insect screen on a window frame would attenuate greatly.)

Roger:
Unfortunately, different manufacturers' systems are not necessarily compatible, even if they are the same RF frequency.

Unlike broadcast FM, where the specs were determined years ago by the FCC (or whoever your local compliance division is), wireless mics have no universal modulation standards.

Some might use no pre-emphasis, some might use a proprietary pre-emphasis curve. Many wireless systems use some sort of companding to improve the S/N ratio, but again there's no standard so one transmitter might seem to produce bad gain pumping with a different brand receiver.

[Roger Van Duyn]

Greg, thanks for the heads up on mixing products from different manufacturers.

A little while after posting this, I found a really good price, $269 with free shipping, on a new Azden 310 receiver, so I ordered it. Hoping it gives me far fewer dropouts. At least I know it's compatible with my transmitters, since they are the same ones sold with the full kit.

[Chris Harding]

Hi Greg

Quite correct ..however the receiver being that poor means that any attenuation might cause a drop out..the door frame was aluminium.....With both systems I walked from the office down the passage and thru the living room to the sliding glass door and out into our driveway. The 330 dropped out everytime at that point yet the 100 didn't falter once!!!

Chris

[Greg Miller]

Hi Chris,

Yes, an aluminum door or window frame could cause some attenuation and/or unwanted reflections.

For that matter, more and more construction these days is done with metal studs, rather than wood, and a wall full of metal studs could certainly cause some problems. Another insidious problem is the foil-faced foam insulation that's being used in a lot of wall construction these days. If your wall is full of 4' x 8' sheets of aluminum foil, then the room is pretty well shielded, depending on the frequencies in use... and the same foil could cause a lot of destructive reflections inside the room, too. It's an ugly world out there.