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Help with understanding Zaxcom ZHD wireless system


Mike H

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So, I got hold of a TRX3.5LT and a QRX200 and was surprised to find out that, at least in the environment I was testing the system in, I was getting slightly LESS distance from the ZHD modulation as compared to the XR mod. Slightly disappointing as I was hoping that the new modulation would extend the working range, which seems to be the received wisdom...

A call to Zaxcom clarified that the ZHD is really most useful in crowded RF environments, places with a lot of reflective surfaces, and suchlike. In (what I'd call) "usual" eng situations, the XR modulation is best.

The tests I performed were using the dual receiver mode (I think thats ZHD96?) mainly, although I did check using the mono modes as well. Firstly I tried line of sight walking down a side street in West Hollywood. Nice clear frequency, settings checked on tx and rx, etc. Bearing in mind that this was an LT receiver, so tops out at 50mw, using XR mod, I was getting approx 100ft with the tx in open air, maybe 50ft with it in a pocket. Whip antennas on the rx, nothing else transmitting in the bag. ZHD mode was very similar, but seemed to start dropping out maybe 10 ft earlier. 

Secondly i I tried the TX in my apartment, and walked the RX out into the street. Both modes maxed out at maybe 50ft, through walls, and again the ZHD mod started dropping out a little earlier. 

With a TRX3.x-LA transmitter I'd guess that one would get another 30% or so? But I was mainly interested in comparing the modes rather than measuring range.

Now, I'm only testing these using the kind of setup I'd be using them in. Bag use, whip antennas, and in a non challenging rf environment. I'd suspect that using directional antennas would make a world of difference (obviously) and perhaps the ZHD mode really shines in that situation?

A little disappointing as I was really hoping that ZHD would extend the working range of a TRX to match or exceed a WM, but for me, at least, it seems not!

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First test I did was indeed just me, so I left the transmitter inside and walked away with the RX (into a 633 in a bag, obviously).

Second test was with a second person, simple walk test. Same frequencies each time, just changed the modulation to see what the difference was.

As I said, my goal was simply to see what the new ZHD modulation did to the range, ie compare XR and ZHD mods.

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On the subject of Zax wireless and range before dropouts,  I've got two TRX LA 2.5 with a QRX 200 receiver.   In a bag, using whips, at 125mw transmitting power, the range before dropouts is consistently about 60% of the range of my 100mw Lectros with 411 receivers.  

 Love the encryption, love the onboard recording - don't love the fact that I HAVE to use the onboard recording when my subjects get any significant distance away from me- it makes extra work at the end of the day.  If anyone has any tricks they are using to make the range better- let me know.  From research on this board, it would seem that everyone who is quite happy with their Zax range is using directional antennas, which is not going to be possible with a stripped down documentary rig.  

Cheers,

Brent Calkin

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31 minutes ago, Freeheel said:

On the subject of Zax wireless and range before dropouts,  I've got two TRX LA 2.5 with a QRX 200 receiver.   In a bag, using whips,  

Cheers,

Brent Calkin

Hi Brent, its the whips. I run a very similar setup and found the whips are hopeless. If a decent antenna setup is not possible with fins then a couple of dipoles like the SNA600 from Lectro are a huge boost. Because I have more receivers than just 1 x QRX200 means I use a mic plexer too which provides another 6db of RF gain. Also try and keep the dipoles elevated or free from too much obstruction. Sure its probably more messing around than the 411's but the extra sound quality is so worth it.

Tony

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Thanks, Tony.  I guess I'll have to make up some dipoles and see how they work.  Unfortunately my hops are already running on dipoles over my shoulder and down my back, so I'll have to be careful with placement.

Rado, what are you using for antennas?  Are you on whips?

Cheers,

Brent Calkin 

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2 hours ago, Jason Todd said:

Using a micplexer with SNA600's on my shoulder has made the range much more usable.

Also, I'm gonna upgrade my QRX200's this weekend since Rado seems to be implying that the latest firmware has even better XR modulation range.

My range with Zaxcom wireless was sub-par on whips at best, and unusable at times far too close to talent.

Then I put dipoles in my bag, and at the same time (literally the same night I added dipoles) I upgraded to the latest QRX firmware available and the range was more than doubled overnight. I've now been using my TRX / QRX combo with up to 12 wireless in one block at the same time while working with another mixer with an incredibly high rate of success and range improved enough that I no longer have worries of dropouts unless someone is quite far away or through too many physical barriers. 

If you're a Zaxcom wireless user, I suggest immediately nuking your whip antenna setup and investing in a set of dipoles, and then immediately updating your QRX and TRX firmware. The Lectrosonics SNA600a are outstanding in my setup, and can be either velcro'd or cable-tied to most bag setups.

 

 

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4 hours ago, Toy Robot said:

My range with Zaxcom wireless was sub-par on whips at best, and unusable at times far too close to talent.

Then I put dipoles in my bag, and at the same time (literally the same night I added dipoles) I upgraded to the latest QRX firmware available and the range was more than doubled overnight. I've now been using my TRX / QRX combo with up to 12 wireless in one block at the same time while working with another mixer with an incredibly high rate of success and range improved enough that I no longer have worries of dropouts unless someone is quite far away or through too many physical barriers. 

If you're a Zaxcom wireless user, I suggest immediately nuking your whip antenna setup and investing in a set of dipoles, and then immediately updating your QRX and TRX firmware. The Lectrosonics SNA600a are outstanding in my setup, and can be either velcro'd or cable-tied to most bag setups.

 

 

I absolutely agree - I've even got much better range with homemade dipoles on my harness. Unfortunately for the particular show I'm prepping for, that won't work as it involves a lot of climbing, rapeling, cave swimming, etc, so the setup needs to be super compact and able to be handed off and literally tied to a bit of rope and dragged up a cliff face and suchlike. Anything extra attached to a bag or a harness is another thing to get caught/snagged/broken. Joy!

Anyway, my point was that the difference between the new ZHD modulation and the "old" XR modulation seems negligible, when I was under the impression that it would be markedly better. It seems that it's horses for courses, and that in certain RF rich circumstances the ZHD mod will be a godsend, though.

Not that this can't work in my situation - in fact I was on a big reality/survival show last year that was all TRX2.5 and QRX200 and it worked great, but we were aware that we were sacrificing range for the advantage of having a one-pack solution which was really necessary with upwards of 14 talent in the jungle for a few weeks! Upcoming show is only two talent (host and celeb) in jungle survival environments, so I'm probably going to stick with WM transmitters and ZFR recorders and have the best of both worlds...

6 hours ago, Jason Todd said:

Using a micplexer with SNA600's on my shoulder has made the range much more usable.

Also, I'm gonna upgrade my QRX200's this weekend since Rado seems to be implying that the latest firmware has even better XR modulation range.

 

On 8/23/2016 at 8:59 PM, RadoStefanov said:

You have to compare to the XR on an older firmware qrx200. (:

Ahhhh I wasn't getting what you're implying, Rado. So maybe ALL the modulations on the new firmware are better? That is interesting.

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+1 on the dipoles and micplexer. You can get creative how compact you can make your bag. Gonna try a fw upgrade tonight

i should clarify - lectro dipoles - my homemade dipoles did great but did not do as well as the lectros. they use a secret sauce with those

-Ken

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I guess I am doing something wong because I match and beat 411 range ...



Same here.
My TRLA2.5 transmitters have been getting range equal to a SMQV since I got them in 2014. Whips versus whips. City (even NYC), desert, jungle, whatever.

The "real world tests" of ZHD that I was there for were freaking impressive. One was with Rado at a location he shoots at all the time. The other was outside Gotham Sound in NY. Very very impressive
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I vaguely remember Howy say that the new guts on the ZHD wireless would improve transmission efficiency even on older modulation schemes. Along with that, remember that there are two ZHD modulation schemes, ZHD48 and ZHD96, the former being the smallest transmission footprint at 48kHz but only usable with QRX receiver in single mode and the latter with the 96kHz footprint but available in dual mode. I would take these into account when doing your tests.

All the comparative tests we did on the field before the product was released (I was part of 3: one in Midtown Manhattan, one in Las Vegas, and one at Gotham Sound) were with the new hardware in ZHD48 (single mode) vs the old hardware in XR.

If you're using the same TRXLA3 and just switching between ZHD96 and XR, I suspect you will not see the same results that we had in those early tests.

21 hours ago, Toy Robot said:

My range with Zaxcom wireless was sub-par on whips at best, and unusable at times far too close to talent.

Then I put dipoles in my bag, and at the same time (literally the same night I added dipoles) I upgraded to the latest QRX firmware available and the range was more than doubled overnight. I've now been using my TRX / QRX combo with up to 12 wireless in one block at the same time while working with another mixer with an incredibly high rate of success and range improved enough that I no longer have worries of dropouts unless someone is quite far away or through too many physical barriers. 

If you're a Zaxcom wireless user, I suggest immediately nuking your whip antenna setup and investing in a set of dipoles, and then immediately updating your QRX and TRX firmware. The Lectrosonics SNA600a are outstanding in my setup, and can be either velcro'd or cable-tied to most bag setups.

 

 

+1 :-)

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