Lectro SR users: are you using UM400 or LMa?

[Philip Perkins]

I was wondering what TX most folks were using with their SRs.  Since the SR is less selective than the 411a, are you finding that you want to be using the more powerful TX rather than the "half-power" LMa?  Or is there a real diff after all?

Philip Perkins

[Marc Wielage]

This has come up several times on the Lectro discussion group. I fretted for a little while about whether to use two UM450s transmitters to the SR for a camera feed, but ultimately decided the extra 4dB increase in power wasn't worth the sharply decreased battery life. I ultimately decided that the UM400a would be "good enough" and was more flexible in the long run. The LM is only 3dB less powerful than the UM, but I figured the latter was a better tradeoff overall.

There's a good table on how mW translates to dB here:  http://www.cisco.com/en/US/tech/tk722/tk809/technologies_tech_note09186a00800e90fe.shtml.

Like a lot of users, I'd like to see Lectro make a tracking front-end version of the SR, but I think it was all they could do to pack the equivalent of two 401's in one box for now.

[Chris Durfy]

I'm using Um400a's with my SRs.

-Chris

[Alex Altman]

Same here, I'm using to UM400's as well. On the shoot I'm on right now, I have to use one of my SM's because I'm short a UM, but everything is working the same.

[Glen Trew]

It is a misconception that the LM transmitter is half the power of the UM transmitter. As explained by Larry Fisher many times, the published spec of 50mW for the LM is a guaranteed MINIMUM output power which saves them the expense of having to fine tune each one to 100mW (like they do with the UM transmitters). This is one reason for the LM being less costly to make. If I recall correctly, Larry has said that the LM transmitters will typically fall between 70mW and 100mW, making a range difference between the LM and UM transmitters, due to power, pretty much negligible.

Glen Trew

[studiomprd]

there are many other factors that will come into play before any raw power difference significantly affects the actual performance.

[Derek H]

So if the power difference is negligible then what are some other pros/cons of using the LMa over the UM for sending to an SR?  I've checked the specs and it seems they're practically the same transmitter.  Anyone have any field experience using the LM for camera hop?  Does it really cost twice as much to guarantee 100mW?

[nickreich]

Can I expand this question a little to include SMa transmitters? I'm looking at buying a kit comprising a SR receiver and two SMa's for use in a lightweight bag rig. Any reason these would not be a good match? I know they're lower output power, but does anyone have any real-world experience of this combination?

cheers,

nick

[Pat Slater]

If you are looking at having the whole bag rig run off a battery distribution the SMa won't work, they can't be externally powered.

Good luck

PS

[nickreich]

Good info, Pat,

In my case, I wasn't intending the SMa's to be in the bag (as a Hop) - rather using the SR as a 2 channel bag receiver, with the SMa's on talent. The lack of external powering wouldn't be an issue in that case.

Cheers,

nick

[Marc Wielage]

In my case, I wasn't intending the SMa's to be in the bag (as a Hop) - rather using the SR as a 2 channel bag receiver, with the SMa's on talent.

The only problem there is the lack of the tracking front-end circuit in the SR receivers. Opinions are divided as to how important this is. I may be just superstitious, but I'm convinced the extra circuit does help a lot, particularly in RF-heavy areas (which seems like everywhere in LA).

I tested the earlier 210's and 211's extensively, and I'm positive the 211's got significantly fewer "hits" in problem areas. I'm assuming the SR's perform similarly to the 401's, but not as good as the 411's.

--Marc W.

[Philip Perkins]

The only problem there is the lack of the tracking front-end circuit in the SR receivers. Opinions are divided as to how important this is. I may be just superstitious, but I'm convinced the extra circuit does help a lot, particularly in RF-heavy areas (which seems like everywhere in LA).

I tested the earlier 210's and 211's extensively, and I'm positive the 211's got significantly fewer "hits" in problem areas. I'm assuming the SR's perform similarly to the 401's, but not as good as the 411's.

--Marc W.

I haven't noticed a diff in RF performance between 210s and 211s at all.  The main deal w/ a 211 is that is much lighter, smaller and has the bitchen display.

Philip Perkins

[Marc Wielage]

It might been the specific units I had. I know the 210's and 211's both have tracking front ends, so that shouldn't be a factor. I agree the display on the latter is better.

I'm waiting to see if Lectro will have the new UH400 version that has the SM-style display with the pushbuttons. I was never a big fan of screwing around with the click-stop frequency selectors. Maybe they'll have something to show at AES in a month.

--Marc W.

[Arnold F.]

I'd love to learn more about this as well.  If, as I understand, the difference between a UM and LMa is negligible in both design and results, why shouldn't I just use LMa's instead of UM's?  I'm also thinking of getting an SR to use not as camera hops but to receive lavs.  I could sell my block 29 411/UM400 kit and that would go a long way toward an SR and two LMa's.

A.

So if the power difference is negligible then what are some other pros/cons of using the LMa over the UM for sending to an SR?  I've checked the specs and it seems they're practically the same transmitter.  Anyone have any field experience using the LM for camera hop?  Does it really cost twice as much to guarantee 100mW?