UHF-R peculiarity

C

Cameron Stuckey

Freshman
Jan 21, 2011
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NYC/ORL
Hey everyone, I had an oddity pop up today that I have never seen before. I had 22 channels of UHF-R and coordinated them using IAS(I'm unsure of the version). Out of the 8 channels in the G1 range(470-538), the first frequency that IAS gave me to use was 470.025 MHz. Using the jog wheel I scrolled all the way to 470.125, and that's as low as the receiver would go. I decided to take a look at the top, and same thing, 469.875MHz was the highest possible frequency. I wasn't able to check receivers in other ranges, but another G1 receiver stopped at the same limits.

Is this normal for UHF-R receivers, to chop of the outside 125KHz limit of the range? Can someone verify on their receivers for me? And if so, does anyone have the most updated version of IAS to verify that the software reflects these actual frequencies?

Thanks.
 
Re: UHF-R peculiarity

Cameron Stuckey said:
Hey everyone, I had an oddity pop up today that I have never seen before. I had 22 channels of UHF-R and coordinated them using IAS(I'm unsure of the version). Out of the 8 channels in the G1 range(470-538), the first frequency that IAS gave me to use was 470.025 MHz. Using the jog wheel I scrolled all the way to 470.125, and that's as low as the receiver would go. I decided to take a look at the top, and same thing, 469.875MHz was the highest possible frequency. I wasn't able to check receivers in other ranges, but another G1 receiver stopped at the same limits.

Is this normal for UHF-R receivers, to chop of the outside 125KHz limit of the range? Can someone verify on their receivers for me? And if so, does anyone have the most updated version of IAS to verify that the software reflects these actual frequencies?

Thanks.
Click to expand...

Did you try coordinating them in WWB for comparison?
 
Cameron Stuckey said:
Hey everyone, I had an oddity pop up today that I have never seen before. I had 22 channels of UHF-R and coordinated them using IAS(I'm unsure of the version). Out of the 8 channels in the G1 range(470-538), the first frequency that IAS gave me to use was 470.025 MHz. Using the jog wheel I scrolled all the way to 470.125, and that's as low as the receiver would go. I decided to take a look at the top, and same thing, 469.875MHz was the highest possible frequency. I wasn't able to check receivers in other ranges, but another G1 receiver stopped at the same limits.

Is this normal for UHF-R receivers, to chop of the outside 125KHz limit of the range? Can someone verify on their receivers for me? And if so, does anyone have the most updated version of IAS to verify that the software reflects these actual frequencies?

Thanks.
Click to expand...

Can't say for the G1 band, but H4 dies start at 518.000mHz with the transmitter, I can't remember what the exact end freq is, but can check later today (with the H4).

Did you verify with a different unit that it wouldn't go lower than 470.125?

BRad
 
Re: UHF-R peculiarity

I got in a little early this morning and ran through as many receivers as I could. Independent of range and independent of UR4D partner, many of the receivers stopped 125KHz short of their advertised limits. I had L3s stop at 697.875 but go all the way to 638, and the other receiver in the unit go the entire range. I had an H4 that both units stopped at 518.125 but would extend all the way up to 578. And then some more that were totally fine. I'm puzzled.
 
Re: UHF-R peculiarity

Philip Roberts said:
While I don't know for sure they may do this so the FM deviation stays with in the frequency band.

Not sure if this is a regulatory thing or not.
Click to expand...

This is not untypical but I'm surprised that the IAS tables and UHF-R selectability don't match. That said, our "block 470" starts at 470.100 MHz as not to dip down below the legal lower limit for these types of devices. With deviation of +- 75 kHz, this gives us a 25 kHz area of "safety". The IAS tables for our products match our actual frequency ranges, though. Something seems amiss, here.
 
Re: UHF-R peculiarity

Phil is correct insofar as the UHF-R G1 will not tune down to the lower channel edge (470MHz) since that’s an adjacent service and the occupied channel bandwidth can’t extend into it. This of course does not explain the limit on the upper edge.

Off the top of my head, I can’t remember if the other splits exhibit the same characteristic.

As far as the discrepancy with IAS, no surprise; remember that Jason manually set the frequency ranges as you see them, as he did with all equipment profiles. You can edit them as you wish. If this is in fact a spec of the G1, it could simply be an oversight on his part.

And as Scott seems to imply, it could be older versus newer firmware.

[I thought there was a Shure factory guy on this forum?]
 
Re: UHF-R peculiarity

Actually, now that I've been thinking about it, I doubt firmware would matter. That would end up changing the preprogrammed groups and channels, which would confuse things considerably for people not running all the same firmware. It would also likely invalidate the recommendations given on their frequency finder web page.
 
Re: UHF-R peculiarity

Cameron Stuckey said:
I got in a little early this morning and ran through as many receivers as I could. Independent of range and independent of UR4D partner, many of the receivers stopped 125KHz short of their advertised limits. I had L3s stop at 697.875 but go all the way to 638, and the other receiver in the unit go the entire range. I had an H4 that both units stopped at 518.125 but would extend all the way up to 578. And then some more that were totally fine. I'm puzzled.
Click to expand...

If by "advertised" you mean the range sticker on the units then they will not tune to the full extents of that range and this is true for the iem stuff as well.
For instance, band G7 says 506-542Mhz but it starts at 506.125Mhz on the transmitters and receivers.
As others have already expained, those ranges have to account for deviation so they wont match up to the lowest/highest frequency you can tune the transmitters to.

That doesn't answer your question of why some receivers tune to a wider range.
I would try phoning the support folks at Shure. They are great at helping out. And you won't hear someone flipping the pages of the customer service manual as they look for the next step.

Shure Incorporated Attn: Applications Engineering. Telephone: Work(847) 600-8440.
 
Re: UHF-R peculiarity

Thanks everybody, Karl in particular for the details. I can't say this is an actual issue but more of an academic curiosity situation.

It appears as if most of the receivers are firmware 1.173, I'm not clear on how old that versions is, but none-the-less I'm going to go through all the units I can on Monday and get as much information as I can about the bands and edit our IAS.

In the shop we have a some Sennheiser 3732 receivers that are tuned to 470-638 that will hit exactly 470.000. I went through a bunch of them as well(and some 3532) and the receivers will reach the entire spectrum of their 'advertised' or owner's manual listed ranges. That was the main reason that I was curious about the discrepancy the UHF-R units were showing.

Thanks again.
 
Re: UHF-R peculiarity

Henry Cohen said:
Phil is correct insofar as the UHF-R G1 will not tune down to the lower channel edge (470MHz) since that’s an adjacent service and the occupied channel bandwidth can’t extend into it. This of course does not explain the limit on the upper edge.
Click to expand...

Yup. The lowest frequency being 470.125 on the G1 is due to keeping occupied channel bandwidth out of the adjacent band.

The offset on the highest frequency, 529.875, was a mistake. The G1 (and X1, etc.) was actually developed by a different team than did the original UHF-R frequencies. The original frequency bands start and stop exactly at the band edges, unless a regulatory requirement forced otherwise.

Have fun.

-Fred
 
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