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Question about RF Scans

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Hello,

 I did 4 scans on my Wireless Receiver, and the first three make sense.  The mixer by itself did not add any significant RF, and the TX by itself added the suspected amount, but when I turn them both on I don't have much to choose from.  Any ideas?

1)RX 2)RX+Mixer 3)RX+TX in IFB mode 4)RX+Mixer+TX

 

Thanks,

Rodrigo

Only RX on.jpg

RX on with Mixer.jpg

RX with TX on in IFB mode, no mixer.jpg

RX, TX and Mixer.jpg

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633, Lectro UM400 in IFB mode and UCR411a, all independently powered for the test.

Rx above Mixer in bag, and IFB TX on the side of the bag.

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7 hours ago, Philip Perkins said:

If you move the TX away does it get better? 

Yes, moving the TX a few yards away does change the results of the scan considerably, but still affects the scan when I turn the mixer on. As I said before, the mixer by it self does not alter the scan, only when the IFB is on.

7 hours ago, Philip Perkins said:

 Are the TX and the RX in the same block?  

Yes, Block 26, and the TX in IFB mode, by itself scans as expected, (3rd picture)

 

7 hours ago, Philip Perkins said:

 Have you run the freqs through an app like FreqFinder to see if they are compato?

Compatible with what? Its only one frequency.

 

2 hours ago, Constantin said:

Did you clear the memory between scans?
Did you hit the menu button and zoomed in?

Many Times.

 

My question is, How can an IFB affect the RF coming from the mixer or vice versa?

I´ll keep trying different things to find out what is going on, and hope to learn something from this.

 

Thanks

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In my experience, having a TX and an RX in the same block within less than 6-10 feet or so, sometimes even further can cause grief - I haven't scanned in that situation, just moved TX far enough away so gremlins go away.

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There is probably low-level, wideband RF coming from the mixer, which then interacts with the IFB transmitter by generating intermods. This is one reason why we (and others) generally recommend having your IFB and your talent transmitters on two different frequency blocks. 

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Here's a question? Now that we have the wide band receivers and transmitters, how will we go about picking the right transmitter setting for hops if we will only have six blocks to choose from?

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At the very least, put things at opposite ends of the band. For instance, if you have IFB on 23 and you're using B1 talent mics, put the IFB at the top of 23 and the talent towards the bottom of B1. And, physically separate everything as much as you can. A handy tool for that is the coax antennas we make, both with BNC and SMA connectors. These can help get your IFB or hop transmitter antennas out of the bag and away from your talent receivers. 

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Trying to allocate my bag freqs.  Here in AZ I've had good success with talent transmitters in the A1 (470-537mhz) block.  I currently send com and ref cam feeds on Senn, G band (566-608), usually in the higher freqs.  Trying now to wedge an SRc for camera hop in B1 (537-608) fed by Blk. 21 (537-563) or 22 (563-588mhz) transmitters (50-100mw).  At least 2 block (50mhz) separation between talent/hops/coms seems to be a good target.  Antennas can be separated sometimes but usually they'll live in the bag.  Suggestions?

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audiofp, your plan looks solid to me. I would suggest keeping your com and cam feeds at the top of the Senn. G band (as close to 608 as possible), and then keep your B1 units in the low part of block 21 as much as possible, or possible the low part of 22. That should give you adequate separation.

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Hi Rosa

Unlock the 400 and watch it's screen

Step it's frequency (either way) until there is no show of any RF signal

Then have a listen and if it sound ok use that freq (change the transmitter to)

The alternative way is to do a scan, put it into "examine) mode

Then look for the biggest clear space and set your 400 there

Neither of these ways are scientific but just field fixes

Best was is to plan your frequencies with planning software

I still use the old Audio Ltd "WinMod"

Hope that helps

mike

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