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Whip Antennas across multiple blocks

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In my bag I have an SRc in band A and 2 block 21 SRb's. If I wanted to run everything through an RF distro like the PSC RF MULTI SMA, which sized whips could be used for best performance for all blocks involved? (470, 19, 20, 21)

 

Thanks,

Ben

 

Sent from my SAMSUNG-SM-G891A using Tapatalk

 

 

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59 minutes ago, John Blankenship said:

All else being equal, I'd pick the mid-point frequency and cut it to that length according to Lectro's cutting charts.

 

I asked the same question directly to Lectro mothership and they suggested the same thing. 

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Thanks guys. So for me, it looks like I'd want something halfway between 19 and 20.

Sent from my SAMSUNG-SM-G891A using Tapatalk

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I’d be interested to see how you have this set up in your bag.

I have the same receivers going to a DADM226 distribution.

But most of the time I just use a single Dipole mounted in side of the bag and whip antennas in the receivers.

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4 hours ago, Christian Spaeth said:

Any word on how far the blocks could be spaced apart for it to still work well? I have blocks 21 and 24.

 

To get an answer that even approaches objective, you'd need to first objectively define what "work well" means.

 

Subjectively, if your receiver is reasonably near the transmitter, you'll likely notice no difference.

 

You're dealing in the realm of a sliding scale. A few dB loss in one situation might mean nothing in terms of dependable reception, whereas, in another, more critical situation, could make a noticable -- but varying -- difference. 

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On 13.12.2017 at 5:34 PM, MattRitt said:

I’d be interested to see how you have this set up in your bag.

I have the same receivers going to a DADM226 distribution.

But most of the time I just use a single Dipole mounted in side of the bag and whip antennas in the receivers.

 

So you use the dipole with the splitter on one of the antenna ins and a whip on the other of each receiver?

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On 12/23/2017 at 9:26 AM, Christian Spaeth said:

So you use the dipole with the splitter on one of the antenna ins and a whip on the other of each receiver?

Ah what I wrote wasn't super clear.

 

 I originally bought the distribution system to use with a RF Venue Fin but it's really not practical for most bag work and especially doesn't make sense if you have to boom as well.  That put me in a bit of a pinch as the sound bag dashboard doesn't fit into the 633 stingray without bending the whips on the far receivers.  And the way my bag is organized makes it harder to mount a second Dipole on the other side.  So lately I end up using either a single dipole going into the distribution system (which doesn’t take advantage of the diversity) or just the whips on my middle SRB’s (and only use the DADM as power distribution).  

 

Using a combination of the Dipole and whips would be interesting but I basically never use my SRB’s in diversity mode so I’m not sure how it would work out.  I figure I’ll probably just grab a BNC whip for the other DADM226 input and find a way to mount that this month.

 

I know it has been booed before but just getting antennas close enough often works.  It would probably help but I doubt anyone is cutting a new antennas every time they change frequencies.  I'm certainly not an expert but I imagine the effectiveness of an antenna decays sorta logarithmically from bell shape node at a half wavelength.  And then they have a smaller bell shaped jump in effectiveness at a quarter wavelengths (which most whips get close to).

 

If Lectrosonics gives you a block 19 whip for an A1 Band receiver that means that whip is meant to cover 470 to 537 (a wavelength range of .7 inches).  Based on this, you can use an antenna to get a signal that should ideally require an antenna a quarter of an inch bigger or smaller. This is a range of almost 100 mhz in each direction but that's just a rule of thumb based on the lectro wide band receivers/whips.  I’m sure you could be effective even farther away from the ideal antenna length.

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7 hours ago, MattRitt said:

Ah what I wrote wasn't super clear.

 

 I originally bought the distribution system to use with a RF Venue Fin but it's really not practical for most bag work and especially doesn't make sense if you have to boom as well.  That put me in a bit of a pinch as the sound bag dashboard doesn't fit into the 633 stingray without bending the whips on the far receivers.  And the way my bag is organized makes it harder to mount a second Dipole on the other side.  So lately I end up using either a single dipole going into the distribution system (which doesn’t take advantage of the diversity) or just the whips on my middle SRB’s (and only use the DADM as power distribution).  

 

Using a combination of the Dipole and whips would be interesting but I basically never use my SRB’s in diversity mode so I’m not sure how it would work out.  I figure I’ll probably just grab a BNC whip for the other DADM226 input and find a way to mount that this month.

 

I know it has been booed before but just getting antennas close enough often works.  It would probably help but I doubt anyone is cutting a new antennas every time they change frequencies.  I'm certainly not an expert but I imagine the effectiveness of an antenna decays sorta logarithmically from bell shape node at a half wavelength.  And then they have a smaller bell shaped jump in effectiveness at a quarter wavelengths (which most whips get close to).

 

If Lectrosonics gives you a block 19 whip for an A1 Band receiver that means that whip is meant to cover 470 to 537 (a wavelength range of .7 inches).  Based on this, you can use an antenna to get a signal that should ideally require an antenna a quarter of an inch bigger or smaller. This is a range of almost 100 mhz in each direction but that's just a rule of thumb based on the lectro wide band receivers/whips.  I’m sure you could be effective even farther away from the ideal antenna length.

 

Thanks for explaining Matt.

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