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[keven mcdonald]

Hi all

Maybe someone can help fill a bit of a gap in my knowledge. We often hire Wisycom reportage kits to cover really large areas, like presenter radio contributions on music festival sites or tunnels for sporting events. They work great, have exceptional battery life but are pretty expensive to purchase!

Occasionally when we are on jobs where the wireless is handled by other providers, like large sporting events or the big music festivals, we are allocated custom belt pack systems with 1W boosters, vlock batteries and shure transmitters that are made by a big UK wireless provider. They pair this with straight forward GP340 radios for cue.

If I was to consider making one of these systems what needs to be considered on the RX end? I assume we'll need some fairly significant attenuation on the input stage of the receiver? Rather than using the low bandwidth GP340 return could we amplify an IEM and use a simple pack? Also - a question relevant to my last post about axient D - am I correct in saying we can do the same thing we have traditionally done with UR4 with an Axient pack?

Thanks as always for any help

Kev

[Henry Cohen]

Hi all

Maybe someone can help fill a bit of a gap in my knowledge. We often hire Wisycom reportage kits to cover really large areas, like presenter radio contributions on music festival sites or tunnels for sporting events. They work great, have exceptional battery life but are pretty expensive to purchase!

Occasionally when we are on jobs where the wireless is handled by other providers, like large sporting events or the big music festivals, we are allocated custom belt pack systems with 1W boosters, vlock batteries and shure transmitters that are made by a big UK wireless provider. They pair this with straight forward GP340 radios for cue.

If I was to consider making one of these systems what needs to be considered on the RX end? I assume we'll need some fairly significant attenuation on the input stage of the receiver? Rather than using the low bandwidth GP340 return could we amplify an IEM and use a simple pack?

First, which do you consider the "RX end"; inbound (reporter/portable to fixed base) or outbound (fixed base to the reporter)? Secondly, to use the IEM, you'd have to boost power considerably, by at least 14-15dB to get the same ERP as the GP340. I'm not that knowledgeable of Ofcom rules, but I suspect that 1) they don't allow that sort of RF power level for wideband operations without some sort of waiver or temporary authority; 2) you need to be licensed for PLMR or something other than merely PMSE.

In the end, it'll likely cost you more money, time and aggravation than just renting it in and charging the client accordingly.

Also - a question relevant to my last post about axient D - am I correct in saying we can do the same thing we have traditionally done with UR4 with an Axient pack?

Yes.

[keven mcdonald]

Understood! Cheers for the response. Apologies for the confusion - I’m referring to the fixed base station as the “RX,” and the mobile pack as the TX.

Given what you’ve said, say we were still to consider a system with the regular GP340 cue arrangement and only “home brew” the remote transmitter pack, am i correct in saying it’s a case of wiring one of these - http://www.sarastech.co.uk/high-power-radio-mics/1w-booster-type-code-spa001-2.html - to a UR4 pack with appropriate antennae and power source, and using a variable attenuator on the mic receiver RF side?

This is all PMSE permitting of course, and I appreciate this doesn’t necessarily follow the same rules as low power operations.

[Henry Cohen]

Understood! Cheers for the response. Apologies for the confusion - I’m referring to the fixed base station as the “RX,” and the mobile pack as the TX.

Given what you’ve said, say we were still to consider a system with the regular GP340 cue arrangement and only “home brew” the remote transmitter pack, am i correct in saying it’s a case of wiring one of these - http://www.sarastech.co.uk/high-power-radio-mics/1w-booster-type-code-spa001-2.html - to a UR4 pack with appropriate antennae and power source, and using a variable attenuator on the mic receiver RF side?

For the mic receive side I would suggest not only a variable attenuator, but a high Q preselector (filter) as well.

The amp you link to is the right concept, but that amp in particular is short on specs:
- Is the 1W output the 1dB compression (P1) point or saturation (Psat)?
- What is the noise figure?

Now all you have to do is rig up an equipment belt for the transmitter, amp and battery pack(s); modify a headset for a TX antenna mounted to the ear muff and run up low loss coax; and tune your filter.

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