New 6 Watt Exciter

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nrgkits.nz
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New 6 Watt Exciter

Post by nrgkits.nz » Sat Oct 12, 2019 10:24 am

Here's the NRG Pro6, it delivers a variable 10mW to 6 Watts RF and is exceptionally clean! Phase noise is down around -115dBc/Hz at 10KHz offset, harmonics better than -60dBc.

I've designed this one to be as low cost as possible without compromising the spectral purity or modulation quality, so there's no non-essential components or features on this, since it is something you'll buy, install, and then later probably end up getting collected by the authorities or a rig thief.

This is just a prototype board, and I got the pinning mixed up for the output device so had to mount it on the other side of PCB, the two voltage regulators will also be replaced with TO220 types and designed to bolt down to the case, as they're drawing around 200mA each.

Cost on each one at this stage I expect to be less than £50 not including shipping.
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sinus trouble
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Re: New 6 Watt Exciter

Post by sinus trouble » Sat Oct 12, 2019 12:41 pm

Nice work once again G!! :)
I am as stupid as I look! :|

nrgkits.nz
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Re: New 6 Watt Exciter

Post by nrgkits.nz » Sun Oct 13, 2019 10:03 am

sinus trouble wrote:
Sat Oct 12, 2019 12:41 pm
Nice work once again G!! :)
Thanks, i've spent the best part of today tweaking it to get better efficiency and less power wasted through the regulators - its working really well now. I've got a PA controller board and SWR bridge on the way also.

This new exciter board is also absolutely quiet, there's no hint of any hum at all even with no shielding, and that's because the VCO is operating in the GHz with the output being divided down to VHF.

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Re: New 6 Watt Exciter

Post by radium98 » Mon Oct 14, 2019 9:09 am

PA controller board and SWR bridge on the way also.
good .waiting for

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Santiago
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Re: New 6 Watt Exciter

Post by Santiago » Tue Oct 29, 2019 2:35 pm

oh wow, cant wait to get my hands on one :P

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Re: New 6 Watt Exciter

Post by Phoenix » Fri Nov 01, 2019 3:13 pm

Put me down for a couple

MiXiN
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Re: New 6 Watt Exciter

Post by MiXiN » Sat Nov 02, 2019 2:36 am

I was going to buy one, but at $350 New Zealand Dollars (£175) including postage I backed out at checkout. 🤣

nrgkits.nz
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Re: New 6 Watt Exciter

Post by nrgkits.nz » Sat Nov 02, 2019 7:58 am

MiXiN wrote:
Sat Nov 02, 2019 2:36 am
I was going to buy one, but at $350 New Zealand Dollars (£175) including postage I backed out at checkout. 🤣
You were probably looking at the current one - the Pro5, because this new one isn’t listed on my site yet. I have an order with the pcb manufacturer I’m waiting for so I can start production.

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Re: New 6 Watt Exciter

Post by MiXiN » Sat Nov 02, 2019 8:25 am

nrgkits.nz wrote:
Sat Nov 02, 2019 7:58 am
MiXiN wrote:
Sat Nov 02, 2019 2:36 am
I was going to buy one, but at $350 New Zealand Dollars (£175) including postage I backed out at checkout. 🤣
You were probably looking at the current one - the Pro5, because this new one isn’t listed on my site yet. I have an order with the pcb manufacturer I’m waiting for so I can start production.
Yes, apologies, my error.

I was tired last night.

Good luck with the production & looks good.

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Re: New 6 Watt Exciter

Post by Bton-FM » Sun Nov 10, 2019 7:47 pm

Out of interest, what pll ic does this exciter use?

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Re: New 6 Watt Exciter

Post by nrgkits.nz » Sun Nov 10, 2019 11:34 pm

The LMX2541 from Texas Instruments

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Re: New 6 Watt Exciter

Post by rocket91fm » Thu Nov 14, 2019 6:31 pm

Does the new exciter have an LCD control option or is it DIP switch only?

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Re: New 6 Watt Exciter

Post by nrgkits.nz » Thu Nov 14, 2019 11:31 pm

Dip switch only to keep the price down. An LCD will require a bigger PIC and more board space or a separate board with connectors and ribbon cable etc... You’re just throwing more money away if the gear gets collected by the authorities.

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Re: New 6 Watt Exciter

Post by Albert H » Fri Nov 15, 2019 5:14 am

I used to keep the costs down by leaving out the switches, and programming the division ratios either with the presence or omission of diodes or with solder blobs between tracks! I also used all hand-wound coils, few (if any) trimmers - I used to bend the coils - as many of the same value of component as I could sensibly get away with, and somewhat inappropriate transistors pushed into VHF use! The logic I used for the PLLs was often right at the limit of its capabilities, and I found that 74HC CMOS ICs - meant to be limited to 5V supply - went quite a lot quicker (and much warmer) at 6V!

For a while, my power supplies - and rig cases - were converted car battery chargers from Halfords. I bought up all the stock in the South-East of England when they had them on sale at £7 each. They would easily power an 80 Watt rig, had a heatsink inside that had their rectifier on it. Their rectifier was useless, so got thrown away, but there was a cheap meter on the front that could be repurposed as a basic SWR bridge if you removed the shunt resistors. The real win was the mains transformer. It was pretty bulky but good for about 150 Watts of supply. It had several tappings on both the primary and secondary windings and could be fiddled to give about 18V AC - about 24V DC on load. The case was folded sheet steel (difficult to drill!) and had a chromed handle on the top. I made about 60 rigs in those cases over about a year. Even the mains lead and the plug was a win - a moulded-on plug with about 6 ft of mains flex. There was even a mains switch with a neon indicator inside it.

I also kept costs right down by getting batches of PCBs made, and shopping around for the components. I got dozens of tubes of logic ICs for the PLLs when there was a sale on at Farnell. I remember having about 30 exciter boards partially populated for a couple of weeks until the price on a particular component dropped.
"Why is my rig humming?"
"Because it doesn't know the words!"
;)

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Re: New 6 Watt Exciter

Post by rocket91fm » Fri Nov 15, 2019 3:15 pm

Interesting. Do you plan on keeping your original thru hole 6 watt exciter around or is it being phased out? You might want to consider the low cost (no LCD) for those on a budget and a 2nd version with all the bells and whistles.

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