VK Logger Ham Radio Forum Archive

Hi

What are people using for PAs at 5760MHz?
Something in the 1-10W output class.

I believe Mark at Mini-Kits had a disappointing response to requests of interest in his TC5351 MMIC based 1W amplifier kit.
(Although you could have missed this, I did. )
As a result the minimum order quantity for the TC5351 could not be achieved, and the kit is not available.
You cannot blame Mark for not wanting $$$$ tied up in a part with an MOQ, if there is a perceived lack of interest.

DownEast Microwave do a 3W 5760 transverter, but strangely enough, do not supply a separate 3W PA kit to complement either their own QRP version of the transverter, or QRP transveters from other suppliers.
(?)

Kuhne, well most of their PA prices are "on request".
(Is that another way of saying, make sure you are sitting down when you learn of the price? )
And their MKU PA 602 4W PA requires 100mW of drive.
I believe the 5.7G XDK transverter board only produces +17dBm (50mW), so the Kuhne amp would not be driven to it's full potential anyway.

And then there's eBay, with the occasional, overpriced, and risky "as is" offering.

With all the XDK 5.7G transverter systems sold recently, there must be some demand for power on that band, surely???

Hi, here in europe is available Toshiba TMD0305-2. This MMC is from 3.4 to 5.1 GHz and have 33dBm power out and 22dB gain.

http://ni.toshiba.co.jp/snis/des/micro/ ... 2_rev3.pdf

Price here is around 100 EUR, also not so cheap...

73 Ondra OK1CDJ

Here in ZL a few years back, there was available 7 GHz PA (around 6~7 Watts) that on tests had a big notch below 7 GHz but came up in power (again) to 5 or so Watts on 5.7 GHz. It was Brian ZL1AVZ that revealed those first test on these amps a number of years ago. I run 2 of these PA's combined, flaked on 5.7 GHz (6~7 Watts each) for around 10 to 11 Watts out. Price at the time, a few years ago was around $40 NZ.

VK4GHZ wrote: Kuhne, well most of their PA prices are "on request".
(Is that another way of saying, make sure you are sitting down when you learn of the price? )
And their MKU PA 602 4W PA requires 100mW of drive.
I believe the 5.7G XDK transverter board only produces +17dBm (50mW), so the Kuhne amp would not be driven to it's full potential anyway.

For anyone interested, I received a reply from Kuhne this evening, and I was sitting down at the time.

Kuhne Electronics wrote:Dear Adam,
many thanks for your enquiry.

The power amplifier MKU PA 602 provides at least 3 W with a drive power of 50 mW.
It costs 347,90 € plus 35,10 € shipment by regular air mail to Australia.

At the moment we can deliver the Power Amplifier from stock. Subject to prior sale

The good news is, it will provide 3W with the 17dBm drive.
The bad news is the price: €383 Euros translates to $500 Aussie, even with our strong dollar.

Hi Adam, I thought the same and nearly fell out of my seat when I got the 10GHz PA price in by email.

There is obviously a market for 10GHz and 5.7GHZ PA's... I wonder if any Australian transverter kitters are reading this *hint hint* The biggest expense cut is buying the devices in some sort of bulk quantities.

73 - Rob VK2GOM / G0MOH

VK2GOM wrote:Hi Adam, I thought the same and nearly fell out of my seat when I got the 10GHz PA price in by email.

There is obviously a market for 10GHz and 5.7GHZ PA's... I wonder if any Australian transverter kitters are reading this *hint hint* The biggest expense cut is buying the devices in some sort of bulk quantities.

73 - Rob VK2GOM / G0MOH

Hi Rob, yes you would think there would be more interest in PAs for 5.7, considering the number of VK3XDK 5.7GHz kits out there now.
Maybe others haven't thought about it, yet?
I can understand Mark not wanting to hold $2k worth of stock, if nobody appears interested.

Anyway, as luck would have it, my search is over.
I have acquired an amplifier, from a local VK4. It was originally obtained from the Wellington VHF Group a few years ago, (perhaps the same as what Steve, ZL1THQ, describes above?).
Coincidentally it is the same as one that went on eBay recently from a G call in the UK.
The G call didn't even have the courtesy to reply to my query days ago about estimated shipping costs to VK.
Quite rude I thought!
If people don't want to ship overseas, then they should be up front about that.
I digress.

These are pictures from that eBay listing which ended at AU$138.
My amp is exactly the same, but was only $80, so I'm very pleased.
5mW in and 5W out.
The amp I have even has the same tester's initials as the unit pictured, but dated 5/12/2000!

Perhaps Steve ZL1TPH can confirm this is the amp he was referring to.

You can also check this site:

http://www.dg0ve.de/lin_3000_24g_001.htm

from the site http://www.dg0ve.de/

I haven't tried them but probably, in the near future, I get the PA6-2-600mW to bust my transverter...

best 73
de
i2NDT Claudio

Yes the same amp that I was refering too .. in ZL they originally started off at $40 NZ and went up to $80 NZ towards the end. They are 6 m/Watt in for 5 Watts out on 5.7 GHz. With a small copper flake, just past the C on the last Gas-As FET the power goes up to around 6 Watts. I believe the only source for theses amps is what amateurs have in their shacks. So maybe a a matter of asking around on reflectors (ZL-VK) if any for sale. I have no spares in my shack - and the last one I gave away recently to Mark VK2AMS for his new 5.7 GHz TRV.

Cheers, Steve ZL1TPH

I use a 5W amp stripped out of an old KPA.
0dBm in +37dBm out.

I would have liked to keep the KPA for a neat 2.5kW output, but I didn't have three phase to power it, nor the equipment to move it.

Gday all, the 5.7 GHz amp that steve ZL1TPH generously donated to my cause (thanks again mate) is a ripper , I use a feedhorn into a 600 mm prime focus dish with great results
cheers. mark VK2AMS

Gidday all,

5.7 GHz is a great band, so is 10 GHz - both could be considered hard going towards VK. Certainly not impossible - but may require two fixed stations either side of the pond, with prime tropo to pull the big one off upstairs.

But 3.4 GHz is real and a possibility ahead toward VK. That’s what I’m working on with new VK3XDK 9 cm TRV and 1.25 metre dish almost complete.

VK4GHZ wrote:Hi

What are people using for PAs at 5760MHz?
Something in the 1-10W output class.

DownEast Microwave do a 3W 5760 transverter, but strangely enough, do not supply a separate 3W PA kit to complement either their own QRP version of the transverter, or QRP transveters from other suppliers.(?)

With all the XDK 5.7G transverter systems sold recently, there must be some demand for power on that band, surely???

however they do supply the MMIC for the 5.7GHz amp and you can use the same kit (less MMIC) that is used for the
10GHz amplifier. its an extremely easy 2 - 3 W output on 5.7GHz at a really affordable price especially with the current US-AU$ exchange rate

FMM5056VF 5.8-7.2GHz Power Amplifier MMIC, 28dBG, Pout +34dBm US$100

Although it doesnt say so on their www site, they will supply the complete kit with out the 10GHz MMIC
just ask, they are quite flexible so that you can stick the 5.7gig MMIC into it instead

cheers
Dave

Almost 2 years on, and I'd like to integrate this C-Band PA (as mentioned above) into a new 5.7 GHz transverter system.

So does anyone have any info on this PA:





If the markings are to be believed, it requires 10.6V, a TX enable (to what polarity?), and I am totally guessing the FPM and RPM could be forward and reverse power monitoring.
(I've contacted the Wellington VHF Group's email list, got an acknowledgment, but silence after that. )

Can any users of this PA, confirm the +ve rail requirements (is +12V or +13.8V excessive), the TX enable is to ground (?) and what the FPM and RPM really do?

There doesn't appear to be any bias requirements, unless the FPM and RPM have something to do with that?

Would like to confirm things before I risk doing damage and appreciate any help/info.

Hi Adam,

Can you trace the wires from the little board onto the PA? Most of the time you can trace the whole circuit just looking at the top of the board.

I can see two couplers on the input & output of the 6472-6. I reckon one or both of them end up FPM, RPM - can you trace them with an ohm meter? The device requires 10V Vdd and negative gate volts probably generated on the second board. The TX enable looks like it goes via a resistor to a SMD transistor next to the pass transistor. Tracing that should tell you what polarity to use.

Hi Adam, I use one and can confirm that the 10.6 is the 10 volt +ve rail. the -Ve bias is generated internaly.
FPM and RPM are the directional coupler outputs with anout 5mw in I get 5 watts out after a bit of snowflaking.
TX enable is not required.
Ralph VK3WRE

Thanks Ralph and Lou.
Much appreciated.

My new Kuhne MKU 57 G3 module generates +25dBm (316mW!) so drive is not a problem.

Ralph, do you have any pictures you could share of the snow flaking?

sorry Adam its all boxed up in the transverter.

Regards Ralph.

Hi Adam,
have a look at my mmic PA board-they work real well!
as for devices- dont now if the fella on ebay (where ive been getting them) is still selling them, ill have a look tomorrow.

I have got some made up here, I have also got some manufacturer part number equivalents that work well.

for a memory im getting over 4W

Hi Adam,

I also have one of these PA's in an almost-completed transverter.
Looking through my collected doco, I came across this web site extract by G8ACE:

I measured what I believe to be the first two 7GHz PAs to land in UK:
The dark blue curve is amp No1 untouched.
The magents curve is amp No2 untouched.
The yellow curve is amp No2 with a small tab to the output line of the PA device.

Test conditions 10mW constant level drive over the test frequencies from a sweeper in manual mode.
10.6v dc supply voltage.  Peak current was around 4.3A  So these results are in saturated output mode.
Heat sink slightly larger than the PA and with fins, about 3/4" thick with a PC proc. (Cooling fan 12v
200mA)  Its much better for devices to keep them cool rather than seeing what you can get away with.
You will note from the Yellow curve the increase in output was negligible but certainly had an effect on the
overall gain/bandwidth compared with the as supplied response.  Its hardly worth the trouble to take the lid
off this amplifier before using.

Just one thing to add to Mike's comments. The TX enable should read TX disable. Leave it open circuit to operate.
Also, the FPM (forward power monitor) produced circa 3V into 1K for about 5W out.

Thanks to everyone who has replied on this topic. I have also found that the semiconductor which is embedded in
the case behind the pcb is an LM335 temperature sensor IC which gives an output of 10mV/Kelvin relative to absolute
temperature so its quite easy to use this to monitor the case temperature. Its fed via 5.6k from the +10.6V line but
its bottom end is floating. Mine had 2.9V across it at 17 degrees C which is correct.[/i]

I used an LDO regulator to generate the 10.6V using discrete bits and pieces. However, an LT1085 would be the go.

I've got info on the snowflaking around here somewhere too ... filed away! I'll update this when I find it.

Regards,
Dave.

Some history of these amps,
With a straight shoot,
When advertised out of WL surplus, stated 2 Watts at 7 GHz,
For $40 bucks,
It was Brian ZL1AVZ that bought the first one, or tested the first one, he rang me up and said they put out 5 Watts on 5.7 GHz,
So I bought some and confirmed the same,
At the time was talking to G8ACE, about this an that (forget exactly) but we did a swap with 2 of these Pa's sent across to the UK and he sent a 300 m/Watt PA for 24 GHz in barter or exchange,
The graphs above was what he sent me, he was the one that worked out (later) with the tab just past the C on the out of the FET would up the power from 5 odd Watts at 5.76 GHz to around 7 Watts at 5.76.
Less output now at 7 GHz etc.,
Once this was circulated around, the price of these amps increased to $80 NZ and still cheap considering.
Likewise placed the tab or small copper tab just past the C of the FET and saw around the 7 Watts,
Nothing like combining two of them with 3 dB couplers and picture below of my past 5.7 GHz PA that put out 11 Watts.
PS the little 24 GHz Pa, the 300 m/Watt units, +9 volt, milli-wave units make very good preamps on 24 GHz, have two of them in operation, but just need to attenuate the output by a lot with adjustable inline attenuators, as expected when using a high gain amp or Pa reversed as (in this case) for a preamp.