Date   

Wolfspeed CGHV59070 70W 50V 6cm GaN HEMT

Neil Smith G4DBN
 

Has anyone played with the CGHV59070 GaN devices? They look relatively easy to match because of running at 50V, and make serious power on 6cm for about £250.

Gain and power are falling off by the time you get to 5760, but should still do around 70W CW with 13dB gain, so perhaps 3.5W input. Pulse rating is typically 100W at 5.4 GHz.

I've ordered one for the giggles. Given their niceness, it would be rude not to, wouldn't it? OK, I could probably find a pair of 20 year old Gasfets to get the same power, but even second-hand they are going to cost more than the new device, and have way less gain.

https://www.wolfspeed.com/downloads/dl/file/id/875/product/568/cghv59070.pdf

I have a huge pile of other projects to finish first, obviously, but given the state of the semiconductor industry, I wanted to have one in my parts box while I can buy them.

Fingers crossed I pass the EAR test again.  A pair of these would be mightily loud, wouldn't they?

Right, time to get back to the machine shop to make more Radio Things after a hard day at the infosec coal face.

Neil G4DBN


Re: Re fixing cores

geoffrey pike
 

A piece of an old thin elastic band,or thin ptfe as suggested
Geoff
GI0GDP

On Friday, 21 May 2021, 16:48:43 BST, Dave via groups.io <davidnewman55@...> wrote:


I wonder what people use to fix cores such as the in the oscillator coils of DB6NT transverters. The brass core in my 5.7 ghz transverter is rather loose ( not good for a portable station) and I have seen wax mentioned on U tube but I would have thought that things like thin  cotton are likely to lock and pre unpredictable.
73
Dave G4GLT.






Re: Re fixing cores

Dave
 

Thanks Andy. 


On 21 May 2021, at 16:50, Andy G4JNT <andy.g4jnt@...> wrote:


Plumbers PTFE tape



On Fri, 21 May 2021 at 16:48, Dave via groups.io <davidnewman55=icloud.com@groups.io> wrote:
I wonder what people use to fix cores such as the in the oscillator coils of DB6NT transverters. The brass core in my 5.7 ghz transverter is rather loose ( not good for a portable station) and I have seen wax mentioned on U tube but I would have thought that things like thin  cotton are likely to lock and pre unpredictable.
73
Dave G4GLT.






Re: Re fixing cores

Andy G4JNT
 

Plumbers PTFE tape



On Fri, 21 May 2021 at 16:48, Dave via groups.io <davidnewman55=icloud.com@groups.io> wrote:
I wonder what people use to fix cores such as the in the oscillator coils of DB6NT transverters. The brass core in my 5.7 ghz transverter is rather loose ( not good for a portable station) and I have seen wax mentioned on U tube but I would have thought that things like thin  cotton are likely to lock and pre unpredictable.
73
Dave G4GLT.






Re fixing cores

Dave
 

I wonder what people use to fix cores such as the in the oscillator coils of DB6NT transverters. The brass core in my 5.7 ghz transverter is rather loose ( not good for a portable station) and I have seen wax mentioned on U tube but I would have thought that things like thin cotton are likely to lock and pre unpredictable.
73
Dave G4GLT.


Re: 6cm rf?

militaryoperator
 

Found one on ebay, £26 from China or £30 from Amazon. 
I blew up two of those, so treat them *very* gently. They usually have  a pair of the same 5mm square devices that everything uses.  In the end, I fixed a slab of aluminium over the top of the chips to press them down to a bigger heatsink and help remove more heat from the package. I also scrapped the noisy switchmode regulator and used a two-stage linear regulator
Neil G4DBN


OK Neil. I see the Kuhne unit uses the SE5005 in the o/p, (£1.06 at digikey!) but limits it to 250mw o/p.

Ben


Looking for SMA male to SMA female pigtail

Andy
 

I'll try here first before buying the bits and making my own or buying something dodgy from eBay.....

I'm looking for a flexible patch lead about 50cms long for use on 13cms at low(ish) powers, currently 2W but doubt it will ever see more than 25W. 

SMA straight male on one end and SMA straight female on the other end in RG-400 or something similarly flexible with the same or lower loss.

Contact me off list if you have something suitable to discuss costs/postage etc. 

Thanks,
Andy
MM0FMF


Re: 6cm rf?

Neil Smith G4DBN
 

On 21/05/2021 13:12, militaryoperator via groups.io wrote:

Found one on ebay, £26 from China or £30 from Amazon. 

I blew up two of those, so treat them *very* gently. They usually have  a pair of the same 5mm square devices that everything uses.  In the end, I fixed a slab of aluminium over the top of the chips to press them down to a bigger heatsink and help remove more heat from the package. I also scrapped the noisy switchmode regulator and used a two-stage linear regulator

Neil G4DBN




Re: 6cm rf?

militaryoperator
 

Hi Ben,
Have you looked at the FPV booster amps for drones?, i used these on 5.8 GHz Analogue ATV from memory they use
a pair of devices and achieve 4 Chinese watts
cheers
Geoff
GI0GDP


Found one on ebay, £26 from China or £30 from Amazon. 


Re: SMD, ah!.

Andy
 

Donate the surplus to the Microwave Group chip bank.


From: UKMicrowaves@groups.io <UKMicrowaves@groups.io> on behalf of militaryoperator via groups.io <Military1944@...>
Sent: Friday, May 21, 2021 4:28 AM
To: ukmicrowaves@groups.io <ukmicrowaves@groups.io>
Subject: [UKMicrowaves] SMD, ah!.
 
Well, SMD might make the pcb's smaller but not on the paperwork packing side.

Just ordered a few bits from Digikey, box arrived, each component in a plastic sealed bag, big bag, and must have misread, thought I'd ordered 10 100pf caps, seems they are in x5 units, so now have 50 of them! on a large reel of audio reel to reel days.

Plus two large printouts of the parts with rows of facts and figures, bar codes, place of manufacture etc etc. 

Just need to wait for boards for W1GHZ for preamp and pa amp then I can start the gluing, hi.

Ben.


Re: SMD, ah!.

Andy G4JNT
 

When I replaced my stock of 100nF 0805 caps, I ordered 1000.   It had taken about 10 years to get through the last lot, of which I think I'd ordered 500 back then.   But they get used up faster now.

This lot might just last me out :-(
 


On Fri, 21 May 2021 at 12:28, militaryoperator via groups.io <Military1944=aol.com@groups.io> wrote:
Well, SMD might make the pcb's smaller but not on the paperwork packing side.

Just ordered a few bits from Digikey, box arrived, each component in a plastic sealed bag, big bag, and must have misread, thought I'd ordered 10 100pf caps, seems they are in x5 units, so now have 50 of them! on a large reel of audio reel to reel days.

Plus two large printouts of the parts with rows of facts and figures, bar codes, place of manufacture etc etc. 

Just need to wait for boards for W1GHZ for preamp and pa amp then I can start the gluing, hi.

Ben.


SMD, ah!.

militaryoperator
 

Well, SMD might make the pcb's smaller but not on the paperwork packing side.

Just ordered a few bits from Digikey, box arrived, each component in a plastic sealed bag, big bag, and must have misread, thought I'd ordered 10 100pf caps, seems they are in x5 units, so now have 50 of them! on a large reel of audio reel to reel days.

Plus two large printouts of the parts with rows of facts and figures, bar codes, place of manufacture etc etc. 

Just need to wait for boards for W1GHZ for preamp and pa amp then I can start the gluing, hi.

Ben.


Re: 6cm rf?

militaryoperator
 

Thanks Mark and Dave. 

All noted and absorbed. 

I think its easier just to just buy a Kuhne. 

Ben. 


-----Original Message-----
From: Dave G8KHU <david@...>
To: UKMicrowaves@groups.io
Sent: Fri, 21 May 2021 10:18
Subject: Re: [UKMicrowaves] 6cm rf?

Ben

As an addendum to Mark's analysis we were looking at Skyworks parts for a commercial application requiring +32 dBm CW continuous. We looked at the SKY66293 and SKY66318 which have very similar specs to the 5089 and asked Skyworks for their opinion, part of their response is below:

“ The SKY66293-21 is an older part.  I’d recommend the SKY66318-11 for this frequency range, however, the target output power of our small cell Pas is +27dBm ~ +28dBm with back off of 8dB.
 For all the SKY662xx series, we ran all of our thermal analysis at case temp = 85C or 100C (depending on the part number) at the rated target output power of +27dBm ~ +28dBm.  Since the target application is LTE modulated or 5G NR, we don’t expect the PAs to continually transmit at output powers higher than +27dBm ~ +28dBm with respect to thermals "

So as Mark says the datasheet doesn't tell you the whole story.

Dave G8KHU


Re: 6cm rf?

Dave G8KHU
 

Ben

As an addendum to Mark's analysis we were looking at Skyworks parts for a commercial application requiring +32 dBm CW continuous. We looked at the SKY66293 and SKY66318 which have very similar specs to the 5089 and asked Skyworks for their opinion, part of their response is below:

“ The SKY66293-21 is an older part.  I’d recommend the SKY66318-11 for this frequency range, however, the target output power of our small cell Pas is +27dBm ~ +28dBm with back off of 8dB.

 For all the SKY662xx series, we ran all of our thermal analysis at case temp = 85C or 100C (depending on the part number) at the rated target output power of +27dBm ~ +28dBm.  Since the target application is LTE modulated or 5G NR, we don’t expect the PAs to continually transmit at output powers higher than +27dBm ~ +28dBm with respect to thermals "

So as Mark says the datasheet doesn't tell you the whole story.

Dave G8KHU


Re: Hi Speed Comparator operation

David GM6BIG
 

Hi Rich,

there were a couple of mistakes on the PCBs depending on the version.
All from memory, and still waking up this morning !

Missing ground on the little 5v regulator.
O/P from the op amp to wrong pin on next chip.
Think I biased up the opamp o/p after coupling cap to centre the waveform better.
One of the divider tracks was wrong too.
(missing track or wrong legend on PCB).
Feedback for the divider chain needed adjusting (I had used an alternative MMIC).
Maybe not obvious, but a track(s) needs cut depending on the configuration, and wires run in.
Sure I used an alternative opamp in the end, the original options hard to get and quite expensive.
Paul has corrected these over the years, but all worth checking - trust nothing !

Will check later to see if I have made any notes on these and my emails to Paul, see if I can be more precise.

Cheers, DAvid  GM6BIG

On 20/05/2021 11:04, G8ZHA via groups.io wrote:
I have built a couple of W1GHz projects: a GPS locked 10MHz osillator and a 100MHz PLL board. Each of his circuits uses a LT1116 hi speed comparator to lift the oscilator signal up to 5V CMOS logic levels to feed the dividers.

On the 100MHz PLL PCB, there is a 3.3V osc, feeding a MC12080 Div by 10 prescaler, AC coupled into the non-inverting input ofthe LT1116. The inverting input is tied directly to ground. I can see a nice square wave signal into this pin, about 1.5V pk-pk, centered on 0V. The outputs, which are open circuit, are very distorted, see photos.

I thought that this may be because the signal is outside the common range of 0 - 2.5V for the LT1116, so I biased the input to the middle of the voltage range but was not successful.

Am I missing something obvious?

I also built the 10MHz version, which feeds the osc straight into the comparator. I hadn't got a LT1116, so used a LT1016 instead, which has a common mode input range of 1.25 tp 3.75V range. Again, I biased the input signal to the middle of the voltage range, but saw the same distored oyutput.

(in the UK, the LT1116 is not available from RS etc)

I am at a loss to understand what is going wrong.

Rich G*ZHA
--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


Re: Adalm Pluto Revision D

Simon Brown
 

Very nice.

 

I have a modified Pluto (Thanks to DD1US who did the mod) and feed it with 40MHz from a dual Leo Bodnar unit.

 

Simon Brown, G4ELI

https://www.sdr-radio.com

 

From: UKMicrowaves@groups.io <UKMicrowaves@groups.io> On Behalf Of Mark G6DDX
Sent: 20 May 2021 21:59
To: UKMicrowaves@groups.io
Subject: [UKMicrowaves] Adalm Pluto Revision D

 

I received an Adalm Pluto today from Digikey which is revision D.  This revision has clock in and out connectors and also RX2/TX2 wired out.  All four ports are provided through u.fl sockets on the pcb.

Details from from Analog Devices below

Image - https://wiki.analog.com/_media/university/tools/pluto/hacking/pluto_c.png
Mine has 3.3V max silked screened next to the clock input.

Wiki - https://wiki.analog.com/university/tools/pluto/hacking/hardware#revision_d

73 de Mark, G6DDX


Re: 6cm rf?

Mark GM4ISM
 

Ben

160 C junction temperature  is pretty standard for this technology, the data that is missing is the thermal resistance, junction to case measured in C/W, and power added efficiency.  Without it you cannot calculate the permitted dissipation of the device and the expected output power WRT the junction temperature. Yes it can manage a P1dB of 2W  but maybe only with a 20% duty cycle for thermal considerations.

If the value  of thermal resistance is say 15C/W, then if you dissipate 5W in the junction, the junction rises to 75 degrees above the case,  that would be manageable as the heatsink would have to keep the case at a max of 85C

if the value is 30 then the same 5W dissipation would put the junction at 170C even if you kept the case anchored at 20C with a fantastic heat sink.

we can guess from the figures.. at 400mW the data sheets states that the max case temperature is 85C  and that this is at 5V and 600mA  That is 3W in, 400mW out   2.6W dissipation  ie about 14% efficiency

If you assume that  at these values the case temperature is allowed to approach the max of 85C the the junction will also be OK below 160 C, some 75C above case.  75/2.6 is  28.8 C/W thermal resistance.

Lets say the efficiency reaches 30% at the P1dB point of 2w out,  that would require a junction dissipation of 4.4W

With that thermal resistance which is a constant, the junction would be 127C above the case. Thus the case must not rise above 33C

Thats quite low, requiring a very good heatsink and likely a low duty cycle

These calculations make a few assumptions and may be quite a bit off, I may even have  made a slip on the calculator  but they look about right to me and support the supposition that  1W or maybe a bit more output, with good design and typical amateur duty cycles, is probably feasible.

There are a lot of devices out there that look good for really high output power at the P1dB point but being designed (thermally) for a lower mean power  means they just cant realise that P1dB for a useful time.  Not all data sheets tell you the whole story :(

Mark GM4ISM

On 20/05/2021 21:26, militaryoperator via groups.io wrote:
The data sheet from Skyworks does not give any thermal info and it may be that key down CW at 2W will overheat the junction.

160deg C Mark.


. if they work as advertised.  If they dont, send em back!
Mark GM4ISM


I doubt worth trying to send back to China. Still you get either a nice little project box or a nice heatsink depending on which you buy, hi. 

Ben,

Virus-free. www.avg.com


Re: Dish Mesh information

Mike GD6ICR
 

Thanks to John API  and ZTR for your advice - It seems I do have a sectional dish available to me which I hope despite the age will give one or two of us on the Island access to EME on the likes of 23/13/3cm in the future. I realize the problems with the weight of the dish if stainless mesh is used, but you must realize that aluminium mesh/perforated metal here on the Island where no-where is more than 7 miles from the sea, that the corrosive capability of salt air here is phenominal. I still need to find the right paint to coat all the dishes we have available - any advice on the right material coating whether its brushed or sprayed I do have the capability and If i dont there are a lot of skill within the community to help. Just hope they dont mind a 12 ft dish on my garage roof or moved onto the back of my trailer to tow to the best places for competitions and eme. Thanks for all your suggestions both on here and direct
We all need to find our way.
--
Mike GD6ICR IO74PF73TW


Re: 6cm rf?

geoffrey pike
 

Hi Ben,
Have you looked at the FPV booster amps for drones?, i used these on 5.8 GHz Analogue ATV from memory they use
a pair of devices and achieve 4 Chinese watts
cheers
Geoff
GI0GDP

On Thursday, 20 May 2021, 11:44:33 BST, militaryoperator via groups.io <military1944@...> wrote:


5G-6GHz One-Way Microwave RF Power Amplifier Module 40DB SBB5089+SE5004
( 114749899192 )

SE5004 1W Microwave Power Amplifier RF Power Amplifier 5.15GHz-5.85GHz 30DBm
( 114556927546 )

Did anyone try these? Both use the SE5004 which seems rated to 34dbm max, 

I'm guessing the first unit rated at 2W is 2 Chinese Watts. The second unit might just do it.

Probably get 1W out of first but it has more gain so smaller i/p needed I guess.

 Ben.


Adalm Pluto Revision D

Mark G6DDX
 

I received an Adalm Pluto today from Digikey which is revision D.  This revision has clock in and out connectors and also RX2/TX2 wired out.  All four ports are provided through u.fl sockets on the pcb.

Details from from Analog Devices below

Image - https://wiki.analog.com/_media/university/tools/pluto/hacking/pluto_c.png
Mine has 3.3V max silked screened next to the clock input.

Wiki - https://wiki.analog.com/university/tools/pluto/hacking/hardware#revision_d

73 de Mark, G6DDX

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