Date   

Re: 2 photos uploaded

Chris Bartram G4DGU
 

That looks to me like a pair of LNAs combined between quadrature hybrids; a typical solution for a mobile phone base-station LNA.  That gives a few advantages re a single device, such as we tend to use in amateur amplifiers:

Each amplifier sees a good load within the bandwidth of the hybrids, The outside world also sees a good match, and stability can be improved, the large signal handling will increase by a couple of dB, depending on how you express it, but the NF will increase by a bit over the insertion losses of the hybrids. There doesn't appear to be any filtering - which is to be expected, as base-station LNAs tend to need better filters than you could make on a PCB - many are pretty sophisticated designs

I can't comment further, as the definition of the photo I looked at wasn't good enough to see too much detail.

On 21/08/2020 15:02, UKMicrowaves@groups.io Notification wrote:

The following photos have been uploaded to the Aerial facilities limited 1800mhz GSM am album of the UKMicrowaves@groups.io group.

By: Andy GD1MIP


Change your notification settings


Re: FRANCO 12ghz to 24ghz doubler

Neil Smith G4DBN
 

Marvellous stuff, I'll have a proper read after work.

Ta, Neil

On 21/08/2020 15:33, Barry Chambers wrote:

Neil

this is what you want! See attached

73 Barry, G8AGN


On 21/08/2020 12:27, Neil Smith G4DBN wrote:

I can vouch for Andy's code working with my ADF5355s.  Saved me scrambling up the nursery slopes of the learning curve unaided.  I hacked it about for my own nefarious purposes of course, but 'tis a marvellous thing to have someone ploughing the furrow and showing how to make it work. Huge thanks as usual for the very useful resources.

Just one thing to consider before going for JT4 on the higher microwave bands.  I cannot get decodes from weak troposcatter signals on 10 GHz from GB3PKT or GB3OSW even when the signal is loud enough to HEAR, never mind see on a waterfall. I reckon that with these very long integration times, I can see signals at least 10 dB lower than those needed to get JT4 decodes.  The scintillation at 3 cm has components of amplitude variation close enough to the symbol rate to remove some symbols completely, often enough to wreck and chance of a decode.

I watched OSW for 30 minutes last night and I could see faint smears of troposcatter from the plain tone segments when I integrated for > 5 seconds per pixel that would have allowed *visual* decoding of DFCW or QRSS at perhaps 10 seconds per symbol, but it was way too weak, chopped up and spread out for any hope of detection by WSJT-X.

As soon as there was a bit of rainscatter, even though the signals were just as faint (but off-axis with no direct troposcatter component) I was able to get solid decodes. Same with PKT when there is a bit of ducting or RS, I can decode it easily, but troposcatter remains stubbornly undecoded.

I have a feeling that the only way we are going to be able to get down to decodes of SHF troposcatter at EME levels will be to move to the slow symbol rate techniques used at VLF, but with wide shifts. DFCW would be an obvious choice for simplicity and human-readability off the waterfall at those ridiculously weak signal levels, or we could look at doing something like the Slow-JT9 modification to drop the data rate of normal slow modes by an order of magnitude or more on receive. Trivial on transmit, but the receive side needs some deep thought.

Ultimately, if a beacon used a simple tone ID, sending 30 seconds of base tone, then 30 second symbols of three other tones in a predefined sequence, it would be possible to get unambiguous visual identifications of beacons at extremely low signal levels, just using Spectrum Lab or something to integrate the signals.

Neil G4DBN


-- 
73
Barry, G8AGN
-- 
Neil
http://g4dbn.uk


Re: FRANCO 12ghz to 24ghz doubler

Barry Chambers
 

Neil

this is what you want! See attached

73 Barry, G8AGN


On 21/08/2020 12:27, Neil Smith G4DBN wrote:

I can vouch for Andy's code working with my ADF5355s.  Saved me scrambling up the nursery slopes of the learning curve unaided.  I hacked it about for my own nefarious purposes of course, but 'tis a marvellous thing to have someone ploughing the furrow and showing how to make it work. Huge thanks as usual for the very useful resources.

Just one thing to consider before going for JT4 on the higher microwave bands.  I cannot get decodes from weak troposcatter signals on 10 GHz from GB3PKT or GB3OSW even when the signal is loud enough to HEAR, never mind see on a waterfall. I reckon that with these very long integration times, I can see signals at least 10 dB lower than those needed to get JT4 decodes.  The scintillation at 3 cm has components of amplitude variation close enough to the symbol rate to remove some symbols completely, often enough to wreck and chance of a decode.

I watched OSW for 30 minutes last night and I could see faint smears of troposcatter from the plain tone segments when I integrated for > 5 seconds per pixel that would have allowed *visual* decoding of DFCW or QRSS at perhaps 10 seconds per symbol, but it was way too weak, chopped up and spread out for any hope of detection by WSJT-X.

As soon as there was a bit of rainscatter, even though the signals were just as faint (but off-axis with no direct troposcatter component) I was able to get solid decodes. Same with PKT when there is a bit of ducting or RS, I can decode it easily, but troposcatter remains stubbornly undecoded.

I have a feeling that the only way we are going to be able to get down to decodes of SHF troposcatter at EME levels will be to move to the slow symbol rate techniques used at VLF, but with wide shifts. DFCW would be an obvious choice for simplicity and human-readability off the waterfall at those ridiculously weak signal levels, or we could look at doing something like the Slow-JT9 modification to drop the data rate of normal slow modes by an order of magnitude or more on receive. Trivial on transmit, but the receive side needs some deep thought.

Ultimately, if a beacon used a simple tone ID, sending 30 seconds of base tone, then 30 second symbols of three other tones in a predefined sequence, it would be possible to get unambiguous visual identifications of beacons at extremely low signal levels, just using Spectrum Lab or something to integrate the signals.

Neil G4DBN


-- 
73
Barry, G8AGN


Re: Aerial facilities 1800 mhz GSM amplifier information.

Andy GD1MIP
 

Just dragging this back to peoples attention.

I have been removing useful bits and pieces for projects (switches, plugs,  sockets, coax  etc) as they're full of quality items. However I have yet to use any of the modules.

Since I last asked has anyone come across Aerial Facilities documentation /  information?  I'd love to use the amp or bits of it.

Thanks Andy GD1MIP 

https://groups.io/g/UKMicrowaves/album?id=76586


Re: WG17 switch

Wilko
 

For people willing to do their own motorising and
are ok with WR90 I have just put this one up for
sale:


Wilko
PA1WBU


Re: FRANCO 12ghz to 24ghz doubler

Neil Smith G4DBN
 

I can vouch for Andy's code working with my ADF5355s.  Saved me scrambling up the nursery slopes of the learning curve unaided.  I hacked it about for my own nefarious purposes of course, but 'tis a marvellous thing to have someone ploughing the furrow and showing how to make it work. Huge thanks as usual for the very useful resources.

Just one thing to consider before going for JT4 on the higher microwave bands.  I cannot get decodes from weak troposcatter signals on 10 GHz from GB3PKT or GB3OSW even when the signal is loud enough to HEAR, never mind see on a waterfall. I reckon that with these very long integration times, I can see signals at least 10 dB lower than those needed to get JT4 decodes.  The scintillation at 3 cm has components of amplitude variation close enough to the symbol rate to remove some symbols completely, often enough to wreck and chance of a decode.

I watched OSW for 30 minutes last night and I could see faint smears of troposcatter from the plain tone segments when I integrated for > 5 seconds per pixel that would have allowed *visual* decoding of DFCW or QRSS at perhaps 10 seconds per symbol, but it was way too weak, chopped up and spread out for any hope of detection by WSJT-X.

As soon as there was a bit of rainscatter, even though the signals were just as faint (but off-axis with no direct troposcatter component) I was able to get solid decodes. Same with PKT when there is a bit of ducting or RS, I can decode it easily, but troposcatter remains stubbornly undecoded.

I have a feeling that the only way we are going to be able to get down to decodes of SHF troposcatter at EME levels will be to move to the slow symbol rate techniques used at VLF, but with wide shifts. DFCW would be an obvious choice for simplicity and human-readability off the waterfall at those ridiculously weak signal levels, or we could look at doing something like the Slow-JT9 modification to drop the data rate of normal slow modes by an order of magnitude or more on receive. Trivial on transmit, but the receive side needs some deep thought.

Ultimately, if a beacon used a simple tone ID, sending 30 seconds of base tone, then 30 second symbols of three other tones in a predefined sequence, it would be possible to get unambiguous visual identifications of beacons at extremely low signal levels, just using Spectrum Lab or something to integrate the signals.

Neil G4DBN

On 21/08/2020 08:38, Andy G4JNT wrote:

#define  UnderstandPicSpeak   Flags, 0
'
btfsc  UnderstandPicSpeak
call   ReadAndUseListing
return

:-)  :-)  :-)


WG17 switch

Paul G8AQA
 

You will need to hurry. Ending in a couple of hours. Looks a good price at the moment. No Bids.

https://www.ebay.co.uk/itm/392908086119?ul_noapp=true

Paul G8AQA


Re: FRANCO 12ghz to 24ghz doubler

Andy G4JNT
 


#define  UnderstandPicSpeak   Flags, 0
'
btfsc  UnderstandPicSpeak
call   ReadAndUseListing
return

:-)  :-)  :-)


On Wed, 19 Aug 2020 at 16:35, Steve G4HTZ via groups.io <essexsteve=icloud.com@groups.io> wrote:
unfortunately for me you may as well be speaking in Martian......I may have a friend who understands of which you speak 😀


Re: SMD solder paste

Neil Smith G4DBN
 

editing finger trouble...

f"ollowed by an IPA rinse, then a *clean* with hot deionised water with a drop of detergent, *then* apply paste..."

On 20/08/2020 13:09, Neil Smith G4DBN wrote:
followed by an IPA rinse, then paste and a clear with hot deionised water with a drop of detergent


Re: SMD solder paste

Neil Smith G4DBN
 

I use Bismuth/Tin/Silver 138C paste for devices, and high-temp stuff to solder the PCBs to the spreaders.  Makes it lots easier if you ever have to swap out a device.  I have Chipquick 138C paste but I've also used Adafruit Makerpaste that works well and is way cheaper (£6 last time).

Flow and wetting with either type seems good on C101 and C111 copper grades with a < 5 micrometer RMS finish, although I have had a bit of balling where the finish is not that good (from using a sharp-corner slot drill to make the grooves in C101 copper, whcih leaves some half-moon work-hardened ridges which are almost imperceptible).

I've done a few devices just using Weller liquid flux and 0.5mm multicore wire which has been rolled into a flat ribbon.  That works in just about any finish.  These days I just polish the device slots with a fine Scotchbrite wheel with a drop of Brasso, then degrease with brake cleaner, then use a Brightboy abrasive rubber to burnish the faces, followed by an IPA rinse, then paste and a clear with hot deionised water with a drop of detergent, but I'm a bit peculiar in my habits.

Blowtorch and Ersin Multicore will probably work just fine.

Neil G4DBN

On 20/08/2020 12:53, G0FVI via groups.io wrote:
Hi all,
some advice needed! Been given a tube of SMD solder paste with a view to using it for copper spreader on LDMOS amps. This stuff is called 'Easy Print' and composition is 96.5% Sn, 3% Ag and 0.5% CuO (other stuff in there as well, made in Eastern Europe). I'm wondering if it's worth risking using this stuff (anyone else heard of it?). I know this topic has probably been covered before, but alternative recommendations would be appreciated (what are people using?), four LDMOS amp projects on the go here, rather not blow any more LDMOS devices (lost one recently to bias problems)!

many thanks

Andy G0FVI


Re: SMD solder paste

Robin Szemeti - G1YFG
 

It is a common mix, I've not heard of the particular brand but I expect it will behave just like any other lead-free paste.

My advice would be to use standard 60/40 lead solder for the lower melting point and just place a zig-zag of solder under the device.  The lower melting point will pay dividends.

All I did for mine was to use some liquid solder flux on a cotton bud applied to the device and the slab, a zig-zag of solder in the trough  (See W6PQL's YouTube video) and then slowly heated the 1/2" thick copper slab on the gas ring ... as soon as the solder melted I waited a few seconds and then turned off the burner, gave the device a little shuffle left-right to make sure it was well bedded, and nudged it back onto the pencil marks. I would say it was in the molten state for about 30 seconds.  As soon as it was solidified, I lifted the slab off the ring and put it on the heatsink, easy peasy.

So my advice would be that solder paste sounds like a good idea, but I'd go with 60/40 tin lead.


On Thu, 20 Aug 2020 at 12:53, G0FVI via groups.io <Andrew.gilfillan=ntlworld.com@groups.io> wrote:
Hi all, 
some advice needed! Been given a tube of SMD solder paste with a view to using it for copper spreader on LDMOS amps. This stuff is called 'Easy Print' and composition is 96.5% Sn, 3% Ag and 0.5% CuO (other stuff in there as well, made in Eastern Europe). I'm wondering if it's worth risking using this stuff (anyone else heard of it?). I know this topic has probably been covered before, but alternative recommendations would be appreciated (what are people using?), four LDMOS amp projects on the go here, rather not blow any more LDMOS devices (lost one recently to bias problems)!

many thanks

Andy G0FVI


--
Robin Szemeti - G1YFG


SMD solder paste

G0FVI
 

Hi all, 
some advice needed! Been given a tube of SMD solder paste with a view to using it for copper spreader on LDMOS amps. This stuff is called 'Easy Print' and composition is 96.5% Sn, 3% Ag and 0.5% CuO (other stuff in there as well, made in Eastern Europe). I'm wondering if it's worth risking using this stuff (anyone else heard of it?). I know this topic has probably been covered before, but alternative recommendations would be appreciated (what are people using?), four LDMOS amp projects on the go here, rather not blow any more LDMOS devices (lost one recently to bias problems)!

many thanks

Andy G0FVI


Re: GB3OSW off line

Adrian G4UVZ
 

Thanks for the info...will keep an eye out in the next few days!


Re: Kuhne 24 GHz transverter IF

DougF VK4OE
 

FYI,

Not many years ago I purchased a 24 GHz transverter from them with a 432 MHz IF.  I think that a 70 cm IF in mm-wave transverters is a great way to go....

Less than a year ago I inquired about purchasing another one and was told that they no longer make or have available one significant part which is unique to Kuhne 24 GHz transverters with a 432 MHz IF.  (I'm guessing that the crucial component here is a specially designed image-reject or I-Q mixer.)

That explains why that listing (and probably many others) has disappeared from their catalogue.  Needless to say, I made do with what I already had....

Cheers and 73,

--Doug Friend, VK4OE.


Re: Kuhne 24 GHz transverter IF

militaryoperator
 

I had a note from Kuhne this morning saying they will look into the
possibility of a low-power version. 
----------------------------------------------------


You'd think at £702 a box they would be falling over themselves to sell the stuff. 

Still, guess when your the only player in the game (?) you can do what you like. 

Might be a while till I get operational on 24. 

Ben 
G4BXD


Re: Kuhne 24 GHz transverter IF

Neil Smith G4DBN
 

I had a note from Kuhne this morning saying they will look into the possibility of a low-power version.  The mod I usually do now is to remove the big power resistor and swap it for an 82 ohm, then change the resistor in series with the 100 ohm pot to a 33 ohm. Still looks like 50 ohm pretty much. On my kit versions, I used 100 ohm parallel and 0 ohm series. I can see it isn't going to be sensible for them to go that far as it might be too easy to cause damage with the pot at max, but we shall see what they say.

Neil G4DBN

On 20/08/2020 07:51, David Robinson wrote:
I have the same experience as G4ZTR, Kuhne transverters require much less drive than the manuals state. My 24GHZ xverter only needs 200mw of drive as now do my other 3  db6nt xverters. My FT817 has had its hidden menus adjusted to produce 200mw on 2m and 70cm irrespective of what output power selection i make on the front panel to avoid accidents.
Looking at the kuhne web pages yesterday i was struck by how the number/range of available products has considerably reduced during this year


Re: Kuhne 24 GHz transverter IF

David Robinson
 

I have the same experience as G4ZTR, Kuhne transverters require much less drive than the manuals state. My 24GHZ xverter only needs 200mw of drive as now do my other 3  db6nt xverters. My FT817 has had its hidden menus adjusted to produce 200mw on 2m and 70cm irrespective of what output power selection i make on the front panel to avoid accidents.
Looking at the kuhne web pages yesterday i was struck by how the number/range of available products has considerably reduced during this year

Dave
G4FRE


Re: GB3OSW off line

Neil Smith G4DBN
 

And as if by magic, the GB3OSW signal appeared, rising slowly out of the noise, direct path vis RS with about 10Hz doppler spreading and 20Hz shift.

2046 -17 -0.1 1015 $* GB3OSW IO82KV
2048 -16 -0.0 1013 $* GB3OSW IO82KV

2050 -16 -0.1 1015 $* GB3OSW IO82KV
2052 -17 -0.1 1017 $* GB3OSW IO82KV

Neil G4DBN
IO93NR08

On 19/08/2020 21:37, Peter G3SMT via groups.io wrote:

HI Adrian,

Probably a little late for this evening but GB3OSW is radiating as usual.



Re: GB3OSW off line

Peter G3SMT
 

HI Adrian,

Probably a little late for this evening but GB3OSW is radiating as usual.

73

Peter  G3SMT



On 19/08/2020 18:26, Adrian G4UVZ via groups.io wrote:
Can anyone confirm if OSW is back on?  WIth big rain in the offing again ..it might be audible in IO80 with any luck...but obviously needs to be on air...No point looking for the black cat in the darkened room which isn't there!!!

A

--
Peter G3SMT


Re: GB3OSW off line

Neil Smith G4DBN
 

I can't see OSW at the moment, but there is a curtain of drizzle over the Pennines which would kill the path anyway.  In other news, I am getting a decent RS signal from GB3KBQ at a mere 342km. My dish is at 8m because of the strong wind up here. I can't hear myself on Mow Cop, which is pretty much indicative of 15-18dB excess loss on that path. PKT is coming in at -17dB RS
Neil G4DBN

GB3KBQ RS waterfall

5781 - 5800 of 63538