1. UKMicrowaves@groups.io
   Date   
Re: RAL parts

SAM JEWELL
 

OK Andy,
Some of it is currently under offer, but quite a bit still available.

Sam

On Saturday, June 15, 2019, 2:15 pm, Andy G4JNT <andy.g4jnt@...> wrote:

I may be interested Sam.



Virus-free. www.avg.com

On Sat, 15 Jun 2019 at 11:34, SAM JEWELL via Groups.Io <jewell=btinternet.com@groups.io> wrote:
Folks,
Well, that generated some interest!
I really want to offer these items at RAL. It saves packaging stuff to post (certainly not the 48cm dish and feed!).
What is left over at the end of the day I will be willing to ship (except that dish).
Please, cash only at RAL.  These are my own items and not part of my normal DDKit hobby business. Just having another shack/garage clear out. All items have not been used for the usual 2-5 yearzzzzzz.

I do have a couple of the WA5VJB 2.4GHz circular patch feeds left for sale. I hope to get more from Kent in the next few weeks. I’ll bring these few to RAL. Why go serial when you can go parallel!

73 de Sam
Re: Maximum Power using FR4 board ?

Chris Bartram G4DGU
 

My, perhaps slightly jaundiced, view is that although fully characterised FR4 from a decent manufacturer with 1oz copper is capable of handing a couple of hundred watts in amateur applications at 1.3GHz when used for microstrip circuitry, there are better ways. John, 'XDY, gets part of the way to the solution I'd use.

That is to forget microstrip! It is a useful transmission line medium for applications which are intended for some form of production, and with care and understanding, can be made to work adequately for many low-power applications - even using FR4 - up to 10GHz. However, as a way making a one-off power hybrid, it's a poor use of the available technologies.

If I wanted to make a combiner for a couple of power amplifiers for 23cm, I'd use air stripline. In fact I've done it, and they are sitting on a shelf waiting for me to find time to get around to putting a decent 1.3GHz system on the air. Stripline, where a conductor is suspended between two ground planes, is capable of very much lower losses than any comparable microstrip design.  My 90degree hybrids use a pair of lines parallel to each other along their broad faces, and each each offset from the centre line of the sandwich. The design equations are relatively simple, and unlike microstrip are not approximations. Unfortunately, I don't think any of this has been published recently in the amateur literature. The classic book on the subject is Harlan Howe's 'Stripline Circuit Design'. That should be available in most decent engineering libraries. The maths which Howe uses isn't intimidating, and as the book was written before the age of the PC, there are a lot of design nomographs. I have a copy, but I don't currently have time to write anything further, however I'm sure that there are others here who could produce an article for 'Scatterpoint' summarising the design method.

73 and enjoy MMRT!

Chris

G4DGU

_._,_._
Re: ADF5355 sketch in latest Scatterpoint

Barry Chambers
 

Hi Brian

I noticed that the RotaryEncoder library at the link you gave had both the .h and .cpp files as just Rotary, hence my slight mod - hope you don't mind my posting to the Group rather than just you.

Anyway, a nice piece of software - many thanks for posting it.

73

Barry, G8AGN
On 15/06/2019 11:09, brian.flynn via Groups.Io wrote:

Hi Barry,

I just double checked out both the Rotary.h library and RotaryEncoder.h library.  Both compile  and work OK on my setup at least.  I confusingly left the reference to the Encoder.h libray on the  line. I have now removed it.

73s
Brian GM8BJF

Feeding an LNB with an external reference through the coax

Arved M0KDS
 

Good afternoon all,

I've been working on locking my LNB with a GPSDO reference signal for QO-100 use.
The LNB I'be got is a GI-202 with two separate outputs. My plan is to modify one side to accept a reference signal while the other one will stay stock for DATV use. 
Unfortunately, I can't seem to get the LNB to lock with the reference signal being fed through the coax. I'm using a 100nF capacitor connected to the more sensitive pad (found by testing) and then running a wire from the cap to the f-connector pin. For some reason that isn't working at all. 

If I connect a piece of coax to the sensitive pad and feeding it directly to the LNB without going through the IF coax it works perfectly, no issues whatsoever. 
Does anyone have an idea why feeding through the IF coax isn't working at all?

I did use a probe to see if the reference signal is actually coming through to the LNB - it comes in loud and clear, with a few dBs of loss which comes from the RG-6 coaxial cable. 
Another thing I noticed is that the pads on the modified side have a voltage of about 0.2V on them, whilst the pads on the other unmodified side have about 2V on them. 

If anyone has an idea what might be happening here that would be great. I attached some pictures of my work to this message/email. 

Many thanks and 73,

Arved M0KDS
Re: Feeding an LNB with an external reference through the coax

Keith Le Boutillier
 

Hi Arved

 

Try a 10nf dc blocking cap with a 62 ohm or similar termination resistor

 

73 Keith GU6EFB

 

From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Arved M0KDS
Sent: 16 June 2019 15:07
To: UKMicrowaves@groups.io
Subject: [UKMicrowaves] Feeding an LNB with an external reference through the coax

 

Good afternoon all,

I've been working on locking my LNB with a GPSDO reference signal for QO-100 use.
The LNB I'be got is a GI-202 with two separate outputs. My plan is to modify one side to accept a reference signal while the other one will stay stock for DATV use. 
Unfortunately, I can't seem to get the LNB to lock with the reference signal being fed through the coax. I'm using a 100nF capacitor connected to the more sensitive pad (found by testing) and then running a wire from the cap to the f-connector pin. For some reason that isn't working at all. 

If I connect a piece of coax to the sensitive pad and feeding it directly to the LNB without going through the IF coax it works perfectly, no issues whatsoever. 
Does anyone have an idea why feeding through the IF coax isn't working at all?

I did use a probe to see if the reference signal is actually coming through to the LNB - it comes in loud and clear, with a few dBs of loss which comes from the RG-6 coaxial cable. 
Another thing I noticed is that the pads on the modified side have a voltage of about 0.2V on them, whilst the pads on the other unmodified side have about 2V on them. 

If anyone has an idea what might be happening here that would be great. I attached some pictures of my work to this message/email. 

Many thanks and 73,

Arved M0KDS
Re: Feeding an LNB with an external reference through the coax

Arved M0KDS
 

Hi keith,

thanks for getting back to me. 

Unfortunately I've only got 1nF and 100nF caps here, so that's a bit unfortunate. 

I tried adding a 56Ohm Resistor, it seems to have made it worse when fed directly at the pad with a coaxial cable. 
Feeding the reference through the coax is still not working.

73 Arved M0KDS
Re: Feeding an LNB with an external reference through the coax

militaryoperator
 




Feeding the reference through the coax is still not working.


Have you tested the coax and the connectors each end ?


Ben
Re: Feeding an LNB with an external reference through the coax

Keith Le Boutillier
 

Hi Arved

 

What LNB and frequency are you using 25 or 27Mhz have you googled to see if there is information on how others have moded their LNB?

Do you have a frequency counter are you seeing that frequency at the LNB  

Have you checked the cable and connectors for continuity silly things that can get over looked

 

73 Keith GU6EFB  

 

From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Arved M0KDS
Sent: 16 June 2019 17:16
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Feeding an LNB with an external reference through the coax

 

Hi keith,

thanks for getting back to me. 

Unfortunately I've only got 1nF and 100nF caps here, so that's a bit unfortunate. 

I tried adding a 56Ohm Resistor, it seems to have made it worse when fed directly at the pad with a coaxial cable. 
Feeding the reference through the coax is still not working.

73 Arved M0KDS

Re: Maximum Power using FR4 board ?

Neil Smith G4DBN
 

Hi Simon, if you need some metalbashing doing to make a stripline combiner, I would be happy to help with the fiddly bits. Drop me an email to neil@...

Seems sad to have to compromise your design for the sake of getting a bit of machining done.

Neil G4DBN

Simon wrote:
This is  a simple question what is the maximum power anyone would risk using a 1/4 length strip line on FR4 on 23cms ? 
 
Why because my metal working tools and skills are close zero and I am thinking of building a Wilkinson divider. 
Re: Feeding an LNB with an external reference through the coax

Colin G4EML
 

Are you sure you have completely disconnected the socket you are using for the reference input from its original connections?
If you have left the DC feed inductor connected it will look like a very low impedance to ground when fed with 25MHz which could be reducing the signal level too much.
 
 
 
 
 

From: Arved M0KDS
Sent: Sunday, June 16, 2019 5:16 PM
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Feeding an LNB with an external reference through the coax
 
Hi keith,

thanks for getting back to me.

Unfortunately I've only got 1nF and 100nF caps here, so that's a bit unfortunate.

I tried adding a 56Ohm Resistor, it seems to have made it worse when fed directly at the pad with a coaxial cable.
Feeding the reference through the coax is still not working.

73 Arved M0KDS

Re: Feeding an LNB with an external reference through the coax

Colin G4EML
 

Are you sure you have completely disconnected the socket you are using for the reference input from its original connections?
If you have left the DC feed inductor connected it will look like a very low impedance to ground when fed with 25MHz which could be reducing the signal level too much.
 
 
 
 
 

From: Arved M0KDS
Sent: Sunday, June 16, 2019 5:16 PM
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Feeding an LNB with an external reference through the coax
 
Hi keith,

thanks for getting back to me.

Unfortunately I've only got 1nF and 100nF caps here, so that's a bit unfortunate.

I tried adding a 56Ohm Resistor, it seems to have made it worse when fed directly at the pad with a coaxial cable.
Feeding the reference through the coax is still not working.

73 Arved M0KDS

Re: Maximum Power using FR4 board ?

KENT BRITAIN
 

Are you looking for a 2 way or a 4 way?    I just picked up a dozen commercial 4 way power dividers.  Kent



On Sunday, June 16, 2019, 1:29:31 PM CDT, Neil Smith G4DBN <neil@...> wrote:


Hi Simon, if you need some metalbashing doing to make a stripline combiner, I would be happy to help with the fiddly bits. Drop me an email to neil@...

Seems sad to have to compromise your design for the sake of getting a bit of machining done.

Neil G4DBN

Simon wrote:
This is  a simple question what is the maximum power anyone would risk using a 1/4 length strip line on FR4 on 23cms ? 
 
Why because my metal working tools and skills are close zero and I am thinking of building a Wilkinson divider. 
Re: Feeding an LNB with an external reference through the coax

Richard <richard@...>
 

What waveform are you putting thru the coax ?
If you are starting off with a square wave , on a short length used on direct connection the input will be quiet happy ,but
if you are shoving a square wave up 15 ~ 20mtrs of coax you can get some very strange effects. Best to put the 25MHz through a LPF and get rid of harmonic content
and put a nice clean sine wave up the coax, At least then you know what getting to the PLL as a reference,
HTH


On Sun, 2019-06-16 at 07:06 -0700, Arved M0KDS wrote:
Good afternoon all,

I've been working on locking my LNB with a GPSDO reference signal for QO-100 use.
The LNB I'be got is a GI-202 with two separate outputs. My plan is to modify one side to accept a reference signal while the other one will stay stock for DATV use. 
Unfortunately, I can't seem to get the LNB to lock with the reference signal being fed through the coax. I'm using a 100nF capacitor connected to the more sensitive pad (found by testing) and then running a wire from the cap to the f-connector pin. For some reason that isn't working at all. 

If I connect a piece of coax to the sensitive pad and feeding it directly to the LNB without going through the IF coax it works perfectly, no issues whatsoever. 
Does anyone have an idea why feeding through the IF coax isn't working at all?

I did use a probe to see if the reference signal is actually coming through to the LNB - it comes in loud and clear, with a few dBs of loss which comes from the RG-6 coaxial cable. 
Another thing I noticed is that the pads on the modified side have a voltage of about 0.2V on them, whilst the pads on the other unmodified side have about 2V on them. 

If anyone has an idea what might be happening here that would be great. I attached some pictures of my work to this message/email. 

Many thanks and 73,

Arved M0KDS

--
 Best wishes /73 
 Richard Bown
 
 Email : richard@...

 HTTP  :  http://www.g8jvm.com
 
 ######################################################################

 Ham Call: G8JVM . QRV: 50-432 MHz + Microwave 
 Maidenhead QRA: IO82SP38, LAT. 52 39.720' N LONG. 2 28.171 W
 QRV 6mtrs 200W, 4mtrs 150W, 2mtrs 300W, 70cms 200W, 
Microwave 1296MHz 140W, 2320MHz 100W & 10368MHz 5W
 OS: Linux Mint 19.1 x86_64 Tessa, on a Dell Inspiron N5030 laptop
 ######################################################################
Activity List for the UK Microwave Group mm-wave contests - Sunday 23rd June 0900-1700z

John Quarmby
 

Next Sunday sees the UKuG's major mm-wave event of the year, covering all bands from 24GHz to 248GHz. I know that maps were being carefully consulted at the RAL round table yesterday to plot possible paths, so I hope there will be some good distances worked on all bands.

The rules are here:

https://www.microwavers.org/files/2019-mwrules.pdf

As usual I will assemble an activity list and post it here, Please send details of your plans by close of play on Friday this week and I will consolidate them and send out the list on Saturday. Please note that the exchange for these events asks for 8 character locator information to be exchanged and logged.

73

John G3XDY

UKuG Contest Manager
Re: Maximum Power using FR4 board ?

simonchettle
 

Hi  All
 
Many thanks for the comments and advice.
 
Kent – It’s a 2 way splitter (Shame) but thanks for the offer.
 
Chris – Yes I vaguely remember building an air strip line back in the 70s and had all the maths – long since lost after several moves.  However that is the route I will probably take.
 
73s
 
Simon
 
 
 

From: KENT BRITAIN
Sent: Sunday, June 16, 2019 8:00 PM
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Maximum Power using FR4 board ?
 
Are you looking for a 2 way or a 4 way?    I just picked up a dozen commercial 4 way power dividers.  Kent
 
 
 
On Sunday, June 16, 2019, 1:29:31 PM CDT, Neil Smith G4DBN <neil@...> wrote:
 
 
Hi Simon, if you need some metalbashing doing to make a stripline combiner, I would be happy to help with the fiddly bits. Drop me an email to neil@...
 
Seems sad to have to compromise your design for the sake of getting a bit of machining done.
 
Neil G4DBN
 
Simon wrote:
This is  a simple question what is the maximum power anyone would risk using a 1/4 length strip line on FR4 on 23cms ?
 
Why because my metal working tools and skills are close zero and I am thinking of building a Wilkinson divider.

Re: Feeding an LNB with an external reference through the coax

G4WIM KT6UK
 

I’ve looked into locking a lnb for narrow band transponder use and while it worked I found that it degraded the the wide band datv MER which is my main interest.
So for narrow band use I now employ sdr console which takes care of the drift and associated frequency offsets.  I use a Lime sdr on tx and it works very nicely with no need to phase lock the lnb.  However I do use a rtl dongle with a 0.2ppm reference.

When I wad phase locking the lnb I made a triplexer at each end of the coax with one port for DC, another for 25MHz sinewave and another for the 750MHz if signals.

73 Tim
RAL Seller with the Florida RF loads

Paul M0EYT
 

Hi all,

I cannot remember who it was at RAL that had the dummy load modules, please could they ping me pjm@... if they are reading this.

Great round table btw!

regards,

Paul M0EYT
digi modes 3cms

Richard <richard@...>
 

Whats the most used digital mode on 3cms now ?
--
Best wishes /73
Richard Bown

Email : richard@...

HTTP : http://www.g8jvm.com

######################################################################

Ham Call: G8JVM . QRV: 50-432 MHz + Microwave
Maidenhead QRA: IO82SP38, LAT. 52 39.720' N LONG. 2 28.171 W
QRV 6mtrs 200W, 4mtrs 150W, 2mtrs 300W, 70cms 200W,
Microwave 1296MHz 140W, 2320MHz 100W & 10368MHz 5W
OS: Linux Mint 19.1 x86_64 Tessa, on a Dell Inspiron N5030 laptop
######################################################################
Re: digi modes 3cms

Neil Smith G4DBN
 

From where I am sitting, I'd say JT4G for tropo and JT9F-fast for aircraft scatter.  Pretty much like 23/13cm in fact. Or for REAL silliness, FT8 over NBFM via rainscatter (yes, REALLY!).

EME is a different matter, and I'm still building, but I see about half and half QRA64 and JT4G on the discussions and spots. Once I get the new dish in place, I'll be able to tell you what I see.  Just had a notification that my damn great 130kg 8 inch galvanised ground post for the 3m solid dish is in progress at the local fabrication shop.

However, and this is a big "however", I'd suggest that there isn't really a "most used" mode for terrestrial on 10GHz, as everyone is experimenting with *every* mode. Obviously for contacts of any distance, where the scintillation is more than a few Hz, narrow modes are not going to work too well, so WSPR and FT4/8 and the very narrow JT9 slow modes are not going to be reliable.

A fair proportion of the stations are only active /P, and there are good practical reasons why those ops are not able to run MGM, but it does feel like we are missing a trick when we could go to much lower S/N ratios with MGM.

There is also a bit of a constraint on tx/rx changeover time for those of us using waveguide relays.  5-second over JT9F-fast is just a bit too much, and 10-second overs mean you can't complete an aircraft-scatter QSO in a single reflection, whereas with CW or SSB, it is usually possible. I'm hoping my new Sivers WR90 relay will be able to manage 5s overs.

If anyone fancies trying digimodes on 3cm, even over unpromising paths or from what you might believe are terrible home locations, I am usually around on Monday and Friday evenings and occasional Wednesdays and happy to make ad-hoc skeds at almost any other time if there is decent tropo or rainscatter.

Neil G4DBN

On 17/06/2019 17:55, Richard wrote:
Whats the most used digital mode on 3cms now ?
Re: digi modes 3cms

SAM JEWELL
 

I have taken my 3cm transverter off my mast for now. Locking problem. However, I am seriously thinking about mounting a PLL controlled (just the internal 25MHz crystal) LNB near the top of my mast, for monitoring purposes. The LNBs are reasonably weatherproof. The complication of mounting the body of the LNB in a box, with the radome poking out, may be a stage too far!

As the horn on the LNB is designed to illuminate high F/D offset dishes with low sidelobes to keep adjacent satellite signals down, it may have an acceptable (but low) gain, sufficient for this purpose. I can run the IF, with dc, over the single RG58 cable normally used for the 106.5MZhz reference. It will be interesting to see what can be heard (and seen) on the RSP2 or Lime mini.
I wonder if the software could be modified to track a single carrier, from a very low power generator on the ground, as in the QO100 beacon? Maybe generate a pseudo PSK signal so that the software doesn’t need modifying?
 
Sam

On Monday, June 17, 2019, 6:44 pm, Neil Smith G4DBN <neil@...> wrote:

From where I am sitting, I'd say JT4G for tropo and JT9F-fast for
aircraft scatter.  Pretty much like 23/13cm in fact. Or for REAL
silliness, FT8 over NBFM via rainscatter (yes, REALLY!).

EME is a different matter, and I'm still building, but I see about half
and half QRA64 and JT4G on the discussions and spots. Once I get the new
dish in place, I'll be able to tell you what I see.  Just had a
notification that my damn great 130kg 8 inch galvanised ground post for
the 3m solid dish is in progress at the local fabrication shop.

However, and this is a big "however", I'd suggest that there isn't
really a "most used" mode for terrestrial on 10GHz, as everyone is
experimenting with *every* mode. Obviously for contacts of any distance,
where the scintillation is more than a few Hz, narrow modes are not
going to work too well, so WSPR and FT4/8 and the very narrow JT9 slow
modes are not going to be reliable.

A fair proportion of the stations are only active /P, and there are good
practical reasons why those ops are not able to run MGM, but it does
feel like we are missing a trick when we could go to much lower S/N
ratios with MGM.

There is also a bit of a constraint on tx/rx changeover time for those
of us using waveguide relays.  5-second over JT9F-fast is just a bit too
much, and 10-second overs mean you can't complete an aircraft-scatter
QSO in a single reflection, whereas with CW or SSB, it is usually
possible. I'm hoping my new Sivers WR90 relay will be able to manage 5s
overs.

If anyone fancies trying digimodes on 3cm, even over unpromising paths
or from what you might believe are terrible home locations, I am usually
around on Monday and Friday evenings and occasional Wednesdays and happy
to make ad-hoc skeds at almost any other time if there is decent tropo
or rainscatter.

Neil G4DBN

On 17/06/2019 17:55, Richard wrote:
> Whats the most used digital mode on 3cms now ?