Date   

Re: Thor Labs lens

Steve Gemeny
 

Zack,

 

The combination of lens and horn is intriguing to me but comes with some questions:

  • Have you any idea the gain of the two; I’m just guessing but maybe 3-6 dB over the horn alone, but a more informed estimate might be nice to know.
  • It’d be nice to see a configuration sketch, and/or photo.  The 150mm FL is easy enough to work from, but that’s from the phase center of the feed which is not usually known; Is the assumed ~30% into the horn good enough or is it just found by experimentation with the lens placement? A measured distance from feed face to lens on a well aligned system might be a better start.

 

This is an interesting configuration and one I am likely to tinker with so actual “user commentary” would be of great value to me (and maybe others).

 

Thanks

73

Steve - AA3NM

 

Steve Gemeny

3212 Patapsco Rd..

Finksburg, MD 21048

 

240-464-2280 (cell)

301-UN 4-4208 (If I’m home)

  Steve@...

 

 

 

 

From: The122GProject@groups.io <The122GProject@groups.io> On Behalf Of Zack Widup
Sent: Wednesday, October 6, 2021 11:40 PM
To: The122GProject@groups.io
Subject: Re: [The122GProject] Thor Labs lens

 

Hi Warren,

 

For one thing, a 12 inch dish at 122 GHz has a beamwidth of 0.56 degrees. A 24 inch dish has a beamwidth of 0.28 degrees. My skills at aiming a dish aren't that good. The teflon lens has a beamwidth of maybe 5 degrees. A lot easier to point. If you're going for really long distances (> 25 km) you would probably want the dish. If you want to work someone closer than that, the 20 dB horn or the horn with lens works well.

 

73, Zack W9SZ

 

On Wed, Oct 6, 2021 at 9:42 PM Warren Ferber <warrenWF0T@...> wrote:

Hi Zack,

What is the benefit of using a lens at 122GHz over a dish?

It sounds like an intriguing option.

Thanks, 73

Warren - WF0T

 

 


Re: Thor Labs lens

Rus Healy, K2UA
 

K9PW measured 13 dB gain over the 20 dBi horn on a range. 

Rus

On Thu, Oct 7, 2021 at 8:28 AM Dave N2OA <kdcarlso@...> wrote:
Is there a way to calculate gain and beamwidth for a lens? I haven't been able to find anything.

Dave
N2OA

On Wed, Oct 6, 2021 at 11:40 PM Zack Widup <w9sz.zack@...> wrote:
Hi Warren,

For one thing, a 12 inch dish at 122 GHz has a beamwidth of 0.56 degrees. A 24 inch dish has a beamwidth of 0.28 degrees. My skills at aiming a dish aren't that good. The teflon lens has a beamwidth of maybe 5 degrees. A lot easier to point. If you're going for really long distances (> 25 km) you would probably want the dish. If you want to work someone closer than that, the 20 dB horn or the horn with lens works well.

73, Zack W9SZ

On Wed, Oct 6, 2021 at 9:42 PM Warren Ferber <warrenWF0T@...> wrote:
Hi Zack,

What is the benefit of using a lens at 122GHz over a dish?

It sounds like an intriguing option.

Thanks, 73

Warren - WF0T


Virus-free. www.avast.com


Re: Thor Labs lens

Dave N2OA
 

Is there a way to calculate gain and beamwidth for a lens? I haven't been able to find anything.

Dave
N2OA

On Wed, Oct 6, 2021 at 11:40 PM Zack Widup <w9sz.zack@...> wrote:
Hi Warren,

For one thing, a 12 inch dish at 122 GHz has a beamwidth of 0.56 degrees. A 24 inch dish has a beamwidth of 0.28 degrees. My skills at aiming a dish aren't that good. The teflon lens has a beamwidth of maybe 5 degrees. A lot easier to point. If you're going for really long distances (> 25 km) you would probably want the dish. If you want to work someone closer than that, the 20 dB horn or the horn with lens works well.

73, Zack W9SZ

On Wed, Oct 6, 2021 at 9:42 PM Warren Ferber <warrenWF0T@...> wrote:
Hi Zack,

What is the benefit of using a lens at 122GHz over a dish?

It sounds like an intriguing option.

Thanks, 73

Warren - WF0T


Virus-free. www.avast.com


Re: Thor Labs lens

 

Hi Warren,

For one thing, a 12 inch dish at 122 GHz has a beamwidth of 0.56 degrees. A 24 inch dish has a beamwidth of 0.28 degrees. My skills at aiming a dish aren't that good. The teflon lens has a beamwidth of maybe 5 degrees. A lot easier to point. If you're going for really long distances (> 25 km) you would probably want the dish. If you want to work someone closer than that, the 20 dB horn or the horn with lens works well.

73, Zack W9SZ

On Wed, Oct 6, 2021 at 9:42 PM Warren Ferber <warrenWF0T@...> wrote:
Hi Zack,

What is the benefit of using a lens at 122GHz over a dish?

It sounds like an intriguing option.

Thanks, 73

Warren - WF0T


Virus-free. www.avast.com


Re: Thor Labs lens

Warren Ferber
 

Hi Zack,

What is the benefit of using a lens at 122GHz over a dish?

It sounds like an intriguing option.

Thanks, 73

Warren - WF0T


Thor Labs lens

 

I don't know if anyone actually posted the links for the lens and lens mount some of us are using. I've been asked by a couple people. So here they are:


73, Zack W9SZ


Re: Weak Signal

Mike Lavelle K6ML
 

as a sanity check, maybe try using your two radios to copy each other (on same tx freq, different directions, same path (maybe a few hundred feet), same horn antennas, without the lens to remove a variable).  see if you get similar or dramatically different SNRs.

also maybe look at the PLL spectrum for each rig, to see if the spurs/phase noise are the same (perhaps one PLL is unhappy with it's reference).  you can look at the DIV test point (1.9 GHz at each Tx) and also look at the received IF spectrum (at each Rx) to check for differences.    

Be sure to do the tests a the same Tx frequencies; PLL spurs and PN (which are lost Tx power) vary with the channel and with the reference OCXO.

On 10/05/2021 9:41 AM Zack Widup <w9sz.zack@...> wrote:


I bought two completed boards in the recent purchase group. I soldered SMA connectors onto the board for IF output and OCXO input. I modified the board for use with an external OCXO. I assembled the unit and used the serial port to change the callsign in the unit to my own. I connected a PICKIT3 to the unit and downloaded the PIC program just to have on hand (This time making sure I powered the unit up first, so the PIC would detect and use the internal 3.3 volts going to the PIC).

I put it in the box I used for the 122 GHz board I wiped out last time. OXCO input level is correct. When it powers up, all sequences are correct. It sends my callsign in beacon mode. I am using the 20 dB horn. Polarization is horizontal. I have it set up for frequency switch position 0 and selected mode A. I tested it out with the other unit I have. I could receive each unit very well with the other unit at a distance of about 4 or 5 feet.

I used it in the September 10 GHz weekend over a distance of 1.1 km. The station I worked reported that I was about 20 dB weaker than several other stations at my location (we were all lined up). Frequency was as expected and I could copy him. He was also using a ThorLabs 3 inch teflon lens in addition to the 20 dB horn. I tried to work another station at his location who was using an identical setup to mine. I could not copy him and he could not copy me. The other people at my end worked him.

I am wondering what the problem is and if anyone has an idea what might be wrong. Have I wiped out another board? I really don't know what I may have done this time to do that.

73, Zack W9SZ


Re: Unit not going in to rx

Noel - G8GTZ
 

Yes, my mistake not reading the datasheet carefully.

Thanks Dave, I'll send you a PM.

73 Noel


Re: Unit not going in to rx

Dave G8KHU
 

Hi Noel

My reading of the datasheet is that the 16LF877A requires 3.0V min to operate at 10 MHz clock - so you should be OK with 3.28V. Re programming, you should be able to program the device normally with your 3.28V supply rail, the only programming function that requires 4.5 V is bulk erase which you would do if you want to clear all memory including code protect bits. The datasheet says:

When using ICSP, the part must be supplied at 4.5V to
5.5V if a bulk erase will be executed. This includes
reprogramming of the code-protect, both from an on
state to an off state. For all other cases of ICSP, the part
may be programmed at the normal operating voltages.

PS - My italics.

If you want to try a different programmer I have a couple of ICD-2 s in addition to a PicKit if you want to pop over at some time

73
Dave
G8KHU



Weak Signal

 

I bought two completed boards in the recent purchase group. I soldered SMA connectors onto the board for IF output and OCXO input. I modified the board for use with an external OCXO. I assembled the unit and used the serial port to change the callsign in the unit to my own. I connected a PICKIT3 to the unit and downloaded the PIC program just to have on hand (This time making sure I powered the unit up first, so the PIC would detect and use the internal 3.3 volts going to the PIC).

I put it in the box I used for the 122 GHz board I wiped out last time. OXCO input level is correct. When it powers up, all sequences are correct. It sends my callsign in beacon mode. I am using the 20 dB horn. Polarization is horizontal. I have it set up for frequency switch position 0 and selected mode A. I tested it out with the other unit I have. I could receive each unit very well with the other unit at a distance of about 4 or 5 feet.

I used it in the September 10 GHz weekend over a distance of 1.1 km. The station I worked reported that I was about 20 dB weaker than several other stations at my location (we were all lined up). Frequency was as expected and I could copy him. He was also using a ThorLabs 3 inch teflon lens in addition to the 20 dB horn. I tried to work another station at his location who was using an identical setup to mine. I could not copy him and he could not copy me. The other people at my end worked him.

I am wondering what the problem is and if anyone has an idea what might be wrong. Have I wiped out another board? I really don't know what I may have done this time to do that.

73, Zack W9SZ


Re: Unit not going in to rx

Don Woodward
 

The PIC in these units is a PIC16LF877A which needs 3.3v

73's

Don W.
KD4APP




From: The122GProject@groups.io <The122GProject@groups.io> on behalf of Noel - G8GTZ via groups.io <noel@...>
Sent: Tuesday, October 5, 2021 9:12 AM
To: The122GProject@groups.io <The122GProject@groups.io>
Subject: Re: [The122GProject] Unit not going in to rx
 
So I checked volts (3.28) and also reference  (10 MHz at the correct level) and having read a thread by Rob M0DTS who had a similar issue and found reprogramming the PIC fixed it, I decided to reprogram the PIC.

Using a PICKIT3 hardware and s/w with set to device volts it fails to program the device with error "Programming failed at program memory address 0x00007e" and the unit is now dead - well the LED now longer flashes :-(

Google seems to indicate that the 16F877A really needs 4.5 volts to erase and program successfully but clearly this is not possible with the device on the PCB...

Any bright ideas are welcome!

73
Noel - G8GTZ


Re: Unit not going in to rx

Noel - G8GTZ
 

So I checked volts (3.28) and also reference  (10 MHz at the correct level) and having read a thread by Rob M0DTS who had a similar issue and found reprogramming the PIC fixed it, I decided to reprogram the PIC.

Using a PICKIT3 hardware and s/w with set to device volts it fails to program the device with error "Programming failed at program memory address 0x00007e" and the unit is now dead - well the LED now longer flashes :-(

Google seems to indicate that the 16F877A really needs 4.5 volts to erase and program successfully but clearly this is not possible with the device on the PCB...

Any bright ideas are welcome!

73
Noel - G8GTZ


Re: Unit not going in to rx

G8ACE
 

Sounds like your reference Noel.
Check ref signal is present.  Check the ref termination at the pcb.  Check the ref amplitude.
73s John G8ACE


Re: Unit not going in to rx

Mike Lavelle K6ML
 

Hi, Noel

I believe fast flashing red means the input voltage is low.   Maybe check your battery/power supply?

73
Mike

On 10/04/2021 6:50 AM Noel - G8GTZ <noel@...> wrote:


I've been doing some work on my previously working unit such as changing dish feed and adding an IQ switch.  However, when I went to test the unit this morning the LED no longer goes green and the unit does not go into rx mode.

The operating table looks like this - it is the same on either A or B channel and I have disconnected the IQ switch when testing.



Looks like the PIC is still reading the ports as functionality changes depending on switch positions - it does occasionally flash green during switch changeover.

Maybe a firmware upgrade is the next step to see if it has become corrupted.

Any help is appreciated - preferably before the weekend when we have the UK 122 contest!

73

Noel - G8GTZ


Re: Unit not going in to rx

Noel - G8GTZ
 

Connecting up to the RS232 diagnostic port gives the following data:

37 0E 7B 01 E8 FF 03 A8 01 3F   >_ PLL LOCK ERROR

Looking at previous messages it appears corrupt firmware can give this error but before I do reprogram it does anyone have any other ideas?

73
Noel - G8GTZ


Unit not going in to rx

Noel - G8GTZ
 

I've been doing some work on my previously working unit such as changing dish feed and adding an IQ switch.  However, when I went to test the unit this morning the LED no longer goes green and the unit does not go into rx mode.

The operating table looks like this - it is the same on either A or B channel and I have disconnected the IQ switch when testing.



Looks like the PIC is still reading the ports as functionality changes depending on switch positions - it does occasionally flash green during switch changeover.

Maybe a firmware upgrade is the next step to see if it has become corrupted.

Any help is appreciated - preferably before the weekend when we have the UK 122 contest!

73

Noel - G8GTZ


122 module

Guy F5BLC
 

Hello everyone,

Do any of you or possibly Tim, have a first or second build 122GHz available module ?

I have two in service but I'm locking for a third to carry out comparative antenna tests (with Edmund low F/D PF, multi-reflector PF and extremely large conical feed)

Pleaase tell me if you can get me one.....

Vy 73, Guy F5BLC


Re: Splash plate feed

Noel - G8GTZ
 

Thanks for all the replies (and no problem Neil - I totally understand).

I have experimented with several feeds and the best seems a 25mm diameter convex reflector cut from the base of an aerosol can - see photo.



Several adjustments were made using my very low power beacon across the garden - the distance the 4mm tube goes into the mount on the PCB is very critical and the distance from the end of the feed tube to the reflector plate is less so but is approximately 5mm. The placement of the reflector at the focal point was done by pointing the dish at the sun and finding the focal point, which even with the weak UK autumn sunshine, was enough to set light to paper within a couple of seconds!

Details of the low power beacon here: https://wiki.microwavers.org.uk/Microwave_signal_source

Whilst the feed or the dish may not be optimum, it does appear to have more than 13 dB gain above the 20 dB horn supplied and will be used for more on-air tests in the UK Microwave Group 122 contest next weekend. 

Even if I don't work you, it will be would be good to hear of some more of the 60 units supplied to the UK last year on air during the contest - at the last count there were about 50 units still sitting on the shelf!

73
Noel - G8GTZ


Re: Mixer and Spectrum Analyser for 122GHz

Paul G8KFW
 

Dear sir 

 

I think you will find that a number of spectrum analysers have the Diplexer built into the Analyser

So from memory you will not have the socket marked IF and possibly not LO

Also from memory this applies to the Spectrum analyser that uses the HP 140 series displays and the HP 8565 Spectrum analyser

 

Regards Paul

 

From: The122GProject@groups.io [mailto:The122GProject@groups.io] On Behalf Of Bas de Jong
Sent: 29 September 2021 16:30
To: The122GProject@groups.io
Subject: Re: [The122GProject] Mixer and Spectrum Analyzer for 122GHz

 

Hi all

 

I made a very simple harmonic mixer which works quite well at least up to 60GHz: http://www.pe1jpd.nl/index.php/external-ghz-mixer-hp8555a/  The LO from the sa is mixed in a bat15 and the resulting IF is fed back to the sa, without diplexer. No experience at 122G yet however because our batch did not arrive yet (sic).

 

73 Bas PE1JPD

 

Verstuurd vanaf mijn iPhone



Op 29 sep. 2021 om 15:38 heeft Paul G8KFW <admin@...> het volgende geschreven:



Hi all

 

As  a reply to Noels question I have created a new folder OML Harmonic mixers  and I suggest you start with  42-120531

 

Please note  the mixers start from $2000 but there is a lot of useful information if you are new to working at these frequencies

 

Regards Paul

 

From: The122GProject@groups.io [mailto:The122GProject@groups.io] On Behalf Of Noel - G8GTZ
Sent: 29 September 2021 10:25
To: The122GProject@groups.io
Subject: Re: [The122GProject] Mixer and Spectrum Analyzer for 122GHz

 

Hi Doug

Very interesting - I have a couple of those Phillips mixers (use one on my 47GHz set up) but I don't quite understand the setup as you don't appear to have any LO injection.

Any chance of a sketch or diagram of the arrangement?

73
Noel - G8GTZ


Re: Mixer and Spectrum Analyzer for 122GHz

Doug Millar
 

Attached is my talk on external mixers. (I hope it comes through)  Doug

Dr.Doug Millar EdD.
K6JEY
drzarkof56@...
562 810 3989  cell/text



On Wednesday, September 29, 2021, 09:37:59 AM PDT, Doug Millar via groups.io <drzarkof56@...> wrote:


I found several diplexers on ebay. Both were internal diplexers from older Tektronix spectrum analyzers. The external ones are very common.  I have more info.
     Doug

Dr.Doug Millar EdD.
K6JEY
drzarkof56@...
562 810 3989  cell/text



On Wednesday, September 29, 2021, 04:16:58 AM PDT, Paul G8KFW <admin@...> wrote:


Hi Noel

 

I think the bit you are missing is the Diplexer

 

The local oscillator and the return Signal (IF ) from the external mixer to the analyser go through a Diplexer

 

Typically the diplexer IF is a low pass filter at 1.5 Ghz and the Local oscillator is a High pass filter at 2 Ghz 

 

Tektronix  made them also HP  but the only New ones available at this time are from the USA at approximately $250

 

Regards Paul

 

From: The122GProject@groups.io [mailto:The122GProject@groups.io] On Behalf Of Noel - G8GTZ
Sent: 29 September 2021 10:25
To: The122GProject@groups.io
Subject: Re: [The122GProject] Mixer and Spectrum Analyzer for 122GHz

 

Hi Doug

Very interesting - I have a couple of those Phillips mixers (use one on my 47GHz set up) but I don't quite understand the setup as you don't appear to have any LO injection.

Any chance of a sketch or diagram of the arrangement?

73
Noel - G8GTZ

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