Date   

Re: TCXO Behaviour

Robin Szemeti - G1YFG
 

And as an update, I fitted the "golden" TCXO to the 13cm transverter and it is indeed very stable as described, can't fault it.   I tuned in the Telford beacon when the shed was nice and warm one evening left it running.  It was still the same tone the next morning when the shed was somewhat cooler.  It appears to be excellent, blowing some warm air over it has minimal effect, certainly for SSB purposes, it is more than adequate.

image.png


On Sun, 6 Sep 2020 at 16:10, Robin Szemeti - G1YFG via groups.io <robin=redpoint.org.uk@groups.io> wrote:
Noted, thanks for the update. Just need something to tame this very wobbly crystal in the PLL ... I suspect it may be made from cheese.  I'll try one with a block of "something" around it to shield it ... polystyrene or similar.

On Sun, 6 Sep 2020 at 12:44, Andy G4JNT <andy.g4jnt@...> wrote:
I only did a quick test on each.    All seem to hold their frequency quite well to a fraction of a PPM, far better then a straight crystal would.  But some seem to have a long time constant in their compensation.  If you  waft  air over them  the frequency changes rapidly, only by a fraction of a PPM, but sudile (at uWaves) , enough to be annoying.  So if using for  GHz, they do need to be inside a closed container in still air - and definitely away from any cooling fans.

BTW, I encountered one, once that was a frequency hopper.   Sounded like JT4 when multiplied up - those are designed / touted to overcome EMC regs by spreading interference.    Or it may have been digital temperature compensation that was applied via a 4 bit D/A and PRN mod.   If that was the case, it would have been a pretty clever bit of design.



On Sun, 6 Sep 2020 at 00:35, Robin Szemeti - G1YFG <robin@...> wrote:
Out of curiosity, did you test the higher frequency TCXOs and come to any conclusions? 

On Fri, 12 Jun 2020 at 11:48, Andy G4JNT <andy.g4jnt@...> wrote:
I'm using this TCXO 
Part No  
RoHS1
449-LFTVXO075802CUTT     Type  LFTVXO075802Cutt     TCXO  10.0MHz .28ppm
 in my 3.4GHz transverter and for a relative low cost frequency source, it's excellent.  But I can't work out why there is a steady frequency drift from turn-on.  It's only about 0.1ppm so is within spec, and occurs over the first 20 - 30 minutes of operation.

Isn't the whole point of a TCXO that it's temperature compensated ?   Perhaps it's just compensation loop-gain is too low. 

Guess I'm expecting too much :-)

I've just bought a batch of each of the low cost TCXOs that Farnell & RS have available in several different frequencies, 19.2, 26 and 40MHz and will investigate their performance as references.    As modern Fract-N synths prefer a higher Fref than 10MHz,  wondering if these will do, and they can always be locked to 10MHz separately.



--
Robin Szemeti - G1YFG


--
Robin Szemeti - G1YFG


--
Robin Szemeti - G1YFG


Re: Activity List for the final session of the UKuG 5.7/10GHz Contests 2021 - Sunday 27th September

Clive Elliott GW4MBS
 

Callsign: GW4MBS/P
Locator: IO71XW37GP Good take-off only to East - South West
Bands: 10GHz 3W Sky Dish
Talkback: ON4KST
Times: Most of day

If wet from home IO71XW74VJ in a valley that sort of points NE

--
Clive GW4MBS (ex-G8ADP)
Pottering on 6m - 3cm in a valley in IO71XW where any QSO is a triumph of optimism over geography!


Re: HP Power Sensor wanted

Chris Bartram G4DGU
 

As they were needed for my former work (apologies for the bad language!) I have a number of power meters complete with sensors to 40GHz. While for historical reasons I don't lend instruments, I'd be quite happy to 'calibrate' anyone's home-made sensor.

While I have working a 8485 and a 8482, I also have a damaged 8481 which suffered a gross overload due to my utter stupidity. Although a repair would be possible, I can't now justify the cost of the replacement thermal sensor module.

I have somewhere seen a design for a diode detector module designed as effectively a drop-in replacement for the 8481 electronics (albeit with out the accuracy!). Does anybody have a reference?

73

Chris G4DGU


On 25/09/2020 08:39, geoffrey pike via groups.io wrote:
Hi,
I have used a AD8317 in a non working HP435B and without changing its original state, just use the meter.
From my notes(i actually have them), its performance at 10 GHz (AD8317 spect to 8GHz) shows it
reads about 20 dB low the real value and fairly good to 8GHz. Scaling on the meter is in my case -5dBm FSD and -30dBm mid scale with 55dB range.
The AD8317 does have a -ve output slope, anyway for about a tenner you have a meter that you can abuse and not worry about the thermistor head
cheers
Geoff
GI0GDP

On Thursday, 24 September 2020, 21:25:07 BST, Paul Randall G3NJV <paulfrandall@...> wrote:


Having explored multiple avenues to get a calibrated power reference into my workshop I finally bit the bullet and bought a cheap HP435B non-working power meter for parts for a home-brew power meter. On delivery, I find it in good condition and might even be completely working - just the power switch not illuminating.
So now I'm in the place I dreaded, I'll find it hard to break this classic instrument just for parts so am wondering if anyone out there has a power sensor and cable just lying around unused that they might part with.
An 8481A is the ideal of course but on ebay with cable it is more than my monthly pension so might as well be made of unobtainium. I guess even a long term loan would be good - once I have finished building my projects to venture into the microwave region, the entire instrument could be retasked to a new home.
So, any possibilities out there? I'd be glad to hear.
73s Paul G3NJV


Re: Activity List for the final session of the UKuG 5.7/10GHz Contests 2021 - Sunday 27th September

G4LDR
 

Callsign, G4LDR
Locator, IO91EC02
Bands, 10GHz and 5.7GHz
Talkback, 144.390, KST, (Zello perhaps)
Times, Hope to be QRV for some periods throughout the contest after about 10:00UTC.

73 Neil G4LDR.


Re: Activity List for the final session of the UKuG 5.7/10GHz Contests 2021 - Sunday 27th September

geoffrey pike
 

Wind and rain permitting:-

Callsign: GI0GDP/P
Locator: IO74BR40LR
Bands: 10GHz and  5.7 GHz 1 watt and 4 watts Sky dish
Talkback: 144.390 and 07817 177907
Times: From about 11:00 clock time

cheers
Geoff
GI0GDP

On Monday, 21 September 2020, 15:59:32 BST, John Quarmby via groups.io <g3xdy@...> wrote:


Next Sunday sees the final session of the UK Microwave Group 5.7 and
10GHz contest series. This takes place between 0600 and 1800 GMT (0700 -
1900 BST), entrants can operate for a maximum of 8 hours during the
period. Full rules can be found here:


Unfortunately i don't think weather and conditions will be quite as good
as the weekend we have just had, but let us see what happens.

Please send your plans in the usual format (as below) and I will issue a
collated list on the 26th September.


Callsign: G3XDY
Locator: JO02OB
Bands: 5.7GHz 15W, 60cm dish
              10GHz  10W, 60cm dish
Talkback: ON4KST, Zello SHF Chat
Times: Various throughout.

73

John G3XDY
UKuG Contest Manager


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Re: Activity List for the final session of the UKuG 5.7/10GHz Contests 2021 - Sunday 27th September

Adrian G4UVZ
 

G4UVZ
IO80 KX
Next door to GB3KBQ ! 10368.870...if you can hear the beacon you can work me!
10 watts on 10GHz 60cm dish
2M talkback and Zello


Re: Microwave oven test

Andrew G8TZJ
 

Yes Clint, that's the material. At least I know it wont soak up water.

73 Andrew


Re: Activity List for the final session of the UKuG 5.7/10GHz Contests 2021 - Sunday 27th September

g4bao
 

Callsign: G4BAO
Locator: JO02CG
Bands: 10GHz
7W 60cm Offset dish @8m AGL
Talkback: ON4KST, Zello SHF Chat, 144.390MHz
Times: From about 10:00 UTC in and out


Re: HP Power Sensor wanted

Neil Smith G4DBN
 

I have an HP33330B 18 GHz Low-Barrier Schottky detector that I use with a set of Radiall attenuators.  I calibrate it now and then against my 8481A and 8481D heads on an HP436A. I'm thinking of building an interface to it with an A/D converter and PIC and building that into a 435 case with a rechargeable battery and a USB interface for charging, updating the calibration curves and reading the output using a 436A or ACPI emulation.

OK, I could build it into a small case with an e-ink display, but I like the big analogue meter when tweaking things.  I have a 435B that is very clean and works well, so I'd have to find an unloved one to gut and re-purpose.  Having it run on batteries would make it a lot more useful.

Neil G4DBN


On 25/09/2020 11:05, Mike Willis wrote:
On Thu, Sep 24, 2020 at 09:25 PM, Paul Randall G3NJV wrote:
8481A
There are plenty of HP8484 heads on Ebay for not unreasonable prices between £100 and £200. If you want professional test gear I am afraid you have to pay a little bit of money to get it. Not a lot compared to the new price. My advice is not to but the thermal heads you will blow them up, eventually. The over power capability of the 8484 diode head is much greater relative to it's upper power limit than the 8481.

You can always go for the cheaper solutions, not as accurate, but maybe accurate enough. Usually you don't really need to know the amplifier output exactly. After all you usually then connecting it via coax where the loss is not exactly known, through several connectors and relays to an antenna so you have really no idea what the actual EIRP is to within a dB or so. Knowing the PA power output to better than 2% doesn't really figure against the other errors.

--
Mike G0MJW
_._,_._,_



Minikits EME23-TRV

 

Hi would any body be interested in a 23cms transverter kit from Minikits  part number EME23-TRV KIT 
thanks Mark M0GUC 


Re: HP Power Sensor wanted

Mike Willis
 

On Thu, Sep 24, 2020 at 09:25 PM, Paul Randall G3NJV wrote:
8481A
There are plenty of HP8484 heads on Ebay for not unreasonable prices between £100 and £200. If you want professional test gear I am afraid you have to pay a little bit of money to get it. Not a lot compared to the new price. My advice is not to but the thermal heads you will blow them up, eventually. The over power capability of the 8484 diode head is much greater relative to it's upper power limit than the 8481.

You can always go for the cheaper solutions, not as accurate, but maybe accurate enough. Usually you don't really need to know the amplifier output exactly. After all you usually then connecting it via coax where the loss is not exactly known, through several connectors and relays to an antenna so you have really no idea what the actual EIRP is to within a dB or so. Knowing the PA power output to better than 2% doesn't really figure against the other errors.

--
Mike G0MJW


Re: QO-100 Tomorrow

Nick Gregory G0HIK
 

I've just got to the car park, I should be on QO100 in around 30mins 11:30 local time 25thsept.

Nick G0HIK


Re: HP Power Sensor wanted

geoffrey pike
 

Hi,
I have used a AD8317 in a non working HP435B and without changing its original state, just use the meter.
From my notes(i actually have them), its performance at 10 GHz (AD8317 spect to 8GHz) shows it
reads about 20 dB low the real value and fairly good to 8GHz. Scaling on the meter is in my case -5dBm FSD and -30dBm mid scale with 55dB range.
The AD8317 does have a -ve output slope, anyway for about a tenner you have a meter that you can abuse and not worry about the thermistor head
cheers
Geoff
GI0GDP

On Thursday, 24 September 2020, 21:25:07 BST, Paul Randall G3NJV <paulfrandall@...> wrote:


Having explored multiple avenues to get a calibrated power reference into my workshop I finally bit the bullet and bought a cheap HP435B non-working power meter for parts for a home-brew power meter. On delivery, I find it in good condition and might even be completely working - just the power switch not illuminating.
So now I'm in the place I dreaded, I'll find it hard to break this classic instrument just for parts so am wondering if anyone out there has a power sensor and cable just lying around unused that they might part with.
An 8481A is the ideal of course but on ebay with cable it is more than my monthly pension so might as well be made of unobtainium. I guess even a long term loan would be good - once I have finished building my projects to venture into the microwave region, the entire instrument could be retasked to a new home.
So, any possibilities out there? I'd be glad to hear.
73s Paul G3NJV


Re: Activity List for the final session of the UKuG 5.7/10GHz Contests 2021 - Sunday 27th September

Martyn G3UKV
 

GM Gigahertzers: Sunday

Callsign: G3ZME/P
Locator: IO82QL
Bands: 10GHz
Talkback: ON4KST, Zello SHF Chat, 144MHz
Times: From about 09:30 UTC

Callsign: G6ZME/P
Locator: IO82QL
Bands: 5.7GHz
Talkback: 144MHz (ideal), ON4KST, possibly Zello SHF Chat, phone 07421 001166
Times: From about 09:30 UTC

73 Martyn G3UKV

On 21/09/2020 15:59, John Quarmby via groups.io wrote:
Next Sunday sees the final session of the UK Microwave Group 5.7 and 10GHz contest series. This takes place between 0600 and 1800 GMT (0700 - 1900 BST), entrants can operate for a maximum of 8 hours during the period. Full rules can be found here:

Callsign: G3XDY
Locator: JO02OB
Bands: 5.7GHz 15W, 60cm dish
              10GHz  10W, 60cm dish
Talkback: ON4KST, Zello SHF Chat
Times: Various throughout.

73

John G3XDY
UKuG Contest Manager

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Re: HP Power Sensor wanted

Colin Ranson
 

Robin,

 

See my post re HP435.  Please let us know how you get on, I would love to use mine if only a few times to finish uW projects.

 

 

Regards

 

 

Colin G8LBS.

 

Sent from Mail for Windows 10

 

From: Robin Szemeti - G1YFG
Sent: 24 September 2020 21:36
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] HP Power Sensor wanted

 

I've been on the same search, with no good result.  

 

I have drawn up the HP sensor head on a 0.6mm thick PCB and whilst I am very doubtful I could get the thermistor variant of the head to work, I think I could make a reasonable stab at the diode-detector version of the head.

 

I may pursue this further once winter is a little closer.

 

If you find yourself with more offers of power sensor heads than you know what to do with, please let me know.

 

On Thu, 24 Sep 2020 at 21:25, Paul Randall G3NJV <paulfrandall@...> wrote:

Having explored multiple avenues to get a calibrated power reference into my workshop I finally bit the bullet and bought a cheap HP435B non-working power meter for parts for a home-brew power meter. On delivery, I find it in good condition and might even be completely working - just the power switch not illuminating.
So now I'm in the place I dreaded, I'll find it hard to break this classic instrument just for parts so am wondering if anyone out there has a power sensor and cable just lying around unused that they might part with.
An 8481A is the ideal of course but on ebay with cable it is more than my monthly pension so might as well be made of unobtainium. I guess even a long term loan would be good - once I have finished building my projects to venture into the microwave region, the entire instrument could be retasked to a new home.
So, any possibilities out there? I'd be glad to hear.
73s Paul G3NJV


--
Robin Szemeti - G1YFG

 


Re: HP Power Sensor wanted

Colin Ranson
 

Paul,

 

I too have a HP 435 power meter minus the measuring head. Believe it or not it came in original British MOD storage packaging, with a date of 1983 ! It’s absolutely pristine.  I am reluctant to power it in case capacitors go pop !   I could of course judicially use a variac but even so I think capacitors will fail after a while.

 

Meanwhile it looks pretty on the test bench shelving.

 

 

Colin de G8LBS.

 

Sent from Mail for Windows 10

 

From: Paul Randall G3NJV
Sent: 24 September 2020 21:25
To: UKMicrowaves@groups.io
Subject: [UKMicrowaves] HP Power Sensor wanted

 

Having explored multiple avenues to get a calibrated power reference into my workshop I finally bit the bullet and bought a cheap HP435B non-working power meter for parts for a home-brew power meter. On delivery, I find it in good condition and might even be completely working - just the power switch not illuminating.
So now I'm in the place I dreaded, I'll find it hard to break this classic instrument just for parts so am wondering if anyone out there has a power sensor and cable just lying around unused that they might part with.
An 8481A is the ideal of course but on ebay with cable it is more than my monthly pension so might as well be made of unobtainium. I guess even a long term loan would be good - once I have finished building my projects to venture into the microwave region, the entire instrument could be retasked to a new home.
So, any possibilities out there? I'd be glad to hear.
73s Paul G3NJV

 


Re: HP Power Sensor wanted

Robin Szemeti - G1YFG
 

It seems this is as far as I had got.   The "RF" bits were in 0402 size ...

image.png


On Thu, 24 Sep 2020 at 21:36, Robin Szemeti - G1YFG via groups.io <robin=redpoint.org.uk@groups.io> wrote:
I've been on the same search, with no good result.  

I have drawn up the HP sensor head on a 0.6mm thick PCB and whilst I am very doubtful I could get the thermistor variant of the head to work, I think I could make a reasonable stab at the diode-detector version of the head.

I may pursue this further once winter is a little closer.

If you find yourself with more offers of power sensor heads than you know what to do with, please let me know.

On Thu, 24 Sep 2020 at 21:25, Paul Randall G3NJV <paulfrandall@...> wrote:
Having explored multiple avenues to get a calibrated power reference into my workshop I finally bit the bullet and bought a cheap HP435B non-working power meter for parts for a home-brew power meter. On delivery, I find it in good condition and might even be completely working - just the power switch not illuminating.
So now I'm in the place I dreaded, I'll find it hard to break this classic instrument just for parts so am wondering if anyone out there has a power sensor and cable just lying around unused that they might part with.
An 8481A is the ideal of course but on ebay with cable it is more than my monthly pension so might as well be made of unobtainium. I guess even a long term loan would be good - once I have finished building my projects to venture into the microwave region, the entire instrument could be retasked to a new home.
So, any possibilities out there? I'd be glad to hear.
73s Paul G3NJV


--
Robin Szemeti - G1YFG


--
Robin Szemeti - G1YFG


Re: Microwave oven test

Clint Sharp <cjaysharp@...>
 

I think I know the type of material, the fascia boards on my house are made of it, it's a sort of foamed plastic with a polished face. 

It doesn't soak up water but the rough faces and edges will hold surface water

On Thu, 24 Sep 2020, 17:56 G8TZJ via groups.io, <g8tzj=talktalk.net@groups.io> wrote:
Thanks for the advice. The "roof" plastic survived the oven test, even for 1 min. However upon closer inspection, I decided against using it. The outer layers are a hard plastic but the inside (it's about 8 mm thick) seems to be some sort of dense foam. So I guess this could soak up water unless it is adequately sealed.
Instead, I found a length of PVC L shaped plastic, 20 x 30 x 3 mm at Homebase. It seems reasonably rigid and it was ok in the oven. I just have to secure the end of the L on the aluminium reflector, probably using a bit of the "roof" plastic as an anchor point.
The helix is for QO-100 to be mounted just above the LNB to replace my patch feed.

73 Andrew G8TZJ


Re: HP Power Sensor wanted

Robin Szemeti - G1YFG
 

I've been on the same search, with no good result.  

I have drawn up the HP sensor head on a 0.6mm thick PCB and whilst I am very doubtful I could get the thermistor variant of the head to work, I think I could make a reasonable stab at the diode-detector version of the head.

I may pursue this further once winter is a little closer.

If you find yourself with more offers of power sensor heads than you know what to do with, please let me know.


On Thu, 24 Sep 2020 at 21:25, Paul Randall G3NJV <paulfrandall@...> wrote:
Having explored multiple avenues to get a calibrated power reference into my workshop I finally bit the bullet and bought a cheap HP435B non-working power meter for parts for a home-brew power meter. On delivery, I find it in good condition and might even be completely working - just the power switch not illuminating.
So now I'm in the place I dreaded, I'll find it hard to break this classic instrument just for parts so am wondering if anyone out there has a power sensor and cable just lying around unused that they might part with.
An 8481A is the ideal of course but on ebay with cable it is more than my monthly pension so might as well be made of unobtainium. I guess even a long term loan would be good - once I have finished building my projects to venture into the microwave region, the entire instrument could be retasked to a new home.
So, any possibilities out there? I'd be glad to hear.
73s Paul G3NJV


--
Robin Szemeti - G1YFG


HP Power Sensor wanted

Paul Randall G3NJV
 

Having explored multiple avenues to get a calibrated power reference into my workshop I finally bit the bullet and bought a cheap HP435B non-working power meter for parts for a home-brew power meter. On delivery, I find it in good condition and might even be completely working - just the power switch not illuminating.
So now I'm in the place I dreaded, I'll find it hard to break this classic instrument just for parts so am wondering if anyone out there has a power sensor and cable just lying around unused that they might part with.
An 8481A is the ideal of course but on ebay with cable it is more than my monthly pension so might as well be made of unobtainium. I guess even a long term loan would be good - once I have finished building my projects to venture into the microwave region, the entire instrument could be retasked to a new home.
So, any possibilities out there? I'd be glad to hear.
73s Paul G3NJV

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