Date   

Re: Low loss receive filter for 23cm

Neil Smith G4DBN
 

"Local" is an interesting concept, the nearest TV transmitter to the best of my knowledge is 51km away at Emley Moor, but it is an optical path from here. We have no cellphone service to speak of here, but there is a mast about 3km away.

I have a long, lossy feeder on receive after the preamp, and an attenuator to keep the signals presented to the transverter to about 8dB over the transverter noise floor. I see the mixing products to a lesser extent with the transverter on the end of the transmit feeder. Putting the bandpass filter after the VLNA has no effect. The products are definitely there in the output of the VLNA according to the spectrum analyser, but the levels of the TV signals are not particularly high, perhaps -45dBm according to the analyser.

I suspect it could be the other stuff which is causing the overload and the DTV mixing products are a side-effect, but I'll see what happens with a simple stub. I'm going to put up a log-periodic to see if I can characterise all of the local sources properly and take appropriate countermeasures.

I'm fully aware that the very wonderful DDK VLNA is not really intended for this use-case, and the primary reason I built it was so I could use it on the dish for moon stuff, but the feeder run is a bit long, so even with very low-loss feeder I don't see much of an increase in band noise, but the key benefit is that I have local birdies in the IF range that are swamped by the extra 8dB of signal from the preamp. I guess a 10dB gain preamp with a reasonable noise figure, huge signal-handling capacity and a simple cavity filter input would make more sense for terrestrial DX.

Neil G4DBN


On 26/09/2016 02:15, Richard Baker perwick@... [ukmicrowaves] wrote:

Neil
Your rounded noise peaks 15-20MHz wide in the 1.15 to 1.35 range wide are probably mixing products from a local DTV transmitter.

I use a notch filter tuned to 650MHz between my antenna and VLNA to keep out local DTV signals which mix in the VLNA to give what sounds like white noise right across the band but looks like equally spaced humps about 15MHz wide on a spectrum analyser. The filter has a loss of ~0.1dB at 1296MHz and 40dB of rejection at 650MHz the centre of the three DTV multiplexes and ~20dB on the flanking multiplexes. Its simply an open coaxial line on a N type T adaptor set up using a tracking generator and spectrum analyser.


The transients may be 4G mobile phone signals.

I tried making a similar notch filter for the local 4G phone signals tuned to around 850MHz from memory however it had too much loss at 1296MHz about 1dB. So I use a 5 pole interdigital filter after the VLNA to stop the amplified mobile phone signals overloading my TS790. The VLNA can cope with the mobile phone signals but the TS790 was overloaded after they were amplified by over 30dB in the VLNA.

Another source of big transient signals near 23cms is the air traffic control radar beacon system on 1030MHz from the ground and 1060MHz from the aircraft. I also have one of these 5 miles away but fortunately behind a hill so not an issue.


Richard
GD8EXI




On 25/09/2016, 23:25, "Neil neil@... [ukmicrowaves]" <ukmicrowaves@...> wrote:






I have major problems with overload of my 23cm VLNA when my mast is
fully extended. Not sure if it is digi TV or something else, but I get
around a dozen sharp peaks of noise from many directions, some more than
30dB over band noise. I'm using a 44-ele Wimo. If I insert 3/6/10dB
attenuators before the VLNA, there is very little improvement. With 20dB
attenuation, the problem goes away almost completely, but so do most DX
signals.

Looking at the output of the VLNA on a spectrum analyser, I see 15-20MHz
wide rounded noise peaks between 1.15 and 1.35 GHz in some directions
with the mast up high. I can also see some *very* big signals (-20dBm
according to the analyser) in the 1.2 GHz range which shift about a lot,
too fast to see on the analyser other than occasional spikes.

With the mast lower, the problem is much reduced. I built a W6PQL-style
two-post bandpass filter in a diecast ally box, using 10mm copper tube
posts and brass tuning screws, with coupling loops on SMAs, but I am
unable to get the insertion loss less than 0.65dB. Also the loss is
very sensitive to the contact between the case and lid. Using a couple
of G-cramps to jam the lid shut helps a bit. I suppose machining an
enclosure from aluminium bar and using a lot of screws on the lid would
help, but it all seems a bit sensitive and delicate and lots of screw
thread to metal connections to go off-tune. Would a PCB stripline filter
or some sort of machined coaxial filter do a similar job? I can
probably manage with less stop-band rejection so long as the insertion
loss is tiny.

With the filter in circuit before the VLNA, the QRM problem is cured
*completely*, so the problem is definitely out of band overload.

Question: What is the lowest loss filter I can make/buy which will drop
600-800MHz TV signals and cellphone stuff by at least 20dB, but have
minimal effect on 23cm signals and stay nice and stable? No point in
having a super VLNA if I'm losing 0.6dB or more in a filter. Happy to
use HPF, band-reject, bandpass, whatever will give me enough rejection
but lowest possible insertion loss. As the problem only happens for
terrestrial use, is there any point in trying to achieve better than say
1.2dB system NF at 23cm? (VLNA 0.45dB-ish, 1.5m total coax, big Radiall
coax relay, 3 x N plug/sockets, 3 x SMA plug/sockets and filter ahead of
the VLNA).

I've read the splendid ITU noise doc several times...
https://www.itu.int/dms_pubrec/itu-r/rec/p/R-REC-P.372-12-201507-I!!PDF-E.pdf
<https://www.itu.int/dms_pubrec/itu-r/rec/p/R-REC-P.372-12-201507-I%21%21PDF-E.pdf>

Neil G4DBN

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Re: 23cm Yagis

Christopher Bartram <cbartram@...>
 

I've spent quite a lot of time designing yagis for my own use as it's an area that interests me. I've been considering publishing my current design, which according to simulation, at 1296 achieves ~20dBd on a 4m boom with just 42 elements. It has excellent performance re unwanted responses, but I need to make measurements of it in the real world, particularly regarding Sun, and cold sky/ground noise. These will provide more useful information than attempts to measure gain on any antenna range that I have access to.

Mike, G3JVL, designed his loop yagis in the 1970s. At that time I used them on both 70 and 23, but I don't now! Since then, there has been a serious revolution in amateur yagi design, starting with the work of Gunter, DL6WU, and continued by a host of others since. There's a lot of good information on DL6WU's designs, and some of the work that has sprung from them on GM3SEK's website, which is, as usual a fount of good sense. Incidentally, the Wimo 44ele antenna (and I presume others in that range) seems to be a pretty well unaltered DL6WU design.

Another source of good designs is G4CQM's website. His designs are generally pretty reliable, but I suspect more work is needed vis-a-vis the feed structures he suggests at 1.3GHz.

Vy 73

Chris
GW4DGU

--


Re: Low loss receive filter for 23cm

John Quarmby
 

Hi Neil

One of my locals, John G4ZTR has had the same problem. You can find a good account of what he did to fix it here:
http://www.g4ztr.co.uk/amateur-radio/23cms/

I use a preamp design by YU1AW which includes a tuned stripline front end which doesn't suffer from DTV overload at this location.
http://www.qsl.net/yu1aw/LNA/atf54143eng.htm

Sam's VLNA's are very good but you really do need a filter in front for terrestrial use if you are anywhere near a DTV transmitter or a mobile phone base station.

73

John G3XDY

On 25/09/2016 22:25, Neil neil@g4dbn.uk [ukmicrowaves] wrote:
I have major problems with overload of my 23cm VLNA when my mast is
fully extended. Not sure if it is digi TV or something else, but I get
around a dozen sharp peaks of noise from many directions, some more than
30dB over band noise. I'm using a 44-ele Wimo. If I insert 3/6/10dB
attenuators before the VLNA, there is very little improvement. With 20dB
attenuation, the problem goes away almost completely, but so do most DX
signals.

Looking at the output of the VLNA on a spectrum analyser, I see 15-20MHz
wide rounded noise peaks between 1.15 and 1.35 GHz in some directions
with the mast up high. I can also see some *very* big signals (-20dBm
according to the analyser) in the 1.2 GHz range which shift about a lot,
too fast to see on the analyser other than occasional spikes.

With the mast lower, the problem is much reduced. I built a W6PQL-style
two-post bandpass filter in a diecast ally box, using 10mm copper tube
posts and brass tuning screws, with coupling loops on SMAs, but I am
unable to get the insertion loss less than 0.65dB. Also the loss is
very sensitive to the contact between the case and lid. Using a couple
of G-cramps to jam the lid shut helps a bit. I suppose machining an
enclosure from aluminium bar and using a lot of screws on the lid would
help, but it all seems a bit sensitive and delicate and lots of screw
thread to metal connections to go off-tune. Would a PCB stripline filter
or some sort of machined coaxial filter do a similar job? I can
probably manage with less stop-band rejection so long as the insertion
loss is tiny.

With the filter in circuit before the VLNA, the QRM problem is cured
*completely*, so the problem is definitely out of band overload.

Question: What is the lowest loss filter I can make/buy which will drop
600-800MHz TV signals and cellphone stuff by at least 20dB, but have
minimal effect on 23cm signals and stay nice and stable? No point in
having a super VLNA if I'm losing 0.6dB or more in a filter. Happy to
use HPF, band-reject, bandpass, whatever will give me enough rejection
but lowest possible insertion loss. As the problem only happens for
terrestrial use, is there any point in trying to achieve better than say
1.2dB system NF at 23cm? (VLNA 0.45dB-ish, 1.5m total coax, big Radiall
coax relay, 3 x N plug/sockets, 3 x SMA plug/sockets and filter ahead of
the VLNA).

I've read the splendid ITU noise doc several times...
https://www.itu.int/dms_pubrec/itu-r/rec/p/R-REC-P.372-12-201507-I!!PDF-E.pdf
<https://www.itu.int/dms_pubrec/itu-r/rec/p/R-REC-P.372-12-201507-I%21%21PDF-E.pdf>

Neil G4DBN




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Posted by: Neil <neil@g4dbn.uk>
------------------------------------


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Yahoo Groups Links




Re: 23cm Yagis

Jim Davidson <seumasd@...>
 

Hi Ian

I, too, would recommend the JVL loopyagi. 26 element in 2m boom at 1296MHz. I find them very good on 23 and 13cm and have one working on 9cm.

Making the reflector loop slide on the boom gives adequate adjustment.

More info if required.

73 JimD, GM3UAG

On 26/09/2016 07:22, pa0jme@veron.nl [ukmicrowaves] wrote:
though it's an aged design by now (30+years) I can recommend the G3JVL loopyagi.


Re: Low loss receive filter for 23cm

ian hope (2E0IJH)
 

John over at Colchester Aerial parts does a 1296 intermod filter, http://aerial-parts.co.uk/epages/626ba059-121d-45c5-8692-ea58514eb29c.sf/en_GB/?ObjectPath=/Shops/626ba059-121d-45c5-8692-ea58514eb29c/Products/APP0003
 
Ian
2E0IJH

 
Sent: Monday, September 26, 2016 at 7:33 AM
From: "DougF uwaves@... [ukmicrowaves]"
To: ukmicrowaves@...
Subject: Re: [ukmicrowaves] Low loss receive filter for 23cm
 

 

Hello Neil and other readers.

If you're willing to engage in a bit of precision metal work (which I do like doing!), I can recommend the solid copper-and-brass interdigital filter that was first described in the 'QST' magazine for March 1968 - yes, nearly 50 years ago!  That article focuses more on such filters for 432 MHz, but does include dimensions for one for 1296 MHz.

I have one here and, in acknowledgement of your 'problems' possibly being as far away as 600 MHz, I have today measured its performance down that far - insertion loss across a broad range of frequency - and the results of my testing were:

MHz     I.L. (dB)
1309     0.2  (the minimum)
1296     0.3
1290     0.4
1280     0.5
1260     1.1
1240     4.1
1220     9.0
1200     13.6
1180     19.5
1160     22.9
1140     25.1
1120     29.5
1100     33.1
1000     42.2
  900     50.5
  800     56.6
  700     57.2
  600     61.5
The pattern further above 1300 MHz is very much a mirror image of the above measurements.  The return loss looking into each port (with the other port terminated) is very good.

I trust that these data may be of assistance - possibly to initiate another project!

If you have difficulty accessing the original article (which must have been copied many times over the years), do get back to me and I should be able to scan and post somewhere Ed's hand-drawn design notes (which are essentially the same as the article), thus avoiding violation of QST's copyright.

And I could post an image or two of the completed filter.

Best 73,

--Doug Friend, VK4OE.

p.s.  I was fortunate a decade or more ago to have been given the precisely-cut elements for this filter by the (now) late Eddie Penikis VK1VP.  Ed had an inspiring ability to work precisely in everything that he set his hands to do - all I had to do was to build the housing, which I did in solid brass.  As you'll see, it works wonderfully well!

p.p.s.  I immediately also thought of the nice off-the-shelf filter made by a German fellow and recommended by the Kuhne company for use with their 28 MHz to 1296 MHz transverters.  However, not having one here to test, I can't vouch for it having similar broadband performance to the 'old' design over the same frequency range shown above.

 
On 26/09/2016 08:25, Neil neil@... [ukmicrowaves] wrote:
 

I have major problems with overload of my 23cm VLNA when my mast is
fully extended. Not sure if it is digi TV or something else, but I get
around a dozen sharp peaks of noise from many directions, some more than
30dB over band noise. I'm using a 44-ele Wimo. If I insert 3/6/10dB
attenuators before the VLNA, there is very little improvement. With 20dB
attenuation, the problem goes away almost completely, but so do most DX
signals.

Looking at the output of the VLNA on a spectrum analyser, I see 15-20MHz
wide rounded noise peaks between 1.15 and 1.35 GHz in some directions
with the mast up high. I can also see some *very* big signals (-20dBm
according to the analyser) in the 1.2 GHz range which shift about a lot,
too fast to see on the analyser other than occasional spikes.

With the mast lower, the problem is much reduced. I built a W6PQL-style
two-post bandpass filter in a diecast ally box, using 10mm copper tube
posts and brass tuning screws, with coupling loops on SMAs, but I am
unable to get the insertion loss less than 0.65dB. Also the loss is
very sensitive to the contact between the case and lid. Using a couple
of G-cramps to jam the lid shut helps a bit. I suppose machining an
enclosure from aluminium bar and using a lot of screws on the lid would
help, but it all seems a bit sensitive and delicate and lots of screw
thread to metal connections to go off-tune. Would a PCB stripline filter
or some sort of machined coaxial filter do a similar job? I can
probably manage with less stop-band rejection so long as the insertion
loss is tiny.

With the filter in circuit before the VLNA, the QRM problem is cured
*completely*, so the problem is definitely out of band overload.

Question: What is the lowest loss filter I can make/buy which will drop
600-800MHz TV signals and cellphone stuff by at least 20dB, but have
minimal effect on 23cm signals and stay nice and stable? No point in
having a super VLNA if I'm losing 0.6dB or more in a filter. Happy to
use HPF, band-reject, bandpass, whatever will give me enough rejection
but lowest possible insertion loss. As the problem only happens for
terrestrial use, is there any point in trying to achieve better than say
1.2dB system NF at 23cm? (VLNA 0.45dB-ish, 1.5m total coax, big Radiall
coax relay, 3 x N plug/sockets, 3 x SMA plug/sockets and filter ahead of
the VLNA).

I've read the splendid ITU noise doc several times...
https://www.itu.int/dms_pubrec/itu-r/rec/p/R-REC-P.372-12-201507-I!!PDF-E.pdf


Neil G4DBN

 


Re: Low loss receive filter for 23cm

DougF VK4OE
 

Hello Neil and other readers.

If you're willing to engage in a bit of precision metal work (which I do like doing!), I can recommend the solid copper-and-brass interdigital filter that was first described in the 'QST' magazine for March 1968 - yes, nearly 50 years ago!  That article focuses more on such filters for 432 MHz, but does include dimensions for one for 1296 MHz.

I have one here and, in acknowledgement of your 'problems' possibly being as far away as 600 MHz, I have today measured its performance down that far - insertion loss across a broad range of frequency - and the results of my testing were:

MHz     I.L. (dB)
1309     0.2  (the minimum)
1296     0.3
1290     0.4
1280     0.5
1260     1.1
1240     4.1
1220     9.0
1200     13.6
1180     19.5
1160     22.9
1140     25.1
1120     29.5
1100     33.1
1000     42.2
  900     50.5
  800     56.6
  700     57.2
  600     61.5
The pattern further above 1300 MHz is very much a mirror image of the above measurements.  The return loss looking into each port (with the other port terminated) is very good.

I trust that these data may be of assistance - possibly to initiate another project!

If you have difficulty accessing the original article (which must have been copied many times over the years), do get back to me and I should be able to scan and post somewhere Ed's hand-drawn design notes (which are essentially the same as the article), thus avoiding violation of QST's copyright.

And I could post an image or two of the completed filter.

Best 73,

--Doug Friend, VK4OE.

p.s.  I was fortunate a decade or more ago to have been given the precisely-cut elements for this filter by the (now) late Eddie Penikis VK1VP.  Ed had an inspiring ability to work precisely in everything that he set his hands to do - all I had to do was to build the housing, which I did in solid brass.  As you'll see, it works wonderfully well!

p.p.s.  I immediately also thought of the nice off-the-shelf filter made by a German fellow and recommended by the Kuhne company for use with their 28 MHz to 1296 MHz transverters.  However, not having one here to test, I can't vouch for it having similar broadband performance to the 'old' design over the same frequency range shown above.


On 26/09/2016 08:25, Neil neil@... [ukmicrowaves] wrote:
 

I have major problems with overload of my 23cm VLNA when my mast is
fully extended. Not sure if it is digi TV or something else, but I get
around a dozen sharp peaks of noise from many directions, some more than
30dB over band noise. I'm using a 44-ele Wimo. If I insert 3/6/10dB
attenuators before the VLNA, there is very little improvement. With 20dB
attenuation, the problem goes away almost completely, but so do most DX
signals.

Looking at the output of the VLNA on a spectrum analyser, I see 15-20MHz
wide rounded noise peaks between 1.15 and 1.35 GHz in some directions
with the mast up high. I can also see some *very* big signals (-20dBm
according to the analyser) in the 1.2 GHz range which shift about a lot,
too fast to see on the analyser other than occasional spikes.

With the mast lower, the problem is much reduced. I built a W6PQL-style
two-post bandpass filter in a diecast ally box, using 10mm copper tube
posts and brass tuning screws, with coupling loops on SMAs, but I am
unable to get the insertion loss less than 0.65dB. Also the loss is
very sensitive to the contact between the case and lid. Using a couple
of G-cramps to jam the lid shut helps a bit. I suppose machining an
enclosure from aluminium bar and using a lot of screws on the lid would
help, but it all seems a bit sensitive and delicate and lots of screw
thread to metal connections to go off-tune. Would a PCB stripline filter
or some sort of machined coaxial filter do a similar job? I can
probably manage with less stop-band rejection so long as the insertion
loss is tiny.

With the filter in circuit before the VLNA, the QRM problem is cured
*completely*, so the problem is definitely out of band overload.

Question: What is the lowest loss filter I can make/buy which will drop
600-800MHz TV signals and cellphone stuff by at least 20dB, but have
minimal effect on 23cm signals and stay nice and stable? No point in
having a super VLNA if I'm losing 0.6dB or more in a filter. Happy to
use HPF, band-reject, bandpass, whatever will give me enough rejection
but lowest possible insertion loss. As the problem only happens for
terrestrial use, is there any point in trying to achieve better than say
1.2dB system NF at 23cm? (VLNA 0.45dB-ish, 1.5m total coax, big Radiall
coax relay, 3 x N plug/sockets, 3 x SMA plug/sockets and filter ahead of
the VLNA).

I've read the splendid ITU noise doc several times...
https://www.itu.int/dms_pubrec/itu-r/rec/p/R-REC-P.372-12-201507-I!!PDF-E.pdf


Neil G4DBN


Re: 23cm Yagis

pa0jme@...
 

Sorry for the typo the callsign should read G3JVL


Re: 23cm Yagis

pa0jme@...
 

Hi Ian, though it's an aged design by now (30+years) I can recommend the G3VL loopyagi.
It's a rather simple but very effective design. I you meet difficulty in surfacing details let me know. I have built them for 23, 13 and 9cm versions in the past and also made a 70 cm version.

73es Rien PA0JME


Re: Low loss receive filter for 23cm

Richard GD8EXI
 

Neil
   Your rounded noise peaks 15-20MHz wide in the 1.15 to 1.35 range wide are probably mixing products from a local DTV transmitter.

 I use a notch filter tuned to 650MHz between my antenna and VLNA to keep out local DTV signals which mix in the VLNA to give what sounds like white noise right across the band but looks like equally spaced humps about 15MHz wide on a spectrum analyser. The filter has a loss of ~0.1dB at 1296MHz and 40dB of rejection at 650MHz the centre of the three DTV multiplexes and ~20dB on the flanking multiplexes. It’s simply an open coaxial line on a N type T adaptor set up using a tracking generator and spectrum analyser.


The transients may be 4G mobile phone signals.

I tried making a similar notch filter for the local 4G phone signals tuned to around 850MHz from memory however it had too much loss at 1296MHz about 1dB. So I use a 5 pole interdigital filter after the VLNA to stop the amplified mobile phone signals overloading my TS790. The VLNA can cope with the mobile phone signals but the TS790 was overloaded after they were amplified by over 30dB in the VLNA.

Another source of big transient signals near 23cms is the air traffic control radar beacon system on 1030MHz from the ground and 1060MHz from the aircraft. I also have one of these 5 miles away but fortunately behind a hill so not an issue.


Richard
GD8EXI




On 25/09/2016, 23:25, "Neil neil@... [ukmicrowaves]" <ukmicrowaves@...> wrote:

 
 
 
   

I have major problems with overload of my 23cm VLNA when my mast is
fully extended.  Not sure if it is digi TV or something else, but I get
around a dozen sharp peaks of noise from many directions, some more than
30dB over band noise.  I'm using a 44-ele Wimo. If I insert 3/6/10dB
attenuators before the VLNA, there is very little improvement. With 20dB
attenuation, the problem goes away almost completely, but so do most DX
signals.

Looking at the output of the VLNA on a spectrum analyser, I see 15-20MHz
wide rounded noise peaks between 1.15 and 1.35 GHz in some directions
with the mast up high.  I can also see some *very* big signals (-20dBm
according to the analyser) in the 1.2 GHz range which shift about a lot,
too fast to see on the analyser other than occasional spikes.

With the mast lower, the problem is much reduced.  I built a W6PQL-style
two-post bandpass filter in a diecast ally box, using 10mm copper tube
posts and brass tuning screws, with coupling loops on SMAs, but I am
unable to get the insertion loss less than 0.65dB.  Also the loss is
very sensitive to the contact between the case and lid.  Using a couple
of G-cramps to jam the lid shut helps a bit.  I suppose machining an
enclosure from aluminium bar and using a lot of screws on the lid would
help, but it all seems a bit sensitive and delicate and lots of screw
thread to metal connections to go off-tune. Would a PCB stripline filter
or some sort of machined coaxial filter do a similar job?  I can
probably manage with less stop-band rejection so long as the insertion
loss is tiny.

With the filter in circuit before the VLNA, the QRM problem is cured
*completely*, so the problem is definitely out of band overload.

Question: What is the lowest loss filter I can make/buy which will drop
600-800MHz TV signals and cellphone stuff by at least 20dB, but have
minimal effect on 23cm signals and stay nice and stable?  No point in
having a super VLNA if I'm losing 0.6dB or more in a filter.  Happy to
use HPF, band-reject, bandpass, whatever will give me enough rejection
but lowest possible insertion loss.  As the problem only happens for
terrestrial use, is there any point in trying to achieve better than say
1.2dB system NF at 23cm?  (VLNA 0.45dB-ish, 1.5m total coax, big Radiall
coax relay, 3 x N plug/sockets, 3 x SMA plug/sockets and filter ahead of
the VLNA).

I've read the splendid ITU noise doc several times...
https://www.itu.int/dms_pubrec/itu-r/rec/p/R-REC-P.372-12-201507-I!!PDF-E.pdf
<https://www.itu.int/dms_pubrec/itu-r/rec/p/R-REC-P.372-12-201507-I%21%21PDF-E.pdf>

Neil G4DBN

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23cm Yagis

ian hope (2E0IJH)
 

Can someone point me in the direction of 23cm yagi designs, Now I've built my transverter up, need to build something better than the little 10 ele one i've been experimenting with. One thing I've learnt testing this little unit , it helps owning a R7000 comms reciever that goes up to 23cm.
 
Ian
2E0IJH


Low loss receive filter for 23cm

Neil Smith G4DBN
 

I have major problems with overload of my 23cm VLNA when my mast is fully extended. Not sure if it is digi TV or something else, but I get around a dozen sharp peaks of noise from many directions, some more than 30dB over band noise. I'm using a 44-ele Wimo. If I insert 3/6/10dB attenuators before the VLNA, there is very little improvement. With 20dB attenuation, the problem goes away almost completely, but so do most DX signals.

Looking at the output of the VLNA on a spectrum analyser, I see 15-20MHz wide rounded noise peaks between 1.15 and 1.35 GHz in some directions with the mast up high. I can also see some *very* big signals (-20dBm according to the analyser) in the 1.2 GHz range which shift about a lot, too fast to see on the analyser other than occasional spikes.

With the mast lower, the problem is much reduced. I built a W6PQL-style two-post bandpass filter in a diecast ally box, using 10mm copper tube posts and brass tuning screws, with coupling loops on SMAs, but I am unable to get the insertion loss less than 0.65dB. Also the loss is very sensitive to the contact between the case and lid. Using a couple of G-cramps to jam the lid shut helps a bit. I suppose machining an enclosure from aluminium bar and using a lot of screws on the lid would help, but it all seems a bit sensitive and delicate and lots of screw thread to metal connections to go off-tune. Would a PCB stripline filter or some sort of machined coaxial filter do a similar job? I can probably manage with less stop-band rejection so long as the insertion loss is tiny.

With the filter in circuit before the VLNA, the QRM problem is cured *completely*, so the problem is definitely out of band overload.

Question: What is the lowest loss filter I can make/buy which will drop 600-800MHz TV signals and cellphone stuff by at least 20dB, but have minimal effect on 23cm signals and stay nice and stable? No point in having a super VLNA if I'm losing 0.6dB or more in a filter. Happy to use HPF, band-reject, bandpass, whatever will give me enough rejection but lowest possible insertion loss. As the problem only happens for terrestrial use, is there any point in trying to achieve better than say 1.2dB system NF at 23cm? (VLNA 0.45dB-ish, 1.5m total coax, big Radiall coax relay, 3 x N plug/sockets, 3 x SMA plug/sockets and filter ahead of the VLNA).

I've read the splendid ITU noise doc several times... https://www.itu.int/dms_pubrec/itu-r/rec/p/R-REC-P.372-12-201507-I!!PDF-E.pdf <https://www.itu.int/dms_pubrec/itu-r/rec/p/R-REC-P.372-12-201507-I%21%21PDF-E.pdf>

Neil G4DBN


hupRF at Hamfest and RSGB Convention

dave powis <g4hup@...>
 

Just a final reminder folks with some detail too!


I'll be trading from the Hamfest flea market on Friday 30th Sept, as previously announced.  Full stock will be available on the stall, plus some second hand items (mainly antennas).


On Sat 1st Oct, I will be on the RSGB TEC/Exam Group stand, and will again hopefully have my stock under the table, so for those who are only able to get there on Saturday, there's still an opportunity to get things from me.  Because my main focus is  Exam Group matters on that day, I would prefer that items are ordered (and paid for) in advance, to minimise the disruption.  I will, of course, offer show prices for advance purchases.


On the following weekend, Sat 8th Oct, I'll be doing a talk on SMD construction at the Convention (1st slot, 9:45am), and following that will be three practical workshops during the day.  Unfortunately, the RSGB publicity and programme makes it look as if it's one all day workshop - meaning you would have to sacrifice all the other talks!  Please take a look at http://huprf.com/huprf/smd-workshops-2016/ for the accurate information!


Again, pre-ordered items can be collected at Convention - I may not have full stock in the car that weekend, so advance ordering is advised.


I look forward to seeing you at one (or both!) of the events.


Best 73

Dave, G4HUP 

http://hupRF.com
http://g4hup.com
twitter  @hupRF


Activity List for the UK Microwave Group 5.7GHz and 10GHz Contests Sunday 25th September

John Quarmby
 

Thanks for your inputs, here is the consolidated list for tomorrow's contests on 5.7 and 10GHz. I hope the weather is kind for the portables.

As I write this there is enhanced tropo across the North Sea, but an advancing weather front will likely mean any enhancement has gone by tomorrow.

Full rules for these contests can be found at: http://www.microwavers.org/files/2016-mwrules.pdf

Activity List:

Callsigns: G0LGS/P and 2E0MDJ/P
Bands: 10GHz 1W 40cm
Locator: IO81XW
Times: 1100 onwards subject to weather
Talkback: ON4KST and 2m Talkback.

Callsign: G1DFL/P
Bands: 10GHz 0.2W 60cm dish
Locator: IO91NM
Times: Likely 3-4pm, depends on Wx.
Talkback: 144.175MHz always preferred, then KST or 07713 432632

Callsign: GM0USI/P
Bands: 10GHz 9W 85cm dish
Locator: IO75TW27GM
Times: 1300 BST onwards
Talkback: ON4KST or 07785744643

Callsign: GM4BYF/P
Bands: 10 GHz 15W 80cm dish
Locator: IO85QV21 & others by request
Times: 1300 onwards
Talkback: KST & 07769822648

Callsign: G4BAO
Bands: 10GHz 7W 60cm dish
Locator: JO02CG33
Times:
Talkback: ON4KST and phone.

Callsign: G3XDY
Bands: 10GHz 10W 60cm dish
5.7GHz 15W 60cm dish
Locator: JO02OB
Times: Early Sunday up to 0900z approx
Talkback: ON4KST

73

John G3XDY
UKuG Contest Manager


Re: Ideas for SHF UKAC 2017- Please add yours

Robert Price <g8dtf@...>
 

Hi

If we are going to continue to use the 2320-2322MHz portion of the13cm band then it would be a really good idea to move all contests on this band to the weekend when we are not restricted to operation after dusk.

73

Bob
G8DTF
--------------------------------------------

On Wed, 21/9/16, Peter Walsh peterdwberkshire@yahoo.com [ukmicrowaves] <ukmicrowaves@yahoogroups.com> wrote:

Subject: [ukmicrowaves] Ideas for SHF UKAC 2017- Please add yours
To: "John Quarmby" <g3xdy@btinternet.com>, "ukmicrowaves@yahoogroups.com" <ukmicrowaves@yahoogroups.com>
Date: Wednesday, 21 September, 2016, 10:50


 










Hi
John,
How do we
feedback ideas, improvements to the SHF part of the
UKAC's for 2017 ?  
I know
that G4PIQ is issuing details of new multiplier options in
early October. I don't want to generate traffic on that
multiplier topic as we have a mechanism ahead of us to
express our views via PIQ.
What I did
want to check-in on is how we make sure we all provide
feedback on the SHF part of the UKAC's so that changes
are considered for 2017.  Do we send them to you John is
that the correct mode?

To start
the discussion, my suggestions would be:
1) Remove
the clash with 6M. This is stopping lots of GHZ inclined
folks from joining in as they are having to choose (and many
are choosing 6M not 6cm!).  I suggest we leave the 4th
Tuesday to be just 6M.
2) Move
GHZ to Thursday evenings (or Sunday evenings?) and create 2
sessions a month just for us folks.  So on 2 Thursdays in
the month (say 2nd or 4th, or 1st and 3rd) when we can focus
on GHZ and get out portable to work folks and have fun.
 - Maybe
make the first Thursday on 13cm, 9cm and 6cm- Make the
second session 10cm and above.  This would create an
evening for folks with 24GHz+ etc to play.  That would make
me build for 24GHz...
3) We need
to put a minimum power level on SAO. Today there is
widespread abuse of the current process with some folks
leaving it late on Tuesdays to put in scores in SAO with
0.6W when they should be in SAR to claim more normalised
points.  Yes this is legal under the current 2016 rules but
I'd like to see it aligned in 2017, as per VHF and UHF
UKAC's.  If you are running QRP you go in the QRP
section.

Anyone
else got some positive ideas for 2017 SHF changes?Please do
share and don't throw too many bricks back at me please,
we are all entitled to an opinion on here and I'm just
trying to help move us forward! 
:)

Regards...Pete
 G1DFL 
















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Re: Activity List for UKuG 5.7 and 10GHz contests on Sunday 25th September

g4bao
 

Oh and I should add

JO02cg33
7W to 60cm dish @8m agl

On 23 September 2016 at 23:48, g4bao <john@...> wrote:
I hope to be QRV 10GHz  for a session on Sunday. 
Look for me on ON4KST and the usual phone number. (I'm QTHR and in the BT online phone book)

73
John

 

On 22 September 2016 at 10:23, G3XDY g3xdy@... [ukmicrowaves] <ukmicrowaves@...> wrote:
 

A bit late this time, I will put together an activity list for the 5.7
and 10GHz contests this coming Sunday. This is the final session in this
year's 5.7 and 10GHz events.

Times are any 8 hours between 0600-1800 GMT in up to two operating
periods. Full rules are here:
http://www.microwavers.org/files/2016-mwrules.pdf

73

John G3XDY

---
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Re: Activity List for UKuG 5.7 and 10GHz contests on Sunday 25th September

g4bao
 

I hope to be QRV 10GHz  for a session on Sunday. 
Look for me on ON4KST and the usual phone number. (I'm QTHR and in the BT online phone book)

73
John

 

On 22 September 2016 at 10:23, G3XDY g3xdy@... [ukmicrowaves] <ukmicrowaves@...> wrote:
 

A bit late this time, I will put together an activity list for the 5.7
and 10GHz contests this coming Sunday. This is the final session in this
year's 5.7 and 10GHz events.

Times are any 8 hours between 0600-1800 GMT in up to two operating
periods. Full rules are here:
http://www.microwavers.org/files/2016-mwrules.pdf

73

John G3XDY

---
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Re: Activity List for UKuG 5.7 and 10GHz contests on Sunday 25th September

Pete - GM4BYF
 

Hi everybody
Weather and equipment permitting I hope to activate IO85QV21 for those  in the central lowlands and up the East coast of Scotland. Starting at 1300 approx.
If there is a demand from anybody south of the border, I could then move on to either  IO85UU42 or further east to near Berwick on Tweed at IO85xt05. Approx time would be 1430 onwards.
If no demand I will go somewhere near Dunbar or maybe Falside Hill near Musselburgh.
Please email me direct tomorrow Saturday if you wish the South facing locations.
Will be active on KST if in range and/or 07769822648.
 
GM4BYF/P    
10 GHz   15W  80cm dish
IO85QV21 & others by request
1300 onwards
KST & 07769822648
73 Pete
 

Sent: Friday, September 23, 2016 12:26 AM
Subject: Re: [ukmicrowaves] Re: Activity List for UKuG 5.7 and 10GHz contests on Sunday 25th September
 
 

Hello all,

 

I should be QRV  on 10GHz from West Muirhouses Farm  - Kilpatrick Hills 785ft asl  IO75TW27GM  on Sunday about 1300local for a few hours - wx looking a bit wet - might get some RS hopefully..

 

9w 85cm dish  -     Will have KST on the phone or 07785744643

 

73 Alan GM0USI/P




From: ukmicrowaves@... on behalf of stewart.g0lgs@... [ukmicrowaves]
Sent: 22 September 2016 18:16
To: ukmicrowaves@...
Subject: [ukmicrowaves] Re: Activity List for UKuG 5.7 and 10GHz contests on Sunday 25th September
 
 


G0LGS/P and 2E0MDJ/P
10GHz 1W 40cm
IO81XW
1100 onwards
ON4KST and 2m Talkback.

Subject to weather.


Re: [Moon] hupRF website update - IC746 instructions

dave powis <g4hup@...>
 

Thanks Ian - that will be very useful.

73,
Dave

----Original message----
From : ukmicrowaves@...
Date : 23/09/2016 - 10:44 (BST)
To : ukmicrowaves@...
Subject : Re: [ukmicrowaves] [Moon] hupRF website update - IC746 instructions

 

When I get Time to order a Board from you , I will take some pics from inside my 746, with everything else going on I havnt got to this project
 
Ian
2E0IJH
 
Sent: Thursday, September 22, 2016 at 10:27 PM
From: "dave powis g4hup@... [ukmicrowaves]"
To: ukmicrowaves@..., w7gj@q.com, moon-net@..., moon@...
Subject: [ukmicrowaves] Re: [Moon] hupRF website update - IC746 instructions
 


Hi Lance,

If you go to http://huprf.com/huprf/pat-board/ and then scroll down the page to the second table, you'll find links to all of the instructions and notes that have been posted so far. There are also pictures of many different installations in the Gallery pages which are linked from the left side bar menu - but I don't have any pictures for the IC746 yet!.

Best 73,
Dave
----Original message----
From : w7gj@q.com
Date : 22/09/2016 - 19:37 (BST)
To : g4hup@...
Subject : Re: [Moon] hupRF website update - IC746 instructions

Hi Dave,

Can you please provide the link to the IC746 notes you talk about? I cannot find it
anywhere on your website. Thanks! Lance

On 9/21/2016 15:24, dave powis wrote:
> Hi folks,
> I've just updated the website to include some guidance notes for the IC746 (not PRO) installation of the PAT board. I've also added, on the SMD 2016 page, more info about the SMD project build at the RSGB Convention on October (for those in the UK!).
> Best 73,
> Dave G4HUP
> http://hupRF.com
> twitter @hupRF
> _______________________________________________
> Moon mailing list
> Moon@...
> http://lists.moonbounce.info/listinfo/moon
>

--
Lance Collister, W7GJ
(ex WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8, E51SIX, 3D2LR, 5W0GJ, E6M, TX5K, KH8/W7GJ, V6M, T8GJ)
P.O. Box 73
Frenchtown, MT 59834-0073
USA
TEL: (406) 626-5728
QTH: DN27ub
URL: http://www.bigskyspaces.com/w7gj
Skype: lanceW7GJ
2m DXCC #11/6m DXCC #815

Interested in 6m EME? Ask me about subscribing to the Magic Band EME
email group, or just fill in the request box at the bottom of my web
page (above)!
 




Re: [Moon] hupRF website update - IC746 instructions

ian hope (2E0IJH)
 

When I get Time to order a Board from you , I will take some pics from inside my 746, with everything else going on I havnt got to this project
 
Ian
2E0IJH

 
Sent: Thursday, September 22, 2016 at 10:27 PM
From: "dave powis g4hup@... [ukmicrowaves]"
To: ukmicrowaves@..., w7gj@q.com, moon-net@..., moon@...
Subject: [ukmicrowaves] Re: [Moon] hupRF website update - IC746 instructions
 


Hi Lance,

If you go to http://huprf.com/huprf/pat-board/ and then scroll down the page to the second table, you'll find links to all of the instructions and notes that have been posted so far. There are also pictures of many different installations in the Gallery pages which are linked from the left side bar menu - but I don't have any pictures for the IC746 yet!.

Best 73,
Dave
----Original message----
From : w7gj@q.com
Date : 22/09/2016 - 19:37 (BST)
To : g4hup@...
Subject : Re: [Moon] hupRF website update - IC746 instructions

Hi Dave,

Can you please provide the link to the IC746 notes you talk about? I cannot find it
anywhere on your website. Thanks! Lance

On 9/21/2016 15:24, dave powis wrote:
> Hi folks,
> I've just updated the website to include some guidance notes for the IC746 (not PRO) installation of the PAT board. I've also added, on the SMD 2016 page, more info about the SMD project build at the RSGB Convention on October (for those in the UK!).
> Best 73,
> Dave G4HUP
> http://hupRF.com
> twitter @hupRF
> _______________________________________________
> Moon mailing list
> Moon@...
> http://lists.moonbounce.info/listinfo/moon
>

--
Lance Collister, W7GJ
(ex WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8, E51SIX, 3D2LR, 5W0GJ, E6M, TX5K, KH8/W7GJ, V6M, T8GJ)
P.O. Box 73
Frenchtown, MT 59834-0073
USA
TEL: (406) 626-5728
QTH: DN27ub
URL: http://www.bigskyspaces.com/w7gj
Skype: lanceW7GJ
2m DXCC #11/6m DXCC #815

Interested in 6m EME? Ask me about subscribing to the Magic Band EME
email group, or just fill in the request box at the bottom of my web
page (above)!
 


Re: Activity List for UKuG 5.7 and 10GHz contests on Sunday 25th September

Alan
 

Hello all,


I should be QRV  on 10GHz from West Muirhouses Farm  - Kilpatrick Hills 785ft asl  IO75TW27GM  on Sunday about 1300local for a few hours - wx looking a bit wet - might get some RS hopefully..


9w 85cm dish  -     Will have KST on the phone or 07785744643


73 Alan GM0USI/P




From: ukmicrowaves@... on behalf of stewart.g0lgs@... [ukmicrowaves]
Sent: 22 September 2016 18:16
To: ukmicrowaves@...
Subject: [ukmicrowaves] Re: Activity List for UKuG 5.7 and 10GHz contests on Sunday 25th September
 
 


G0LGS/P and 2E0MDJ/P
10GHz 1W 40cm
IO81XW
1100 onwards
ON4KST and 2m Talkback.

Subject to weather.