Date   

Re: Dishes again - POTY antenna

Chris Bartram G4DGU
 

Hello John,

What you have is a 1.2m offset dish. Because it is effectively only part  of a larger dish, and effectively 'slopes' by around 20degrees, the wave front will see the reflector as as having the same area as a symmetrical dish 1.2m in either direction. That may seem a waste of reflector area, but because the feed is shifted outside the direct path of the incoming wave, 'feed blockage' isn't an issue. Also, because the effective f/D ratio of the dish is relatively large, it is easier to feed the dish efficiently than an antenna with a small f/D.

The feed position will be exactly the same as that of the original TV LNB. You need to duplicate that. If the original feed support structure is present, then use the original support. If not, good luck! There are a couple of pieces of software which will help you solve the problem, and I think I also have a copy of a paper which, if my memory isn't too damaged, looks more-or-less rigorously at extracting the dish parameters.

Hope that's useful.

73

Chris

G4DGU

On 14/05/2020 19:13, John E. Beech wrote:
My latest acquisition is an elliptical ie offset feed dish 1.2 X 1.35 m which I plan on using on 2.45 GHz Tx for satellite comms. Question will the POTY patch antenna work with this dish on its own ie without the 10 GHz LNB. If so how do I mount it? ( 22 mm Cu tube up the middle?).
And (sanity check) the gain of this elliptical dish will be the same as a prime focus dish of the same (short) diameter.

Going back to an ealier thread, this dish is all fibre glass, no metal to be seen anywhere inside or out. ( I know this because the rim got damaged when it was blown over in a gale.) It does have a rippled finish a bit like a golf ball which is supposed to increase the surface area and therefore the gain. That sounds like bollocks to me - more likely a device for reducing the reflectivity in the infra red to stop the LNB getting cooked in bright sunlight.

de John G8SEQ


Dishes again - POTY antenna

John E. Beech
 

My latest acquisition is an elliptical ie offset feed dish 1.2 X 1.35 m which I plan on using on 2.45 GHz Tx for satellite comms. Question will the POTY patch antenna work with this dish on its own ie without the 10 GHz LNB. If so how do I mount it? ( 22 mm Cu tube up the middle?).
And (sanity check) the gain of this elliptical dish will be the same as a prime focus dish of the same (short) diameter.

Going back to an ealier thread, this dish is all fibre glass, no metal to be seen anywhere inside or out. ( I know this because the rim got damaged when it was blown over in a gale.) It does have a rippled finish a bit like a golf ball which is supposed to increase the surface area and therefore the gain. That sounds like bollocks to me - more likely a device for reducing the reflectivity in the infra red to stop the LNB getting cooked in bright sunlight.

de John G8SEQ


Re: Speaking of MOQs

Andy G4JNT
 

Isn't the Mini-Circuits MOQ based on value of the total, not the number of one product ?
That certainly used to be the case, I've done it before to build up the junk box. (ERA devices, I think it was)
Ring them and ask.
 


On Thu, 14 May 2020 at 18:46, Conrad, PA5Y <g0ruz@...> wrote:

I am after 4 or so PHA-1+ or PHA-1H+ devices. The MOQ from Mini circuits is 20, add the shipping and I am looking at €70,00! This is too much. I want the real deal, mouser stock them but don’t ship them to the Netherlands. Is anyone aware of an alternative that will not take 6 weeks to get here.

 

Also a PA2V is looking for some MGA53543, same situation he tells me.

 

Any ideas?

 

Regards

 

Conrad PA5Y


Speaking of MOQs

Conrad, PA5Y
 

I am after 4 or so PHA-1+ or PHA-1H+ devices. The MOQ from Mini circuits is 20, add the shipping and I am looking at €70,00! This is too much. I want the real deal, mouser stock them but don’t ship them to the Netherlands. Is anyone aware of an alternative that will not take 6 weeks to get here.

 

Also a PA2V is looking for some MGA53543, same situation he tells me.

 

Any ideas?

 

Regards

 

Conrad PA5Y


Re: What Moon/Sun tracking software is being used.

Nick Gregory G0HIK
 

For the time being a 10 turn pot will have to do on 23cm's and portable.

But going up to 10G I'm sure things are going to get a whole lot more serious.

Nick G0HIK


Re: N plug for RG401

ian hope (2E0IJH)
 

Try Asking Matt Jeffery M0MAT on Ebay or webstore, He might know a source
 
Ian
2e0ijh

 
 
Sent: Thursday, May 14, 2020 at 10:31 AM
From: "Phil Guttridge G3TCU" <p.guttridge@...>
To: UKMicrowaves@groups.io
Subject: [UKMicrowaves] N plug for RG401
Can anyone suggest where I can get a straight N plug for RG401 (0.250" semi-rigid) e.g. Amphenol 172139 without the high shipping cost or MOQ of the main distributors that stock these?

I can only find right angle types on eBay.

Thanks & 73, Phil G3TCU

 


Re: N plug for RG401

DougF VK4OE
 

Greetings to all!

Another suggestion is to identify which company is your local agent for the Taiwanese connector manufacturing group "Jyebao", a source of excellent quality products.

Here in Australia, an Adelaide-based outfit called "RF Shop" keeps a fair range of Jyebao connectors, and is able to acquire any of the entire Jyebao catalogue, including the exact 'N' connector that you seek.

I'm not sure if "RF Shop" is still operating there in the UK, but a few years ago they were....  If they still are 'around', then it's likely that they should be able to get them in for you in small quantities.  I know this because I have used their services for exactly that type of connector (plus the .25" semi-rigid as well).

Very best wishes,

--Doug Friend, VK4OE.

On 14/05/2020 7:31 pm, Phil Guttridge G3TCU wrote:
Can anyone suggest where I can get a straight N plug for RG401 (0.250" semi-rigid) e.g. Amphenol 172139 without the high shipping cost or MOQ of the main distributors that stock these?

I can only find right angle types on eBay.

Thanks & 73, Phil G3TCU


Re: What Moon/Sun tracking software is being used.

Conrad, PA5Y
 

Hello Alan, for big dish EME pointing the ERC-M and PSTRotator solution is unsuitable. The ERC-M has a 10 bit ADC so for AZ 360/1024 ideally would give you 0.35 deg. PSTRotator with the ERC-M interface allows 1 deg increments for AZ and 0.1 deg for EL. So definitely not good enough for such a large dish. However it is perfectly adequate for anything that you are going to turn with a KR400!

The VK5DJ controller is one popular solution and the other (and by far the most popular) is the OE5JFL stand alone tracker combined with MAB25 or equivalent encoders.  It order to reduce backlash to acceptable levels most new systems are using solar slewing rings. Mine are on a slow boat from China and they have 0.1 deg backlash. They are for a 5m dish which is in a slow factory in China.

I opted for the OE5JFL controller and HH12 encoders which are 12bit absolute encoders, resolution is more than adequate.

I hope to get it all finished some time this year....

73

Conrad PA5Y


From: UKMicrowaves@groups.io <UKMicrowaves@groups.io> on behalf of Alan Beard via groups.io <beardal@...>
Sent: 14 May 2020 03:28
To: UKMicrowaves@groups.io <UKMicrowaves@groups.io>
Subject: Re: [UKMicrowaves] What Moon/Sun tracking software is being used.
 
Hi guys,

I'd ask of the software: What accuracy does it support?

23cm, 5m dish, required pointing accuracy: 0.5 deg.

The John Drew VK5DJ controller  as designed for VK3UM, as I recall, 
does 0.01 deg. in his software.

One's biggest problem is the position accuracy in the rotator.
My KR-400 could be up to 20 deg. out. Readily available absolute shaft encodes
do 1024 steps per rotation. 1024 / 360 => 0.3 deg. resolution. 

BTW: I've asked the "hamlib" developers to consider this and they have improved
the available accuracy in the "hamlib" library.

80                    (A problem solver, have AC, need DC)

Alan VK2ZIW


On Wed, 13 May 2020 12:25:03 -0700, Nick Gregory G0HIK via groups.io wrote
> Thanks guys,
>
> I'll look at both of those and MoonSked and will report back how I get on, pretty sure I tried WXTrack in the past at some time.
>
> Nick G0HIK

---------------------------------------------------
Alan Beard

OpenWebMail 2.53


Re: N plug for RG401

Paul G8KFW
 

Hi Phil

 

Just a line on right angle N connectors  as I do not now the frequency you are considering but good quality right angle N connecters result in strange frequency responses and any inferior makes more so

All should be OK up to 2.5  ghz

 

Paul


From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Stephen Tompsett
Sent: 14 May 2020 10:52
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] N plug for RG401

 

Mouser? there is a minimum order value to get free delivery. If you don't want a few spare connectors just take the opportunity to stock up on things you will need!

e.g. A Radiall connector I used in some preamps I built:  https://www.mouser.co.uk/ProductDetail/501-R161054000

On 14/05/2020 10:31, Phil Guttridge G3TCU wrote:

Can anyone suggest where I can get a straight N plug for RG401 (0.250" semi-rigid) e.g. Amphenol 172139 without the high shipping cost or MOQ of the main distributors that stock these?

I can only find right angle types on eBay.

Thanks & 73, Phil G3TCU

-- 
Stephen Tompsett (G8LYB)
Tel: 01788 578940
Mob: 07956 855816

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.8048 / Virus Database: 4793/15886 - Release Date: 08/14/18
Internal Virus Database is out of date.


--
Paul Bicknell G8KFW   South Coast UK


Re: N plug for RG401

Stephen Tompsett
 

Mouser? there is a minimum order value to get free delivery. If you don't want a few spare connectors just take the opportunity to stock up on things you will need!

e.g. A Radiall connector I used in some preamps I built:  https://www.mouser.co.uk/ProductDetail/501-R161054000

On 14/05/2020 10:31, Phil Guttridge G3TCU wrote:
Can anyone suggest where I can get a straight N plug for RG401 (0.250" semi-rigid) e.g. Amphenol 172139 without the high shipping cost or MOQ of the main distributors that stock these?

I can only find right angle types on eBay.

Thanks & 73, Phil G3TCU


-- 
Stephen Tompsett (G8LYB)
Tel: 01788 578940
Mob: 07956 855816


N plug for RG401

Phil Guttridge G3TCU
 

Can anyone suggest where I can get a straight N plug for RG401 (0.250" semi-rigid) e.g. Amphenol 172139 without the high shipping cost or MOQ of the main distributors that stock these?

I can only find right angle types on eBay.

Thanks & 73, Phil G3TCU



Re: Carp (anag) design

Alan Melia
 


Just shows you should be using SMB or SMC John :-))
Alan
G3NYK
 

----- Original Message -----
Sent: Thursday, May 14, 2020 9:29 AM
Subject: Re: [UKMicrowaves] Carp (anag) design

Yes, I've made cables like that myself. A true D'OH!!! Moment.
Just take a fine file and dress the points of the SMA nut by about half a mm. Then it'll fit through the bnc nut and you can still use a spanner on the SMA

73 john

On Thu, 14 May 2020, 09:07 Paul Randall G3NJV, <paulfrandall@...> wrote:
Oh that's funny! Gave me a good laugh to start the day. 



Sent from my Samsung Galaxy smartphone.



-------- Original message --------
From: Martin Phillips G4CIO <martin@...>
Date: 11/05/2020 11:37 (GMT+00:00)
Subject: Re: [UKMicrowaves] Carp (anag) design



On 11 May 2020 11:31:20 BST, Andy G4JNT <andy.g4jnt@...> wrote:
Can you post a photo. 

On Mon, 11 May 2020 at 11:29, Martin Phillips G4CIO <martin@...> wrote:
I've just purchased some very nicely made SMA to BNC bulkhead connectors
to mount some kit in a box. The nut for the BNC is behind the fitting.
How do you get the nut off the cable when it's too small to slide over
the SMA?

Doh!




--
Andy 'JNT (out Boris Walking)

--
Martin Phillips


Re: Carp (anag) design

Martin Phillips G4CIO
 

I'd have hoped that a commercial manufacturer might have spotted it. Perhaps that's why they were cheap. Unfortunately, I'd left +ve feedback on Ebay before noticing.

Coming from what one of my former technicians called the "Dewhurst school of engineering", I used a rather rough bastard file to take the points off for a twelve-sider. It didn't look pretty but worked. Do Dewhurst's still exist?

Martin/

On 14/5/20 9:29 AM, John Worsnop wrote:
Yes, I've made cables like that myself. A true D'OH!!! Moment.
Just take a fine file and dress the points of the SMA nut by about half a mm. Then it'll fit through the bnc nut and you can still use a spanner on the SMA

73 john

On Thu, 14 May 2020, 09:07 Paul Randall G3NJV, <paulfrandall@...> wrote:
Oh that's funny! Gave me a good laugh to start the day. 



Sent from my Samsung Galaxy smartphone.



-------- Original message --------
From: Martin Phillips G4CIO <martin@...>
Date: 11/05/2020 11:37 (GMT+00:00)
Subject: Re: [UKMicrowaves] Carp (anag) design



On 11 May 2020 11:31:20 BST, Andy G4JNT <andy.g4jnt@...> wrote:
Can you post a photo. 

On Mon, 11 May 2020 at 11:29, Martin Phillips G4CIO <martin@...> wrote:
I've just purchased some very nicely made SMA to BNC bulkhead connectors
to mount some kit in a box. The nut for the BNC is behind the fitting.
How do you get the nut off the cable when it's too small to slide over
the SMA?

Doh!




--
Andy 'JNT (out Boris Walking)

--
Martin Phillips



Re: Carp (anag) design

John Worsnop
 

Yes, I've made cables like that myself. A true D'OH!!! Moment.
Just take a fine file and dress the points of the SMA nut by about half a mm. Then it'll fit through the bnc nut and you can still use a spanner on the SMA

73 john

On Thu, 14 May 2020, 09:07 Paul Randall G3NJV, <paulfrandall@...> wrote:
Oh that's funny! Gave me a good laugh to start the day. 



Sent from my Samsung Galaxy smartphone.



-------- Original message --------
From: Martin Phillips G4CIO <martin@...>
Date: 11/05/2020 11:37 (GMT+00:00)
Subject: Re: [UKMicrowaves] Carp (anag) design



On 11 May 2020 11:31:20 BST, Andy G4JNT <andy.g4jnt@...> wrote:
Can you post a photo. 

On Mon, 11 May 2020 at 11:29, Martin Phillips G4CIO <martin@...> wrote:
I've just purchased some very nicely made SMA to BNC bulkhead connectors
to mount some kit in a box. The nut for the BNC is behind the fitting.
How do you get the nut off the cable when it's too small to slide over
the SMA?

Doh!




--
Andy 'JNT (out Boris Walking)

--
Martin Phillips


Re: Carp (anag) design

Paul Randall G3NJV
 

Oh that's funny! Gave me a good laugh to start the day. 



Sent from my Samsung Galaxy smartphone.



-------- Original message --------
From: Martin Phillips G4CIO <martin@...>
Date: 11/05/2020 11:37 (GMT+00:00)
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Carp (anag) design



On 11 May 2020 11:31:20 BST, Andy G4JNT <andy.g4jnt@...> wrote:
Can you post a photo. 

On Mon, 11 May 2020 at 11:29, Martin Phillips G4CIO <martin@...> wrote:
I've just purchased some very nicely made SMA to BNC bulkhead connectors
to mount some kit in a box. The nut for the BNC is behind the fitting.
How do you get the nut off the cable when it's too small to slide over
the SMA?

Doh!




--
Andy 'JNT (out Boris Walking)

--
Martin Phillips


Re: What Moon/Sun tracking software is being used.

Paul G8AQA
 

These might be worth a look.  We are using them on a 24" telescope.

https://www.cuidevices.com/product/motion/rotary-encoders/absolute/modular/amt21-v-kit

Paul G8AQA

On 14/05/2020 02:28, Alan Beard wrote:
Hi guys,

I'd ask of the software: What accuracy does it support?

23cm, 5m dish, required pointing accuracy: 0.5 deg.

The John Drew VK5DJ controller  as designed for VK3UM, as I recall, 
does 0.01 deg. in his software.

One's biggest problem is the position accuracy in the rotator.
My KR-400 could be up to 20 deg. out. Readily available absolute shaft encodes
do 1024 steps per rotation. 1024 / 360 => 0.3 deg. resolution. 

BTW: I've asked the "hamlib" developers to consider this and they have improved
the available accuracy in the "hamlib" library.

80                    (A problem solver, have AC, need DC)

Alan VK2ZIW


On Wed, 13 May 2020 12:25:03 -0700, Nick Gregory G0HIK via groups.io wrote
> Thanks guys,
>
> I'll look at both of those and MoonSked and will report back how I get on, pretty sure I tried WXTrack in the past at some time.
>
> Nick G0HIK

---------------------------------------------------
Alan Beard

OpenWebMail 2.53



Re: 122 GHz Chips - UK group purchase ?

Dave G8KHU
 

Good morning all

Just a reminder to anyone who's interested and hasn't yet contacted me. I'm putting in an order to Silicon Radar for the 122 GHz and 24 GHz radar chips, TRA_120_002 and TRX_024_006 respectively, with the aim of reducing their per order carriage and handling charges to an affordable level. So far I have confirmed orders for 23 of the 120 GHz chips and 16 of the 24 GHz devices which has brought the Silicon Radar handling charge down to around £2.67 per chip.

So currently the cost per chip is £ 27.26 for the 122 GHz device and £ 14.17 for the 24 GHz device - these prices include the amortised handling charge contribution. Postage within the UK is gratis.

If anyone else would like to join in the purchase then plaese let me know by Sunday mid-day (17th May) so I can close off the list and get tghe order placed next week. The devices are ex-stock Germany and they are quoting 6-7 days delivery from receipt of payment.

73
Dave G8KHU


Re: What Moon/Sun tracking software is being used.

Alan Beard
 

Hi guys,

I'd ask of the software: What accuracy does it support?

23cm, 5m dish, required pointing accuracy: 0.5 deg.

The John Drew VK5DJ controller  as designed for VK3UM, as I recall, 
does 0.01 deg. in his software.

One's biggest problem is the position accuracy in the rotator.
My KR-400 could be up to 20 deg. out. Readily available absolute shaft encodes
do 1024 steps per rotation. 1024 / 360 => 0.3 deg. resolution. 

BTW: I've asked the "hamlib" developers to consider this and they have improved
the available accuracy in the "hamlib" library.

80                    (A problem solver, have AC, need DC)

Alan VK2ZIW


On Wed, 13 May 2020 12:25:03 -0700, Nick Gregory G0HIK via groups.io wrote
> Thanks guys,
>
> I'll look at both of those and MoonSked and will report back how I get on, pretty sure I tried WXTrack in the past at some time.
>
> Nick G0HIK

---------------------------------------------------
Alan Beard

OpenWebMail 2.53


Re: Water cooling question

Lou Blasco
 

On Thu, May 14, 2020 at 02:10 AM, militaryoperator wrote (in part):

Hi Ben,

Perhaps you were just having a laugh but in case you weren't, I've seen what you've done with your museum and that shows determination which is just what's required above 1000MHz. There's always going to be a station you can't reach or out do. Perhaps a better way to go about it is to challenge yourself and try to better your previous achievements. I've found that to be a goal that leads to great satisfaction rather than frustration. Just Sayin'


Guess its time to throw it all in the skip and stop wasting
time, mine and the station who can't hear me......

Ben


--
Regards

Lou
VK3ALB


Re: Water cooling question

Chris Ruddy MM0KOS
 

Hi Ben

 

Plenty of 2M stations will tell you I spent months shouting CQ night after night with no reply under an MM3 call, im sure folk heard me and didn’t reply. I went to the MM0 call and upped the power to 100w, it was at the time of the infancy of JT44 (I feel old lol). I worked for every QSO I had on SSB, MS,ES and EME. Thats my story back then, I gave up radio for 8 years but im back at it, 23cms is nearly there, home brew transverter, homebrew beams, 2x 41 element (1 built today) but will be 4, homebrew amplifier solid state. 13cm, homebrew transverter, homebrew beams 4x 41 ( 2 built) and im sure the amp will be mostly homebrew aswell. 9Cm 1.8m dish and a half built transverter that im struggling with a wee bit but ill get to it soon and a septum for the feed. Dont give up!!! Every day and every QSO can be hard on the VHF and up, we aint on HF where fishing is easyish. Youve came this far and I know times can be hard with no CNDX etc but hey you’ve got this far, don’t turn back now!!!

 

On the subject of water storage im sure my old copper water tank will be having a new life soon as we dont use it now a days but I will be lining it with some sort of apoxy or something after a bit of research to see whats best to stop the corrosion.

 

Chris MM0KOS

 

Sent from Mail for Windows 10

 

From: militaryoperator via groups.io
Sent: 13 May 2020 17:10
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Water cooling question

 

Last night I ran my new water-cooled PA for 4.5hrs during the NAC/UKAC. I use 50l of distilled water in a barrel and a 30l/min pond pump.



-- ----------------

OMG........ water cooled pa's.............. strikes me that with my dismally pathetic 25watt no matter how well 'I' hear this BIG signal 
the same will not happen in reverse. 
Guess its time to throw it all in the skip and stop wasting time, mine and the station who can't hear me...... 

Pity the pubs are shut. Hey ho. 

Ben


 

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