Date   

Re: How much loss will this 3cm feed have ?

Paul G8KFW
 

Hi Nick         

 

As someone has mentioned  from the photo your big issue is the right angle N connector 

These do start to misbehave at about 5 ghz  and at 10 ghz can have a very lumpy response and -10 Db is possible at 10 GHz

 

The same goes for the SMA right angle connector  except the useable frequency is higher there are swept bends that reduce this problem

 

You ask about  does anyone have a suitable flange in WG16 that suits the dish

From the picture I do not recognise the dish fitting it appears it could be wave guide larger than WG 16  if that is so and it fits snugly over the WG 16  then it is old English  not a problem

but the addition of tuning screws might improve things if it is a change of wave guide sizes ( I have no information on this )

 

Changing the N to wave guide adapter for one with a sq flange would allow for the dish and radio to be mounted closer together if this is not a problem then wave guide is good  

 

Other common mistakes is the use of chocked flanges these are to reduce RF leakage at the joints when using high power (above 10 watts )

But having a joint with choke to choke can give some weird results and should not be used

 

What is behind the N connectors  ?  hopefully it is not an earth tag and an un screened joint  if so this requires changing

 

Your best improvement could be to use an SMA adapter on the waveguide to N transition and use Hard line /semi rigged and SMA connectors

 

lookout for bad N and SMA  connectors so avoid chrome plated , bright gold plated  

the better ones are silver plated brass or stainless steal with gold plated centre connectors

on SMA I do not use the SMA connectors that uses the coax conductor for the centre pin

 

Best of luck  you could always test the transition frequency response possibly at a microwave round table

 

Regards Paul          West Sussex

 

 


From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Nick Gregory G0HIK via Groups.Io
Sent: 23 August 2019 22:05
To: UKMicrowaves@groups.io
Subject: [UKMicrowaves] How much loss will this 3cm feed have ?

 



Should I be worried about the amount of loss this 3cm feed has ?
The dish has the threaded WG connector and I have had to use two adapters to get it to match the WG Transition, which has a "C" connector. I have had to convert to "N" with adapters.
Would a homemade coax to WG transition with the correct flange and a small coax pigtail be better ?

Next question does anyone have a suitable flange in WG16 that suits the dish, that I can use to make a "N" or SMA transition with. (Sorry I dont know the name of the flange, but it the one on the Dish Sanders maybe ?)

Nick G0HIK

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Re: Activity List for the UK Microwave Group 5.7Ghz and 10GHz contests - Sunday 25th August

Noel G8GTZ
 

I plan to be out portable as follows:

Callsign: G8GTZ/P
Locator: IO91JH
Bands: 5.7GHz 10W wifi mesh dish
             10GHz 6W  0.8m dish
Talkback: ON4KST, Zello SHF Chat, 144.390MHz
Times: 10am - 1pm local


Re: How much loss will this 3cm feed have ?

geoffrey pike
 

Well i was just hoping there might be enough room to get a sma fitted in there as it would be good to do away with all the
those couplings.
Oh dear another Honda, only ever had a Honda 50, more of a Ducati/Triumph household here.
cheers
Geoff
GI0GDP

On Saturday, 24 August 2019, 08:48:38 BST, Nick Gregory G0HIK via Groups.Io <nickg0hik@...> wrote:


Is there Geoff ?

I've found the Radcom article on line (Microwavers.org) that used a Kuhne module , unfortunately it does not blow up with enough  clarity to make out the dimensions.

I think the probe is 4.5mm and the back measurement 6mm, which sort of ties up with W1GHZ pages.

I dont really want to mess around with the feed I have, just in case I mess it up, so I'll look around for what bits I have.

Oh the Bike, Honda CBR600R FY, 2001, I've had it from new. Poor girl has not been ridden for 3 years now.

Nick G0HIK


Re: How much loss will this 3cm feed have ?

Nick Gregory G0HIK
 

OK thanks Neil, Noted.

I have some rigid coax terminated with SMA's.

I'll go straight from the the waveguide to the relay with these then.

Nick G0HIK





 


Re: How much loss will this 3cm feed have ?

Neil Smith G4DBN
 

It might be worth investigating, because if you can eliminate all of the connectors apart from the one on the transition and the one on the relay by making up a custom patch lead with a gland in place of the connector on the equipment box, it would improve the rx noise figure and give you a bit more on tx

No extra plug/socket in line, no adaptors, just one (very good) coax lead.  

Neil

On 24 Aug 2019, at 08:37, Nick Gregory G0HIK via Groups.Io <nickg0hik@...> wrote:

The "C" connector is terminated  in a  "Tee" bar inside the waveguide, I pulled this from HMS Ajax when she was scrapped in 1988, so sort of nice keeping a bit of her alive.
I would not know how to connect it direct to the C/O relay yet, but I can see that would make a nice low low connection.
Maybe in the future.
I have a Waveguide switch, but it is large and heavy. All my kit needs to be portable and ideally very portable for Fell Topping.

Nick G0HIK

ajax12


Re: How much loss will this 3cm feed have ?

Nick Gregory G0HIK
 

Is there Geoff ?

I've found the Radcom article on line (Microwavers.org) that used a Kuhne module , unfortunately it does not blow up with enough  clarity to make out the dimensions.

I think the probe is 4.5mm and the back measurement 6mm, which sort of ties up with W1GHZ pages.

I dont really want to mess around with the feed I have, just in case I mess it up, so I'll look around for what bits I have.

Oh the Bike, Honda CBR600R FY, 2001, I've had it from new. Poor girl has not been ridden for 3 years now.

Nick G0HIK


Re: How much loss will this 3cm feed have ?

Nick Gregory G0HIK
 

The "C" connector is terminated  in a  "Tee" bar inside the waveguide, I pulled this from HMS Ajax when she was scrapped in 1988, so sort of nice keeping a bit of her alive.
I would not know how to connect it direct to the C/O relay yet, but I can see that would make a nice low low connection.
Maybe in the future.
I have a Waveguide switch, but it is large and heavy. All my kit needs to be portable and ideally very portable for Fell Topping.

Nick G0HIK

ajax12


Re: How much loss will this 3cm feed have ?

geoffrey pike
 

There is just enough room to blank there nearest to the dish coupling and put a sma  transition in there and remove heaps of losses.
BUT what is the bike ?
cheers
Geoff
GI0GDP

On Friday, 23 August 2019, 22:26:12 BST, Nick Gregory G0HIK via Groups.Io <nickg0hik@...> wrote:


Excellent, thanks Andy.

I'll get on with making new transition then.

Nick G0HIK


Re: How much loss will this 3cm feed have ?

Neil Smith G4DBN
 

What is inside the box with the C connector?  Can you replace that with a cable gland and run Sucoflex cable all the way from the tx/rx relay to the transition? I do that on my 6cm system to avoid any adaptors or extra plugs/sockets. Admittedly, on 3cm, I use waveguide all the way from the feed to the waveguide relay and there is a waveguide LNA bolted on to a relay port, but I'm a bit obsessive about receive performance.

Not that it is much use as the entire system is stuck on the flat roof about 20ft from the new mast.  I need some strong blokes round here sharpish.

Neil G4DBN


Re: How much loss will this 3cm feed have ?

Nick Gregory G0HIK
 

Excellent, thanks Andy.

I'll get on with making new transition then.

Nick G0HIK


Re: How much loss will this 3cm feed have ?

Andy G4JNT
 

AH, OK.   Probably right to still be suspicious.   The WG adapters are probably fine.   YOu can get away with a lot in waveguide and still get low loss.  You can always add tuning screws to correct a mismatch.
    


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On Fri, 23 Aug 2019 at 22:20, Nick Gregory G0HIK via Groups.Io <nickg0hik=googlemail.com@groups.io> wrote:
Thanks Andy,

The Right angle is a "C", but I presume it's has just as much loss as an "N".

Well if I am going to have to make a coax transition with a "SMA" or "N" should I be worried about the WG adapters ?

Nick G0HIK


Re: How much loss will this 3cm feed have ?

Steve G4HTZ
 

Ok ...I have told someone in the past they were transmitting on wrong polarisation due to be confused re waveguide ....I'm no expert on these things ...still got to connect my DB6NT G4 and 10w amp up at some point .
Good luck on 10ghz 
Steve G4HTZ JO01JN 

On 23 Aug 2019, at 22:14, Nick Gregory G0HIK via Groups.Io <nickg0hik@...> wrote:

<20190730_181001.jpg>

Thanks, Steve,

But yes I will have to correct you, the feed has a twist :)

Nick G0HIK

--
Steve G4HTZ 
JO01JN


Re: How much loss will this 3cm feed have ?

Nick Gregory G0HIK
 

Thanks Andy,

The Right angle is a "C", but I presume it's has just as much loss as an "N".

Well if I am going to have to make a coax transition with a "SMA" or "N" should I be worried about the WG adapters ?

Nick G0HIK


Re: How much loss will this 3cm feed have ?

Nick Gregory G0HIK
 



Thanks, Steve,

But yes I will have to correct you, the feed has a twist :)

Nick G0HIK


Re: How much loss will this 3cm feed have ?

Andy G4JNT
 

Oh yes so it is.
That will even swamp the discontinuity-loss of a right angle N



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On Fri, 23 Aug 2019 at 22:10, Steve G4HTZ via Groups.Io <essexsteve=icloud.com@groups.io> wrote:
Nick 
Unless the picture has been turned it looks like your TX /RX with vertical polarisation .....I stand to be corrected as I have known to be wrong ..often ..
Steve G4HTZ 


On 23 Aug 2019, at 22:05, Nick Gregory G0HIK via Groups.Io <nickg0hik@...> wrote:

<20190823_202807.jpg>

Should I be worried about the amount of loss this 3cm feed has ?
The dish has the threaded WG connector and I have had to use two adapters to get it to match the WG Transition, which has a "C" connector. I have had to convert to "N" with adapters.
Would a homemade coax to WG transition with the correct flange and a small coax pigtail be better ?

Next question does anyone have a suitable flange in WG16 that suits the dish, that I can use to make a "N" or SMA transition with. (Sorry I dont know the name of the flange, but it the one on the Dish Sanders maybe ?)

Nick G0HIK

--
Steve G4HTZ 
JO01JN


Re: How much loss will this 3cm feed have ?

Steve G4HTZ
 

Nick 
Unless the picture has been turned it looks like your TX /RX with vertical polarisation .....I stand to be corrected as I have known to be wrong ..often ..
Steve G4HTZ 


On 23 Aug 2019, at 22:05, Nick Gregory G0HIK via Groups.Io <nickg0hik@...> wrote:

<20190823_202807.jpg>

Should I be worried about the amount of loss this 3cm feed has ?
The dish has the threaded WG connector and I have had to use two adapters to get it to match the WG Transition, which has a "C" connector. I have had to convert to "N" with adapters.
Would a homemade coax to WG transition with the correct flange and a small coax pigtail be better ?

Next question does anyone have a suitable flange in WG16 that suits the dish, that I can use to make a "N" or SMA transition with. (Sorry I dont know the name of the flange, but it the one on the Dish Sanders maybe ?)

Nick G0HIK

--
Steve G4HTZ 
JO01JN


Re: How much loss will this 3cm feed have ?

Andy G4JNT
 

YES

Sharp right angle N adapters do not behave themselves at 10GHz - there's a nasty mismatch in there.   You'd do better to replace it with a semi-rigid coax with, ideally, N connectors or even SMA with N adapters.

When we used a sharp right angle at 12GHz for th GB3SCK beacon, there was something like 20dB signal loss.   I don't recall measuring at 10GHz, but certainly wouldn't trust it above around 6GHz



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On Fri, 23 Aug 2019 at 22:05, Nick Gregory G0HIK via Groups.Io <nickg0hik=googlemail.com@groups.io> wrote:


Should I be worried about the amount of loss this 3cm feed has ?
The dish has the threaded WG connector and I have had to use two adapters to get it to match the WG Transition, which has a "C" connector. I have had to convert to "N" with adapters.
Would a homemade coax to WG transition with the correct flange and a small coax pigtail be better ?

Next question does anyone have a suitable flange in WG16 that suits the dish, that I can use to make a "N" or SMA transition with. (Sorry I dont know the name of the flange, but it the one on the Dish Sanders maybe ?)

Nick G0HIK


How much loss will this 3cm feed have ?

Nick Gregory G0HIK
 



Should I be worried about the amount of loss this 3cm feed has ?
The dish has the threaded WG connector and I have had to use two adapters to get it to match the WG Transition, which has a "C" connector. I have had to convert to "N" with adapters.
Would a homemade coax to WG transition with the correct flange and a small coax pigtail be better ?

Next question does anyone have a suitable flange in WG16 that suits the dish, that I can use to make a "N" or SMA transition with. (Sorry I dont know the name of the flange, but it the one on the Dish Sanders maybe ?)

Nick G0HIK


Re: Looking for 3cm's contacts this Friday evening from IO84

Nick Gregory G0HIK
 

Many Thanks Denis for my first narrow band 3cm's contact this evening.

Hopefully I will make it with the ops soon.

On Sunday I will be operating from another location which is several 100's of feet higher, so it maybe worth another try.

Nick G0HIK


Contest 25th August 2019

Ralph
 

Callsign: G4ALY

Locator: IO70VL

Band: 10GHz 10W 70cm

           5.7GHz 14W 70cm

Talkback: KST and 144.390

 

73 and good luck

 

Ralph

G4ALY

 

 

 

 

 

 

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