Date   

Re: JVL Quad loop

KENT BRITAIN
 

We have certainly measured over 100 of them on the Central States VHF Society
and Microwave Update antenna ranges.  But that information has never been organized.

WA5VJB/2E0VAA/G8EMY



From: "Andy Talbot andy.g4jnt@... [ukmicrowaves]"
To: "Ukmicrowaves (ukmicrowaves@...)"
Sent: Tuesday, September 18, 2018 8:01 AM
Subject: [ukmicrowaves] JVL Quad loop

 
In all the documentation for this, and the on-line calculators, and 'JVL's original design programmes, nowhere have I seen a quoted gain.  Or better, a gain vs. number of elements / length graph.

I have a couple of rather old 27 element ones for 1296MHz, and could try to measure the gain to see if they're still working OK, or corrosion has damaged the effectiveness.
But with no specified figure to check against ...





Re: JVL Quad loop

Andy G4JNT
 

Tnx.
They quote a 25 ele as 17dBi,  so my 27 ele probably is around 17dBi on a good day.

Well....  that IS interesting:
MJW_Profile suggests the path loss (local single diffraction) from G8MBU to me is -147dB

Beaconspot quotes 10W for the G8MBU Isle of Wight beacon, so 40dBm EIRP

-147dB + 17dBi  = -90dBm could reasonably be expected in the Rx at the 50% confidence level (or whatever the "percentage" value means on Mike programme)

The transverter has around +7dB net gain (ish,  It's the SG Labs one with no additional LNA or anything) and I just measured -84dBm at 144MHz IF out from that.

So pretty close I reckon !

I do like it when theory/prediction agrees with measurement.

On 18 September 2018 at 14:10, 'John Lemay' john@... [ukmicrowaves] <ukmicrowaves@...> wrote:
 

Andy

 

Directive Systems in the US make them and you’ll see some quoted gains:-

 

https://directivesystems.com/1200-mhz/23-cm-1250-1300-mhz/

 

John G4ZTR

 

From: ukmicrowaves@... [mailto:ukmicrowaves@yahoogroups.com]
Sent: 18 September 2018 14:01
To: Ukmicrowaves (ukmicrowaves@...)
Subject: [ukmicrowaves] JVL Quad loop

 

 

In all the documentation for this, and the on-line calculators, and 'JVL's original design programmes, nowhere have I seen a quoted gain.  Or better, a gain vs. number of elements / length graph.

 

I have a couple of rather old 27 element ones for 1296MHz, and could try to measure the gain to see if they're still working OK, or corrosion has damaged the effectiveness..

But with no specified figure to check against ...

 

 



Re: JVL Quad loop

John Lemay
 

Andy

 

Directive Systems in the US make them and you’ll see some quoted gains:-

 

https://directivesystems.com/1200-mhz/23-cm-1250-1300-mhz/

 

John G4ZTR

 

From: ukmicrowaves@... [mailto:ukmicrowaves@...]
Sent: 18 September 2018 14:01
To: Ukmicrowaves (ukmicrowaves@...)
Subject: [ukmicrowaves] JVL Quad loop

 

 

In all the documentation for this, and the on-line calculators, and 'JVL's original design programmes, nowhere have I seen a quoted gain.  Or better, a gain vs. number of elements / length graph.

 

I have a couple of rather old 27 element ones for 1296MHz, and could try to measure the gain to see if they're still working OK, or corrosion has damaged the effectiveness.

But with no specified figure to check against ...

 

 


JVL Quad loop

Andy G4JNT
 

In all the documentation for this, and the on-line calculators, and 'JVL's original design programmes, nowhere have I seen a quoted gain.  Or better, a gain vs. number of elements / length graph.

I have a couple of rather old 27 element ones for 1296MHz, and could try to measure the gain to see if they're still working OK, or corrosion has damaged the effectiveness.
But with no specified figure to check against ...



Re: WG18 Square Flange Sealing Rings

Stuart G1ZAR
 

I would guess they are standard O-rings obtainable from your local supply (see yellow pages?).
If you could also show the groove depth then this would determine what cross section is required.
might have some in stock, or could visit my supplier if you can't source anywhere else.

Stuart
G1ZAR


Re: WG16 Square Flange

Paul G8KFW
 

Hi regarding choke flanges how much power are you putting through the wave guide ?

as I do not think you will see the benefit of choke flanges

 

Regards Paul B

 


From: ukmicrowaves@... [mailto:ukmicrowaves@...]
Sent: 15 September 2018 21:04
To: ukmicrowaves@...
Subject: Re: [ukmicrowaves] WG16 Square Flange

 

 

Adrian

I will have a look in the loft, I may have some square sets.  I am pretty sure I have round flange sets  and I think I know where the rings could be obtained from.

Remember  to mate the  choke / o-ring flange to a plane flange. Never put 2 choke flanges together (without a  proper shim)

Regards

Mark GM4ISM

 

 

Sent: Saturday, September 15, 2018 3:14 PM

Subject: [ukmicrowaves] WG16 Square Flange

 

 

As part of the next phase of the GB3KBQ rebuild I am hoping to raise the antenna a couple of metres to clear local vegetation. I have a couple of old square flanges but would ideally like to use a choked flange AND sealing rings..rather than silicon sealer!

I wonder if anyone has these items which they would be prepared to donate to the project?

See attached pictures of the size of sealing rings required.

Many thanks

Adrian G4UVZ Beacon Keeper GB3KBQ

 

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Re: GB3CSB - CQ for Donation's !

David GM6BIG
 

Hi All,

While at the farm, I took the opportunity to pay Walter the electricity bill for GB3CSB.

A little earlier than usual, but hopefully that helped make up for being rather late last year...

As always, Walter's support and help is much appreciated, so its the electric bill, and a little extra as a thanks.

If anyone would like to donate towards the upkeep and running of GB3CSB you can send me donations using the details below, or get in touch.

For Paypal, send it to...
aware@freeuk.com

(Do not email me at that address though).

Or by post to..

David Anderson
20 Greenrig Rd
Hawksland
Lesmahagow
ML11 9QA

Unless you wish to remain anonymous, make sure you include your name and call, its not always obvious who has helped out !

Many Thanks for your support in the past.

BTW
The High RF Performance 10GHz beacon, the subject of a talk at the GM Round Table last year when it was still in "breadboard" form, is now all but complete, just some tidying of the software and the addition of some remote monitoring before going to site.


Cheers David GM6BIG.

On 16-Sep-18 21:30, David GM6BIG wrote:
Hi All,
There had been power company faults in the area with 11kV transformers failing, several times.
The farm, and much of the neighbourhood supported on power company generators while the worked on the 11kV network.
During this, a few RCD protected supplies at the farm were tripping, including the one supplying GB3CSB and other amateur radio gear.
I managed to get up last Tuesday to help investigate/fix. By the time I arrived, Walter GM8IIH, the farm owner, had done much of the work already. A few Neutral-Earth "leaky" items identified and disconnected.
Fingers crossed, power was restored on Tuesday, and so far still good - no more RCD trips.
Cheers, David GM6BIG
On 08-Sep-18 16:42, David GM6BIG wrote:
Hi All,

Just to let you know there is an electrical fault at the farm where GB3CSB beacon is located.

The supply to the beacon and other amateur equipment at the site is "currently" off.

It has only just happened, so not sure of any timescale yet, will keep you all posted...


73 David GM6BIG


Re: GB3CSB - ON air

David GM6BIG
 

Hi All,

There had been power company faults in the area with 11kV transformers failing, several times.
The farm, and much of the neighbourhood supported on power company generators while the worked on the 11kV network.

During this, a few RCD protected supplies at the farm were tripping, including the one supplying GB3CSB and other amateur radio gear.

I managed to get up last Tuesday to help investigate/fix. By the time I arrived, Walter GM8IIH, the farm owner, had done much of the work already. A few Neutral-Earth "leaky" items identified and disconnected.

Fingers crossed, power was restored on Tuesday, and so far still good - no more RCD trips.

Cheers, David GM6BIG

On 08-Sep-18 16:42, David GM6BIG wrote:
Hi All,
Just to let you know there is an electrical fault at the farm where GB3CSB beacon is located.
The supply to the beacon and other amateur equipment at the site is "currently" off.
It has only just happened, so not sure of any timescale yet, will keep you all posted...
73 David GM6BIG


Re: [test-equip-trader] Anritsu MG3693B rf connector

Chris Bartram G4DGU
 

Roger wrote:

Does anyone have an 2.92 RF connector, for an Anritsu MG3693B signal generator?  Some kind person has just ruined mine, and Anritsu have quoted over $1000 for a replacement.
I can't help, even if I once thought I'd acquired a bag of 2.92mm free plugs. They weren't! However, Roger's appeal does highlight the high cost of coax connectors for the bands above 24GHz. My own 47GHz kit, once it's finished, will be firmly based on low-cost waveguide, utilising standard tube sizes, with coax interconnects being used below 18GHz.

73

Chris
G4DGU

--


Re: WG16 Square Flange

Adrian whatmore <g4uvz@...>
 

All understood Ed   I have a second length of guide I need to 'flange up'  I am hoping that whilst adding height ..I will not increase the number of joints..i.e  replace two short lengths with two longer lengths!


On Sunday, 16 September 2018, 11:31, "Edward Harland g3vpf@... [ukmicrowaves]" wrote:


 
Adrian

The length of waveguide has square flanges at each end. One is choked the other is plain. However, I do not have any sealing rings.

Ed G3VPF 


On Sat, 15 Sep 2018 at 20:22, g4uvz@... [ukmicrowaves]
wrote:
 
As part of the next phase of the GB3KBQ rebuild I am hoping to raise the antenna a couple of metres to clear local vegetation. I have a couple of old square flanges but would ideally like to use a choked flange AND sealing rings..rather than silicon sealer!
I wonder if anyone has these items which they would be prepared to donate to the project?
See attached pictures of the size of sealing rings required.
Many thanks
Adrian G4UVZ Beacon Keeper GB3KBQ




Scottish Microwave Round Table 2018 open for bookings

Brian Flynn GM8BJF
 

The 2018 Scottish Microwave Round Table will be held on the 3rd of November and is now open for registrations at:
As in past years it is being held in the Museum of Comminication in Burntisland in Fife. During the day there will be a series of talks/lectures with plenty of time in between for ragchewing. There will be the usual bring and buy stalls, measurement facilities and a dinner will be held in the evening at the nearby Kingswood Hotel.
More detailed information is available at the website at:
Any offers of talks or presentations will be well received!

73s
Brian Flynn GM8BJF




Re: WG16 Square Flange

Adrian whatmore <g4uvz@...>
 

Many Thanks Mike
Your donation would be much appreciated !

I will email you my details

Adrian


On Sunday, 16 September 2018, 9:49, "'Michael Scott' g3lyp@... [ukmicrowaves]"


 
Hi Adrian
 
I have a couple of unused square choked flanges as well as some plain ones. I also have a few of the rubber ‘O’ rings. I also have a few round choked and plain ones as well!
 
I would be happy to donate them to your beacon. Let me know the mailing address and I will send them to you.
 
73, Mike, G3LYP.
 

Sent: Saturday, September 15, 2018 3:14 PM
Subject: [ukmicrowaves] WG16 Square Flange
 
 
As part of the next phase of the GB3KBQ rebuild I am hoping to raise the antenna a couple of metres to clear local vegetation. I have a couple of old square flanges but would ideally like to use a choked flange AND sealing rings..rather than silicon sealer!
I wonder if anyone has these items which they would be prepared to donate to the project?
See attached pictures of the size of sealing rings required.
Many thanks
Adrian G4UVZ Beacon Keeper GB3KBQ




Re: WG16 Square Flange

Michael Scott
 

Hi Adrian
 
I have a couple of unused square choked flanges as well as some plain ones. I also have a few of the rubber ‘O’ rings. I also have a few round choked and plain ones as well!
 
I would be happy to donate them to your beacon. Let me know the mailing address and I will send them to you.
 
73, Mike, G3LYP.
 

From: g4uvz@... [ukmicrowaves]
Sent: Saturday, September 15, 2018 3:14 PM
To: ukmicrowaves@...
Subject: [ukmicrowaves] WG16 Square Flange
 
 

As part of the next phase of the GB3KBQ rebuild I am hoping to raise the antenna a couple of metres to clear local vegetation. I have a couple of old square flanges but would ideally like to use a choked flange AND sealing rings..rather than silicon sealer!

I wonder if anyone has these items which they would be prepared to donate to the project?

See attached pictures of the size of sealing rings required.

Many thanks

Adrian G4UVZ Beacon Keeper GB3KBQ



Re: WG16 Square Flange

Mark GM4ISM
 

Adrian
I will have a look in the loft, I may have some square sets.  I am pretty sure I have round flange sets  and I think I know where the rings could be obtained from.
Remember  to mate the  choke / o-ring flange to a plane flange. Never put 2 choke flanges together (without a  proper shim)
Regards
Mark GM4ISM
 
 

Sent: Saturday, September 15, 2018 3:14 PM
Subject: [ukmicrowaves] WG16 Square Flange
 
 

As part of the next phase of the GB3KBQ rebuild I am hoping to raise the antenna a couple of metres to clear local vegetation. I have a couple of old square flanges but would ideally like to use a choked flange AND sealing rings..rather than silicon sealer!

I wonder if anyone has these items which they would be prepared to donate to the project?

See attached pictures of the size of sealing rings required.

Many thanks

Adrian G4UVZ Beacon Keeper GB3KBQ



Re: WG16 Square Flange

Ed G3VPF
 

Adrian

The length of waveguide has square flanges at each end. One is choked the other is plain. However, I do not have any sealing rings.

Ed G3VPF 


On Sat, 15 Sep 2018 at 20:22, g4uvz@... [ukmicrowaves]
wrote:
 

As part of the next phase of the GB3KBQ rebuild I am hoping to raise the antenna a couple of metres to clear local vegetation. I have a couple of old square flanges but would ideally like to use a choked flange AND sealing rings..rather than silicon sealer!

I wonder if anyone has these items which they would be prepared to donate to the project?

See attached pictures of the size of sealing rings required.

Many thanks

Adrian G4UVZ Beacon Keeper GB3KBQ



Re: UK Microwave Group mm-wave contest Sunday 16th September

Martyn G3UKV
 

Thanks for list, John.
My email did not appear until about 45 minutes after I sent it, by which time the list appeared!
I expect now to be on tomorrow, although no stations listed appear to be line-of-sight. Where has the midland/northern activity gone ?
73 Martyn

On 15/09/2018 18:02, G3XDY g3xdy@... [ukmicrowaves] wrote:
 

Thanks for your inputs for the activity list for tomorrow's 24/47/76GHz contests. Weather in the south eastern half of the UK looks set fair, maybe with some tropo enhancement early on.

Callsign: G4LDR/P
Locator: IO81XG25, probably
Bands:  24GHz, 1W, 30cm dish
              47GHz, 250mW, 25cm dish
              76GHz, 13mW, 25cm dish.
Talkback: 144.390MHz and maybe KST
Times: Probably mid-late morning onwards

Callsign: G4BAO
Locator:  JO02cg33
Bands: 24GHz 2Watts to 60cm dish @8m AGL
Activity solely dependent upon anyone being QRV in range, or any anomalous propagation, or sked requests
Talkback via KST, 23cms or the usual phone number. email john@... for skeds etc

Callsign: G1DFL/P
Locator: IO91NM78VW
Bands: 24GHz SSB 0.25W 30cm Nortel ODU
Talkback: i) 144.390MHz SSB, ii) KST, iii) 07713 432632 , iv) Zello (SHF Chat)
Times: 10am-12.
This farm gate site at Remenham Hill is only clear to the SW so Walbury Hill, Basingstoke M3 Garlic Lane, Salisbury and IO80.
If anyone is on Blorenge, Brown Clee or Hackpen, I may rove to Britwell Hill (IO91LO98FM) on the Chiltern Ridge to work NW and W later.

Callsign: G3ZME/P
Locator: IO82QL (Brown Clee)
Bands: 24 GHz
Talkback: 2m 144.390 MHz (preferred), ON4KST,  phone 07421 001166
Times: From about 10:30 am local

Callsign: G4SJH/P
Locator: IO91GI44 (Walbury) – until around lunchtime then Cheesefoot Head IO91JB00
Bands: 24 GHz
Talkback: 2m 144.390 MHz (preferred), ON4KST,  phone 07484 800855
Times: From about 10:00 am local
On Walbury I may need to operate on north side then south side depending on the situation.

73

John G3XDY


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Re: Modifying the Crawley 115V AC relays

Andy G4JNT
 


Type 402-182-1
402 series on the graph suggests they are OK for just about 500 Watts at 1.3GHz and just short of 1kW at 432

On 15 September 2018 at 16:45, Andy Talbot <andy.g4jnt@...> wrote:
Leave the IN400x type diode in place, it is a transient catcher and protects the magnetics from reverse polarity (permanent magnet biassed)
If you just jumper the bridge connections across, pin F becomes the +ve one, [pin H the -Ve 


On 15 September 2018 at 16:35, Andy Talbot <andy.g4jnt@...> wrote:
Earlier I reported these pull in at 60V DC, so it looks as if 70 - 90V DC may be a suitable working voltage, unmodified.  That's to high for simple inverters so :

I modified mine by connecting the two coils in parallel instead of series, and removed the bridge rectifier and smoothing capacitor inside,

It now just about pulls in at 30V, and seems good at 40V - just within range of a simple-switcher Boost converter. A voltage doubler pulsed arrangement in conjunction with a 35 - 40V supply would be better still

Be careful cutting the link between the two coils  It's PTFE covered wire and normal strippers don't treat it well at all.



Re: UK Microwave Group mm-wave contest Sunday 16th September

Roger Ray
 

A bit late, but planned activity as follows:

G8CUB/P
24G 1W
47G 50mW
76G 50mW
10.30 - 12.00 Hackpen IO91CL
14.00 - 15.30 Ditchling Beacon IO90WV
local times
Talkback; KST, 144.390. mob: 07900 261121
Roger G8CUB


UK Microwave Group mm-wave contest Sunday 16th September

John Quarmby
 

Thanks for your inputs for the activity list for tomorrow's 24/47/76GHz contests. Weather in the south eastern half of the UK looks set fair, maybe with some tropo enhancement early on.

Callsign: G4LDR/P
Locator: IO81XG25, probably
Bands:  24GHz, 1W, 30cm dish
              47GHz, 250mW, 25cm dish
              76GHz, 13mW, 25cm dish.
Talkback: 144.390MHz and maybe KST
Times: Probably mid-late morning onwards

Callsign: G4BAO
Locator:  JO02cg33
Bands: 24GHz 2Watts to 60cm dish @8m AGL
Activity solely dependent upon anyone being QRV in range, or any anomalous propagation, or sked requests
Talkback via KST, 23cms or the usual phone number. email john@... for skeds etc

Callsign: G1DFL/P
Locator: IO91NM78VW
Bands: 24GHz SSB 0.25W 30cm Nortel ODU
Talkback: i) 144.390MHz SSB, ii) KST, iii) 07713 432632 , iv) Zello (SHF Chat)
Times: 10am-12.
This farm gate site at Remenham Hill is only clear to the SW so Walbury Hill, Basingstoke M3 Garlic Lane, Salisbury and IO80.
If anyone is on Blorenge, Brown Clee or Hackpen, I may rove to Britwell Hill (IO91LO98FM) on the Chiltern Ridge to work NW and W later.

Callsign: G3ZME/P
Locator: IO82QL (Brown Clee)
Bands: 24 GHz
Talkback: 2m 144.390 MHz (preferred), ON4KST,  phone 07421 001166
Times: From about 10:30 am local

Callsign: G4SJH/P
Locator: IO91GI44 (Walbury) – until around lunchtime then Cheesefoot Head IO91JB00
Bands: 24 GHz
Talkback: 2m 144.390 MHz (preferred), ON4KST,  phone 07484 800855
Times: From about 10:00 am local
On Walbury I may need to operate on north side then south side depending on the situation.

73

John G3XDY


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24G Sunday ??

Martyn G3UKV
 

GA All

No list has been received for activity tomorrow on 24/47/76 GHz here.
Is anyone else going to be on (apart from Pete G1DFL/P and John G4BAO noted) ?

Quite a drive from here to Brown Clee. Already had one session this year with NO (Nil, Zilch, zero) QSOs - don't want another!
I'm game if someone else is to give a likely path a chance. WX forecast not too bad in the Shropshire Hills area.
Will make final decision 08:30 local time on Sunday. Batteries and laptop charged and raring for action this end.

Wotsa ?
(email, text (07421 001166) or phone call (01952 255416) please.
73 Martyn G3UKV (aka G3ZME/P)

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