Date   

Re: VNA waveguide calibration - 0 + 1/4 wavelength shorts vs 1/8 and 3/8 wavelength offset shorts.

mjniman@...
 

Hi David

It goes back many years so i cant find a HP/Agilent ref for you but Maury mention it here

http://www.maurymw.com/Precision/Offset_Short_Waveguide.php

Its actually useful for engineering when de-embedding and calibrating on microstrip and stripline situations as well as its waveguide origins

Murray


Re: Activity List - UK Microwave Group Contest 4th May 2014

Alan
 

Hi all,
The /p season has arrived again, although heavy rain now forecast!
I will be qrv at IO76xa on 10Ghz with usual system of 9w to 90cm dish from about 1430 to 1600 local...not long l know but hopefully can try with sone folk..kst should be possible or 07785744643.
73 Alan GM0USI/P


Sent from Samsung Mobile


-------- Original message -------- Subject: Re: [ukmicrowaves] Activity List - UK Microwave Group Contest 4th May 2014 From: Martyn Vincent To: ukmicrowaves@... CC:

 

Callsign: G3Z
Locator: IO82QL (Brown Clee)
Bands: (provisional) 10 GHz, 24 GHz
Talkback: 2m SSB/CW (preferred), KST (iffy, and hard to see at times)
Times: 14-22z hrs Saturday
Also G3UKV on Sunday Low Bands from the comfort of home.

73 Martyn G3UKV

On 03/05/2014 00:35, G3XDY wrote:
Thanks for your inputs, here is what I have received so far:

Callsign: M0HNA/P
Locator: IO91RF
Bands:
1.3GHz - 250W to 4 x 35ele
2.3GHz - 60W to 90cm dish
3.4GHz - 15W to 70cm dish
Talkback: KST (one login for 23cm and another for 13/9cm)
Times: Throughout

Callsign: GM3HAM/P; GM4BYF/P
Locator:IO74WV
Bands: 1.3GHz 80W – 57 elements call GM3HAM/P
2.3GHz 120W – 1.3m dish GM4BYF/P
3.4GHz 60W – 1.3m dish GM4BYF/P
Talkback: 144MHz , KST (not reliable from this location) for skeds phone 
Pete 07769 822648
Times: whole contest (Wx permitting!!)

73 & GL to all

John G3XDY


---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com



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

Yahoo Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/ukmicrowaves/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/ukmicrowaves/join
    (Yahoo! ID required)

<*> To change settings via email:
    ukmicrowaves-digest@... 
    ukmicrowaves-fullfeatured@...

<*> To unsubscribe from this group, send an email to:
    ukmicrowaves-unsubscribe@...

<*> Your use of Yahoo Groups is subject to:
    https://info.yahoo.com/legal/us/yahoo/utos/terms/




Re: Activity List - UK Microwave Group Contest 4th May 2014

Martyn G3UKV
 

Callsign: G3Z
Locator: IO82QL (Brown Clee)
Bands: (provisional) 10 GHz, 24 GHz
Talkback: 2m SSB/CW (preferred), KST (iffy, and hard to see at times)
Times: 14-22z hrs Saturday
Also G3UKV on Sunday Low Bands from the comfort of home.

73 Martyn G3UKV

On 03/05/2014 00:35, G3XDY wrote:
Thanks for your inputs, here is what I have received so far:

Callsign: M0HNA/P
Locator: IO91RF
Bands:
1.3GHz - 250W to 4 x 35ele
2.3GHz - 60W to 90cm dish
3.4GHz - 15W to 70cm dish
Talkback: KST (one login for 23cm and another for 13/9cm)
Times: Throughout

Callsign: GM3HAM/P; GM4BYF/P
Locator:IO74WV
Bands: 1.3GHz 80W  57 elements call GM3HAM/P
2.3GHz 120W  1.3m dish GM4BYF/P
3.4GHz 60W  1.3m dish GM4BYF/P
Talkback: 144MHz , KST (not reliable from this location) for skeds phone 
Pete 07769 822648
Times: whole contest (Wx permitting!!)

73 & GL to all

John G3XDY


---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com



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

Yahoo Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/ukmicrowaves/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/ukmicrowaves/join
    (Yahoo! ID required)

<*> To change settings via email:
    ukmicrowaves-digest@... 
    ukmicrowaves-fullfeatured@...

<*> To unsubscribe from this group, send an email to:
    ukmicrowaves-unsubscribe@...

<*> Your use of Yahoo Groups is subject to:
    https://info.yahoo.com/legal/us/yahoo/utos/terms/




Activity List - UK Microwave Group Contest 4th May 2014

John Quarmby
 

Thanks for your inputs, here is what I have received so far:

Callsign: M0HNA/P
Locator: IO91RF
Bands:
1.3GHz - 250W to 4 x 35ele
2.3GHz - 60W to 90cm dish
3.4GHz - 15W to 70cm dish
Talkback: KST (one login for 23cm and another for 13/9cm)
Times: Throughout

Callsign: GM3HAM/P; GM4BYF/P
Locator:IO74WV
Bands: 1.3GHz 80W 57 elements call GM3HAM/P
2.3GHz 120W 1.3m dish GM4BYF/P
3.4GHz 60W 1.3m dish GM4BYF/P
Talkback: 144MHz , KST (not reliable from this location) for skeds phone Pete 07769 822648
Times: whole contest (Wx permitting!!)

73 & GL to all

John G3XDY


---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com


Re: Query: Use of different Callsigns

John Quarmby
 

Stewart

Making two contacts with the same station even though they might be with different operators and callsigns really falls outside the spirit of the contest, unless they use separate equipment. I think you should make a choice of one of the following options:

1. Enter the RSGB event, operating during the full 24hrs.
2. Enter the UKuG event, operating on the Sunday only.
3. Enter the RSGB event for the first  18hrs then switch to a different callsign to enter the UKuG event for the last 6 hrs.

73

John G3XDY



On 29/04/2014 18:43, stewart.g0lgs@... wrote:

Hi,


Sorry if this has been answered before, but I failed to see how to search messages in the group.


I am new to the microwave contests and I am trying to make sure that neither I or other members of our small team do not in some way fall foul of the rules, especially during this weekends Low Band Contest that runs concurrently with the last 6 hours of the RSGB May UHF Contest.


If I am part of a team operating on one of the bands that is included in both events, can we use one callsign for contacts submitted in the RSGB event another callsign (with or without a change of operator) to make contacts with the same 'distant' station to count as a contact for the other contest ?


As only one entry will be made to the RSGB contest and one using a different cal lsign will be made for the Microwavers contest I don't see that this breaks the rules for 'our station', but would both contacts count for anyone that we work using both 'our' callsigns.


I can see that the RSGB general rules have a 15 minute rule and both contests have a rule that says you cannot change callsign during the contest, but as there are two events and only one callsign is really used for each entry does this strictly speaking break the rules ?


If using 2 calls like this is deemed to be contrary to the rules then we may decide to only operate for the last 6 hours on the band(s) involved.


Stewart G0LGS






This email is free from viruses and malware because avast! Antivirus protection is active.



Re: New PAT versions for Transverters

dave powis <g4hup@...>
 

Thanks Conrad.  Should have copied from the url instead of trying to type from memory!

73,
dave


From: Conrad Farlow
To: ukmicrowaves@...
Sent: Friday, May 2, 2014 2:56 AM
Subject: Re: [ukmicrowaves] New PAT versions for Transverters

It seems that http://g4hup.com/PAT.htm is the correct link Dave.

73

Conrad G0RUZ IO93FR

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

North Wakefield Radio Club <http://www.g4nok.com>

On 01/05/2014 22:43, dave powis wrote:
>
>
> Introducing two new PAT Panoramic Adaptor Tap variants for direct
> transverter connection.
>
> The PAT30M and PAT146M respectively have LPFs for 30MHz and 146MHz, so
> that they can be used directly on the Rx output of VHF, UHF and
> microwave transverters with 10m and 2m IF's to connect your SDR. The
> bandwidth available for the SDR at this point will be rather wider
> than that obtained by tapping on the filters inside the IF rig, so may
> be of more use in some applications.
>
> Kits and built/tested units available - see http://g4hup.com/pat.htm
>
> 73,
> Dave
> G4HUP
>
> http://g4hup.com
>
>
>



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

Yahoo Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/ukmicrowaves/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/ukmicrowaves/join
    (Yahoo! ID required)

<*> To change settings via email:
    ukmicrowaves-digest@...
    ukmicrowaves-fullfeatured@...

<*> To unsubscribe from this group, send an email to:
    ukmicrowaves-unsubscribe@...

<*> Your use of Yahoo Groups is subject to:
    https://info.yahoo.com/legal/us/yahoo/utos/terms/




Re: VNA waveguide calibration - 0 + 1/4 wavelength shorts vs 1/8 and 3/8 wavelength offset shorts.

Dr. David Kirkby <drkirkby@...>
 


On 2 May 2014 14:16, <mjniman@...> wrote:
>
>
>
> Hi David
>
> The disadvantage of  the Short Circuit is its high current at a physical point where you need a perfect metal flange/coax connection
>
> So that why the offset shorts have featured in some more modern calkits and cal-maths to keep teh current point down where you get metal-junction issues
>
> regards
>
>  Murray G6JYB

Thank you - thay does make sense. I spent some time this morning looking for research papers on the problem, but never found anything useful. 

Are you aware of any references on this? Now I know why the offset shorts are better, I will hopefully be in better position to search for material.

I wonder in practice how much an advantage the 1/8 and 3/8 are for an engineering application as opposed to a metrologist working in a standards laboratory.

Dave


Re: VNA waveguide calibration - 0 + 1/4 wavelength shorts vs 1/8 and 3/8 wavelength offset shorts.

mjniman@...
 

Hi David

The disadvantage of  the Short Circuit is its high current at a physical point where you need a perfect metal flange/coax connection

So that why the offset shorts have featured in some more modern calkits and cal-maths to keep teh current point down where you get metal-junction issues

regards

 Murray G6JYB



GS3PYE/P QRV 1296.200 until 1345UT

g4bao
 

The title says it all!

73
JOhn


Re: New PAT versions for Transverters

Conrad Farlow <conrad@...>
 

It seems that http://g4hup.com/PAT.htm is the correct link Dave.

73

Conrad G0RUZ IO93FR

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

North Wakefield Radio Club <http://www.g4nok.com>

On 01/05/2014 22:43, dave powis wrote:


Introducing two new PAT Panoramic Adaptor Tap variants for direct transverter connection.

The PAT30M and PAT146M respectively have LPFs for 30MHz and 146MHz, so that they can be used directly on the Rx output of VHF, UHF and microwave transverters with 10m and 2m IF's to connect your SDR. The bandwidth available for the SDR at this point will be rather wider than that obtained by tapping on the filters inside the IF rig, so may be of more use in some applications.

Kits and built/tested units available - see http://g4hup.com/pat.htm

73,
Dave
G4HUP

http://g4hup.com



New PAT versions for Transverters

dave powis <g4hup@...>
 

Introducing two new PAT Panoramic Adaptor Tap variants for direct transverter connection.

The PAT30M and PAT146M respectively have LPFs for 30MHz and 146MHz, so that they can be used directly on the Rx output of VHF, UHF and microwave transverters with 10m and 2m IF's to connect your SDR.  The bandwidth available for the SDR at this point will be rather wider than that obtained by tapping on the filters inside the IF rig, so may be of more use in some applications.

Kits and built/tested units available  - see http://g4hup.com/pat.htm

73,
Dave
G4HUP

http://g4hup.com


Re: Microwave Amplifiers

 


Agreed,Chris, so the idea that no matched amplifier can be more than 50% efficient is a fallacy.
I guess it has come from analysing the "equivalent circuit"
But the "equivalent circuit" is just that, it is not the real circuit, and in particular it is assuming linear operation and that is not valid for a high efficiency amplifier.

Ken,
G3YKI

---In ukmicrowaves@..., <cbartram@...> wrote :

Hello Ken
> So what do you get if have two amplifiers of more than 50% efficiency
> and combine them in quadrature hybrid combiners to make the output
> impedance 50 ohms?
Each amplifier continues to work efficiently as it sees its designed
load, and the quadrature hybrid sums the two output powers. There is a
small hit on efficiency due to combiner losses. The combiner also
effectively does some vector arithmetic which lets the outside world see
the internal termination. No physical laws are broken and no icons
smashed in pulling off this rather neat 'trick'.

I've used the technique in designing amplifiers which have to meet
external intermodulation specifications eg. for multi-transmitter
locations. It can allow the design of a transmitter without the cost
implications of ferrite isolators.

Vy 73

Chris
GW4DGU


Re: Microwave Amplifiers

Christopher Bartram <cbartram@...>
 

Hello Ken
So what do you get if have two amplifiers of more than 50% efficiency and combine them in quadrature hybrid combiners to make the output impedance 50 ohms?
Each amplifier continues to work efficiently as it sees its designed load, and the quadrature hybrid sums the two output powers. There is a small hit on efficiency due to combiner losses. The combiner also effectively does some vector arithmetic which lets the outside world see the internal termination. No physical laws are broken and no icons smashed in pulling off this rather neat 'trick'.

I've used the technique in designing amplifiers which have to meet external intermodulation specifications eg. for multi-transmitter locations. It can allow the design of a transmitter without the cost implications of ferrite isolators.

Vy 73

Chris
GW4DGU


Re: Microwave Amplifiers

 


So what do you get if have two amplifiers of more than 50% efficiency and combine them in quadrature hybrid combiners to make the output impedance 50 ohms?
------
As regards measuring the output impedance, my experience is with UHF TV transmitters such as 25 or 40 kW klystron amplifiers. Transmit the "pulse and bar" video waveform. There is a reflected pulse from the antenna but because it is delayed by twice the feeder length, it is one or two microseconds later and it is not masked by the transmitter output if you view demodulated output on a scope.
At a directional coupler on the transmitter output you can easily see what level comes down the feeder and what level is reflected from the amplifier.

The answer is that they are not much different; 1 or 2 dB return loss.

This was all to do with BBC requirement at main stations for the delayed image from the transmitter to be less than 1%.
So with an amplifier return loss of 2 dB and two way feeder loss of maybe 4dB the antenna return loss requirement becomes 34dB.

Of course this is all for historical interest. With digital TV no-one would notice the difference until the tx trips off on reflected power!

Ken G3YKI

---In ukmicrowaves@..., <andy.g4jnt@...> wrote :

If th eoutput of any amplifier were 50 ohms, it could inherently never ever possibly be more than 50% efficient.
The most efficient amplifiers would have either zero or infinite ouptut impedance corresponding to a voltage source or a current source respectively.
 
Practical designs fall somewhere in between.    How can you measure the output impedance of a high power  amplifier anyway?  Load pull ?
 
Andy
G4JNT


Re: VNA waveguide calibration - 0 + 1/4 wavelength shorts vs 1/8 and 3/8 wavelength offset shorts.

 

I don't know, so this is a bit of speculation:

With 1/8 and 3/8 method you have a (hopefully) small but stationary mismatch at the first interface and a large moving mismatch at the short. Hence the small mismatch, which will also be there when you connect the DUT, is included as part of the system and in the calculated corrections.

With 0 and 1/4 technique any mismatch at the transition from test equipment port  to calibration wave-guide  is missing from one of the measurements. 

You could say you are changing two things at the same time, just ignoring one of them because it is very small and the other is very big, but there must be some potential accuracy improvement by only changing one thing at a time.



---In ukmicrowaves@..., <drkirkby@...> wrote :



So why do some kits have 0 and 1/4 shorts, and others have 1/8 and 3/8 shorts?

There must be some advantage in the 1/8 and 3/8 wave method, since it
is simpler to make the 0 and 1/4 shorts.

I guess I am going to have to spend some time trawling the IEEE
microwave journals to see the difference. But on the off chance anyone
knows, please fill me in.

At some point I will try a P-band calibration myself with both methods
and compare them. But does anyone know of a theoretical advantage of
the 1/8 and 3/8 method?

Dave


Re: Activity List for the Low Band Contest on Sunday 4th May - M0HNA/P

Pete - GM4BYF
 

Callsign: GM3HAM/P; GM4BYF/P
Locator:IO74WV
Bands: 1.3GHz 80W – 57 elements call GM3HAM/P
2.3GHz 120W – 1.3m dish GM4BYF/P
3.4GHz 60W – 1.3m dish GM4BYF/P
Talkback: 144MHz , KST (not reliable from this location) for skeds phone Pete 07769 822648
Times: whole contest (Wx permitting!!)

 

Sent: Thursday, May 1, 2014 3:15 PM
Subject: [ukmicrowaves] Activity List for the Low Band Contest on Sunday 4th May - M0HNA/P
 
 

Looking forward to better activity than the April event.
We will be calling CQ on 1296.245 (+/- QRM) throughout.

Callsign: M0HNA/P
Locator: IO91RF
Bands:
1.3GHz - 250W to 4 x 35ele
2.3GHz - 60W to 90cm dish
3.4GHz - 15W to 70cm dish
Talkback: KST (one login for 23cm and another for 13/9cm)
Times: Throughout


73, Phil G3TCU (on behalf of G1EHF, G4SJH, G3TCT & G3WBQ)


On 25/04/2014 14:04, G3XDY wrote:
 

Another Low Band contest is coming up on Sunday 4th May, coincident with
the latter stages of the RSGB event the same weekend. This is also an
IARU coordinated date, so there will be good activity from the continent.

Please send details of your operating plans in the usual format, as
below, and I will endeavour to get the list out on Friday evening.

Callsign:
Locator:
Bands: 1.3GHz
2.3GHz
3.4GHz
Talkback:
Times:

I won't be able to take part due to family commitments, but wish you all
good luck and good DX.

73

John G3XDY

---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com



Activity List for the Low Band Contest on Sunday 4th May - M0HNA/P

Phil Guttridge G3TCU
 

Looking forward to better activity than the April event.
We will be calling CQ on 1296.245 (+/- QRM) throughout.

Callsign: M0HNA/P
Locator: IO91RF
Bands:
1.3GHz - 250W to 4 x 35ele
2.3GHz - 60W to 90cm dish
3.4GHz - 15W to 70cm dish
Talkback: KST (one login for 23cm and another for 13/9cm)
Times: Throughout


73, Phil G3TCU (on behalf of G1EHF, G4SJH, G3TCT & G3WBQ)


On 25/04/2014 14:04, G3XDY wrote:
 

Another Low Band contest is coming up on Sunday 4th May, coincident with
the latter stages of the RSGB event the same weekend. This is also an
IARU coordinated date, so there will be good activity from the continent.

Please send details of your operating plans in the usual format, as
below, and I will endeavour to get the list out on Friday evening.

Callsign:
Locator:
Bands: 1.3GHz
2.3GHz
3.4GHz
Talkback:
Times:

I won't be able to take part due to family commitments, but wish you all
good luck and good DX.

73

John G3XDY

---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com



VNA waveguide calibration - 0 + 1/4 wavelength shorts vs 1/8 and 3/8 wavelength offset shorts.

Dr. David Kirkby <drkirkby@...>
 

There are lots of ways of calibrating vector network analyzers.
Typically, one uses 3 standards for a one-port calibration.

* Load (absorbs 100% of power).
* Reflection standard #1, reflects 100%
* Reflection standard #2, reflects 100%, but at a phase that is
ideally 180 degrees different from reflection standard 1.

In coax, reflection standard #1 is usually a short, and #2 is an open.
So we have

* Load (absorbs 100% of power)
* Open, reflects 100%
* Short, reflects 100%, but at a phase that is 180 degrees different
from the open.

With suitable design, that can work over a very wide frequency range.
(DC to many tens of GHz), though of course no components are
idealized. The short is actually the best defined of the lot.

For waveguide it is different, as leaving a waveguide open does not
result in it reflecting all the signal at a well defined phase.
Instead it radiates most of it, and reflects some at a phase that is
not too easy to predict. Hence you can't use the short/open/load
method in waveguide. Instead two shorts are used and no opens. So one
has

* Load
* Short #1
* Short #2, in a different position to the short #1, with the position
arranged so the phase angle on reflection is 180 degrees away from
the first.

To calibrate over the frequency range of a waveguide, it is impossible
to maintain close to 180 degree phase difference, but one has to put
up with that and do best one can. The positions of the shorts must
take into account the fact that the wavelength is dispersive, so the
wavelength is not the nice simple relationship of coax or free space.

There is a nice little video on YouTube from Maury Microwave which
shows how to calibrate a VNA for waveguide

https://www.youtube.com/watch?v=l_hlrQDcJAo

In that video the Maury Microwave engineer uses two offset shorts. One
is 1/8 wave, and the other 3/8 wave. The difference is 1/4 wave, so on
reflection the signal is 180 degrees out of phase with the incident
signal. He uses a sliding load, which is preferable to a fixed load,
but that can be ignored.

But there is another way of getting the quarter wave difference, which
is easier to make mechanically.

* Use a flush short, with 0 offset. Basically a short screwed right on
the end of the waveguide.
* A quarter wave spacer is then combined with the short, to give
effectively a quarter wave offset short.

So we have two methods

A) 1/8 and 3/8 wavelength - used by some Maury Microwave kits.
B) 0 and 1/4 wavelength. - used by most if not all Agilent kits, and
the "economy" kits from Maury Microwave.

So why do some kits have 0 and 1/4 shorts, and others have 1/8 and 3/8 shorts?

There must be some advantage in the 1/8 and 3/8 wave method, since it
is simpler to make the 0 and 1/4 shorts.

I guess I am going to have to spend some time trawling the IEEE
microwave journals to see the difference. But on the off chance anyone
knows, please fill me in.

At some point I will try a P-band calibration myself with both methods
and compare them. But does anyone know of a theoretical advantage of
the 1/8 and 3/8 method?

Dave


Re: Microwave Amplifiers

Andy G4JNT
 

If th eoutput of any amplifier were 50 ohms, it could inherently never ever possibly be more than 50% efficient.
The most efficient amplifiers would have either zero or infinite ouptut impedance corresponding to a voltage source or a current source respectively.
 
Practical designs fall somewhere in between.    How can you measure the output impedance of a high power  amplifier anyway?  Load pull ?
 
Andy
G4JNT

On 1 May 2014 11:58, Matthew Twyman <matthew.twyman63@...> wrote:
 

Good Morning
I have followed recent discussion on connectors and cables with interest.
I wonder how many people have measured the output impedance of a microwave amplifier
and been surprised to find if there is no isolator fitted how far from 50R it is.
As I am constantly telling myself the important thing is to be QRV....
Having spent a fruitless afternoon some years ago trying to repair gore cables I realise this is something's best left to the manufacturer.
Going to visit G3OHM at weekend for some inspiration....
Best wishes
Matthew GW6KOA



Re: Microwave Amplifiers

Christopher Bartram <cbartram@...>
 

Hello Matthew

<I wonder how many people have measured the output impedance of a microwave amplifier >

Yes, it's done all of the time! It's usually measured as an s-parameter and called s22.

<and been surprised to find if there is no isolator fitted how far from 50R it is>

That's not surprising. As you seem to be talking about power amplifiers, it's very important to appreciate that unless it's a class-A amplifier, it will be designed to deliver power into a load, not to match it. This is why class-B, C, D, and E amplifiers are more efficient than class-A amplifiers.

Isolators aren't the only way to avoid a poor output mismatch. One of the most common ways is to combine a pair of identical amplifiers between quadrature hybrids. In this case the output hybrid sums the RF input power into the load whereas power either reflected into or arriving at the summing port of that output hybrid will be directed to the it's termination. That means that the outside world sees a good mismatch. The technique has a number of important applications.

<As I am constantly telling myself the important thing is to be QRV....>

I agree. Perhaps sometime soon!

<Having spent a fruitless afternoon some years ago trying to repair gore cables I realise this is something's best left to the manufacturer.>

Microwave cable repair can be difficult. Gore cables seem to be amongst the most difficult of the difficult, as both their cables and connectors are proprietary. I've also tried ...

Give my regards to the guys at the Carmarthen Club. I hope to get to at least one more meeting before I finally move.

Vy 73

Chris
GW4DGU



--
Christopher Bartram MIET
Christopher Bartram RF Design
37 Mortimer Road
MONTGOMERY SY15 6UP

phone: +44 1686 669017
mobile: +44 7545 094490
email: cbartram@theiet.org
URL: www.christopherbartramrfdesign.com

Note: This message is for the named person's use only. It may contain confidential, proprietary or legally privileged information. No confidentiality or privilege is waived or lost by any mistransmission. If you receive this message in error, please immediately delete it and all copies of it from your system, destroy any hard copies of it and notify the sender. You must not, directly or indirectly, use, disclose, distribute, print, or copy any part of this message if you are not the intended recipient. Christopher Bartram RF Design reserves the right to monitor all e-mail communications through its network. Any views expressed in this message are those of the individual sender, except where the message states otherwise and the sender is authorised to state them to be the views of any such entity.