Date   

Re: 432...... digitise ??

Andy Talbot <andy.g4jnt@...>
 

Can't find any details on the 432 B/C, but I suspect they used a A/D
on the processed 1V output. Resurrected my old serial port A/D
(early generation PIC with 8 bit digitising to 115200 baud RS232 as
publish in RadCom a decade or so back) and threw together a VB prog
this afternoon to give a digital display from the 1V recorder output,
just for the satisfaction of doing it, really. Resolution wasn't very
good as the A/D FSD was 5V and couldn't be changed, so only about 6
bits of useable resolution. Only a toy as range switching is still
needed.

The real solution is to use a pair of high resolution A/Ds with a
seriously good calibrated reference measuring the V+ and V- outputs
from the back, then calculate the power from first principles,
bypassing the 432's internal analogue computer. Tested the concept
using that 6 digit DVM I bought from you and the calculated power was
within 0.1dB of what it showed on the analogue display when set to the
correct range and zeroed. But down at the -25 to -20dBm region, the
voltages on the V- port are minute. Digitising that accurately will
be a real challenge to low DC offset design!

I well-remember having to use BCD data, driving 7447s and 7-seg
displays. Back in the days before micros/PICs made things so simple.
Whole boards of TTL just to generate a simple display function.

Andy G4JNT

2008/7/19 Alan Melia <Alan.Melia@btinternet.com>:

Hi Andy it has already been done see the 432B/C which even has a digital
output in "sensible" BCD TTL :-)) if you remember that!

Alan G3NYK

--
Andy G4JNT
www.scrbg.org/g4jnt


Re: Emley Moor South

Peter Day <microwaves@...>
 

Richard Newstead wrote:
--- In ukmicrowaves@yahoogroups.com, Peter Day <microwaves@...> wrote:

Did you go to the trig point at Cowper Stone?
Peter
I am sorry to report that we were at the trig and when I said that the mast was loS, I meant that we could see it (easily). At only 18 miles distance it should have been a huge signal even with just a few milliwatts but it wasn't particularly strong.

Thanks for the clarification Richard. In that case the beacon has a serious fault or has been damaged, as I heard it quite well the last time I was out a few months ago. What we need now is someone to build a new beacon and for me to organise it's installation by a couple of the people I know who work there. Just today I was at our local Sheffiele Ham Fun day (ugh.. I hate that word ham!!)and met an old 10GHz wideband pal of mine who is now working at Emley. At present he is undergoing the training for access to the tower so he'd be the ideal person to swap a new beacon for the old one. The question is.. who's going to build it? Don't ask me ..I've no spare time:-)

I drove up that way several times in attempts to hear it when I was experimenting with wideband. I am now not at all surprised that it was not audible! I have alse been at Axe Edge when rain should have allowed easy reception of Emley but heard nothing.
I assume that the North beam is a separate system as it is on a different frequency?
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Yes! I warm weather the southbound beacon drifts aross the northbound one like a lunar eclipse!

73

Peter G3PHO


Re: 10GHz Cumulative

David Ackrill <dave.g0dja@...>
 

Richard Newstead wrote:
A while back I offered to take someone along for the next 10GHz cumulative (next Sunday). There have been no takers so far. If anyone wants to join me they will be very welcome. I don't envisage being out for more than about 2 hours (in the morning) so it wont be too onerous; it might even be fun.

Where are you planning to go to Richard? If it's not to far away, I might come along to see how things go.

However, I'm very out of shape from the days when I used to go hiking and climbing, so I might not try to keep up whilst you yomp off up a hill. :-)

Dave (G0DJA)


Re: FS: HP 432A c/w head and cable

Richard Newstead <g3cwi@...>
 

--- In ukmicrowaves@yahoogroups.com, mikeg3pfr@... wrote:
I'm not interested in
measurements to
the last 0.1dB...relative measurements in a short time-span are
good enough
for me. I shall now go out and look for heads beyond 18GHz (my
present limit)

Mike

If you can spare time from your busy measurement schedule I would
love to have a contact on 10GHz sometime!

73

Richard
G3CWI


10GHz Cumulative

Richard Newstead <g3cwi@...>
 

A while back I offered to take someone along for the next 10GHz
cumulative (next Sunday). There have been no takers so far. If anyone
wants to join me they will be very welcome. I don't envisage being
out for more than about 2 hours (in the morning) so it wont be too
onerous; it might even be fun.

Don't be put off by my previous reports. I exaggerate massively. The
reality is that my butler drops me on all these hilltops in my
helicopter. If only.

73

Richard
G3CWI


432...... digitise ??

Alan Melia
 

Hi Andy it has already been done see the 432B/C which even has a digital
output in "sensible" BCD TTL :-)) if you remember that!

Alan G3NYK


Re: FS: HP 432A c/w head and cable

mikeg3pfr@...
 

In a message dated 19/07/2008 18:36:29 GMT Standard Time, g3cwi@... writes:
If you can spare time from your busy measurement schedule I would
love to have a contact on 10GHz sometime!
 
Richard,
 
I'd love to *but* at the moment I'm not operative on 10G NB. However, Tim, M0SIN, who is local to me, has a DB6NT set-up which is portable and potent in RX terms (<1dB preamp and ProCom dish/feed), although the TX power is "barefoot" (ca200mW?). Might be worth an attempt from our radio club site at Cotebrook (MIDCARS) - Tim expects to be there next Wednesday evening from approx. 19.30hrs to 22.30hrs, with the eqpt. as we have an ongoing experiment to monitor GB3XGH (using Spectran) from a very indifferent site..
 
I've taken the liberty to send a copy of this email to him, and maybe he'll respond. (Tim it's up to you, now - I'll come out to some local spot with you and be delighted to assist)
 
Regards, Mike, G3PFR


Re: Who was calling on CW at 13:45 Local?

Eddie G0EHV
 

--- In ukmicrowaves@yahoogroups.com, "Richard Newstead" <g3cwi@...> wrote:

I went up to axe edge this lunchtime on 10GHz. No QSOs but I did hear
a few characters of CW on 10368.100 at 13:45 local. Was it anyone
here I wonder?

73

Richard
G3CWI
Richard,
I was either myself G0EHV or much more likely Rob M0DTS.

I've just completed my 1st rainscatter QSO from home (IO94FU)!

Indoor 35 cm dish, pointing through double glazed unit partially open.
Reflecting at 45 degrees off the pane toward the North Sea rain clouds
at just South of East. Elevation about 15 degrees.

Power 1 watt here, 10 watts from Rob. Exchanged 52/57 reports.

Talkback on 13 cms TV from me via GB3KM ATV repeater. Talkback from
Rob was a mix of 13 and 3 cms ATV via the repeater. We do do things
the hard way up here!

I can send you a picture if you wish of set up here.

Rob did listen for you but nothing heard.

Regards,
Eddie
G0EHV


Who was calling on CW at 13:45 Local?

Richard Newstead <g3cwi@...>
 

I went up to axe edge this lunchtime on 10GHz. No QSOs but I did hear
a few characters of CW on 10368.100 at 13:45 local. Was it anyone
here I wonder?

73

Richard
G3CWI


Re: FS: HP 432A c/w head and cable

mikeg3pfr@...
 

In a message dated 19/07/2008 13:00:29 GMT Standard Time, G3at@... writes:
Absolutely the same here.
Swapped my HP432 system, with a full set of heads to 50GHz, because I have an HP435 with heads to 26.5GHz. Worst thing I ever did. If you have a HP432 and heads, keep them for the reasons already given. 2/5 year rule or not............
Hi Sam
 
Well if I "pop me clogs" before you - ring and you can have your 432 back - but not before
 
Absolutely, guys! I wouldn't part with mine for a gold clock!!! Simple and reliable, not a lot to go wrong. Anyway, I'm not interested in measurements to the last 0.1dB...relative measurements in a short time-span are good enough for me. I shall now go out and look for heads beyond 18GHz (my present limit)
 
Regards, Mike, G3PFR


Re: Sheffield R/ T

SAM JEWELL
 


Another good one is.
If you see it and you REALLY need it. Buy it now, 'cause it won't be there when you come back!

OK. That's home-spun enough philosophy  from me.

Sam



----- Original Message ----
From: David Robinson
To: ukmicrowaves@...
Sent: Saturday, 19 July, 2008 2:03:33 PM
Subject: [ukmicrowaves] Re: Sheffield R/ T

that one was started at Dayton 5 years ago, and as you say has saved a
lot of money since; probably enough for my sdr1000!

Dave

> Another good credo is 'when at a rally/flea market, if it doesn't
solve an immediate problem, don't buy it.'  You don't need it!
> It's amazing how useful and money-saving this last one is.....
>
> Sam
>
>
>




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Re: Sheffield R/ T

G4FRE
 

that one was started at Dayton 5 years ago, and as you say has saved a
lot of money since; probably enough for my sdr1000!

Dave

Another good credo is 'when at a rally/flea market, if it doesn't
solve an immediate problem, don't buy it.' You don't need it!
It's amazing how useful and money-saving this last one is.....

Sam



Re: FS: HP 432A c/w head and cable

G4FRE
 

mine did

Dave

ww2r

--- In ukmicrowaves@yahoogroups.com, SAM JEWELL <jewell@...> wrote:
I wonder if it will indicate at 134GHz, since it will do 122GHz?

73 de Sam



----- Original Message ----


Re: FS: HP 432A c/w head and cable

Andy Talbot <andy.g4jnt@...>
 

To save anyone Googling, here's one reference...

http://www.xertech.net/Tech/Pwr_Mtr/Pwrmtr_main.html


2008/7/19 Andy Talbot <andy.g4jnt@googlemail.com>:

Ahhh - so that explains a few things that felt wrong. I was wondering
how the DC substitution techniqe could possibly be made stable enough
using thermal heads to measure down to -50dBm, even using the latest
chopper stabilised opamps etc. And to do it so well just a decade or
so later.

Will go and find the AN64s now...

Andy G4JNT
www.scrbg.org/g4jnt



Sorry to cross swords etc, but the 435 etc. are quite a different
breed to the 431/2 series and although the 435/6/7/8 etc do have a
second thermocouple, it is only concerned with temperature
balance, not a dc substitution like the 431/2 meters.

The thermocouple sensors benefit for much better stability than
the thermistor sensors due to ~20 years design improvement - the
new diode sensors are another order better still in terms of
stability.

Regarding the zero drift of the recorder circuitry, I think that
you will find this to be directly related to the sensor thermal
drift.

The old HP AN64-1 through -3 gave a considerable amount of info on
the various systems. I believe it has been re-written and is
available on the net.
--
Andy G4JNT
www.scrbg.org/g4jnt


Re: FS: HP 432A c/w head and cable

Andy Talbot <andy.g4jnt@...>
 

Ahhh - so that explains a few things that felt wrong. I was wondering
how the DC substitution techniqe could possibly be made stable enough
using thermal heads to measure down to -50dBm, even using the latest
chopper stabilised opamps etc. And to do it so well just a decade or
so later.

Will go and find the AN64s now...

Andy G4JNT
www.scrbg.org/g4jnt


Sorry to cross swords etc, but the 435 etc. are quite a different
breed to the 431/2 series and although the 435/6/7/8 etc do have a
second thermocouple, it is only concerned with temperature
balance, not a dc substitution like the 431/2 meters.

The thermocouple sensors benefit for much better stability than
the thermistor sensors due to ~20 years design improvement - the
new diode sensors are another order better still in terms of
stability.

Regarding the zero drift of the recorder circuitry, I think that
you will find this to be directly related to the sensor thermal
drift.

The old HP AN64-1 through -3 gave a considerable amount of info on
the various systems. I believe it has been re-written and is
available on the net.


Re: SCP calculation

bart_ghz <shf2@...>
 

Tnx for theVery fast replies with interesting info.
73 de on7bv



--- In ukmicrowaves@yahoogroups.com, Rainer <df6na@...> wrote:

http://home.hccnet.nl/uffe.noucha/radar3.htm

bart_ghz schrieb:

Hello,

During the last contest i made some RS qqso's on 10 GHz.
I had internet acces and had pictures of the rain radar on my pc.
But some station asked to make qso via a SCP.
How do they calculate the scp point?Is it experiance or just
logic
thinking or do they have a locator overlay over those rain radar
pictures.


HP 432A as an optical detector

Christopher Bartram <cbartram@...>
 

Hello All

I was intrigued by Sam's observation that he could see a flash lamp with his
432. I've just tried shining a laser (which as a narrowband optical source
won't have the IR radiation of an incandescent bulb, suggested by Geoff...)
into my R486 26 - 40GHz sensor. I can detect the laser, and making a very
rough head calculation, the calibration is probably not that far out..!

Vy 73

Chris
GW4DGU


Re: SCP calculation

DF6NA Rainer
 


Hello,

During the last contest i made some RS qqso's on 10 GHz.
I had internet acces and had pictures of the rain radar on my pc.
But some station asked to make qso via a SCP.
How do they calculate the scp point?Is it experiance or just logic
thinking or do they have a locator overlay over those rain radar
pictures.


Re: SCP calculation

Richard Newstead <g3cwi@...>
 

--- In ukmicrowaves@yahoogroups.com, "bart_ghz" <shf2@...> wrote:
do they have a locator overlay over those rain radar
pictures.
http://home.hccnet.nl/uffe.noucha/weurope.htm


Re: FS: HP 432A c/w head and cable

Geoff Blake <geoff@...>
 

On Sat, 19 Jul 2008, Andy Talbot wrote:

Talking of the 432 power meter, I was considering adding a pair of A/D
converters to measure the two outputs from the BNCs on the back to
give a digital readout with automatic power scaling and zeroing. Had
intended using the raw V+ and V- voltages supplied from the head and
my own digital calculation of the power rather than the internally
generated value 1V recorder output which is subject to zero drift.
Looking at the equations and accuracy needed, it would require at
least 14 bit A/Ds to realise the same sort of resolution that their
internal electronics manages though a pulse width modulator design.

For an analogue processor (actually an analogue computer) design based
around 1960's technology, that is a really impressive performance.
It works on thermal power-balancing in the head, and all subsequent HP
power meters of the similar type-no family like 435 etc do too. They
benefit from more modern devices and can hence go lower in power and
maintain a better zero offset. Better head design also means they
don't go pop when you feed 100mW into them! You may be thinking of the
other sort of power meter, the diode type? They wouldn't keep the 432
as such - no one uses discrete transistor opamps and chopper
multipliers now! I think you probably mean they keep the 400 family
going? The 435 / 436 / 437 (we have several at work) are quite a lot
nicer than the 432 with digital readout, auto zero, auto ranging with
le -30 to +20dBm coverage rather than my 432's -20 to +10dBm range -
hence the attempt to digitise it.

I've popped the head of my 432 twice, so keep a permanent (calibrated)
20dB attenuator taped onto it, and just sacrifice the ability to
measure much below 5dBm. A home made diode power meter using a good
quality HP detector diode is good for low power measurement anyway,
covers -50 to 0dBm with good accuracy and its calibration can be
checked against the 432 at any time.
Andy,

Sorry to cross swords etc, but the 435 etc. are quite a different
breed to the 431/2 series and although the 435/6/7/8 etc do have a
second thermocouple, it is only concerned with temperature
balance, not a dc substitution like the 431/2 meters.

The thermocouple sensors benefit for much better stability than
the thermistor sensors due to ~20 years design improvement - the
new diode sensors are another order better still in terms of
stability.

Regarding the zero drift of the recorder circuitry, I think that
you will find this to be directly related to the sensor thermal
drift.

The old HP AN64-1 through -3 gave a considerable amount of info on
the various systems. I believe it has been re-written and is
available on the net.

73 Geoff

--
Geoff Blake G8GNZ located near Chelmsford, Essex, U.K.
Please reply to: geoff(at)palaemon(dot)demon(dot)co(dot)uk
Using Linux on Intel & Linux or NetBSD on Sun Sparc platforms

Please avoid sending me Word or PowerPoint attachments.
See <http://www.gnu.org/philosophy/no-word-attachments.html>
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