Date   

Re: Writing articles and RadCom ....

Chris G8BKE
 

I'm also interested in radio controlled electric flying models and
buy a number of magazines associated with this hobby too. What a
breath of fresh air they are. They try to cater for the novice and
advanced hobbyist, but unlike Radcom the articles manage to appeal to
both types of flyer, without being patronising towards either.

Plus there are constructional articles too, as well as reviews of
ready to fly models, to cater for either builder or a buyer.

Yes, there are advertisements too, but these seem to complement the
content rather than just being page fillers and revenue earners.

Radcom could take a lesson from these mags.

73 de Chris G8BKE


Dave Wrigley wrote:-

The content of PEE is good value and quite interesting - it has a
full range
of articles covering all stages of development and is a good all
round read.
Interesting ads too.


Re: SSB 10Ghz transverter manual wanted

g1irg <g1irg@...>
 

Hi Eric
Thanks for the reply at the moment i do not have any info on these
items so i would like to take up your offer and would be greatfull for
any info.
73
Simon

--- In ukmicrowaves@yahoogroups.com, "F1GHB" <f1ghb@c...> wrote:

Hello Simon,

These papers were in VHF COMMUNICATIONS 2/89 and 3/89 by DC0DA.

I have a copy for the Part 2 ( 3/89 ) for the XRM-1 and XTM-1 , I
can "scan" it for you

Unfortunately , some pages are missing in the copy of the part 1 (
2/89 ) about the XLO-1 ( to much used in the past may be... )

Sure they are somewhere here but... where ????

Anyway there is the part list , the PCB views with components ,
but... no schematic . " Scan " possible as well

Please let me know if you want a copy .

73s
Eric F1GHB



----- Original Message -----
From: Simon Manning
To: ukmicrowaves@yahoogroups.com
Sent: Thursday, December 15, 2005 6:17 PM
Subject: [ukmicrowaves] SSB 10Ghz transverter manual wanted


Has any one got a copy of the SSB Electronics
transverter Manuals and circuit for the XLO-1/01 local
oscillator module, the XRM-1 receive down converter,
the XTM-1 transmit up converter.

Simon
G1IRG





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Re: Frequency Standard Crystal filters

David Wrigley <davidwrigley@...>
 

Hi Malcolm,

£67 + VAT is outrageous. If you wanted a 60KHz crystal it would be less than
£10.

We had this problem a few years ago and Mike Scott designed a trf receiver
using several TOKO tuned ccts instead of the crystal. I can let you have
this cct if you haven't seen it.

However since that time and after playing with such a receiver I have
reached the conclusion that a better design would be a superhet. Now I
realise that a superhet would require a super stable LO but this could be
derived form the 10MHz freq std......

Regards
David Wrigley

-----Original Message-----
From: ukmicrowaves@yahoogroups.com [mailto:ukmicrowaves@yahoogroups.com] On
Behalf Of g0mic@aol.com
Sent: 16 December 2005 00:27
To: ukmicrowaves@yahoogroups.com
Subject: [ukmicrowaves] Frequency Standard Crystal filters

Hi all,

I am looking for a 198 KHz crystal filter to finish an off air frequency
standard project. Does anyone know of a source of 198 KHz crystals at a
sensible price, say under £10, please? So far I have been quoted a price of
£67 +VAT each with a minimum order of 5 pieces!

Alternatively a source of the Halcyon units that were available a while back
at unde £50 to do the same job

TIA Regards

Malcolm G0MIC

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Re: Writing articles

David Wrigley <davidwrigley@...>
 

Yes Alan

The point you make, I learnt from an older lecturer a long time ago when I
taught part time in a technical college - the best teachers are those who
understand the problems of their students - not those whose mind is on
higher things.

Anyway Amateur radio is a pastime not a profession, it should be about
having fun - enjoying a laugh - sometimes about how we made a big mistake -
and I've made plenty. You know what they say - if you ain't making mistakes
then perhaps you ain't doing anything.

Very often a problem that you have struggled for days over turns out to be
something you assumed - There is a saying "It ain't what you don't know -
it's what you know that ain't so". Just that piece of wire perhaps that
isn't making the connection that you thought it did.

As a Professional Engineer turned Amateur, I can mess about all day making
measurements and trying things and in the end achieve nothing other than to
advance my own knowledge. I'm still learning at 67 and the one thing I know
is that life is too short to do everything I want to do.

Well perhaps after all these lectures from others on the need for us to be
writing articles maybe I will write a few things down for the benefit and
perhaps amusement of others.
- but only if I have some fun or satisfaction from doing it!!

I hope Conrad gets a lot of satisfaction from his degree course.

73 David G6GXK

-----Original Message-----
From: ukmicrowaves@yahoogroups.com [mailto:ukmicrowaves@yahoogroups.com] On
Behalf Of Alan Melia
Sent: 16 December 2005 00:18
To: ukmicrowaves@yahoogroups.com
Subject: [ukmicrowaves] Re:Writing articles

Hi Conrad, please do not let yourself be put off telling us how you solved a
problem..... climbed a hurdle ....tripped over a well known trap. Just
think how many guide books there are written to cover a particular part of
the world. Everyone looks for something different, everyone sees something
different.

If you follow the news groups and other special interst groups, there have
been a couple of guys who have taken the time to describe how they have
tracked down and solved a problem on some old (and much loved ) test gear. I
found these particularly instructive although I dont have the equipment
described. What was quite amazing was the shower of replies from other
appreciative readers, many of them "professionals".

Whilst technical articles written by professionals are polished they do not
always provide the practical detail that some of us find useful (why you did
it that way, and not another way) It does not matter if your solution is not
optimum, it works !! We can always hone an idea later to get the last 0.1dB.
Long ago at University I found some of the best lecturers were recent
Post-grads who had struggled a little themselves and appreciated that some
of the topics were a little difficult to grasp. They went the "extra mile"
to explain in an understandable way, whereas the Prof would often look
confused at how someone could fail to grasp such a "simple concept" !!

Remember it is nice to be able to stand on the shoulders of giants, but some
of us need a leg up from lesser mortals !! Please share you agonies, and
successes with us. I am sure Peter will appreciate your efforts. This, and
the informed feedback it generates, is how we all (well most of us) learn. I
may be ex BTRL but I am a semiconductor man not a radio engineer, and have a
lot yet to learn.

Best Wishes de Alan G3NYK






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Re: Writing articles and RadCom ....

David Wrigley <davidwrigley@...>
 

Hi folks

Well I just picked up a copy of Everyday Practical Electronics for £3.30
from our local Billy Smiths. They also had Practical Wireless - but I
resisted that.

The content of PEE is good value and quite interesting - it has a full range
of articles covering all stages of development and is a good all round read.
Interesting ads too.

I actually bought it for the article on Hall effect measurement - just what
I wanted - an intro example application. This mag is really being
competitive in a very competitive area.

Does anyone know what the circulations of the QST and of RadCom are? The
reason I ask is the the ARRL's test facilities appear to be much better than
those of the RSGB.

I have read the technical reviews of the ARRL and I am impressed by their
detail technical content. Compare that with the Microphone test published
in this months Rad Com - conclusion - spend £120 on a desk mike and it
should sound OK, spend anything less and perhaps not so good. I'll bet you
could get results just as good with a second hand mic from a camcorder -
cost zilch - in fact just for a bit of devilment I think I'll try it. I
have some JVC ex camcorder mics - I'll do some tests - and compare them with
the Standard Yaesu types.

Incidentally the "Test" involved nothing more than a subjective listening
test with a series of unnamed respondents and it was not clear whether they
were the same ones for each mic. Maybe interesting but this is not what I
would describe as a scientific approach.

-----Original Message-----
From: ukmicrowaves@yahoogroups.com [mailto:ukmicrowaves@yahoogroups.com] On
Behalf Of mikeg3pfr@aol.com
Sent: 15 December 2005 23:06
To: ukmicrowaves@yahoogroups.com
Subject: Re: [ukmicrowaves] Re: Writing articles

In a message dated 15/12/2005 22:53:01 GMT Standard Time,
eightgoes@yahoo.co.uk writes:

But who would buy it at the cover price shown of £4.25 when there
are
cheaper and much better value magazines there?!


Chris,

Probably some, since it not uncommon for many mags. to be £4+. The "cover
price" is nominal because 12 x £4.25 = £51, which is a lot more than the
RSGB sub.

Not that it's worth it (unlike L'Oriale)!

Regards, Mike, G3PFR




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Re: Question for the holiday season

Uffe Lindhardt <uffe.noucha@...>
 

I do not accept the term "path loss". In most cases the propagation
of radio signals is rightly assumed to be lossless. The energy is
spread, but isn´t lost. Is "path attenuation" a better term ? or my
preferrred one: "path gain" expressed as a negative number ?

73 Uffe PA5DD

--- In ukmicrowaves@yahoogroups.com, Talbot Andrew <actalbot@m...>
wrote:

To get away from the Comic bashing that has taken up a lot of this
reflector's bandwidth recently...

The following conumdrum reared its head during a discussion around
the
whiteboard with a PhD software-type engineer trying to understand
RF.

Here it is :

Each of the following statements is true.

1) "RF transmission path loss increases with frequency."

2) "RF transmission path loss decreases with frequency."

Discuss :-)



Andy G4JNT






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November Low-Band contest entries

g4knz <g4knz@...>
 

Sorry for the delay in giving this,

Entries from the November low-band contest received from the following:

M0GHZ, G0JMI/P, G0UPU, G1EHF, GW3HWR, G3PHO/P
G3TCU/P, G3XDY, G4BEL, G4BRK, G4EAT, G4HUP, G4LDR

There were no postal entries. If anyone else sent an entry and it is
not listed above, please let me know asap.

Steve G4KNZ.


Re: Question for the holiday season

Mike Willis <m.j.willis@...>
 

Talbot Andrew wrote:

To get away from the Comic bashing that has taken up a lot of this reflector's bandwidth recently...

The following conumdrum reared its head during a discussion around the whiteboard with a PhD software-type engineer trying to understand RF.
Here it is :

Each of the following statements is true.

1) "RF transmission path loss increases with frequency."

2) "RF transmission path loss decreases with frequency."

Discuss :-)
How about -

1 RF path length increases with frequency
2 RF path length is constant with frequency
3 RF path length decreases with frequency

discuss...



Andy G4JNT



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Re: RE Question for the holiday season

Gaëtan Horlin <on4khg@...>
 

Free space and in vacuum (if vacuum not already "included" in free space)

----- Original Message -----
Sent: Friday, December 16, 2005 2:52 PM
Subject: RE [ukmicrowaves] Question for the holiday season

   1)    "RF transmission path loss increases with frequency."
    2)    "RF transmission path loss decreases with frequency."
  Discuss :-)

I have a 3rd option , RF transmission path loss is constant watever
frequency....( free space I mean)


RE Question for the holiday season

F6DRO
 

1) "RF transmission path loss increases with frequency."
2) "RF transmission path loss decreases with frequency."
Discuss :-)

I have a 3rd option , RF transmission path loss is constant watever
frequency....( free space I mean)


Question for the holiday season

Talbot Andrew <actalbot@...>
 

To get away from the Comic bashing that has taken up a lot of this reflector's bandwidth recently...

The following conumdrum reared its head during a discussion around the whiteboard with a PhD software-type engineer trying to understand RF. 

Here it is :

Each of the following statements is true.

    1)    "RF transmission path loss increases with frequency."

    2)    "RF transmission path loss decreases with frequency."

  Discuss :-)

 

Andy  G4JNT

 

 

"The Information contained in this E-Mail and any subsequent correspondence"
"is private and is intended solely for the intended recipient(s)."
"For those other than the recipient any disclosure, copying, distribution, "
"or any action taken or omitted to be taken in reliance on such information is"
"prohibited and may be unlawful."


Re: Question for the holiday season

f5efd
 

Dans un e-mail daté du 16/12/2005 18:39:26 Paris, Madrid, uffe.noucha@... a écrit :
I do not accept the term "path loss". In most cases the propagation
of radio signals is rightly assumed to be lossless. The energy is
spread, but isn´t lost. Is "path attenuation" a better term ? or my
preferrred one: "path gain" expressed as a negative number ?
And the power consumption of your transmitter as negative power generation ?
 
 73
       Maurice  F5EFD


Re: Radcom and something to think about over Christmas

Martyn G3UKV
 

Very well written, Peter.
As an editor of umpteen years doing a bi-monthly Club Newsltter, I know what it's like getting input. However, I'm grateful for what I get, and have been known to 'lift' bits of articles to fill a gap or two.
RSGB-Bashing of course is a hobby in its own right. I well remember the editor of SWM, Arthur G6FO, used to devote pages to this hobby, and then a few years back there was the UKRS, which eventually fell apart with lots of recriminations. They (mis-)used Packet Radio to promote their vitriole.

I prefer to support our National Society, warts and all. Over the years, they have achieved a lot - BR68 is a testimony to that.
The latest RSGB Handbook is far better than I expected (pity about the commercial illustration on the cover), and particularly chapters 3, 6, 8 9, 10, 14, 19 and 26 are good bedside reading. (check them out !). The articles cover the whole range of construction from a humble balun to complete transceivers. Weblinks are provided and so on.
The £5 'loyalty voucher' (for those with 10+ years membership) was a good innovation too.

Anyway, - enough....this is supposed to be a MICROWAVE REFLECTOR.

Have a good Christmas all.

73 Martyn G3UKV

----- Original Message -----
From: "Peter Day" <microwaves@blueyonder.co.uk>
To: <ukmicrowaves@yahoogroups.com>
Sent: Thursday, December 15, 2005 3:26 PM
Subject: [ukmicrowaves] Radcom and something to think about over Christmas


Hello folks,

In my reply to this thread please be aware, from the outset, that I am not
employed or paid by RSGB to say what follows :-)

I've followed the thread with much interest and concern. All of the
criticism of Radcom on this reflector seems to come from people who are
professionally involved in electronics of some sort and of whom some seem
to me to have tunnel vision! Please spare a thought for those of us who
came into amateur radio from a totally different direction ... read on!

David Wrigley wrote:

Part of the problem is that we are getting so specialized and sophisticated
that only our own mag is likely to satisfy us.
Exactly! Such mags exist mags ... QEX for example. VHF Comms and Dubus
ought to do the same for those of interested in the spectrum above 144MHz.
Notice I said "ought to do" :-)

I don't think the AF amp
presented on vero board is really anywhere near the standard we are looking
for. I think it does however probably indicate the level of the mass of
newcomers to the pastime.
I justify it being in Radcom for that very reason. Those of us who are not
professional engineers were all at this level once. Lots of beginners,
SWLs, M3s read Radcom. We mustn't make the mag too technical for them but
at the same time we need some pages of much more advanced stuff for the
more technical members. However getting the balance right is another thing!


In other professional mags.
^^^^^^^^^^^^^^^^^^^^

By this you imply Radcom is a also professional mag! I'm sure you didn't
mean to do so David :-)

I hope Radcom never does try to become a professional mag because it is for
an amateur pursuit or hobby, not a profession. Aren't we in danger of
trying to elevate amateur radio to something that is isn't and should never
be? If we on this reflector are not careful, we'll confirm in the minds of
those on the fringe of the "hobby" that we are indeed the secret and
elitist group that many believe.

I've noticed that they [other professional mags] have a range of articles
to suit each stage of development.
I'm sure Radcom editorial department *try* to do this.

Also an educational feature - perhaps on
a topical subject to bring us up to date. Sam's article on 3rd order
intercept was that sort of thing
Gentlemen, the solution is in our hands... like any other amateur hobby
publication, RadCom relies on reader input. They can only publish what we,
the existing subscribers, send to them. I have exactly the same problem
with Scatterpoint. You can't expect the editorial staff at Radcom to write
the articles for you. In the same way, you can't expect me to write the
whole of Scatterpoint (although I once had to!)

It's the same old story... you only get out what you put in. Put in less
and you won't get out more.

So, all you professional, technical people out there get busy and write
something!

Also please keep in mind that Amateur Radio is a broad spectrum hobby. I
believe it *IS* a hobby/spare time pursuit and not what I feel many of you
folk "in the industy" would like it to be ...an extension of your
professional life :-) If you want professional type tech articles then read
the professional mags (Microwave Journal, etc) that cater for you. The rest
of us, lowly ex schoolteachers, bin men, taxi drivers, etc, are not as
technically clued up as those of you who work for BT, NTL and the like.
Our National Society has over 20 thousand members and a large percentage of
them are not all like some of you, professional electrical/electronic
engineers. So please give them a break. If an article on making a 14MHz
dipole is not to your taste then read QEX instead. I gave up QEX (excellent
though it is) because it wasn't down to earth and practical enough for me
... far too much theory and not enough practical.

Ideally, I'd like Radcom to have lots more practical construction articles
... modern gear with circuits, component layout, parts list with
suppliers and prices, etc and, IMPORTANTLY, little in the way of maths and
theoretical stuff that only serves to put off people trying to build the
gear. If you want theory you'll buy the books with it in. Before I was
licenced in '61, I grew up reading the old PW Mag back in the late 50s. It
was full of such practical articles. You could see exactly where every
component and wire went. The mag was packed with articles from beginner
level to advanced. Sadly that mag eventually went the way of all flesh as
amateur electronics and radio became an appliance hobby. PW had regular
writers who did this stuff for them. Who are the people who write Radcom's
articles? ... you, the readers of course. We need more practical material
from YOU.

I don't believe Radcom should try to emulate the kind of stuff seen in
professional journals. There is much room for improvement though, along the
lines of practical radio projects. I didn't really want to read about
"Eugene the Ham Icon" this month but I'm sure many readers liked the
article. I have to accept the fact that Radcom is not written for just me.
Likewise I have no interest in datacoms, HF operating and ATV but I'm just
one of thousands of members who span a broad range of interests and
abilities so I have to accept pages of irrelevant stuff every month. I'm
certain that Scatterpoint is the same for many readers. We do have PTT
operators on microwaves you know!

BTW, I didn't became a member of RSGB just to receive the magazine.

I can't see us ever turning back the tide of consumer, appliance radio.
Those of you who, like myself, started into amateur radio before the 1960s
had the advantage of entering a hobby where it was necessaary to be able to
make much of your own gear. There was no CB, no Martin Lynch, no Lowe
Electronics. Had there been, I'm certain you and I would have tried CB and
bought much of our gear instead of building it! The same thing is happening
in microwaves today. Lots of people, who don't have the time or the
technical expertise to design and make a system from scratch, now buy ready
made modules from DB6NT and string them together to make a working system.
They may not know the theory of how it all works but they know how to use
it. In fact I'm surprised that Michael hasn't yet brought out a complete
10GHz box that just needs DC and antenna connecting to it. He'd surely sell
lots of them. We on this reflector would then pour wrath and scorn on those
who had descended to the "lowly level" of microwave appliance operator ...
but imagine the increase in activity on the bands! I'm sure it will come
one day. We are going to have to live with with black box radio amateurs
and accept that many of those coming into the hobby these days have little
or no technical backgound. This has to be reflected in the style and
content of the magazines. It's up to existing "experts" or "elmers" to help
the newcomers along the road to being fairly technical proficient. You
could do this by contributing easily understandable articles for Radcom.

There's room in our excellent hobby for everyone, PTT operators and those
who never come on the air because they are too busy building test gear,
writing software, designing preamps with 0.1dB NFs, etc. Personally, I
don't understand why the latter types need an amateur radio licence... they
never operate anyway and could all their work using a dummy load!

To sum up...

Spare a thought for the editorial staff at Radcom... they are not the
hi-tech experts that lurk on this reflector. They can only publish what
they are given. If you can do a better job then offer your services to RSGB.

I have a lot of problems with RSGB but the mag isn't one of them, as I've
been there and got the T shirt.

Happy Crimble,

Peter, G3PHO


Re: Frequency Standard Cr ystal filters

usuallyqrt@...
 

On 16 Dec 2005 at 9:55, Talbot Andrew wrote:

But, why not just get the best OCXO you can lay your hands on?
I agree with Andy. Although you don't get the battery backup the old HP nixie tube counters appear at Junk
sales for £5-10 as everyone turns there nose up at these quality pieces of kit. The oscillator lives behind the
frequency converter plugins with coarse medium and fine frequency adjustment accessible when the plugin
is removed. Inside is the excellent (and well aged) 1 MHz oscillator with selection switch on the back to
give various output frequencies. The oven stays on all the time the unit is plugged into the mains so if your
a casual user then front panel switching on gives you stable immediate output for minimum mains power
consumption. The only downside is whilst its very stable you still need some method of it being set up
correctly. Perhaps you just use it to measure R4 198KHz periodicaly using the 10sec gate time to average
out the wriggles.
73s John.


Re: Frequency Standard Cr ystal filters

Talbot Andrew <actalbot@...>
 

I seem to recall Wireless World (Electronics world, EWW etc etc what ever they call themselves) did an article some years back on using the data from the R4 transmission for a self setting clock.  The data format was covered in detail and I vaguely remember the article stating the phase mod was intentionally forced to give zero mean phase over a transmission frame (?..?), so the frequency standard functionality wasn't compromised.

But, why not just get the best OCXO you can lay your hands on?  Build it into a box with its own PSU and battery back up and never switch it off. A simple 13.8V PSU with 4Ah Pb/H+ battery works fine, and the battery will keep the OXCO going for several hours between power outages.  

Compare periodically aginst R4 if you like, or MSF, or GPS with a scope.   You'll be surprised just how stable a good OCXO can be after its been on for a few months.  In fact, the older the unit, usually the better because the crystal has aged all-the-more.  I think they've all gone to good homes now, but the units from the old Decca Navigator chain were superb as they'd been operating  continuously for > 10 years (Alan ?).  I had one controlling GB3SCX until its PSU outage last June after which it was GPS locked.  During its six months of operation on this, the freq only shifted some 50 - Hz at 10GHz ie.  5in 10^-9.  Which is not very much worse that you'll get from an MSF source, or R4,.  GPS will do better though

At home I've got a bog-standard OCXO from an old HP synth (late 1970s, early 80's?) going 24/7 to re-age it, and continuously compared with the O/P from a commercial GPSDO.  Initially it was quite bad, wobbling +/- 0.5Hz (at 10MHz) but after 2 months it stabilised considerably and the phase meter now just moves slowly over tens of seconds - suggesting sub 10^-8.

Andy  G4JNT



From: usuallyqrt@... [mailto:usuallyqrt@...]
Sent: 16 December 2005 09:27
To: ukmicrowaves@...
Subject: Re: [ukmicrowaves] Frequency Standard Crystal filters


A word of caution in using 198KHz R4 as a frequency standard.  As its never mentioned either everyone
knows, or maybe not.  The 198KHz signal contains a 25Hz +/- 45deg phase mod (or thereabouts as the
BBC failed to supply me with accurate info on enquiry).  You will not see the phase mod if you simply put
the 198KHz into an internally triggered scope as the scope will just follow the signal.  You must externally
lock your scope and by using both beams and maybe even configuring as an xy lisajoe display you can
study the magnitude of the phase mod which is quite gross.  A long time constant will remove the phase
wobble, it appears to get quite asymetric at times but the mean frequency over a period must of course
remain correct, refer to the long time constant approach used in the G4JNT 60KHz system.  A way around
the need for the 198KHz crystal is to divide your PLL reference frequency to 200KHz and mix with the
198KHz producing 2KHz.  A 2KHz RC tuned amplifier works well as a filter.  An FM chip works well as a
limiting amplifier removing the mod on the incoming 198KHz.  Add further capacitance to 455KHz IF coils
for easy 198KHz tuned circuits.  Further divide the reference crystal to 2KHz and apply both to an XOR
gate followed by a very long time constant as above.  This approach gives a very good answer comparing to
an HP Z3801A GPS reference.  Since the stability will suffer at night with the ionospheric effects (although
its still perfectly adequate at night on 10G) I never bothered to publish this arrangement as it was overtaken
by the availablity of OEM GPS modules which of course overcome the nightime effect and also possible
mains sourced interference which effects should not be underestimated on reception.  Lastly capacitance
effects to the antenna if your using a ferrite rod should not be under estimated.  Walking anywhere near a
ferrite rod antenna will pull the phase of the signal.  It will need screening, not with a shorted turn!
73s john.
"The Information contained in this E-Mail and any subsequent correspondence"
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Re: Frequency Standard Crystal filters

usuallyqrt@...
 

A word of caution in using 198KHz R4 as a frequency standard. As its never mentioned either everyone
knows, or maybe not. The 198KHz signal contains a 25Hz +/- 45deg phase mod (or thereabouts as the
BBC failed to supply me with accurate info on enquiry). You will not see the phase mod if you simply put
the 198KHz into an internally triggered scope as the scope will just follow the signal. You must externally
lock your scope and by using both beams and maybe even configuring as an xy lisajoe display you can
study the magnitude of the phase mod which is quite gross. A long time constant will remove the phase
wobble, it appears to get quite asymetric at times but the mean frequency over a period must of course
remain correct, refer to the long time constant approach used in the G4JNT 60KHz system. A way around
the need for the 198KHz crystal is to divide your PLL reference frequency to 200KHz and mix with the
198KHz producing 2KHz. A 2KHz RC tuned amplifier works well as a filter. An FM chip works well as a
limiting amplifier removing the mod on the incoming 198KHz. Add further capacitance to 455KHz IF coils
for easy 198KHz tuned circuits. Further divide the reference crystal to 2KHz and apply both to an XOR
gate followed by a very long time constant as above. This approach gives a very good answer comparing to
an HP Z3801A GPS reference. Since the stability will suffer at night with the ionospheric effects (although
its still perfectly adequate at night on 10G) I never bothered to publish this arrangement as it was overtaken
by the availablity of OEM GPS modules which of course overcome the nightime effect and also possible
mains sourced interference which effects should not be underestimated on reception. Lastly capacitance
effects to the antenna if your using a ferrite rod should not be under estimated. Walking anywhere near a
ferrite rod antenna will pull the phase of the signal. It will need screening, not with a shorted turn!
73s john.


Construction

zl1ujg <zl1ujg@...>
 

Hi ,
I've got the Ailtech 7514 all 100 working again. Multiple failures of
reed relays on the relay board.

I have got a 5760 MHz system going, using N1BWT transverter and EME65
LO (and X 2 multiplier.) Using a 6 watt PA from the Wellington VHF
group.

Had fun tuning the x5 Multiplier on the N1BWT board.(-20 dB down after
tuning of pipecaps and before tuning of MMIC's).
LO came right after tuning. Will be adding an additional RF filter
(from Wellington VHF group)

Made contacts with two stations over 150 to 200 km path. One was LOS
(Anyone got a replacement meter for a IC202.. HiHi)
The other was over an obstructed path (1000 to 1500 ft)
Dish was prime focus and circular horn feed.

A friend of mine is almost finishing a DXR700 transverter. (from the
Wellington VHF Group) He has retuned the multiplier to be a X5,
instead of a x3. This is fed from a 1123.2 MHz crystal osc/
multiplier, which feeds both TX and RX sides.

Have a few other projects on the go.

Radcomic sounds as though it's changed since I was a RSGB member. A
while back, an Aussie Mag, EA (Electronics Australia) which was doing
well, changed its format in an effort to aim for a different market.
(Only lasted an issue...Its gone!)

Bye

Kevin
ZL1UJG


Re: New Bandplan now Downloadable

Murray Niman <mjniman@...>
 

Hi Dave et al

You are right and now on the Operating Page of microwavers.org is an
edited version of the 2006 Bandplans with that and the earlier typos
fixed on 3.4GHz

Look back at 2004 and 2005 versions and you find the same mistake
- which shows how often we read these!

It was our task to check these a few weeks ago but we only really
payed attention to this years changes!

Murray (& Mike) :-)

- info also fed back to Colin Thomas at RSGB

--- In ukmicrowaves@yahoogroups.com, "g4fre" <g4fre@m...> wrote:

there must be a digit missing in the line:-

"3,456.000-3,48.000 3,456.000 MHz EME to USA"

dave

g4fre


Re: Radcom comments

Chris Bartram <yahoo@...>
 

Alan said:

But then are todays microwavers actually desiging
things or just making up kits ( ducks hastily as the bricks start to
rain down !!
This one certainly is.

Over the last few weeks, prompted by the incipient failure of my old 10GHz
transverter, I've designed a 10GHz, 16dB small signal gain, +10dBm (P1dB)
gain block with a NF of about 5dB (which can be built for ~£5) and 432MHz IF
interface/sequencer unit. The transverter uses a LO modified from a brick
purchased from the amazing Pyrojoseph and surplus BPFs and mixer from the
same source..

In the last year or so I've designed several 10GHz LNAs, (they're slowly
getting better...) a PSU for a 40W TWT (a very interesting learning
experience!) a PIC-based interface unit for my dish az-el tracking system,
filters for my 1.3GHz receiver front-end, and a 120W SSPA for that band.

My work on microwave SDR systems hasn't been forgotten, and I think I've
solved the problem of making a half decent kHz stepping synthesiser at 10GHz
(which is the major problem in implementing a system) for a few quid.

I've also spent time trying to understand and document a commercial 7GHz link
transceiver which looks like a very good way of getting on 5.6GHz...

My job is very demanding and often sees me working 10+hours a day. We have a
small farm, and I also need quite a lot of sleep! I'm not a one-dimensional
radio geek, and I have a number of important (to me...) interests outside
radio!!

I'd like to write-up some of the microwave projects, but I'm unlikely to. My
experience has been rather poor. A couple of years ago I contributed a design
for a very good, stable, (and rather simple!) 1.3GHz preamp to Scatterpoint.
FWIW, I've had _zero_ reaction to that. I'll continue to contribute ideas to
Scatterpoint, but the time and effort required to sit down and make sure that
my designs are capable of being easily reproduced is something I don't have.
To write a half-decent article on most of these projects would eat too much
into what little spare time I have. I certainly wouldn't bother to write
something for Radcomic only to have it thrown back in my face as 'too
technical'...

73

Chris
GW4DGU


Re: Writing articles

Alan Melia
 

Hi Conrad, please do not let yourself be put off telling us how you solved a
problem..... climbed a hurdle ....tripped over a well known trap. Just
think how many guide books there are written to cover a particular part of
the world. Everyone looks for something different, everyone sees something
different.

If you follow the news groups and other special interst groups, there have
been a couple of guys who have taken the time to describe how they have
tracked down and solved a problem on some old (and much loved ) test gear. I
found these particularly instructive although I dont have the equipment
described. What was quite amazing was the shower of replies from other
appreciative readers, many of them "professionals".

Whilst technical articles written by professionals are polished they do not
always provide the practical detail that some of us find useful (why you did
it that way, and not another way) It does not matter if your solution is not
optimum, it works !! We can always hone an idea later to get the last 0.1dB.
Long ago at University I found some of the best lecturers were recent
Post-grads who had struggled a little themselves and appreciated that some
of the topics were a little difficult to grasp. They went the "extra mile"
to explain in an understandable way, whereas the Prof would often look
confused at how someone could fail to grasp such a "simple concept" !!

Remember it is nice to be able to stand on the shoulders of giants, but some
of us need a leg up from lesser mortals !! Please share you agonies, and
successes with us. I am sure Peter will appreciate your efforts. This, and
the informed feedback it generates, is how we all (well most of us) learn. I
may be ex BTRL but I am a semiconductor man not a radio engineer, and have a
lot yet to learn.

Best Wishes de Alan G3NYK