Date   

UHF Transverter Sold

Christopher Bartram <cbartram@...>
 

My old transverter went within a few minutes, such is the power of this list!

Now, is anyone interested in an equestrian smallholding (not a bad VHF -
microwave site with no immediate neighbours...) in IO71? :-)

Vy 73

Chris
GW4DGU


Re: 432MHz Transverter For Sale

David Robinson
 

I just dusted off mine about a week ago to allow the FLEX1500 to drive my 10/24/47G xverters. I knew I had hung onto it for a reason!

Dave



2b. Re: 432MHz Transverter For Sale

Posted by: "Sam" jewell@btinternet.com sam38525
Date: Tue Aug 3, 2010 2:08 pm ((PDT)) I took one of those to offer at the Amsat event on Sunday as part if my own continuing clear out.
Not an iota of interest, even though it is clearly a very useful transverter and absolutely ideal for use with SDRs that will only tune up to 30MHz, when wanting to observe 70cm.
Oh well. Black boxes rule.........
73 de Sam, G4DDK


Re: 432MHz Transverter For Sale

mike.willis@...
 

I recall they were not possessed of the largest dynamic range. In any case, if you were wondering why I was not interested in yours Sam, I have one already for SDR applications.

 

Mike


--
Scanned by iCritical.



Re: 432MHz Transverter For Sale

SAM JEWELL
 

I took one of those to offer at the Amsat event on Sunday as part if my own continuing clear out.
Not an iota of interest, even though it is clearly a very useful transverter and absolutely ideal for use with SDRs that will only tune up to 30MHz, when wanting to observe 70cm.
Oh well. Black boxes rule.........
73 de Sam, G4DDK

On 3 Aug 2010, at 22:01, Christopher Bartram <cbartram@theiet.org> wrote:

In my continuing clear-out, I've discovered an old Microwave Modules 144/432
transverter at the bottom of a box. I think it came as part of a bundle of kit
I brought in the 1980s.

For those of you who don't remember them, this transverter went from 144 to
28MHz and then up to 432, so it could be fairly easily modified as a 28/432
box. It has a second LO enabling the use of 1.6MHz shift repeaters. I've never
used this box, and I have no idea if it works.

I've no idea of what this is worth nowadays. Probably not a lot! I'll offer it
here first. If anyone is interested, make me an offer!

Vy 73

Chris
GW4DGU

--


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

Yahoo! Groups Links



432MHz Transverter For Sale

Christopher Bartram <cbartram@...>
 

In my continuing clear-out, I've discovered an old Microwave Modules 144/432
transverter at the bottom of a box. I think it came as part of a bundle of kit
I brought in the 1980s.

For those of you who don't remember them, this transverter went from 144 to
28MHz and then up to 432, so it could be fairly easily modified as a 28/432
box. It has a second LO enabling the use of 1.6MHz shift repeaters. I've never
used this box, and I have no idea if it works.

I've no idea of what this is worth nowadays. Probably not a lot! I'll offer it
here first. If anyone is interested, make me an offer!

Vy 73

Chris
GW4DGU

--


Re: M/ACOM N type male 50 Ohm termination

Bill <radio.m@...>
 

In message <4C57C2C0.9030305@g4bao.com>, g4bao <john@g4bao.com> writes
 
Thanks for that John, I'll be in touch.

Bill.


Hi Bill..
Don't recognise it, but if you want to pop over with it I can measure
its return loss up to 18GHz...

73
John

Bill wrote:
Hi,
a bit of a long shot but does anyone recognise the following part No.
N15X4OH999X99 or it could be NI5........ or ....40H...... depending
on how you read it, Google has failed me miserably on this one.

The part number along with "M/ACOM INTERCONNECTDIVISION" is printed
on
the sealed bag and 50(omega) is stamped into the body of the load.


It looks like a good quality item and it would be a shame to assign
it
some mundane application if it aspired to higher things, GHz rather
than
MHz :-)
--
Bill


Re: M/ACOM N type male 50 Ohm termination

g4bao
 

Hi Bill..
Don't recognise it, but if you want to pop over with it I can measure its return loss up to 18GHz...

73
John

Bill wrote:

Hi,
a bit of a long shot but does anyone recognise the following part No. N15X4OH999X99 or it could be NI5........ or ....40H...... depending on how you read it, Google has failed me miserably on this one.

The part number along with "M/ACOM INTERCONNECTDIVISION" is printed on the sealed bag and 50(omega) is stamped into the body of the load.


It looks like a good quality item and it would be a shame to assign it some mundane application if it aspired to higher things, GHz rather than MHz :-)
--
G4BAO
Beacon keeper GB3CAM/24GHz
www.g4bao.com


Re: Warning re surplus Nokia Tetra base station Power amps on 70cms

Storer, Darren
 

Hi Russ,

please drop me a note directly: darren at callsign dot com

73 de Darren
G7LWT


On 2 August 2010 18:40, Russ Stewart <g4pbp@...> wrote:
 

Storer, Darren wrote:
>
>
> Hi Russ,
>
>
> I may have a spare unit with faulty driver devices... Do you know
> anyone who visits the Manchester area who could help with transport?
>
> 73 de Darren
> G7LWT
>
> On 31 July 2010 12:47, Russ Stewart <g4pbp@...
> g4pbp@...>> wrote:
>
>
>
> THE LATEST !!!! ..... it's dead.
>
> The newly modified Tetra 70cm amp passed away peacfully last night
> whilst testing with DF9IC :-)
>
> It passed my 1hr / 5min thermal cycling test. I did not do my 80%
> carrier on test for > 1hr test as I reckoned the Tetra would set on
> fire, as it is being run too far above it's design spec. for
> comfort. I
> opened it it up expecting to see 'burned things' but there were none !
>
> Everything looked new and shiney except the device gates had 26V
> on them
> :-(
>
> It looks like an overdrive issue (the SWR was fine). Mark
> suggested it
> could be the common problem with Jap rigs of a high peak switch on RF
> pulse. I never thought to check this; the IC810H has only ever driven
> valves histortically. Very remiss really missing such an important
> test,
> as I was trying to push the BLF 548's to near their maximum rating.
>
> So a salutary warning again to those trying to push these amps above
> 200W, yes they will do nearly 300w but for how long I will now
> never know.
>
> Anyway it died honourably in the persuit of DX so it will recieve a
> hero's burial later today ..... RIP TETRA
>
> regards de Russ ..... G4PBP
>
>
>
Hi Darren I'm interested. Don't need the driver as I cut the 2 PA
devices off the main board anyway, just leaving the driver's o/p 50ohm
line for input termination purposes. If necessary I will shoot up the
motorway and we can meet somewhere.

regards de Russ .... g4pbp



M/ACOM N type male 50 Ohm termination

Bill <radio.m@...>
 

Hi,
a bit of a long shot but does anyone recognise the following part No. N15X4OH999X99 or it could be NI5........ or ....40H...... depending on how you read it, Google has failed me miserably on this one.

The part number along with "M/ACOM INTERCONNECTDIVISION" is printed on the sealed bag and 50(omega) is stamped into the body of the load.


It looks like a good quality item and it would be a shame to assign it some mundane application if it aspired to higher things, GHz rather than MHz :-)
--
Bill


Sods Law...!

Paul M0PDA
 

Hi All

Posted this on Codgers as well in the hope I will find the right
John. At the last truck stop meeting a couple of members expressed
an interest in a 23cm homebrew panel aerial I had built and e-mail
addresses were taken.Unfortunately it was raining at the time and
one of the addresses is not completely legible.

All that remains is John????123atBeeTeeInternet.Com.So John if
you know who you are and remember writing your e-mail address
in the rain last Saturday at the truck stop can contact me please
I would be very grateful.

Thanks everyone

Paul

M0PDA


Re: Warning re surplus Nokia Tetra base station Power amps on 70cms

Russ Stewart <g4pbp@...>
 

Storer, Darren wrote:

Hi Russ,


I may have a spare unit with faulty driver devices... Do you know anyone who visits the Manchester area who could help with transport?

73 de Darren
G7LWT

On 31 July 2010 12:47, Russ Stewart <g4pbp@blueyonder.co.uk <mailto:g4pbp@blueyonder.co.uk>> wrote:


THE LATEST !!!! ..... it's dead.

The newly modified Tetra 70cm amp passed away peacfully last night
whilst testing with DF9IC :-)

It passed my 1hr / 5min thermal cycling test. I did not do my 80%
carrier on test for > 1hr test as I reckoned the Tetra would set on
fire, as it is being run too far above it's design spec. for
comfort. I
opened it it up expecting to see 'burned things' but there were none !

Everything looked new and shiney except the device gates had 26V
on them
:-(

It looks like an overdrive issue (the SWR was fine). Mark
suggested it
could be the common problem with Jap rigs of a high peak switch on RF
pulse. I never thought to check this; the IC810H has only ever driven
valves histortically. Very remiss really missing such an important
test,
as I was trying to push the BLF 548's to near their maximum rating.

So a salutary warning again to those trying to push these amps above
200W, yes they will do nearly 300w but for how long I will now
never know.

Anyway it died honourably in the persuit of DX so it will recieve a
hero's burial later today ..... RIP TETRA

regards de Russ ..... G4PBP


Hi Darren I'm interested. Don't need the driver as I cut the 2 PA devices off the main board anyway, just leaving the driver's o/p 50ohm line for input termination purposes. If necessary I will shoot up the motorway and we can meet somewhere.

regards de Russ .... g4pbp


Re: Warning re surplus Nokia Tetra base station Power amps on 70cms

Storer, Darren
 

Hi Russ,

I may have a spare unit with faulty driver devices... Do you know anyone who visits the Manchester area who could help with transport?

73 de Darren
G7LWT


On 31 July 2010 12:47, Russ Stewart <g4pbp@...> wrote:
 

THE LATEST !!!! ..... it's dead.

The newly modified Tetra 70cm amp passed away peacfully last night
whilst testing with DF9IC :-)

It passed my 1hr / 5min thermal cycling test. I did not do my 80%
carrier on test for > 1hr test as I reckoned the Tetra would set on
fire, as it is being run too far above it's design spec. for comfort. I
opened it it up expecting to see 'burned things' but there were none !

Everything looked new and shiney except the device gates had 26V on them
:-(

It looks like an overdrive issue (the SWR was fine). Mark suggested it
could be the common problem with Jap rigs of a high peak switch on RF
pulse. I never thought to check this; the IC810H has only ever driven
valves histortically. Very remiss really missing such an important test,
as I was trying to push the BLF 548's to near their maximum rating.

So a salutary warning again to those trying to push these amps above
200W, yes they will do nearly 300w but for how long I will now never know.

Anyway it died honourably in the persuit of DX so it will recieve a
hero's burial later today ..... RIP TETRA

regards de Russ ..... G4PBP



Re: Clip-on Crystal Ovens/Heaters

Russ Stewart <g4pbp@...>
 

Richard wrote:

On Sat, 31 Jul 2010 15:15:49 -0000
"GM8BJF" <brian.flynn@tiscali.co.uk <mailto:brian.flynn%40tiscali.co.uk>> wrote:

I am currently building up a new Tx for the Edinburgh 23cm beacon,
GB3EDN and
am looking for a ssource of clip-on ovens for HC49 crystals. I know that
Kuhne do them but wondered if there is another source of such
devices. It
does not need to be terribly high spec as the crystal is going to be
locked
up to a decent standard. The purpose is just to keep it close to
frequency so
that the RDDS will pull into lock under all ambient conditions.

73s

Brian.

Gm8BJF
Hi
Eisch-Kafta-Electronic do them www.eisch-electronic@t-online.de <mailto:www.eisch-electronic%40t-online.de>
part no Qterm1 @ €5.50 they might be a bit more as my catalog is out of date.

HTH

--
Best wishes

Richard Bown G8JVM

###################################################################################
Registered Linux User 36561
OS: Mandriva 2010.1 Powerpack on an AMD Dual Athlon 64 +4400: 8 GB RAM DDR2
Ham Call: G8JVM , QRA IO82SP, Interests Microwave 1.3 GHz,2.3 GHz & 5.7GHz & 10
GHz
###################################################################################

Got some if you need one Brian they are Murata PTH bg330n .... Russ .... g4pbp


Tonight - Microwave Activity Night, 8/2/2010, 8:00 pm

ukmicrowaves@...
 

Reminder from:   ukmicrowaves Yahoo! Group
 
Title:   Tonight - Microwave Activity Night
 
Date:   Monday August 2, 2010
Time:   8:00 pm - 9:00 pm
Repeats:   This event repeats every week.
Notes:   Monday nights are traditionally microwave activity nights. Why not try listening around at 20:00 local time? Better still, call CQ! Consider using KST to co-ordinate activities:

http://www.on4kst.com/chat/start.php
 
Copyright © 2010  Yahoo! Inc. All Rights Reserved | Terms of Service | Privacy Policy


Re: Off Topic -- Warning re surplus Nokia Tetra base station Power a

F1CHF
 

Mark
I don't remember why, but my Excel page for slot antenna
was updated ...
please find the link
 
regards,
 

----- Original Message -----
Sent: Sunday, August 01, 2010 12:17 PM
Subject: Re: [ukmicrowaves] Re: Off Topic -- Warning re surplus Nokia Tetra base station Power a

 

Roy,
some pictures of these on my website  www.dc2light.co.uk with a few notes on problems found. Russ managed to get round these issues with major surgery, I have yet to modify mine since cooking the op pcb transmission line, but I think that as per Chris DGU's suggestion, a fin on the track will greatly reduce the temperature without too much radiation, even though the board seems to be fibreglass not PTFE. An additional small fan here will also cool the sageline op coupler (which will also get a fin!)
 
still available on eBay i believe
 
 Regards
Mark GM4ISM

Sent: Sunday, August 01, 2010 10:53 AM
Subject: [ukmicrowaves] Re: Off Topic -- Warning re surplus Nokia Tetra base station Power a

 

hi all
sorry to plead ingorance but im new to the goup .
what Tetra Amplifier are we talking about please.
cheers
roy
GM4VKI
 



No virus found in this incoming message.
Checked by AVG - www.avg.com
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Re: Off Topic -- Warning re surplus Nokia Tetra base station Power a

Mark GM4ISM
 

Roy,
some pictures of these on my website  www.dc2light.co.uk with a few notes on problems found. Russ managed to get round these issues with major surgery, I have yet to modify mine since cooking the op pcb transmission line, but I think that as per Chris DGU's suggestion, a fin on the track will greatly reduce the temperature without too much radiation, even though the board seems to be fibreglass not PTFE. An additional small fan here will also cool the sageline op coupler (which will also get a fin!)
 
still available on eBay i believe
 
 Regards
Mark GM4ISM

Sent: Sunday, August 01, 2010 10:53 AM
Subject: [ukmicrowaves] Re: Off Topic -- Warning re surplus Nokia Tetra base station Power a

 

hi all
sorry to plead ingorance but im new to the goup .
what Tetra Amplifier are we talking about please.
cheers
roy
GM4VKI
 



No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 9.0.851 / Virus Database: 271.1.1/3042 - Release Date: 07/31/10 19:34:00


Re: Off Topic -- Warning re surplus Nokia Tetra base station Power a

Russ Stewart <g4pbp@...>
 

rkavampsev@aol.com wrote:

hi all
sorry to plead ingorance but im new to the goup .
what Tetra Amplifier are we talking about please.
cheers
roy
GM4VKI

Hi Roy it's a 70cms unit with a pair of BLF548's; or should I say was a 70cms amp.

70cms is a bit 'off topic' for this reflector but really all sorts gets discussed / reported here; anyway welcome

regards des Russ .... g4pbp


Re: Off Topic -- Warning re surplus Nokia Tetra base station Power amps on 70cms

Russ Stewart <g4pbp@...>
 

Russ Stewart wrote:
Christopher Bartram wrote:

Having designed TETRA PAs, I assume that these surplus amplifiers are designed to deliver 50 - 60W pep, and will produce >200W simply because they were run 'backed-off' in order to get good large signal linearity with a relatively poorly-performing lineariser. I should stress that I don't know these amplifiers, but the problems which Mark and Rob describe aren't black magic!

The issues which will arise from running the amplifiers at higher powers will (probably) be due to the choice of substrate for the microstripline output matching elements. If, as I suspect, the amplifiers are built on 0.62 or 0.31mm FR4 to save money, the major issue will be resistive heating due to dielectric losses, not dielectric breakdown. While you can't do a lot about the latter, the heating due to resistive losses in the substrate can be dealt with in the same way as you'd deal with losses in a resistor: heatsinking!
The power dissipated in a microstripline can be calculated, but as a rule of thumb, those in a 200W PA will probably only dissipate a few watts.
The characteristic impedance of a microstripline is relatively uneffected by heatsinking structures placed on top of the conductor. A U-shaped heatsink of, say, 0.25mm copper sheet soldered to the conductor will radiate the heat dissipated.

One tool which anyone designing, building or modifying a solid state power amplifier should possess is an infra-red thermometer. These are cheap and being non-contact, can be used to look at a the temperatures of PA components while it is running. Thermal design is often neglected in amateur designs.

Vy 73

Chris
GW4DGU


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

Yahoo! Groups Links




Hi Chris and I guess you are right on all counts.

I am actually using one these amps but envoked radical surgery to stop it burning up. It currently gives 280W o/p cold and drops to 240W when hot. It easily does 250W PEP !

The surgery involved firstly, cutting out the PA section from the main board and remounting it on the original heatsink. I left the bit of board which was the o/p line of the driver stage, (for matching purposes). I connected a piece of UT141-50 to this line and put a 10pf ceramic trimmer across the the coax / stripline transition to the gnd plane; this gave a 1:1 match when the o/p peaked (1st time ever :-)

At the output end I cut off the SWR monitor line part and stripped off the 50ohm track feeding it, right back to the Sageline combiner, just leaving a small pad which the Sageline is connected to. The used a piece of UT141-50 to bring out the RF. Without the line removal I could only get 230W cold.

It was interesting to note that when I stripped off the stripline, the bit of board under where the o/p N-type spigot was soldered, was already black + burned even under the amps normal operating condition !

The o/p Sageline combiner is at or just over it's power limit at 280W and seems to be the primary heat source; you can't hold your finger on it after 5mins of carrier !!! So I blow the combiner and am currently testing use of a 20mm fin (copper strip) soldered to it's length in the air flow. I will know how well this works shortly .... need an IR camera for Christmas for all this PA work Hi. It would be easy to replace the Sageline with an external Wilkinson in UT141-75 as an alternative.

Finally and most importantly, as Mark found in his original mods, you must 'beef-up' the DC feed to each device and not rely on the via's and pc tracks than feed the DC pwr; this will result in a 'burn-up' and general mess.

If anyone needs it, I have photographs of the finished PA, these may already be on Mark's website.

All I need now is someone to work on 70cms :-(


regards de Russ G4PBP



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

Yahoo! Groups Links




THE LATEST !!!! ..... it's dead.

The newly modified Tetra 70cm amp passed away peacfully last night whilst testing with DF9IC :-)

It passed my 1hr / 5min thermal cycling test. I did not do my 80% carrier on test for > 1hr test as I reckoned the Tetra would set on fire, as it is being run too far above it's design spec. for comfort. I opened it it up expecting to see 'burned things' but there were none !

Everything looked new and shiney except the device gates had 26V on them :-(

It looks like an overdrive or maybe a sequencing issue, the SWR was fine but I thought I had the sequencing sorted. Mark suggested it could be the common problem with Jap rigs of a high peak switch on RF pulse. I never thought to check this; the IC810H has only ever driven valves histortically. Very remiss really missing such an important test, as I was trying to push the BLF 548's to near their maximum rating.

So a salutary warning again to those trying to push these amps above 200W, yes they will do nearly 300w but for how long I will now never know.

Anyway it died honourably in the persuit of DX so it will recieve a hero's burial later today ..... RIP TETRA


regards de Russ ..... G4PBP


Re: Off Topic -- Warning re surplus Nokia Tetra base station Power a

rkavampsev@...
 

hi all
sorry to plead ingorance but im new to the goup .
what Tetra Amplifier are we talking about please.
cheers
roy
GM4VKI
 


Re: Clip-on Crystal Ovens/Heaters

Richard <richard.bown@...>
 

On Sat, 31 Jul 2010 15:15:49 -0000
"GM8BJF" <brian.flynn@tiscali.co.uk> wrote:

I am currently building up a new Tx for the Edinburgh 23cm beacon, GB3EDN and
am looking for a ssource of clip-on ovens for HC49 crystals. I know that
Kuhne do them but wondered if there is another source of such devices. It
does not need to be terribly high spec as the crystal is going to be locked
up to a decent standard. The purpose is just to keep it close to frequency so
that the RDDS will pull into lock under all ambient conditions.

73s

Brian.

Gm8BJF
Hi
Eisch-Kafta-Electronic do them www.eisch-electronic@t-online.de
part no Qterm1 @ €5.50 they might be a bit more as my catalog is out of date.

HTH

--
Best wishes

Richard Bown G8JVM

###################################################################################
Registered Linux User 36561
OS: Mandriva 2010.1 Powerpack on an AMD Dual Athlon 64 +4400: 8 GB RAM DDR2
Ham Call: G8JVM , QRA IO82SP, Interests Microwave 1.3 GHz,2.3 GHz & 5.7GHz & 10
GHz
###################################################################################