Unused Unloved K2RIW Amp


Derek Brown G8ECI
 

Anyone have a unused K2RIW 432 Amp built or partially or even just the chassis, I have the Sk630 bases, being a serious long time user of the 4CX250B, I need a few more watts than what my IC9700 puts out as as evident during last night UKAC on 70cm heard loads of stations, but they not hearing moi !!   Also as I qsying from JO03 to IO93, will no longer have that tempting Locator to lure in the stations. So if you have one lurking in that shed, under the bench or about to be scrapped.

Please email me,
 
73 Derek G8ECI


ian hope (2E0IJH)
 

G8DOH had a chassis as I was looking for one as had a damaged one, but I then got gifted our clubs units as our Club chair became serious ill 
 
Ian
M5IJH

 
 
Sent: Wednesday, June 09, 2021 at 6:00 PM
From: "Derek Brown G8ECI via groups.io" <g8eci@...>
To: UKMicrowaves@groups.io
Subject: [UKMicrowaves] Unused Unloved K2RIW Amp
Anyone have a unused K2RIW 432 Amp built or partially or even just the chassis, I have the Sk630 bases, being a serious long time user of the 4CX250B, I need a few more watts than what my IC9700 puts out as as evident during last night UKAC on 70cm heard loads of stations, but they not hearing moi !!   Also as I qsying from JO03 to IO93, will no longer have that tempting Locator to lure in the stations. So if you have one lurking in that shed, under the bench or about to be scrapped.

Please email me,
 
73 Derek G8ECI


Andy Rutter, G8HCK
 


I have a complete kit purchased a LONG time ago, back when I was overly enthusiastic! I have excavated it from the store room and taken some photos

    https://www.dropbox.com/sh/d1s9o6uoegj20gz/AABJOhsV2lr7xpgFAd6SYXmha?dl=0

It is in good unused condition, a bit tarnished due to the 30 odd years storage, but I am sure that will clean up. The kit comprises metalwork, sockets, PTFE, EHT connectors and cable. I have honestly no idea what it is worth so, if you want it, make me a reasonable offer (andy <at> acronym.co.uk).

I also have the EHT transformer which I will photo tomorrow if there is any interest.

--
    Andy, g8hck


On 09/06/2021 18:00, Derek Brown G8ECI via groups.io wrote:
Anyone have a unused K2RIW 432 Amp built or partially or even just the chassis, I have the Sk630 bases, being a serious long time user of the 4CX250B, I need a few more watts than what my IC9700 puts out as as evident during last night UKAC on 70cm heard loads of stations, but they not hearing moi !!   Also as I qsying from JO03 to IO93, will no longer have that tempting Locator to lure in the stations. So if you have one lurking in that shed, under the bench or about to be scrapped.

Please email me,
 
73 Derek G8ECI


Frank, G0GSR
 

Isn't the combined AM/PM noise so bad from the 9700 that it would be antisocial to run a high power amp, especially in the UK where its hard to get any distance away from anyone?
Frank


Tim Hague M0AFJ
 

Correct, see the presentation by Alwyn Seeds at the convention, available on the RSGB web site.

Best Regards
Tim Hague


On 9 Jun 2021, at 21:36, Frank, G0GSR <frank.g0gsr@...> wrote:

Isn't the combined AM/PM noise so bad from the 9700 that it would be antisocial to run a high power amp, especially in the UK where its hard to get any distance away from anyone?
Frank


Dave G6HEF
 

Being a long way from people isn’t a problem in IO84…….

Dave
G6HEF


Richard GD8EXI
 

If you are building a K2RIW amp from scratch or a kit there are few improvements that can be made. Modify the grid circuit to make it easier to get a good return loss at resonance. Also use 4CX400As not 4CX250Bs as they perform unpredictably in this design. I can supply details of these modifications offline.
 
I have yet to find an amateur radio solid-state power amp, which can improve on a pair of 4CX400As in terms of linearity.
 
Richard
GD8EXI



On 10/06/2021, 08:56, "Dave G6HEF" <hardknottdave@...> wrote:

Being a long way from people isn’t a problem in IO84&hellip&hellip.

Dave
G6HEF  


Frank, G0GSR
 


Andy
 

On 13/06/2021 11:53, Frank, G0GSR wrote:
"K2" amp on Fleabay!
https://www.ebay.co.uk/itm/224491852759?hash=item3444c1d3d7:g:QpAAAOSwBO1gwQwS
Frank

Have you not figured out who the vendor is Frank? :-)


ian hope (2E0IJH)
 

It's the one I mentioned at start of thread I Knew G8DOH had when I was looking for one, before I got gifted the ex club one
 
Ian
M5IJH

 
 
Sent: Sunday, June 13, 2021 at 5:12 PM
From: "Andy" <mm0fmf@...>
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Unused Unloved K2RIW Amp
On 13/06/2021 11:53, Frank, G0GSR wrote:
> "K2" amp on Fleabay!
>
> https://www.ebay.co.uk/itm/224491852759?hash=item3444c1d3d7:g:QpAAAOSwBO1gwQwS
>
> Frank


Have you not figured out who the vendor is Frank? :-)





 


Derek Brown G8ECI
 

Hi Frank

Yes have sent, Its Alwyn's 
, but had already made an offer on an unbuilt Gordon High Precison unit, which has an excellent pedigree with a full copper chassis, and hopefully by the time I will have operational ICOM may have a firmware update that will improve the noise etc generated by 9700. To make it more sociable. 73 Derek G8ECI



Sent from my Galaxy


-------- Original message --------
From: "Frank, G0GSR" <frank.g0gsr@...>
Date: 13/06/2021 11:53 (GMT+00:00)
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Unused Unloved K2RIW Amp

"K2" amp on Fleabay!

https://www.ebay.co.uk/itm/224491852759?hash=item3444c1d3d7:g:QpAAAOSwBO1gwQwS

Frank


Frank, G0GSR
 

On Sun, Jun 13, 2021 at 10:51 PM, Derek Brown G8ECI wrote:
I will have operational ICOM may have a firmware update that will improve the noise etc generated by 9700.
I wouldn't hold your breath...
Frank


Tim Hague M0AFJ
 

Correct, the poor Spectral purity of the 9700 is a design problem, not curable by any firmware updates

Best Regards
Tim Hague


On 14 Jun 2021, at 08:10, Frank, G0GSR <frank.g0gsr@...> wrote:

On Sun, Jun 13, 2021 at 10:51 PM, Derek Brown G8ECI wrote:
I will have operational ICOM may have a firmware update that will improve the noise etc generated by 9700.
I wouldn't hold your breath...
Frank


Dominique Dehays
 

Hello,

And it is not the only Icom transceiver like this, same pb with 7k3
73
Dom

-------- Message d'origine --------
De : "Tim Hague M0AFJ via groups.io" <m0afj@...>
Date : 14/06/2021 09:34 (GMT+01:00)
À : UKMicrowaves@groups.io
Objet : Re: [UKMicrowaves] Unused Unloved K2RIW Amp

Correct, the poor Spectral purity of the 9700 is a design problem, not curable by any firmware updates

Best Regards
Tim Hague


On 14 Jun 2021, at 08:10, Frank, G0GSR <frank.g0gsr@...> wrote:

On Sun, Jun 13, 2021 at 10:51 PM, Derek Brown G8ECI wrote:
I will have operational ICOM may have a firmware update that will improve the noise etc generated by 9700.
I wouldn't hold your breath...
Frank


Derek Brown G8ECI
 

Ok,

Well, I will promise not to use it from any Hill tops during contests, not that there's that many in North East Lincolnshire. 73 Derek G8ECI

On Monday, 14 June 2021, 08:51:53 BST, Dominique Dehays <f6dro@...> wrote:


Hello,

And it is not the only Icom transceiver like this, same pb with 7k3
73
Dom

-------- Message d'origine --------
De : "Tim Hague M0AFJ via groups.io" <m0afj@...>
Date : 14/06/2021 09:34 (GMT+01:00)
À : UKMicrowaves@groups.io
Objet : Re: [UKMicrowaves] Unused Unloved K2RIW Amp

Correct, the poor Spectral purity of the 9700 is a design problem, not curable by any firmware updates

Best Regards
Tim Hague


On 14 Jun 2021, at 08:10, Frank, G0GSR <frank.g0gsr@...> wrote:

On Sun, Jun 13, 2021 at 10:51 PM, Derek Brown G8ECI wrote:
I will have operational ICOM may have a firmware update that will improve the noise etc generated by 9700.
I wouldn't hold your breath...
Frank


Conrad, PA5Y
 

Here are some links to measurements of the IC7300 on various bands. The measurements were made with an R & S FSWP.


Here are some for the IC9700

Shared with Dropbox
www.dropbox.com


Regards

Conrad PA5Y


From: UKMicrowaves@groups.io <UKMicrowaves@groups.io> on behalf of Dominique Dehays via groups.io <f6dro@...>
Sent: 14 June 2021 09:51
To: UKMicrowaves@groups.io <UKMicrowaves@groups.io>
Subject: Re: [UKMicrowaves] Unused Unloved K2RIW Amp
 
Hello,

And it is not the only Icom transceiver like this, same pb with 7k3
73
Dom

-------- Message d'origine --------
De : "Tim Hague M0AFJ via groups.io" <m0afj@...>
Date : 14/06/2021 09:34 (GMT+01:00)
À : UKMicrowaves@groups.io
Objet : Re: [UKMicrowaves] Unused Unloved K2RIW Amp

Correct, the poor Spectral purity of the 9700 is a design problem, not curable by any firmware updates

Best Regards
Tim Hague


On 14 Jun 2021, at 08:10, Frank, G0GSR <frank.g0gsr@...> wrote:

On Sun, Jun 13, 2021 at 10:51 PM, Derek Brown G8ECI wrote:
I will have operational ICOM may have a firmware update that will improve the noise etc generated by 9700.
I wouldn't hold your breath...
Frank


alwyn.seeds1
 

Dear All,

With NOS valves, both 3CX and 4CX, I have found it helpful to run with heaters only for 24hours before applying high voltage; I understand that the getter on these is at the top of the cathode column and is activated by the heater- it cannot be activated by RF induction, as in glass envelope valves, of course.

I neglected this precaution, once- with one of a batch of NOS Eimac 3CX800A7s. Result, instant vaporisation of high voltage current limit resistor and destruction of valve. Following the procedure described above for the others in the batch, I had no failures.

I’m no valve expert, so experts please correct me, if I’m wrong.

Regards,

Alwyn G8DOH

_____________________________________________________

Alwyn Seeds, Director
SynOptika Ltd.,
114 Beaufort Street,
London,
SW3 6BU,
England.


SynOptika Ltd., Registered in England and Wales: No. 04606737
Registered Office: 114 Beaufort Street, London, SW3 6BU, United Kingdom.
_____________________________________________________


Reg Woolley
 

Have you seen the price of a 3cx800 now, you will need deep pockets 

Reg g8vhi 



Sent from my Galaxy


-------- Original message --------
From: "alwyn.seeds1" <a.seeds@...>
Date: 15/06/2021 10:31 (GMT+00:00)
To: "UK Microwaves groups.io" <UKMicrowaves@groups.io>
Subject: Re: [UKMicrowaves] Unused Unloved K2RIW Amp

Dear All,

With NOS valves, both 3CX and 4CX, I have found it helpful to run with heaters only for 24hours before applying high voltage; I understand that the getter on these is at the top of the cathode column and is activated by the heater- it cannot be activated by RF induction, as in glass envelope valves, of course.

I neglected this precaution, once- with one of a batch of NOS Eimac 3CX800A7s. Result, instant vaporisation of high voltage current limit resistor and destruction of valve. Following the procedure described above for the others in the batch, I had no failures.

I’m no valve expert, so experts please correct me, if I’m wrong.

Regards,

Alwyn G8DOH

_____________________________________________________

Alwyn Seeds, Director
SynOptika Ltd.,
114 Beaufort Street,
London,
SW3 6BU,
England.


SynOptika Ltd., Registered in England and Wales: No. 04606737
Registered Office: 114 Beaufort Street, London, SW3 6BU, United Kingdom.
_____________________________________________________


Derek Brown G8ECI
 

Thanks for the heads up Alwyn, I will certainly carry out the heaters on task first, but its gonna be a while until get anything operational, as I am in the middle of moving and currently trying to pack the shack, I think packing is pushing a bit, I have come across all sorts of things, like QQV03-20A's and a couple of brand new QQVO6-40A's, dont think I will be doing much with those !!! But I certainly have a fair collection of used and new 4CX250B's of various makes, Eimac, ITT and Penta, also a number of 2C39A's and such.  So much reasonable possibly will use stuff and the rest I think a third skip is required.....

Have received the GHP chassis and parts from Andy, not sure if its a steel copperplated chassis or actual copper ? could not find a magnet to see.

Was hoping to have my old 23150 EME 23cm amp up and running for the UKAC tonight but thats been in the rebuild status for around 20 years, although its not far off completion, I just lost faith when the house sale came up, so will need to wait until I am in my new shack in IO93XM, after losing the nice JO03 of the last 40 years !!!

73 Derek G8ECI, QRV for the next 12 days from JO03


alwyn.seeds1
 

Dear Reg,

Yes, I have seen that the Eimac 3CX800A7s are now $1,200 each plus shipping, VAT and import charges.

The NOS batch I bought were a bit cheaper, but scarcely cheap.

Thus,  the impolite expression I uttered when I destroyed my first one by not using the heaters only conditioning trick

 reflected the pain to my wallet, as well as my surprise as I dodged the jet of flaming nichrome from the safety resistor.

Taught me a lesson, that I will not forget.

Anyone have recent experience of the Chinese ones sold under multiple brands including Thomson CSF?

Regards,

Alwyn



_____________________________________________________

Alwyn Seeds, Director
SynOptika Ltd.,
114 Beaufort Street,
London,
SW3 6BU,
England.


SynOptika Ltd., Registered in England and Wales: No. 04606737
Registered Office: 114 Beaufort Street, London, SW3 6BU, United Kingdom.
_____________________________________________________