Re: "Black Spot" gaasfet replacement?


John E. Beech
 

Birkett was at Newark the last time I went. It is more or less on his doorstep. I was surprised to see John there in person.

de John G8SEQ

-------Original Message-------
From: Martin Phillips G4CIO <martin@douglas-phillips.org.uk>
To: UKMicrowaves@groups.io <UKMicrowaves@groups.io>
Subject: Re: [UKMicrowaves] "Black Spot" gaasfet replacement?
Sent: Jun 01 '20 12:41

Blackspots and a few other Birkett devices (possibly green spot?) went
in the post this morning.

Has anyone visited the J Birkett emporium recently (well, before
lockdown)? He seems to be running still. His stall used to the the
best (possibly only sometimes) reason for going to rallies in the
seventies.

Martin/

On 1/6/20 12:29 PM, Robin Szemeti - G1YFG wrote:

> I think I am sorted, thank you for the offer.
>
> On Mon, 1 Jun 2020 at 09:31, Michael Scott via groups.io
> <g3lyp=btinternet.com@groups.io> wrote:
>
> The Chipbank has a box of miscellaneous devices not listed in the
> catalogue which people rummage through at RTs. There are some
> devices which look as though they were intended for LNBs. I also
> have some black spot and other devices I have used as replacements
> in WDG units. You are welcome to these if they would help.
>
> 73, Mike, G3LYP.
>
> FROM: Robin Szemeti - G1YFG
> SENT: Monday, June 1, 2020 1:18 AM
> TO: UKMicrowaves@groups.io
> SUBJECT: Re: [UKMicrowaves] "Black Spot" gaasfet replacement?
>
> Finding lower noise substitutes is probably not hard ... but finding
> something that will deliver +20dBm is perhaps a little harder, the
> Black Spot devices were quite good in that respect. Assuming the
> kind person who emailed me can locate them, I should be sorted .. it
> was somewhat irritating today to make a final power check before
> heading off to a hill and finding absolutely nothing coming out!
>
> On Sun, 31 May 2020 at 23:13, Andy G4JNT <andy.g4jnt@gmail.com>
> wrote:
>
> When I was working at Marconi Space in 1990, those devices had just
> appeared and were seriously expensive in small-off quantities;
> something like £100 each. I used a few in a satellite LNA
> breadboard for 6GHz. However, they were about to go into SAT-TV LNBS
> so the LNB manufacturers were going to be ordering them by the tens
> of millions.
>
> I recall the Fujitsu Rep at the time, who was Radio Amateur
> friendly, offering them to amateurs in one-off quantities at the
> million-off price. Can't recall what that price actually was, but
> ISTR perfectly reasonable for a serious 10GHz op to build into an
> LNA .
>
> A couple of years later they were down to a few quid each.
>
> Andy
> www.g4jnt.com
>
> On Sun, 31 May 2020 at 22:54, Gordon REASON via groups.io
> <gordonj.reason=virgin.net@groups.io> wrote:
>
> The Fujitsu FHX35 are good m but some NEC devices have better noise
> figure .
>
> #
>
> On 31 May 2020 at 22:44 Andy G4JNT <andy.g4jnt@gmail.com> wrote:
>
> Charlie did recommend a replacement device when the red/black spot
> devices became hard-to-get, I think it may have been the NE32184
> IIRC someone was giving away strips of them at one of the
> Roundtables-past. Either that, or selling for peanuts.
>
> Andy
> www.g4jnt.com
>
> On Sun, 31 May 2020 at 22:26, G3UVR Denis IO83KH via groups.io
> <g3uvr= btinternet.com@groups.io> wrote:
> I am pretty sure I still have three paper data sheets for the Red
> Black and Green spot types when I bought these devices from Birket.
> The transverter is still in use today or rather would have been if I
> wasnt in hospital right now but can look when I get out over next
> few days.
>
> 73 de Denis G3UVR

--

Best regards,

Robin Szemeti

Redpoint Consulting Limited

E: robin@redpoint.org.uk
T: +44 (0) 1299 405028
M: +44 (0) 7971 883371

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Please accept the sender's apologies, notify the sender immediately
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Thank you.

--

Best regards,

Robin Szemeti

Redpoint Consulting Limited

E: robin@redpoint.org.uk
T: +44 (0) 1299 405028
M: +44 (0) 7971 883371

CONFIDENTIALITY NOTICE
The information contained in this e-mail is intended only for the
confidential use of the above named recipient. If you are not the
intended recipient or person responsible for delivering it to the
intended recipient, you have received this communication in error
and must not distribute or copy it.
Please accept the sender's apologies, notify the sender immediately
by return e-mail and delete this communication.

Thank you.

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