Substrate thickness for 10 GHz
Greg - ZL3IX
I've now completed my 10 GHz transverter and am starting on an LNA and PA. For the transverter I used PCBs with a 0.8 mm FR4 substrate and, apart from the 1 dB per inch track loss, it seemed to work out well. I have been thinking of using a thinner substrate for the LNA and PA, to minimise both the inductance and the thermal resistance of the vias. I have looked at both 0.4 mm and 0.6 mm substrates but the supplier I have been using puts a heavy engineering charge on to the 0.4 mm boards, resulting in a $50 + cost, compared with just $2 for the 0.6 mm option.
Does anyone have any opinion about the use of 0.6 mm vs 0.4 mm substrates in this application? Issues are obviously via inductance on the FET source connections that will affect the noise figure, and the via thermal conductivity under the paddle of the HMC952 device. The latter needs to lose about 8 W of heat. 73, Greg, ZL3IX
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Re: Modderman 23cms PA for sale with extras
Phil Williams
Hello Bob,
PA is sold and winging its way to downtown Leicestershire Sorry! Phil G3YPQ
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Re: RS
David I might be around if there is something local to get me out the valley.
-- Clive GW4MBS (ex-G8ADP) Pottering on 6m - 3cm in a valley in IO71XW where any QSO is a triumph of optimism over geography!
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Re: 10 GHZ SSPAs
John Lambo
Hello Robin,
Thank you for the nice words.
Enjoy you sailing trip and take care..
73 John PA7JB
Op 20-8-2021 om 19:00 schreef Robin
Szemeti - G1YFG:
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RS
Dave - G4RQI
Hello...
There’s quite a bit rain about tomorrow so anyone around in the afternoon on 10Ghz?
I’ll log into KST when I’m about
David – G4RQI IO93IR Sent from Mail for Windows
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Re: 10 GHZ SSPAs
Robin Szemeti - G1YFG
Nice units, i have one, not tested yet as i am sailing, but a really nice build
On Fri, 20 Aug 2021, 16:55 John Lambo, <pa7jb@...> wrote:
--
Robin Szemeti - G1YFG
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Re: ALC Overrun
Andrew Cartwright
Algenon,
Out of interest how did you get on? have you been using the transverter with your IC7100? I ask because I am considering the very same route. Regards Andrew - G7MNS
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10 GHZ SSPAs
John Lambo
Hello Group, We still have some 10ghz SSPAs for sale. We think that there are amteurs who are not qrv from the moon but this is a nice amplifier for tropo. Sent a mail to Jac if you want more info.. 73 John PA7JB off the EME Moonbounce Group We have some nice
modified 10GHz SSPAs for sale
Dutch EME Moonbounce Group PA0BAT Gerard, PA7JB John and PA3DZL Jac
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Re: Modderman 23cms PA for sale with extras
Bob Lockley VK6KW
Hi Phil, Can you give me an estimate of the P&P to Australia 6401 please? It would probably need to have the modules separated to pack efficiently. But as you suggest reworking of the layout is on the cards anyway. 73, Bob VK6KW.
From: UKMicrowaves@groups.io <UKMicrowaves@groups.io> On Behalf Of Phil Williams
Hello, I'm selling my Bert Modderman 2W in 140W out 23cms PA .
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Modderman 23cms PA for sale with extras
Phil Williams
Hello, I'm selling my Bert Modderman 2W in 140W out 23cms PA .
It built up in a rather basic way and works fine. Included is a 12v-28v 20A up converter and input and output relays. Its only been used into a dummy load and then for a few minutes only. You'd probably dismantle my efforts and do the job properly! The PA is as new and the relays are pretty valuable too. I'm asking £270 plus £10 p+p to UK Phil G3YPQ N.Cornwall
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Connectors
Colin Ranson
Further to Simon G0FCU, et al
M0MAT on ebay now stocks SMA compression plugs for TM LMR-240 at £4.49 or 4 for £3.95 each, including post, https://www.ebay.co.uk/itm/154575829863 - a bit pricey, but if anyones willing to wait snail trail from China ....................
From RFstore2015 (223642254878) these can be had for £1.85 each with an initial postage of £1.54 for one, thereafter free. Probably out of the same stable in China.
Regards to all
Colin de G8LBS.
Sent from Mail for Windows
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Re: -- Was Waveguide Design - Book Recommendation
Mark GM4ISM
Hi Paul Be careful what you wish for :) I developed a high dynamic range preamplifier based on the RFMW
RFMC8818 device that has 16dB gain Nf below 2dB and an output P1dB
of about +27dBm (at UHF) it should survive 1W on the input in
theory It was bomb proof at even unreasonable signal levels ( eg Cellular TX antenna 2m away) The downside is that it would output about 800mW given a big signal (see below) and would be capable of frying subsequent stages My calcs suggest that a 100W 50MHz Tx with 10dB gain antenna pointed at a similar antenna 100m away will produce about 200mW into the frontend of the RX The whole chain will need to be bombproof and perhaps have a pair of diodes as a limiter. When they start clipping you will get worse intermods too. A lower gain device with reasonable nF (3dB or so) is probably more what you need the PGA103 is good but will need an attenuator, 26dB gain at 50MHz is too much and that gain lowers the input overload level the PHA1 is perhaps better The last time I hit a rig with a lot of RF on receive it was
not the front end device that expired, it was the pin diode band
switches
On 19/08/2021 16:49, Paul G8AQA via
groups.io wrote:
Hi Mark,
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Re: -- Was Waveguide Design - Book Recommendation
Since you don't require a fantastic noise figure on 50MHz, you'll probably find a bipolar device is a better option. One of several GHz Ft medium power devices running at 70mA Ic. Or a PGA103 type modamp. Andy
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Re: -- Was Waveguide Design - Book Recommendation
Paul G8AQA
Hi Mark,
I was recently looking at nuvistors for a very high dynamic range preamp to work in very close proximity to a transmitter on 50 MHz. The idea is not to blow up the device if 2 beams are pointing at each other on rare occasions. I haven't done the sums yet. Probably need a switchable attenuator after it to avoid overloading the RX. Playing with ideas at the moment. 73 Paul G8AQA On 19/08/2021 09:54, Mark GM4ISM via
groups.io wrote:
Sounds good Chris, hope to work you on 3cm EME sometime
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Re: -- Was Waveguide Design - Book Recommendation
Mark GM4ISM
Sounds good Chris, hope to work you on 3cm EME sometime
toggle quoted messageShow quoted text
I was going to suggest casting a swept bend, electroforming one on an aluminium shaped mandrel or machining one from a block with CNC.. all quite a bit of effort but fun? Glad you found something.. A clear case of one of the major rules of the junk box. You don't know what you've got till you find it again / I wish I knew I had that before I spent loads of time / money on another. You don't need it until after you throw it away. You know you've got one but cant find it. I wonder if it will still work after all this time ... Bang Oh no its gone rusty / filled with water / has critters living in it. Why did i keep that? / What is it? That was valuable once, now totally worthless and not worth using. (I just found a GAT5 in my microwave semiconductor drawer and some nuvistors) Yep its clear-out time. There's a lot in the last 4 categories, all soon to move to category 2 There are also a lot of great projects coming back to the light The joys of retirement! Mark GM4ISM
On 19/08/2021 09:29, Chris Bartram G4DGU wrote:
Although I have been able to come to an understanding of waveguide operation and design techniques from a variety of sources, I've never really found a clearly comprehensible reference. Many books which claim to explain the subject seem more to want to show-off their author's extensive mathematical skills, than provide any form of clear explanation. I know that I'm not alone in finding this ...
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Waveguide Design - Book Recommendation
Chris Bartram G4DGU <chris@...>
Although I have been able to come to an understanding of waveguide operation and design techniques from a variety of sources, I've never really found a clearly comprehensible reference. Many books which claim to explain the subject seem more to want to show-off their author's extensive mathematical skills, than provide any form of clear explanation. I know that I'm not alone in finding this ...
Many times, I've noted references to the work of Theodore Moreno, and his 1944 book 'Microwave Transmission Design Data' but had never managed to find a copy for sale. This happened again while deciding on the best way to approach the design of a 68degree e-plane WG17 bend. Needing some old books for for another research project (not related to engineering) I've discovered 'Abe Books' a French-owned multi-national grouping of secondhand booksellers (including many from the UK). A quick look on the Abe web site showed several copies of Moreno's 1944 book (and later editions)at sensible prices, including a near mint softcover copy of the 1948 second edition published by Dover Books for not much more than UKP10. I bought that from a bookseller in Hamburg. It has now arrived, and the book has already been very useful in understanding the design of mitred e-plane waveguide bends. With more thought, I've decided not to use a mitred bend (which can be made to work as well as a swept bend in a narrow-bandwidth application) as I discovered an additional treasury of WG17 parts in my garage! Amongst them are some easily modifiable swept WG17 e-plane bends ... Chris G4DGU
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Re: SMA questions
On Tue, 17 Aug 2021 at 00:47, Robin Szemeti - G1YFG <robin@...> wrote:
A lot of NanoVNAs supplied by Hugen were supplied with an adapter with a poor dielectric. It was very lossy, even at the frequency of an early NanoVNA. So I would not assume a bad dielectric in a plug would be acceptable, even at 2’.4 GHz. Dave Dr. David Kirkby, Kirkby Microwave Ltd, drkirkby@... https://www.kirkbymicrowave.co.uk/ Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom
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Re: SMA questions
Colin Ranson
Simon,
I have found these to be very good and easy to terminate., to be honest would not expect great performance above 2.3ghz. From e-bay – second one also fits RG223 premium 5mm coax. I have had no problems with patches made from these, purists may say they are crap compared to the real ‘bee’s knee’s’ ones.
1pce SMA Male Plug Clamp for RG316 RG174 LMR100 Cable RF Coax Connector 1pce SMA Male Plug Clamp for RG58 RG142 LMR195 RG400 Cable RF Coax Connector
1pce Connector SMA male plug clamp RG8X RG-8X LMR240 RF COAXIAL straight - from RF store2015.
This one fits Times Microwave LMR-240 which is 6mm premium coax up to 6GHz. I have a couple of patch leads for 3.4GHz made up from it.
RFstore 2015 also supplies the top two examples cheap in lots of 10.
Best regards
Colin de G8LBS.
Sent from Mail for Windows
From: G0FCU
Sent: 18 August 2021 22:50 To: UKMicrowaves@groups.io Subject: Re: [UKMicrowaves] SMA questions
Thanks for all the advice. I will be placing orders based on it.
73 Simon G0FCU.
On Tue, 17 Aug 2021 at 10:58, Alan Melia via groups.io <Alan.Melia=btinternet.com@groups.io> wrote:
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Re: SMA questions
ian hope (2E0IJH)
Speak to M0MAT he has a EBAY shop, does decent quality connectors
https://www.ebay.co.uk/str/m0mat?norover=1&mkevt=1&mkrid=710-153696-560033-8&mkcid=2&keyword=&crlp=355246904595_&MT_ID=&geo_id=&rlsatarget=dsa-764521878456&adpos=&device=c&mktype=&loc=1006960&poi=&abcId=&cmpgn=2033188068&sitelnk=&adgroupid=71572595973&network=g&matchtype=b&gclid=EAIaIQobChMIiYynn8278gIV4mDmCh1Jbw4KEAAYASAAEgKl5PD_BwE
Ian
M5IJH
Sent: Wednesday, August 18, 2021 at 10:50 PM
From: "G0FCU" <simon@...> To: UKMicrowaves@groups.io Subject: Re: [UKMicrowaves] SMA questions Thanks for all the advice. I will be placing orders based on it.
73 Simon
G0FCU.
On Tue, 17 Aug 2021 at 10:58, Alan Melia via groups.io <Alan.Melia=btinternet.com@groups.io> wrote:
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Re: SMA questions
G0FCU
Thanks for all the advice. I will be placing orders based on it. 73 Simon G0FCU.
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