开云体育

I have ordered a limited batch of boards from JLCPCB for the QEX September/October 2021 “Miniature SMA Step Attenuator” pp 9-21 by Tom Alldred VA7TA.

If you are interested in a board, at $3.00 ppd CONUS, please reply off line [click the “Private” button].
I expect to receive the boards in the first week of October and will have 8 spare boards available.
If there is sufficient additional interest, I would be willing to make a second order.

See attached for some additional info.

Dick K9IVB

Dick,

Does the article indicate how much "blow-by" you get (due to the mechanical switches in this design) as the frequency increases?

Roger

The author discusses this some and there are numerous response graphs in the QEX supp files. Can you read the article or do you need a copy
Dick K9IVB

If you are interested in a board, at $3.00 ppd CONUS, please reply off line [click the “Private” button].
The first order is sold out and there is sufficient additional interest for a second order.
I will be making a second order next week.

I expect to receive the second set boards near the end of October.

Dick K9IVB

On Tue, Sep 21, 2021 at 11:11 PM, dick faust wrote:

The author discusses this some and there are numerous response graphs in the
QEX supp files. Can you read the article or do you need a copy
Dick K9IVB

I am not an ARRL member so I don't have access to the article.

Roger

Good evening All.

Dick K9IVB, is there any chance that you could email me a copy of that
article?

Fred - N4CLA

If you want to send it direct, it is n40cla@....

On Wed, Sep 22, 2021 at 3:11 PM Roger Need via groups.io <sailtamarack=
[email protected]> wrote:

On Tue, Sep 21, 2021 at 11:11 PM, dick faust wrote:

The author discusses this some and there are numerous response graphs in

the

QEX supp files. Can you read the article or do you need a copy
Dick K9IVB

I am not an ARRL member so I don't have access to the article.

Roger

For a poor ham's step attenuator design, look here:

Works well up to about 500MHz. The blowback is very small because of the type of "switches" used.
Feel free to order on JLCPCB. The design is under CC license.

73, Mike AF7KR

What is the throughput loss with all attenuators bypassed by the
switches, at 500 MHz?
*Clyde K. Spencer*

If you are asking about my design, it is -1dB at 500MHz and -2dB at 1GHz.

73, Mike AF7KR

Thanks
*Clyde K. Spencer*

On Thu, Sep 23, 2021 at 09:31 AM, vbifyz wrote:

For a poor ham's step attenuator design, look here:

Nicely done Mike!

Just a quick question - why do you need "dual" jumpers? Would it work if you have a single jumper per attenuator, so either you have attenuator engaged (jumper off) or shorted "jumper on"?

If I see it correctly, in your design, in order to "engage" the attenuator u must remove one "bridge" (horizontal) and put two (vertical) in, right?

THANKS for the work put in!

Hi Miro,
Yes, you need 2 jumpers to engage a section, but only 1 to bypass it.
It is more convenient to keep the 2 jumpers together, this way you switch the section with a single motion of turning the pair. Not as good as a single button push, but I think it is a good tradeoff between cost, performance, and convenience.

73, Mike AF7KR

I'd never have thought to use jumpers at hundreds of MHz, assuming they'd be too reflective. Though I admit, I've done little work at hundreds of MHz. Nice work!

I see what appears to be quite small ground vias along the lines. Is this a quasi copanar waveguide?

I've got to put a test structure like this on a TDR and see how it looks!

I have ordered two batches of boards from JLCPCB for the QEX September/October 2021 “Miniature SMA Step Attenuator” pp 9-21 by Tom Alldred VA7TA. There is a quantity of excess PCBs available. I do not anticipate that I will place another order, but I will continue to accept orders until my supply is gone.

More information is available on my web page

I expect to receive the second set boards near the end of October. The first board orders will be mailed next week about October 5, 2021.

Dick K9IVB

Demand continues and I will place a third order.
Will order enough that I will have additional spares.

Now have information for International orders.
1 board @ $3.00 CONUS 1 board @ $3.75 International

More info and still adding to the web page


Please reply off list.

Dick K9IVB

Hi Dick

do you have any PCBs available?

Best regards,

Malcolm

Hi Dick, I want to order but your website only says contact me with no link? Please provide a link or an email address please.