Happy New Year Gents
Hi Al & Peter et All
I have successfully replaced the original MRF19125 Mosfets with three MRF 21125s in my 13 cm amp.
I'm in the process of turning on the whole amp in stages. So far I have the driver reduced in power output since originally it was delivering 50 watts . Peter was surprised by that level of drive so I backed way down to begin. Maybe that had something to do with the failure of the MRF19125s.
The 21125s are internally filtered to cover 2.1 Ghz instead of 1.9 Ghz so I'm shooting for higher efficiency. I cannot find a device for higher frequency.
It's been a long time since I had the amp running and I have forgotten what drain current should be for each device max. The data I find on the internet is confusing to me. I admit I am no expert on SS. I can monitor each device independently.
I plan to reduce the drain voltage to 24 volts for initial turn on. 28 volts is normal. Can I turn on the three stages one at a time or does the three way divider / combiner input and output require that all three be on at the same time? That's my main concern at this point and I will stop until I have an answer.
With a bit of luck and warm wx I should be back on 13 cm soon.
73
Steve N4PZ
PS. I have about 12 MRF19125s free to anyone who needs them. The MRF21125s are available for reasonable prices.. I hope they work without modifying the board. We'll see.
________________________________
From: Al Katz <alkatz(a)tcnj.edu>
Sent: Tuesday, January 1, 2019 10:33 PM
To: Al Katz
Subject: Re: HNY
Best wishes off the Moon and on tropo... and to you and your family for a Happy Holiday and a Healthy, Happy and Prosperous 2019.
73, Al (& Sal) - K2UYH
[cid:part1.C314D3A6.4EAD1E56@tcnj.edu]
--
Dr. Allen Katz, Prof. E/CE TCNJ
President, Linearizer Technology, Inc.
<http://www.lintech.com><http://www.lintech.com>
Tel 609-584-8424, Cell 609-947-3889
This is probably a long shot but if anyone here has tried locking a
Yeasu FT-2000 to GPS, either using the internal TCXO or a complete
external replacement, please contact me. I am interested in what
approach was used and how the rig was modified.
Locking to a 10 MHz reference would be ideal but I am quite certain
that is beyond my ability. I'm considering using an off-the-shelf
external GPSDO programmable reference to replace the internal TCXO
but I have never attempted something like this before.
73,
Paul N1BUG
Hi all
First thank you all for all the mail.
I did try a lot of things buth my TS2000 is still not working.
I did try a full reset buth this is not working.
I did test all Flat Flexible cables and other cables on all boards buth
all looks fine
With the power on i set some little pressure on all electronica boards
buth no results.
I knock on the boards off the tranceiver buth nothing happening.
I will not remove the boards out off the TS2000 and check the soldering.
Bad eyes etc (yes we got older also hi)
So i am thinking about it and sent the TS2000 back again to the Kenwood
service.
73 GYS PA1GYS
HAPPY NEW YEAR OM
Thank God I close the end of the 4x27 EME 432mhZ antenna and soon there
are in the moon
eme uhf frequencies ?
Regarding 9K2YM
On Tue, 1 Jan 2019, 14:00 <moon-net-request(a)mailman.pe1itr.com wrote:
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> Today's Topics:
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> 1. HAPPY NEW YEAR (Serge Szpilfogel)
> 2. Re: HAPPY NEW YEAR (Ray Rector)
> 3. Re: HAPPY NEW YEAR (Edward R Cole)
> 4. Re: HAPPY NEW YEAR (Stephen Hanselman)
> 5. HNY2019 (Frantisek Strihavka)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 31 Dec 2018 20:27:32 -0000
> From: "Serge Szpilfogel" <ve1kg(a)eastlink.ca>
> To: "Edward R Cole" <kl7uw(a)acsalaska.net>,
> <moon-net(a)mailman.pe1itr.com>
> Subject: [Moon-Net] HAPPY NEW YEAR
> Message-ID: <000301d4a147$4259ac30$c70d0490$(a)eastlink.ca>
> Content-Type: text/plain; charset="us-ascii"
>
> Ed I want to wish you & family a Happy new year. As well I want to thank
> you
> for the help you provided me & many others. We are lucky to have you on
> moonet. You are without questions the resident novelist of this reflector.
> Always happy to help newcomers to the hobby.
>
> Have a wonderful New year Ed
>
> 73, Serge VE1KG
>
>
Happy New Year
Swedish EME 2019
Now its time to get the pappers in for the agenda.
we need more speakers for the list,
Hope to cu all on moon
73 Lars SM4IVE
It may be worthwhile to be sure this is an Audio issue and not an RF issue. Most people seem to have RF issues when it is the filters which is totally different from audio issues, from my reading and understanding of the circuits involved. If the S-meter levels change it is quite possibly the filter issue although one very good Youtube source had found issues with a few other minor parts like an inductor and so on in the initial RF area, before the band switched filters.
My issue is strictly audio at this point as my RF levels are good and do not drop off, just the audio does. In my case it seems to drop out randomly. I have tapped on the main RF board, jiggled and reseated all cables, wiggled the main audio output IC, checked it for excessive heat, examined (but not tested) all the electrolytic caps near the audio IC, tapped all the relays, pressed on the board at various places and checked the tightness of all the grounding screws. Still comes and goes. I feel I am truely down to a small component failing at this point so I will dig out the service manual and start checking voltages when it fails the next time.
I did replace the IF filters out of an abundance of caution even though my radio was out of the supposed date range for the failures. It still had Toko filters and I don't trust them. My next easy bet will be to check levels and quite possibly just replace the electrolytic caps in the audio amp section. I do know those are prone to failure as well. I had a TS-50 as a bench radio that lost its mind one day due to a bad electrolytic. Started screaming like a police siren when turned on, and about as loud as a siren too. Bad cap.
SeanKB8JNE
Sent from my dumb smartphone,Spell checked by NSA.
null
I have several N type failsafe relays, typically made by Ducommon, RLC,
etc. that cause noise on receive.
I think this is caused by oxidation on the contacts, although I assume
are gold plated. Maybe the plating is fatally damaged already?
I have tried running ~100 ma through the contacts while switching them
rapidly without much effect.
By disassembly, I could apply the typical burnishing tool or "business
card" stock but don't know if that would do more damage than good. Is
"deoxit" completely out of the question for a high power relay? What
methods should I absolutely avoid?
Any suggestions on these or other methods would be appreciated. Also
looking for suggestions on testing them after "treatment". I am
thinking that using a NF meter would be a good test method, but I would
like to hear other ideas.
Steve, k5dog
