Hi Reg,
Do you have a schematic for the linear? Because I don't. Or for the
LPF.
Inspecting the LPF I note something strange - the inductors for the
40M filter are exactly the same as those for the 80M one. Same core, same # of turns. Which doesn't make a whole lot of sense.
Looking at the 5-element Chebyshev tables in the back of the ARRL handbook,
it's obvious that the 40M inductor needs to be quite a bit smaller than the
80M one ( duhhhh ).
So I get to spend some quality time unsoldering, unwinding, and measuring toroids.
- Jerry KF6VB
toggle quoted message
Show quoted text
|
Re: Rx Tx relay sticking
#rx
#cw
Chuck,
From the symptoms you describe, I would start with replacing K1. The fact that tapping on it allows it to reset suggests it is a mechanical issue.
I found a sucking desoldering tool that worked great for the 2 v4 relay sets (6 total) that I needed to replace for the harmonic suppression fix.? This is the tool that I found to work the best:
The thing is to compress the bulb before applying it to the pin and pad, let set for a few seconds then release the bulb.? It took two or three times on each pin to clear out the solder enough to free the pin.? I clear the tool by pumping the bulb over a cardboard box to catch the removed solder.? There were no board tabs damaged.
73
Evan
AC9TU
|
On 2021-05-20 12:10, R. Tyson via groups.io wrote: Hi,
Are you using one of the Chinese low pass filter kits ? ** Yes, I am. Actually an assembled filter, not a kit. But I had to solder the RF cables to it. Same vendor as the amp ( 2012moon816 ). The amp was also assembled, with a heat sink and a cute little fan. It has its own 30MHz lowpass filter on the card. The switchable lowpass filter has 2 coils and 3 caps for each band. There is an input for 12V to run the relays. Each relay is activated by grounding its pin. It's possible to activate multiple sections at the same time, don't know if that will improve ultimate rejection or not. I still need to test the setup with the tinySA. But I've run out of SMA cables, need at least one more. Whups, and also need a N to BNC... I think there's a problem with the 40M filter. Band noise goes down somewhat on 40 when I put the filter in. Also, RF output is down from 75W to 25W. Sounds like a job for the nanoVNA. Or maybe I get to just take the thing apart and measure components. Sigh. - Jerry KF6VB I have my linear built and working but haven't had time to sort out low pass
filters yet. I was undecided whether to build filters or buy one of
those kits. I bought a couple of spare linear amp kits as they are so
darned cheap. I was a bit sceptical until I actually built the first
one and it worked fine. The first kit had good quality transistors.
The spare kits I bought had transistors with the make, etc ground off.
I have good branded transistors that I will use in them and throw the
unmarked ones away.
Reg G4NFR
Links:
------
[1] /g/BITX20/message/88548
[2] /mt/82962817/243852
[3] /g/BITX20/post
[4] /g/BITX20/editsub/243852
[5] /g/BITX20/leave/10189903/243852/952924773/xyzzy
|
Save those de-marked power transistors.? They make good voltage or current
regulators for DIY power supplies. _._
Hi,
Are you using one of the Chinese low pass filter kits ?? I have my linear built and working but haven't had time to sort out low pass filters yet. I was undecided whether to build filters or buy one of those kits. I bought a couple of spare linear amp kits as they are so darned cheap. I was a bit sceptical until I actually built the first one and it worked fine. The first kit had good quality transistors. The spare kits I bought had transistors with the make, etc ground off. I have good branded transistors that I will use in them and throw the unmarked ones away.
Reg?????????????????????????? G4NFR
|
Re: Rx Tx relay sticking
#rx
#cw
Chuck?
I have not experienced any relay sticking problem with my uBITX V3, but have
seen it happen in other equipment.?
Have you changed the relays as part of an upgrade, or are you using the
original relays?
What are the symptoms of your T/R relay sticking?
Many on this forum have way more experience than me, so maybe they
will have a cure readily available.
Arv _._
On Thu, May 20, 2021 at 5:56 AM Chuck Eglhaut < ceglhaut@...> wrote: Is there a fix for the Rx Tx relay sticking?
|
Re: Rx Tx relay sticking
#rx
#cw
Dave exactly tap on it with a screwdriver it works. I made a contact doing that I had the top off so when stopped receiving I could tap it and continue.
|
Forgot to mention....? I replaced R4 and R5 with higher wattage resistors. The original resistors got very hot and I didn't like that. The replacement resistors get barely warm to the touch. Might just be me being overly cautious.
Reg?????????????????????????? G4NFR
|
Re: Rx Tx relay sticking
#rx
#cw
I seen another person on here had a similar problem and he tapped it and it worked.
I have tired tapping the relay and it will reset. when that doesn't work I key the mic or the key and turn radio off then back on it seems to work. Evan It happens with ssb or cw.
When I first turn it on it work for a while but then it will happen. the radio is working normal in the beginning then there nothing come over the speaker when i unkey the mike or key. if I keep keying the mike the watt meter shows output. but there is no receive signal. I running v1.20 on the the display.and I set the tx rx delay to 1. yes the radio worked fine. I was concerned when it heated up I was doing some cw but it seem to work proper, I have over 200 contacts logged in FT8. I was working fine . Chuck
|
Hi,
Are you using one of the Chinese low pass filter kits ?? I have my linear built and working but haven't had time to sort out low pass filters yet. I was undecided whether to build filters or buy one of those kits. I bought a couple of spare linear amp kits as they are so darned cheap. I was a bit sceptical until I actually built the first one and it worked fine. The first kit had good quality transistors. The spare kits I bought had transistors with the make, etc ground off. I have good branded transistors that I will use in them and throw the unmarked ones away.
Reg?????????????????????????? G4NFR
|
On Thu, May 20, 2021 at 11:53 AM, jerry@... wrote:
And the smell... This may sound silly, but one whiff of an ARC-5 chassis, and I'm 15 years old again. Just for a moment.
That reminds me, many years ago Hoppe's (gun cleaning solvent) made a promotional air freshener in the shape of their bottle like the little trees you hang from your rear view mirror.? One whiff of that stuff and my brain is flooded with fond memories. ? --
|
|
|
Re: Rx Tx relay sticking
#rx
#cw
I have had three of them fail. Also have had the control circuit fail to switch because of RF on the control line.?
So depending you should either replace the relay. If it is sticking you can sometimes tap on it with a screwdriver handle and get it to open. If it opens I would say sticky relay If it is rf start putting common mode chokes on things.Start with the antenna then try a small one on the PTT and elsewhere till it starts working. I doubt if it is in the electronics.?
--
73
Dave
|
And the caps would likely have been pyranol-paper, not electrolytic.
Gerry
Sent by the Thunderbird
toggle quoted message
Show quoted text
On 2021-05-20 11:34 a.m., Jerry Gaffke via groups.io wrote: You're right, any big caps would have been in the power supply for it.
And big electrolytics are the ones I'd be most afraid of.
The small ones might fail, but they did build those Arc-5's to take a beating.
Jerry, KE7ER
|
You're right, any big caps would have been in the power supply for it.
And big electrolytics are the ones I'd be most afraid of.
The small ones might fail, but they did build those Arc-5's to take a beating.
Jerry, KE7ER
toggle quoted message
Show quoted text
On Thu, May 20, 2021 at 09:28 AM, jerry@... wrote:
I bet you power it up and it just works. No electrolytics.
|
|
|
Still have my 40m ARC-5 transmitter, sitting on a shelf down in the basement.
Hasn't been powered up in 45 years.
Should probably replace all the caps first if I were to try it now.
Either that or set it outside on a concrete pad, don safety glasses and a cup.
Jerry, KE7ER
|
When I got my license in 1970, the Age of ARC-5's was already winding down. But I got my share. I built a 400W linear in an ARC5 transmitter cabinet. Crammed 4 6LQ6's in there. Bolted a muffin fan to the top. Used the roller coil to change bands. I remember that on 15M it only used about an eighth of a turn of roller coil.
- Jerry KF6VB
toggle quoted message
Show quoted text
On 2021-05-20 09:09, Jack, W8TEE via groups.io wrote: I (barely) remember when I was young and you could go to a hamfest and
find a bazillion ARC-5 for sale for next to nothing. Now the roller
inductor alone costs 10x what you paid for the entire ARC-5 back
then...
Jack, W8TEE
On Thursday, May 20, 2021, 12:01:58 PM EDT, Gerald Sherman
<ve4gks@...> wrote:
My 1st transmitter was a homebrewed unit. I tore a war surplus ARC-5
TVI generator apart - got the 1625 PA tube & its socket, plus a spare
1625 & a few other parts. The power transformer was a repurposed unit
from an old TV. The perforated metal for the PA tube compartment
cover
came from a old automotive air filter.
Gerry
Sent by the Thunderbird
--
Jack, W8TEE
Links:
------
[1] /g/BITX20/message/88539
[2] /mt/82962817/243852
[3] /g/BITX20/post
[4] /g/BITX20/editsub/243852
[5] /g/BITX20/leave/10189903/243852/952924773/xyzzy
|
I (barely) remember when I was young and you could go to a hamfest and find a bazillion ARC-5 for sale for next to nothing. Now the roller inductor alone costs 10x what you paid for the entire ARC-5 back then...
Jack, W8TEE
On Thursday, May 20, 2021, 12:01:58 PM EDT, Gerald Sherman <ve4gks@...> wrote:
My 1st transmitter was a homebrewed unit.? I tore a war surplus ARC-5
TVI generator apart - got the 1625 PA tube & its socket, plus a spare
1625 & a few other parts.? The power transformer was a repurposed unit
from an old TV.?? The perforated metal for the PA tube compartment cover
came from a old automotive air filter.
Gerry
Sent by the Thunderbird
-- Jack, W8TEE
|
I sold mine a long time ago...never should have done that.? I picked up a Hygain GT-550 about 10 years ago, but it wasn't the same. It was in great shape and worked well, but I think my enjoyment of QRP operating jaundiced my experience with it:
I sold it a few years ago.
Jack, W8TEE
On Thursday, May 20, 2021, 11:46:26 AM EDT, jerry@... <jerry@...> wrote:
On 2021-05-20 08:32, Jack, W8TEE via groups.io wrote: > my first full-time job then got a GT-550. That was a nice rig. *** They sure did make pretty radios back then, didn't they?? Back in the 90's I once scored a Galaxy V at the ham swap for IIRC $50.? It was brand new NOS.? The seller claimed that he had pulled the shipping tape off the tubes.? But no power supply. ? I built a supply - wound my own power transformer.? Never quite got it working though - the BFO crystals had aged away from their proper frequency, and could not be trimmed up. ? ? ? ? ? ? ? ? - Jerry KF6VB ? Used it > for phone patch traffic between Guam/Marshall Islands and SAC > headquarters (Offutt) in Omaha with a HB 15M 2 ele beam. Did that 3 > times a week for 4 years. The XYL's were so appreciative. Christmas > was a flood of cookies, cakes, pies, candy, and booze! Fun stuff... > > Jack, W8TEE > >? On Thursday, May 20, 2021, 10:33:47 AM EDT, jerry@...> < jerry@...> wrote: > > All, > >? Got my Chinese linear working!? A temporary setup - everything > strapped to an oak board with cable ties.? A row of toggle switches to > > choose the band. > > That's not a viable long-term solution, because sooner or later I will > > transmit on the wrong band and possibly fry the finals.? The LPFs are > quite effective - if I choose, say 40M while the uBITX is on 20M - the > > band noise goes away. > >? I found the TX signal on top of the uBITXv6 circuit board, right > near > the tuning knob.? Was able to tack a wire to it without taking the > whole > radio apart. > >? It is satisfying to hit the key and see my wattmeter show 75W.? The > last time I did 75W of CW was back in the 70's, and my call was > "WN6EPS". It was a Heathkit DX-40 transmitter. > >? ? ? ? ? ? ? ? - Jerry KF6VB > > -- > Jack, W8TEE > > > Links: > ------ > [1] /g/BITX20/message/88534> [2] /mt/82962817/243852> [3] /g/BITX20/post> [4] /g/BITX20/editsub/243852> [5] /g/BITX20/leave/10189903/243852/952924773/xyzzy
-- Jack, W8TEE
|
Aror, Loris, and Evan, To build the Easy Bitx firmware, you will need Sunil's VFO_BFO_DDS.ino file. ? ?? /g/BITX20/files/EASY%20BITX%20FILES/easy%20bitx%20vfo%20bfo%20code/VFO_BFO_DDS/VFO_BFO_DDS.inoYou will also need version 1.0.0 of the Etherkit Si5351 library found here: ? ? I have verified with Sunil that the checksum of these files is the same as what he used to build the firmware. You will also need the Rotary library installed, here is a possibility: ? ?? Note that the Rotary library does not have a system of releases, but is seeing regular updates. Hard to tell how well the most recent version will work, but debugging the rotary encoder should be fairly easy. The above code compiles fine for me, but I don't have appropriate hardware to try it on. Let me know if that works. It's not unusual for Arduino projects to get fouled up due to library version issues. I feel the best solution is to zip up all required source files when archiving a project. Since all of the above code is open source, I doubt providing a copy of the libraries would be an issue. If I have that wrong, somebody let me know. ? Aror, if you have working code based on Allard's Bitx40 code, perhaps you could post that? Jerry, KE7ER
On Thu, May 20, 2021 at 03:30 AM, Evan Hand wrote:
Sunil,
As Loris is interested, so am I in looking at the Nano code for the Easy Bitx that I purchased.
I too am not able to find the code files in the files folder of this board.? All of the build pdf files are there.? Would you please repost, or provide another way to look at the files?
Thank you,
73
Evan
AC9TU
|
_Dave_ AD0B