Keyboard Shortcuts
Likes
- RacalRadio
- Messages
Search
|
SMT
I have? a few? Racal Cougar Radio SMT amplifiers TA4523L, 70 Mhz band that are set for 10 Watt Tx output. A while ago I remember there was website with details and photos,? how to revert the PA back to 25 watt, but I cant locate it ! Does anyone have a clue if this information is available elsewhere ? Thank you. |
|
Re: WANTED RACAL TA940B 100 WATT HF LINEAR AMP.
Hi Jeff and Terry,
How about making one. You just need a scrap RA17 for some hardware. I moved from RSA to France in 2016 and This one I had got hold of with the intention of rebuilding. It has 2 x TT21's in it. I gave it away to a good friend as I couldn't bring it all. It is quite historic since it was built to match a Wadley loop transmitter in the genre of the MA79 and a clone of the RA17, amazingly all homebrew.
There is a longer story if you are interested.
73, Richard, F4WCD/ZS6TF
|
|
Re: WANTED RACAL TA940B 100 WATT HF LINEAR AMP.
HI Terry,
No luck at all .?? stilll ooking for one.
G8XXI
|
|
Question on RA1779 Sensitivity
Hi everyone,
?
After G0FCT has kindly scanned and sent me a manual for this radio, I now have it working quite well. The first Mixer had a cooked resistor and there were some issues with the preselector, but after a fair bit of effort and some board repairs I now have it working OK.
?
So far it is a very impressive receiver, but it seems to be about 5dBm or so less sensitive on all bands than both the RA6790 I have and also less sensitive that the old RA1217. It is not really noticeable on the lower bands but is obvious on the quieter bands above 20Mhz.
?
Is this normal for this receiver? and if not, does anyone have any suggestion for where to start checking the alignment? I also note that the sensitivity is best in the WB position on the preselector - is this normal also?
?
Cheers,
Peter - VK2AN |
|
TA4793 Harness Option?
¿ªÔÆÌåÓýHi all, ? I have a TA4793A (non-harness) PA/VIU for a Syncal 2000 (thank you, Jeff). Might anyone here have a Harness Option kit, part number 754332? I believe this consists of 1 PCB, one 7-pin connector for the harness and two internal cables to install the PCB into the PA/VIU. One cable connects to the 7-pin harness connector and the other connects to an interface PCB in the PA/VIU. ? Any snowball¡¯s chance someone out there has one of these kits they were saving for a rainy day? ? ? Happy New Year to all. ? ? 73 Eugene W2HX
? |
|
Re: RA6790 Bad Filters?
Yes the U21 on the A4 card,
?
The A7 card cane be the cause of the filters not working correctly, go to CW and vary the frequency up and down and check that it is smooth in both directions.
?
Gary ---------- Original Message ---------- From: "thoyer via groups.io" <thoyer1@...> To: <[email protected]> Subject: Re: [RacalRadio] RA6790 Bad Filters? Date: Sat, 28 Dec 2024 21:05:55 -0500 Thanks Gary, ? Is the 10v adjustment you reference the -10v for the DAC (U21)? If so it is -10V. ? Tom ? From: [email protected] <[email protected]> On Behalf Of gewingerd@... via groups.io ? You can force the filters with the attached file, the A2 is +2 to -4 DB of gain, the A3 is +55 DB of Gain and the A4 is about +60?DB of gain, the 10.00 Volt adjustment on the A4 card is critical for the BITE to run the filters. ? Gary After changing out several IC¡¯s on A4, A6 and A9 and replacing the EPROM sockets, that were corroded by a bad battery, I now have my 6790 up and running. Signal levels seem low though and running the BITE I get errors 33 thru 37 ¨C bad filters in slots 3 thru 7. I bench tested the filters using my sig gen and spectrum analyzer - I know the impedances don¡¯t match but this was just to see if they passed any signal. They each seem to have ¡°reasonable¡± response curves and all seem to have the similar peak amplitudes. The LSB and USB filters pass BITE and also tested ok with similar levels through them in my crude setup. ? My question is, I¡¯m wondering if the test level is possibly low (similar to the received signal level being low) and causing these indicated failures. I¡¯m going through the schematics looking for how the test signal is generated but could maybe use some guidance by those that know these receivers better then I. ? Thoughts? ? Tom W3TA ?
|
|
Re: RA6790 Bad Filters?
¿ªÔÆÌåÓýThanks Gary, ? Is the 10v adjustment you reference the -10v for the DAC (U21)? If so it is -10V. ? Tom ? From: [email protected] <[email protected]> On Behalf Of gewingerd@... via groups.io
Sent: Saturday, December 28, 2024 8:18 PM To: [email protected] Subject: Re: [RacalRadio] RA6790 Bad Filters? ? You can force the filters with the attached file, the A2 is +2 to -4 DB of gain, the A3 is +55 DB of Gain and the A4 is about +60?DB of gain, the 10.00 Volt adjustment on the A4 card is critical for the BITE to run the filters. ? Gary After changing out several IC¡¯s on A4, A6 and A9 and replacing the EPROM sockets, that were corroded by a bad battery, I now have my 6790 up and running. Signal levels seem low though and running the BITE I get errors 33 thru 37 ¨C bad filters in slots 3 thru 7. I bench tested the filters using my sig gen and spectrum analyzer - I know the impedances don¡¯t match but this was just to see if they passed any signal. They each seem to have ¡°reasonable¡± response curves and all seem to have the similar peak amplitudes. The LSB and USB filters pass BITE and also tested ok with similar levels through them in my crude setup. ? My question is, I¡¯m wondering if the test level is possibly low (similar to the received signal level being low) and causing these indicated failures. I¡¯m going through the schematics looking for how the test signal is generated but could maybe use some guidance by those that know these receivers better then I. ? Thoughts? ? Tom W3TA |
|
Re: RA6790 Bad Filters?
You can force the filters with the attached file, the A2 is +2 to -4 DB of gain, the A3 is +55 DB of Gain and the A4 is about +60?DB of gain, the 10.00 Volt adjustment on the A4 card is critical for the BITE to run the filters.
?
Gary ---------- Original Message ---------- From: "thoyer via groups.io" <thoyer1@...> To: <[email protected]> Subject: [RacalRadio] RA6790 Bad Filters? Date: Sat, 28 Dec 2024 19:56:17 -0500 After changing out several IC¡¯s on A4, A6 and A9 and replacing the EPROM sockets, that were corroded by a bad battery, I now have my 6790 up and running. Signal levels seem low though and running the BITE I get errors 33 thru 37 ¨C bad filters in slots 3 thru 7. I bench tested the filters using my sig gen and spectrum analyzer - I know the impedances don¡¯t match but this was just to see if they passed any signal. They each seem to have ¡°reasonable¡± response curves and all seem to have the similar peak amplitudes. The LSB and USB filters pass BITE and also tested ok with similar levels through them in my crude setup. ? My question is, I¡¯m wondering if the test level is possibly low (similar to the received signal level being low) and causing these indicated failures. I¡¯m going through the schematics looking for how the test signal is generated but could maybe use some guidance by those that know these receivers better then I. ? Thoughts? ? Tom W3TA |
|
RA6790 Bad Filters?
¿ªÔÆÌåÓýAfter changing out several IC¡¯s on A4, A6 and A9 and replacing the EPROM sockets, that were corroded by a bad battery, I now have my 6790 up and running. Signal levels seem low though and running the BITE I get errors 33 thru 37 ¨C bad filters in slots 3 thru 7. I bench tested the filters using my sig gen and spectrum analyzer - I know the impedances don¡¯t match but this was just to see if they passed any signal. They each seem to have ¡°reasonable¡± response curves and all seem to have the similar peak amplitudes. The LSB and USB filters pass BITE and also tested ok with similar levels through them in my crude setup. ? My question is, I¡¯m wondering if the test level is possibly low (similar to the received signal level being low) and causing these indicated failures. I¡¯m going through the schematics looking for how the test signal is generated but could maybe use some guidance by those that know these receivers better then I. ? Thoughts? ? Tom W3TA |
|
Syncal TA4793 PA/VIU documentation?
¿ªÔÆÌåÓýHi all, ? I have documentation on the Syncal 2000, but I am looking for any and all documentation on the TA4793 which is the 100W VIU/amplifier and DC-DC converter for the Syncal 2000. If you have such documentation, please contact me. ? For starters, I¡¯m keen to know, which pin on the TA4793 is +24V and which pin is ground. ? Additionally, I would like to accomplish interfacing the VIU with a US-based VIC-3 system. It seems the VIU has provisions for a harness interface, but any of the pictures of these units seem to be lacking this option. I am investigating whether I can just use 2nd audio connector on the radio, or whether it is better to install a connector where the harness connector is located. ? To interface with the VIC-3, I simply need PTT input (grounded to activate), fixed-audio input and fixed-audio output for the radio/VIU. The VIC-3 radio interface has the following specifications:
? Thanks and Happy New Year! ? ? 73 Eugene W2HX
? |
|
Re: Back to my TRA931
Odds are:
You have something wrong on the audio section, and audio is not getting to the modulator. Odds are: The nature of the equipment and the way in which it failed soon after keying up would probably indicate a shorted tantalum cap. Odds are: If you replace the bad tantalum cap the radio will work great until the next tantalum cap fails into a short. It may not take too long. --scott |
|
Back to my TRA931
Hello everyone. It is time to look at my TRA931 again.
Model MA930, s/n 3707.
?
The last I used it a couple of years ago I was outside with the whip antenna and made a ssb contact on 20 meters.
I then went to AM and tried CW. Somewhere during my CQ I lost RF output and that is where I am today.
Hooked up to a Motorola service monitor I can see that it is dead on frequency when I go into the tune mode.
The RX is working just fine when I generate a CW signal on the same frequency.
This rules out most of the rig as being a problem.
When I put it into tune I am only drawling about 660 ma.
This seems to be strictly a PA deck problem.
I do have some manuals here and will start looking at the RF path and see what I can? learn.
Any suggestions from the experience out here?
?
Thanks much,
Dave KC3AM
? |
|
Re: FOR SALE RACAL HAND SET with volume and channel rotary switches built in
Hi, Jeff, is it in nice cosmetic condition? Happy to purchase if you have a price in mind, or deal on a similar-looking US H-250 handset if that night interest you, new unissued, curly cord but no fitted plug.
toggle quoted message
Show quoted text
Bob, G8IYK
|
|
Re: FOR SALE RACAL HAND SET with volume and channel rotary switches built in
Jeff Do you have a photo, and as is customary, can you state a price,Happy Christmas Stuart G0TBI
On Thursday, 26 December 2024 at 12:17:50 GMT, Jeff via groups.io <jeff.akines@...> wrote:
I have for sale a Racal hand set type (unreadable) this has 2 rotary switches one for channel selection, and one for volume.
only thing is, it needs re-wireing as for some strange reason the cable has been cut off but it is reparable with cable and plug of your chose.
I obtained this handset to use wit my CalPac RT-2000 but never got round to re-wireing it. So open to offers.
Jeff?? G8XXI
|
|
FOR SALE RACAL HAND SET with volume and channel rotary switches built in
I have for sale a Racal hand set type (unreadable) this has 2 rotary switches one for channel selection, and one for volume.
only thing is, it needs re-wireing as for some strange reason the cable has been cut off but it is reparable with cable and plug of your chose.
I obtained this handset to use wit my CalPac RT-2000 but never got round to re-wireing it. So open to offers.
Jeff?? G8XXI |
|
Re: RA1778 Maintenance Manual
Hi All
Just a quick thank you to everyone who has responded to my request directly and via the group.
Really appreciate the help and advice. I'm sure I will be able to crack the fault now I'm playing with a full deck.
Will let you know how I get on.
If I can be of help to anyone re other Racal stuff I have a fairly good collection of documentation for the 3700 series.
Best wishes for Christmas and New Year
Richard G3VDE |
|
ISO: Racal Yeoman/ TRA3900 VIU
¿ªÔÆÌåÓýAnyone have a VIU ¨C preferably with cables ¨C for a Racal Yeoman VHF/ TRA-3900 they¡¯d care to part ways with?? ?LR Series used to have them but I missed the boat there.? ?It would be going to Canada if that makes any difference. ? Cheers. ? ? ? ? |
Peter E