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Juma TRX-2 Firmware Version 3.0a Build 31

This version changes the way the Rapid Band-Switch function operates. In the previous versions, in order to eliminate the possibility of a cross-band transmission when operating in the SPLIT mode (VFO-A for receive, VFO-B for transmit), whenever a band change occurred, even in the simplex mode, the ...
by 5B4AIY
23 Aug 2017 05:53
 
Forum: Juma Firmware by 5B4AIY
Topic: Juma TRX-2 Firmware Version 3.0a Build 31
Replies: 0
Views: 117

Juma TRX-2 Version: 3.0a Build 30

There is a new version of my firmware which modifies the way that the Rapid Band-Switch feature operates. It adds a sub-mode that allows the User Memory to be used as a temporary 'scratch-pad'. I was asked if it was possible to save a frequency temporarily. The scenario envisioned tuning, for exampl...
by 5B4AIY
13 Aug 2017 10:37
 
Forum: Juma Discussion
Topic: Juma TRX-2 Version: 3.0a Build 30
Replies: 0
Views: 83

Juma TRX-2 Version: 3.0a Build 30

Version 3.0a Build 30 modifies the way the Rapid Band-Switch feature operates. In this version RBS has 5 modes of operation: DEFAULT In this mode the frequencies are fixed, and are roughly in the centre of the 9 bands from 160m to 10m, and are legal for the IARU Region 1 as well as the USA General/E...
by 5B4AIY
13 Aug 2017 10:28
 
Forum: Juma Firmware by 5B4AIY
Topic: Juma TRX-2 Version: 3.0a Build 30
Replies: 0
Views: 72

Re: Circuit diagram of TRX2A Main Board Rev. C?

Hi, Frank, Attached to this post are the details of the Revision C version of the Main Board. The principle change is the incorporation of the Spur Elimination module rather than having it as a separate attachment as it is in the Revision B version. On the image, you can see this in the top left-han...
by 5B4AIY
06 Aug 2017 07:08
 
Forum: Juma Discussion
Topic: Circuit diagram of TRX2A Main Board Rev. C?
Replies: 3
Views: 143

Re: RX1 Adjustment

Good Morning, Martin, Perhaps I can help. You are referring to the crystal oscillator frequency compensation adjustment. The master oscillator is a 20MHz crystal, and it has a manufacturing tolerance such that the frequency of oscillation may not be exactly 20MHz. By performing this adjustment you c...
by 5B4AIY
25 Jul 2017 05:25
 
Forum: Juma Discussion
Topic: RX1 Adjustment
Replies: 2
Views: 187

Re: DDS and PIC soldering on TRX2A DDS board

Hi, Alain, I used RMA (Rosin Mildly Activated) flux that I obtained on eBay. It has the brand name of Powerfix, and is to DIN EN 29454-1, and is manufactured by Abraham Diederichs GmbH & Co, Oberkamper Strasse 37-39, D-42349, Wuppertal, Germany. This flux is a soft, light honey coloured paste, a...
by 5B4AIY
14 Jun 2017 14:00
 
Forum: Juma Discussion
Topic: DDS and PIC soldering on TRX2A DDS board
Replies: 4
Views: 295

Re: DDS and PIC soldering on TRX2A DDS board

Hi, Alain, I am sorry that you encountered such difficulty in mounting the DDS and PIC chips. I would agree that these are the two most difficult aspects of the assembly, and, as you have discovered, there is no room for error. I can only speak for myself, but having made a similar mistake as you, f...
by 5B4AIY
14 Jun 2017 05:57
 
Forum: Juma Discussion
Topic: DDS and PIC soldering on TRX2A DDS board
Replies: 4
Views: 295

Re: TRX2A Main Board short diagnostic

Hi, Frank, You are right, there is no mention of this in the constructional notes I sent you, and indeed, to try and write a document to diagnose every fault is clearly impossible, there are just far too many variables to deal with. In this case you will have to try and discover what is drawing the ...
by 5B4AIY
31 May 2017 12:37
 
Forum: Juma Discussion
Topic: TRX2A Main Board short diagnostic
Replies: 5
Views: 435

Re: TRX2A Main Board short diagnostic

Hi, Frank, You still have a problem. The major current consumption is by Q1 and Q2 on the receiver section if you have recent (Revision C) main board, or the Spur Elimination module if an older version. These two transistors consume about 13mA to 15mA each. the rest of the integrated circuits fed fr...
by 5B4AIY
31 May 2017 06:54
 
Forum: Juma Discussion
Topic: TRX2A Main Board short diagnostic
Replies: 5
Views: 435

Re: TRX2A Which screws?

TRX2 Front Panel.JPG Hi, Frank, I am attaching a photo of the front panel of my Juma TRX-2. You will note that the DDS board is secured to the front panel by means of a threaded spacer, illustrated in your parts list, and identified as a 12mm M3 'spacer screw', which is secured to the DDS board. Th...
by 5B4AIY
22 May 2017 10:02
 
Forum: Juma Discussion
Topic: TRX2A Which screws?
Replies: 4
Views: 418
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