Confirms it many times. :D

Here is the original source.

/g/DRAKE-RADIO/message/28549

73

-Jim
NU0C

On Sun, 4 Feb 2024 09:39:21 -0800
"VE7PS" <ve7ps@...> wrote:

Paul:

A quick search of the group posts confirms Belden #8421.

73
Peter
VE7PS

On Sun, Feb 4, 2024 at 9:33?AM Paul Kraemer <elespe@...> wrote:

Excuse the interruption.

Elderly mind forgot---was the cable recommended for 4 line injection
cable Belden 8421?

Or something different?

Thanks

Paul K0UYA

--

73

-Jim
NU0C

Yes, they do still carry them under different part numbers. Look for Molex KK series 156. Here is one example:





73

-Jim
NU0

On Sun, 04 Feb 2024 09:16:06 -0800
"Dale Parfitt" <PARINC1@...> wrote:

I have a bag of the Molex edge connectors used in the TR-7/R7 if anyone is interested. Looks like Mouser no longer carries them.
Dale W4OP

--

73

-Jim
NU0C

I think I fingered out. I now have my 2 mostly used freq's programmed. It has been many years since using BCD, but I am definitely relearning now.? Thanks for the pointing me in the right direction.

73? Bob

That is correct. Rob, NC0B

Excuse the interruption.

Elderly mind forgot---was the cable recommended for 4 line injection cable Belden 8421?

Or something different?

Thanks

Paul K0UYA

I have a bag of the Molex edge connectors used in the TR-7/R7 if anyone is interested. Looks like Mouser no longer carries them.
Dale W4OP

It's really not that hard but I can see how someone can feel intimidated if they have never worked with BCD before. Binary Coded Decimal. Each of our base-10 digits 0 through 9 is encoded as its 4-bit binary equivalent. That is the reason the switches are treated in groups of 4. The weighting (value) of the switches is 8, 4, 2, 1 reading from left to right. Obviously zero would be 0000 (all switches off). One would be 0001, switch one is on. Simple enough. But what is two? If you said switch 2 on you would be correct, 0010. Since the most convenient way to get to three would be to add 2 + 1 that would be switches one and two on, 0011. Four is just switch 4 on, 0100. And so on up through nine, which is 8 + 1 or 1001. Alert readers may note that if we used three bits instead of four we would have to stop at 7 (111) which would not work very well for us.

Once you have the magic number figured out by doing the math for the actual RF frequency you just set the switches accordingly - paying close attention to the switch layout diagram because things look backwards. You might need to twiddle the least significant switch group number a little to compensate for oscillator error in the rig but the formula should get you pretty darn close. Note that there an 800 Hz offset for CW mode, and the TR5 formulas are a little different so don't use those. :)

While you are bending your mind around binary stuff, think about this: What can we two with two bits? That gives is four numbers, 0 1 2, and 3. The filter switches on the TR7 are a two bit switch, giving us a choice of three optional filters. Where else do we see a two bit switch? The A and B buttons on the RV75! Without changing much at all Drake could have given us a third Fixed switch bank by using the case of both buttons pushed in just like the filter switches! And yes, I have thought about doing just that...

How about computer frequency control? I remember hearing of someone doing just that in the pre-CAT days. A relatively simple hardware interface connected in place of one of the switch banks and some custom software would make for a basic CAT interface. But that's a project for someone else.

73

-Jim
NU0C

On Sat, 3 Feb 2024 15:29:58 -0800
"VE7PS" <ve7ps@...> wrote:

Bob:

You are correct....the manual is a nightmare, especially for those of us
not familiar with programming BCD switches. I also believe there is an
error in the manual in one of the mathematical calculations they show.

You have two programmed frequencies available, A and B. A is the right
half of the entire BCD switch row on the back and consists of two 8 switch
groups and one of four. I found it faster and easier to just alter the
switches, starting with the most significant group of four (the 100's) on
the extreme right (as you look at the rear) and get it set right.....for
40m SSB you may want 200 khz. Continue working to the left with each 4
switch group (treat the 8 switch groups as two 4's) until you get down to
the HZ group. Repeat for Switch B on the left, again starting with the 4
switch group just left of the centre of that entire switch row, and working
to the left.

This is harder to explain than it actually is!

Once you get the hang of what the switches do to the numbers, it gets
easier fast.

Good luck!

73
Peter
VE7PS

On Sat, Feb 3, 2024 at 3:08?PM K6OXN Bob <bobk6oxn@...> wrote:

How do I set the Fixed A or B on the back of the RV-75. I am looking at 40
meter SSB frequencies. The manual is not very clear.

Help

73 Bob

--

73

-Jim
NU0C

How do I set the Fixed A or B on the back of the RV-75. I am looking at 40 meter SSB frequencies. The manual is not very clear.

Help

73? Bob

开云体育

There nothing at all complex to building the FAUX-7 Far Circuits board. Stuff a bunch of common diodes and some connectors onto a circuit board. Solder. Done.

Compared to street price for 2x genuine AUX-7 plus diode modules for the bands of interest you will save a bunch of money.

73

-Jim
NU0C



On Sat, 3 Feb 2024 11:57:26 -0500
"Joseph K4JNG" <jgraif1@...> wrote:

Unfortunately, I don’t believe I possess the required building skills. I’m going to ask the individual working on my 7-line equipment.



joseph n. graif

k4jng



From: [email protected] <[email protected]> On Behalf Of David
Sent: Saturday, February 3, 2024 11:55 AM
To: [email protected]
Subject: Re: [DRAKE-RADIO] Searching for AUX-7 boards…



The aux 7 from Fair Radio is the way to go.. the rest of parts you can get from Mouser or other supply houses.i have used about 10 of these with no issues.



David Assaf III
W5XU VP8RXU



On Sat, Feb 3, 2024, 10:49 AM Jim Shorney <jimNU0C@... <mailto:jimNU0C@...> > wrote:


You will pay a premium price for a genuine AUX-7. A workable substitute that gives you WARC and VLF coverage is what I call the "FAUX-7" board available from Far Circuits. It is a reproduction of a diode matrix AUX-7 replacement published in QST July 1982. You buy the bare board from them and you supply the diodes and connectors. There is also an article I think on wb4hfn.com <> on building your own AUX-7 board. Neither of these includes the provision for a fixed frequency crystal, but in all my travels I have only seen almost one person who used this.

73

-Jim
NU0C

On Sat, 03 Feb 2024 01:38:55 -0800
"Joseph K4JNG" <jgraif1@... <mailto:jgraif1@...> > wrote:

I am in the hunt for two AUX-7 boards, for my TR7 and R7. Please help if you are able…

Best 73,
joe
K4JNG

--

73

-Jim
NU0C

开云体育

开云体育

You will pay a premium price for a genuine AUX-7. A workable substitute that gives you WARC and VLF coverage is what I call the "FAUX-7" board available from Far Circuits. It is a reproduction of a diode matrix AUX-7 replacement published in QST July 1982. You buy the bare board from them and you supply the diodes and connectors. There is also an article I think on wb4hfn.com on building your own AUX-7 board. Neither of these includes the provision for a fixed frequency crystal, but in all my travels I have only seen almost one person who used this.

73

-Jim
NU0C

On Sat, 03 Feb 2024 01:38:55 -0800
"Joseph K4JNG" <jgraif1@...> wrote:

I am in the hunt for two AUX-7 boards, for my TR7 and R7. Please help if you are able…

Best 73,
joe
K4JNG

Here's the epilogue....

The K4DPK stabilizer wouldn't lock on the TR-4Cw/RIT's 5 MHz PTO.? I replaced it with a now-obsolete Cumbria X-Lock device. The X-Lock would only lock on some bands.? The root cause is heterodyne crystal leakage through the 6EA8 converter.? That leakage combined with the PTO output results in a waveform that is troublesome to lock.? The solution required a J310 JFET source follower installed ahead of the converter, leaving a pure sinewave into the X-Lock.? While I had difficulty with lock, perhaps converter leakage isn't consistent across all TR-4 models.? ?

I also took advantage of the existing TR-4Cw/RIT circuit and coupled the X-Lock DC output to the RIT control line.? That method eliminates the addition of another varactor diode inside the PTO can.? In fact, there's no connection made inside the PTO can for either the frequency sense or the output control bus.? Lock is extraordinarily good.? From a cold start to hours later, the PTO stays absolutely locked.? The result is so good, I'm going to replace the K4DPK stabilizer in my TR5 with another X-Lock.? Photo below of the X-Lock installed.

Paul, W9AC

I am in the hunt for two AUX-7 boards, for my TR7 and R7. Please help if you are able…

Best 73,
joe
K4JNG

Are such axial-lead caps used in the R4-B?

Michael (UK) 2E0IHW

Nice find! You should send the info on that QC tag to WB4HFN for his serial number database.

73

-Jim
NU0C

On Fri, 02 Feb 2024 15:07:06 -0800
"K6OXN Bob" <bobk6oxn@...> wrote:

I was able to locate a NIB RV-75 at a reasonable price and it is now part of my shack. Works like it should and I don't think that it was ever installed anywhere. Still in original box and had the temporary manual and QC tag's. I am a happy camper now. Have a great 7 line system.? Late SN TR7, L7 amp, L7PS, MN2000, RV-75, and WH7. Putting out almost legal limit on 40 meters and will be checking other bands soon.

73? Bob

--

73

-Jim
NU0C