QCX+ 6 meters ? #6m #qcx


sylcou12@...
 

Good morning all,

I am new in this group, and I just finished building my QCXmini 40m with success.  While it worked the first time i put the power on, I am still a beginner in electronics, even though I already have built a few CW transceivers such as Frogsound, Pixie, Rockmite, 49er, etc...  I understand the basic components, but am still learning on how they interact in a transceiver.

Having completed a 40m QCX, i was looking at building another one, but that would operate in the 6 meters band.  I really don't know how to tackle this one, but if i could find a plan or schematics somewhere, i probably would be able to build it.  I am not sure  if i would have to modify the radio itself, or would have to build what you call a "transverter".

Would anyone have any insight into this ?  Many thanks in advance,

Sly C
VA2YZX


Dean Smith
 

I've successfully built a 10m version,  but stopped short of 6m one as the fst3253 ic is being pushed a little to far for this band. Having said that I know of one ham that has built and is using one for qrss grabber purposes.
Dean (G7EOB)


sylcou12@...
 

Thanks Dean,

so a transverter might be the solution then... 
i am not sure though of what frequency would be converted to 6m.  Would it work from 40m?

73,

Sly VA2YZX


Timothy Fidler
 

Sly,  Transverters generally work by tripling or  5x  (144 Mhz) the transmitter output.  The tranmistter clearly has to be attenuated  for this to happen and the power is added later with a class C amplifier.  There is a two meter transverter available for  10 m out of  Russia for a reasonable price - around 70 USD or so and it is fully built up.  Pout is around 7 W. 
if you want 6mtrs I don't think there are any kits or built up PCBs available to convert a more conventional  HF band.  

If you start at  17 mtrs, specifically  18 Mhz and triple it then you end up at the high end of the US  6mtr band.   There are projects for signal sources in the  2015 edn of the ARRL H B that do this  (based on a  crystal source) that are "reference designs  " for modification..  Claimed Pout is 1 W.   I don't believe the PCBs are available for this and how successful  a rebuild on veroboard might be I could not say.  Anyway it is a starting point.

For  Rx  you 'd likely be safest with a  Cmos canned oscillator at , converting it to a sine wave (not trivial at that frequency) and using it to drive the mixer of a SA612 to convert  53 Mhz bad down to  18 Mhz .  This however will give you effectively only a transmitter / Rx combination.   A  25 Mhz oscillator  will difference off  54 Mhz to give you 29 Mhz so  doing the Rx with a  BFO equipped comms receiver  like the Degen 1102 or Tecsun PL330  is indeed a practical possibility. Hans has  BPF kits that have been modified for VHF use - you'd need one of these ahead of the  SA612 mixer  and even building and testing that is not a trivial matter. 

DIP versions of the SA612 are  now getting rather hard to find.  The SA 612 is good as a mixer to  200 Mhz.


Mike Perry, WA4MP
 

On Dec 9, 2021, at 5:46 am, sylcou12@... wrote:

so a transverter might be the solution then...
i am not sure though of what frequency would be converted to 6m. Would it work from 40m?

This guy in the Ukraine makes a variety of all-mode HF to VHF transverters. He starts with 10 meters, since that has the widest HF band and thus offers the widest range when translated. Just keep in mind he describes his gear the opposite of how I would. "50 to 28 MHz ASSEMBLED TRANSVERTER” means a 10 meter transceiver sending and receiving on 6 meters. The power out is from 10-15 watts. He also offers a kit version for less.

With this transverter you can operate on 6 meter band using any type of HF radio that has 10 meter band. It would work the whole 6m band at 50 to 54 MHz if your base radio has 28 to 32 MHz band. It works any modes such SSB, CW or FM if its available in your radio.
https://www.ebay.com/itm/291757178238

He offers it with and without an attenuator board, so you can adapt it to the output of your HF transceiver. I’ve only saved him as a seller just in case. I’ve not bought anything from him.

—Mike Perry, WA4MP


sylcou12@...
 

Many thanks Tim, ill look into this for sure.

Sly VA2YZX


sylcou12@...
 

Thanks Mike,

Apparently he does not ship to Canada, but i'll ask him just in case.  That would be awesome if he did, until i can build something myself one of these days.

I'd love to do meteor scatter 6m someday with the QCX, an ambitious project...

73,

Sly VA2YZX


Mike Perry, WA4MP
 

Perhaps it is some issue with customs or with the shipping firm he uses. I imagine he does ship to the U.S., so you might have ship to a friend there.It’s not like you’re ordering something illegal. Get in touch with him. I did have an email exchange with him about my suggestion that he create a compact transverter that’d put one of the cheap 2 meter handhelds that almost everyone owns onto 10 meter FM for the upcoming sunspot cycle.

With supply, shipping and a host of other issues it really does feel like the world is falling apart. As you may have heard, even Amazon, huge as it is, can’t keep its servers up.

—Mike Perry, WA4MP

On Dec 9, 2021, at 6:39 pm, sylcou12@... wrote:

Thanks Mike,

Apparently he does not ship to Canada, but i'll ask him just in case. That would be awesome if he did, until i can build something myself one of these days.

I'd love to do meteor scatter 6m someday with the QCX, an ambitious project...


Jim Allyn - N7JA
 

On Thu, Dec 9, 2021 at 12:31 PM, Timothy Fidler wrote:

Sly,  Transverters generally work by tripling or  5x  (144 Mhz) the transmitter output.

     That may have been true at one  time, but it isn't true now.  Years ago, hams who had a 2 meter radio (for example) would triple the CW or FM output  to get on 70 centimeters.  This provided a CW or FM transmit signal, but a receiving solution was still required.  These days transverters use mixing to convert signals up and down, and do not use multiplication.  Multiplication may be used in the local oscillator (LO) chain, but not in the signal chain.

The tranmistter clearly has to be attenuated  for this to happen and the power is added later with a class C amplifier. 

Most hams wanting to get on higher bands would like to use SSB or other modes that require linear amplification, therefore, Class C amplification is NOT suited for typical transverter applications.  Typically, Class B, Class AB, or Class A amplification is used in transverters.

There is a two meter transverter available for  10 m out of  Russia for a reasonable price - around 70 USD or so and it is fully built up.  Pout is around 7 W. 
if you want 6mtrs I don't think there are any kits or built up PCBs available to convert a more conventional  HF band.

I'm thinking when you say Russia you are probably actually meaning Ukraine.  transverters-store.com (in Ukraine) has transverters to/from 6 meters from the 10 meter band.

If you start at  17 mtrs, specifically  18 Mhz and triple it then you end up at the high end of the US  6mtr band.

Again, transverters do not generally use multiplication.  The 17 meter band is from 18.068 to 18.168 MHz.  Tripling either of those frequencies will put you well **above** the 6 meter band.  (54.204 to 54.504 MHz)  At least in the US, amateur operation above 54 MHz is illegal.

For  Rx  you 'd likely be safest with a  Cmos canned oscillator at , converting it to a sine wave (not trivial at that frequency)

I'm not sure why that would be "safest" but regardless, converting a CMOS oscillator to a sine wave would in fact be trivial.  All you need is a low pass filter to eliminate the harmonics.  This would give you a sine wave at the fundamental frequency of the oscillator.  Some mixers will work with either sine wave or square wave LO input, while other mixer architectures may require only square wave or only sine wave.  The Analog Devices AD831, for example, has a limiting amplifier built into it to ensure that the mixer core is driven with a square wave.  And MiniCircuits says their double balanced mixers will usually show reduced distortion with square wave LO drive.

When I say multiplication in this context I mean the integer frequency multiplying ( x2, x3, x4, etc.) of a signal, not the mathematical multiplication that we usually refer to as mixing.


sylcou12@...
 

Thanks Jim for your explanation, it all starts to make sense now.  Thant explains why the "input" has such a wide MHz range.

I found other vendors who seem to sell the same kit with attenuator:
https://www.ebay.com/itm/141919334080?hash=item210b0d2ec0:g:qyYAAOSwP8BZuASe
Does it also work in "receive"?
I am not sure to understand the 2 outs "vhf" vs "trx"

Should that work, i guess i'd have to be looking for a 50hz-specific Amp, since my 50W QCX amp is band specific ?

73,
Sly VA2YZX


sylcou12@...
 

... i forgot a subsequent question:  how do you know what frequency you are transmitting on, since there does not seem to be a frequency readout ?

73

Sly VA2YZX


Mike Perry, WA4MP
 

That’s a good find. Judging by what is said in the description, this source is approved by that Ukrainian developer. It’s irritating to see gear from sources like QRP Guys copied by Chinese sources down to the “QRP Guys” lettering on the PC board.

Those who plan to go on VHF with digital modes, might look at that developer’s new offerings. Digital modes require a more stable frequency source. Like Hans, he has models that come with a TCXO for more stability.

This NEW MODEL TCXO SERIES of Transverters contains SPECIAL ORDERED SMD type of TCXO with +-1ppm stability. It makes this Transverter especially good for Digital Modes operation. Additionally we added the narrow two coils Band Pass filter of the LO frequency that more suppressed unwanted emission.

https://www.ebay.com/itm/224379614336

—Mike Perry, WA4MP

On Dec 10, 2021, at 5:12 am, sylcou12@... wrote:

Thanks Jim for your explanation, it all starts to make sense now. Thant explains why the "input" has such a wide MHz range.

I found other vendors who seem to sell the same kit with attenuator:


ajparent1/KB1GMX <kb1gmx@...>
 

As someone that has built several radios for 6M and operates there on a regular basis...
I'll hit the high points.  Keep in mind unlike HF signal at a distance are often weak.

FOR USA:
Band plan is 50.000 though 50.99999 ius CW only!
SSB start at 50.100 though 50.4.
AM can be found regionally on 50.4
Generally above 52mhz is FM, some repeaters.

The best band for transverter to 50mhz is 10M (28mhz), or some cases
20M 14.000 depending on the transverter ( one I have is the old tentec 1208).
 Rare is the transverter for 40M to 6.

I believe Canada is close to the same as here (USA).

Transverters or basically bidirectional frequency changers with power
amp stages.  There are band pass and low pass filter plus the various
amplifier stated to make them work.

The QCX does not have a preamp in RX and as such would be considered
by any as chronically deaf compared to the usual 6M radio or
transverter/radio combo.  Doing class E on 6M is harder than it looks and
most fail and end up with class C or maybe class B amps at lower power.

Many cmos canned oscillator have far to much phase noise to be  a
passable RX LO or TX CW source.  For 10M to 6M  trnasverter LO a
simple 22mhz osc using a transistor will do far better.

Transmit CQ/SSB/FT8 are the common modes.  During sporadic E season 
(late spring to early summer  in NA) SSB  and FT8 are dominant.  CW is
more common for contests.

If you want to get out of your own yard with QRP, not less than a 3 element beam 
higher than ones roof is a start, rotor to turn it as well..


Allison
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due to address harvesting


Jim Allyn - N7JA
 

On Fri, Dec 10, 2021 at 03:12 AM, <sylcou12@...> wrote:
I found other vendors who seem to sell the same kit with attenuator:
https://www.ebay.com/itm/141919334080?hash=item210b0d2ec0:g:qyYAAOSwP8BZuASe
I would probably buy direct from transverters-store.com.  The link may actually be to the same vendor, but it may also be to someone who sells an inferior product.  I have bought several items direct from transverters-store.com and have been happy with the product and the service.  You never know what you will get if you go somewhere else.

Does it also work in "receive"?
Yes, it does.

I am not sure to understand the 2 outs "vhf" vs "trx"
Some people like to use a separate transmitter and receiver instead of the all-in-one transceiver most of us use.  The 2 outputs are for that.  Would also be useful when using an external power amplifier.

Should that work, i guess i'd have to be looking for a 50hz-specific Amp, since my 50W QCX amp is band specific ?
Yes.  The QRP-Labs 50 watt amplifier won't operate as high as  6 meters, and will only work with CW (and some digital modes), not with SSB.  So yes, you'd be looking for another amplifier.


Jim Allyn - N7JA
 

On Fri, Dec 10, 2021 at 05:25 AM, <sylcou12@...> wrote:
i forgot a subsequent question:  how do you know what frequency you are transmitting on, since there does not seem to be a frequency readout ?
Ordinarily, a transverter will align the bottom of the VHF band with the bottom of the HF band.  So, 28 MHz in will give you 50 MHz out, 29 MHz in will give you 51 MHz out, and so on.  Some HF transceivers can be programmed for working with transverters.  In that case, the HF radio would read out the actual VHF frequency you will be receiving and transmitting on.

I see that the transverters-store does have an ebay store.  Now that I am reminded of it, I think the transverters-store items I bought were bought through ebay.


sylcou12@...
 

Jim, many thanks for taking the time to answer my questions.  I know a bit more where to look and what to look for.

73,

Sly VA2YZX


Jim Allyn - N7JA
 

On Sun, Dec 12, 2021 at 04:42 PM, <sylcou12@...> wrote:
Jim, many thanks for taking the time to answer my questions.
You're quite welcome, Sly!