VHF on HL2

[Duncan Clark]

Hi Folks,

As 2m was mentioned I wonder how many have seen what G4JNT has done for
the ELAD FM-Duo as recently published in the RSGB's Radcom.

http://www.g4jnt.com/FDM-DUO_at_VHF.pdf

I ran the numbers, I think OK, for the HL2 but haven't got around to do
anything about it yet other than get hold of a few PGA103s.

I keep thinking that the underside of the HL2 enclosure with it's own
slot would take a nice board for 6m and 4m. No idea if 2m would be
usable.

Normally I etch my own boards but a professionally made plated-through
board would be nicer. I have no skill in using Kicad but if others have
.....

Chris Bartram G4DGU has also hinted at doing a design for the DUO which
he will share when it's finished.

Duncan
--
Duncan Clark
G4ELJ

[dick_...@hotmail.com]

I do not know if anyone is interested in a reasonably priced [$85 US] 144MHz transverter that is completely assembled and about the same size as the HL2 case.

The Transverter store, in the Ukraine is the vendor.  Several other bands and unassembled options are available.

The transverter has an 30Db input attenuator and is usable with a 5-10 W tranceiver like the HL2.

A Down East Microwave / Q5 Signal this is not, but then it is an order of magnitude or two less expensive.

http://transverters-store.com/assembled_tr.htm

Dick K9IVB

[Walter Holmes]

Anyone have experience on their frequency stability?  As that would be critical.

Certainly the price is attractive.

thanks,

Walter/K5WH

[in3otd]

Hello,

some time ago I bought a 144/28 MHz transverter board very similar to the one shown on that website. There are/used to be several vendors on eBay offering these transverters at a very low price, apparently all using the same circuit and only minor differences on the PCB layout.

For that price one should not complain much, anyway there are a couple of things that I did not like

- the RX noise figure is much higher than the 1 dB specs; it's actually more around 4 dB IIRC

- the LO is based on a 58 MHz XTAL which is doubled to 116 MHz; unfortunately the LO filtering leaves a non-negligible 58 MHz third harmonic so there is an image at 58 MHz * 3 - f_rx which is not suppressed much. So when you tune to 28 MHz you will receive not only at 58 MHz *2 + 28 MHz = 144 MHz but will hear also any strong station at 58 MHz * 3 - 28 MHz = 146 MHz

- the TX output must be limited to much less than the stated 10 W max to have a reasonably clean output, IIRC its output is good up to a couple of watt maximum.

Having said that, my intention is to use the transverter as IF for another microwave transverter and it may be good enough for this purpose. It also fits nicely in the same case with the H-Lv2 and can be driven with the H-L low-power driver output. With some clever switching one could be able to get a complete HF/VHF RTX, with separate antenna connections in the same case.

I did not measure the original XTAL frequency stability since I actually later disconnected it and feed the LO from the VersaClock output on the H-Lv2, programmed to provide 38.4 MHz * 3 = 115.2 MHz which is near enough to 116 MHz and surely has better stability.

I should have some measurements around, I just need to find where, hi.

73 de Claudio, DK1CG / IN3OTD

[dick_...@hotmail.com]

Hello Claudio

Your comments are very interesting.  The source that I posted is of a different design with a 38.666MHz oscillator.  The picture shows a low profile crystal and I would think it would be in the 10 - 50 ppm area.

The input is a MOSFET cascode circuit but there is no way to predict performance from the schematic.

Do you have any details on how and where the "VersaClock output on the H-Lv2, programmed to provide 38.4 MHz * 3 = 115.2 MHz" is located.  I can find the 38.4 MHz output on page 4 of the schematic  with a DNI jack CL3 but not the location of the 115.2 MHz output.

I think others would like to use this feature for any 2M transverter.

I have some ICS501's remaining [now $1.50 ea] and they are a  LOCO PLL Clock Multiplier that work very well as a tripler [programmable from x2 to x8].  I even have a small board with multiple options from a previous project for a 2M converter.  So it would be easy to tap the 38.4 MHz signal shown on page 4 and add an output on the rear panel that was 115.2 MHz.

73,

Dick K9IVB

[Jan OZ1OY]

Hi Dick, Claudio and group
I have 3 transverters (4M, 2M and 70 cm) from Ukraine and I agree with Claudio's comments. On 4M and 2M I have used a ADF4351-board from Ebay to generate LO at 42 or 116 MHz to the transverters. Output signal from ADF4351 is transfered via a small capacitor (25-50 pF) direct over the crystal in the transverter.
In this way I also can stay stable on the frequence when the PA-transistor warm up the transverter-PCB and the crystal.

73 OZ1OY, Jan

[dick_...@hotmail.com]

I did find the documentation on my ICS501 board and circuit.  Thought I put on web page, but no.

It is attached here.

Dick K9IVB

[Steve Haynal]

Hi Dick,

The HL2 provides a oscillator output via the unpopulated CL2 on the front of the board. See page 4/7 with title "Clock" in the schematic. You can add an SMA connector and create a second clock with the low jitter Versa5 clock generator. The source oscillator for the Versa5 is 38.4 MHz, <= 1ppm. This is what Claudio used. Quisk has code to set the oscillator. See VersaOut2 in hermes/quisk_hardware.py.

73,

Steve

kf7o

  def VersaOut2(self, divisor): # Use the VersaClock output 2 with a floating point divisor

    div = int(divisor * 2**24 + 0.1)

    intgr = div >> 24

    frac = (div & 0xFFFFFF) << 2

    self.WriteVersa5(0x62,0x3b) # Clock2 CMOS1 output, 3.3V

    self.WriteVersa5(0x2c,0x00) # Disable aux output on clock 1

    self.WriteVersa5(0x31,0x81) # Use divider for clock2

    # Integer portion

    self.WriteVersa5(0x3d, intgr >> 4)

    self.WriteVersa5(0x3e, intgr << 4)

    # Fractional portion

    self.WriteVersa5(0x32,frac >> 24) # [29:22]

    self.WriteVersa5(0x33,frac >> 16) # [21:14]

    self.WriteVersa5(0x34,frac >>  8) # [13:6]

    self.WriteVersa5(0x35,(frac & 0xFF)<<2) # [5:0] and disable ss

    self.WriteVersa5(0x63,0x01) # Enable clock2

  # Thanks to Steve Haynal for VersaClock code:

  def WriteVersa5(self,addr,data):

    data = data & 0x0ff

    addr = addr & 0x0ff

    ## i2caddr is 7 bits, no read write

    ## Bit 8 is set to indicate stop to HL2

    ## i2caddr = 0x80 | (0xd4 >> 1) ## ea

    self.pc2hermeslitewritequeue[0:5] = 0x7c,0x06,0xea,addr,data

    self.WriteQueue(1)

  def EnableCL2_sync76p8MHz(self):

    self.WriteVersa5(0x62,0x3b) ## Clock2 CMOS1 output, 3.3V

    self.WriteVersa5(0x2c,0x01) ## Enable aux output on clock 1

    self.WriteVersa5(0x31,0x0c) ## Use clock1 aux output as input for clock2

    self.WriteVersa5(0x63,0x01) ## Enable clock2

  def EnableCL2_61p44MHz(self):

    self.WriteVersa5(0x62,0x3b) ## Clock2 CMOS1 output, 3.3V

    self.WriteVersa5(0x2c,0x00) ## Disable aux output on clock 1

    self.WriteVersa5(0x31,0x81) ## Use divider for clock2

    ## VCO multiplier is shared for all outputs, set to 68 by firmware

    ## VCO = 38.4*68 = 2611.2 MHz

    ## There is a hardwired divide by 2 in the Versa 5 at the VCO output

    ## VCO to Dividers = 2611.2 MHZ/2 = 1305.6

    ## Target frequency of 61.44 requires dividers of 1305.6/61.44 = 21.25

    ## Frational dividers are supported

    ## Set integer portion of divider 21 = 0x15, 12 bits split across 2 registers

    self.WriteVersa5(0x3d,0x01)

    self.WriteVersa5(0x3e,0x50)

    ## Set fractional portion, 30 bits, 2**24 * .25 = 0x400000

    self.WriteVersa5(0x32,0x01) ## [29:22]

    self.WriteVersa5(0x33,0x00) ## [21:14]

    self.WriteVersa5(0x34,0x00) ## [13:6]

    self.WriteVersa5(0x35,0x00) ## [5:0] and disable ss

    self.WriteVersa5(0x63,0x01) ## Enable clock2

On Tuesday, June 4, 2019 at 10:48:55 AM UTC-7, dick_...@hotmail.com wrote:

[Marc OLANIE]

Hi
There is a very simple, low noise, rather stable and easy to build transverter working on 2 meters or 70 cm band, designed many years ago by N2PK for it's high-end VNA
https://www.makarov.ca/vna_transverter.htm
http://n2pk.com/VNA/SimpleTransverter1.zip
Alas, Ivan do not sell the pcb anymore, but it's a rather simple schematic. Some attenuators should be lowered or strapped.

If you are looking for a good transverter without the cost of a DB6NT, this one could be a good challenger. And it's a nice link between a HL2 and a 10 GHz downconverter.

Marc f6itu

-----Message d'origine-----
De : herme...@googlegroups.com <herme...@googlegroups.com> De la part de Jan OZ1OY
Envoyé : mardi 4 juin 2019 20:25
À : Hermes-Lite <herme...@googlegroups.com>
Objet : Re: VHF on HL2

--
You received this message because you are subscribed to the Google Groups "Hermes-Lite" group.
To unsubscribe from this group and stop receiving emails from it, send an email to hermes-lite...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/hermes-lite/b5d66922-3854-4a55-a50d-e733642fc37d%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Reid Campbell]

Hi Group,

First off I would like to thank everybody who has brought us the HL and
in particular Steve, where do you get the time!! So far I have only been
playing with my HL into a dummy load but I hope to get a decent aerial
up so.

I have been watching the discussion on transverters with great interest
and have a suggestion.

Most transverters transpose the higher frequency down to the 10 metre
band but I was wondering if a better choice for the HL would be around
34MHz, into a dead band area. If the signal from the filter board, on
receive, was directed to the transverter board, it could be low passed
filtered to remove anything above 30 MHz. The transverter could then
inject the 34MHz down converted signal (140, 60, 70 MHz) into the
receive path.

This would apply the full HF spectrum and the down converter frequency
to the HL, so allowing the converted frequency to be included in one of
the HL's 4 receivers. I hope you see where I'm coming from.

I'm not sure of the exact path of the Rx and Tx signals and if they
could be directly taken from the 20way HL to filter connector. The ideal
situation would be to replace the 20 way connector jumper PCB with the
convertor board.

 Lastly, could the transverter be made multi band if we have a
programmable clock source? Food for thought.

Cheers

Reid Gi8TME/Mi0BOT

[Steve Haynal]

Hi Reid,

There is a low pass filter on the HL2 RX path. This starts attenuation in the 30 MHzs range. It might cause problems at 34MHz. 

73,

Steve

kf7o

[Reid Campbell]

Hi Steve,

Ok, just checked the circuit and I see the LPF. I see there is a connector (RF4) after the LPF, so I assume a BPF'ed 34MHz converted signal could be diplexed in at that point. I would all assume that would also be the point that a under-sampled signal would be introduced. RF4 looks like it will accept a surface mount micro RF connector.

Cheers

Reid Gi8TME/Mi0BOT

--
You received this message because you are subscribed to the Google Groups "Hermes-Lite" group.
To unsubscribe from this group and stop receiving emails from it, send an email to hermes-lite...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/hermes-lite/f0df2e42-a0b1-4523-878c-bc49a491b767%40googlegroups.com.

[Alan Hopper]

Hi Reid,

we did some experiments with undersampling a while ago and that is one reason why that connector is there, there are issues though as the analog bandwidth of the adc is not very usable past 50Mhz, you can pick up broadcast fm transmisions  but that is about it. Should a HL3 ever appear it would be nice to find a device with enough analog bandwidth for undersampling at higher frequencies as it is a nice solution and avoids all the the mixing issues of conventional solutions.

73 Alan M0NNB

To unsubscribe from this group and stop receiving emails from it, send an email to herme...@googlegroups.com.

[Steve Haynal]

Hi Reid,

Yes, that connector is for undersampling. It could be used also for 34MHz reception, but that is close to the Nyquist frequency of 38.4 MHz, so some care to avoid aliasing is necessary. See the link below for the intended RF surface mount connector.

https://github.com/softerhardware/Hermes-Lite2/wiki/Hermes-Lite-2.0-Getting-Started-Kit#rf-and-clock-connectors

73,

Steve

kf7o

[Reid Campbell]

Hi Alan,

You're not the first to mention the broadcast FM issue but that should
be taken out by any LPF. I think a 6 metre signal would under sample to
around 12 MHz but all other reception of the HF would not be possible,
so negating the use of 4 receivers which is one of the big SDR and HL
features.

A first test would be to take a conventional 144 to 28 MHz transverter
and diplex the output into the under sample input of the HL, being
careful to disable transmit in the transverter. I imagine the matching
and termination will be an issue as the LPF be will look like 50 ohms at
28 MHz. but signals should be receivable.

If that proved the basic concept of mixing a down converted signal with
HF signals, then the transverter LO could be modified from the usual 116
to 110MHz, giving a 34MHz signal. The output filters of the transverter
would need to be adjusted as well, hopefully within their tunable range.

Cheers

Reid Gi8TME/Mi0BOT

[Alan Hopper]

Hi Reid,

I mentioned fm broadcast not as a problem but a fun feature keen experimenters could play with, 6m reception works quite well (tested on HL1 without the lpf). It is an interesting idea to inject the down converted signal into a clean hole in the spectrum so multiple receivers still work. You have got me pondering sw configuration for this.

73 Alan M0NNB

ps 6m downconverts to fs/2 - (50MHz-fs/2) as alternate nyquist zones are reversed, Spark hides this and also keeps usb as usb.