HL2 for Satellite Communications: What do I Need to Get Rolling?

[Elan Portnoy]

Have an HL2 and love it. Would like to try working satellites. I have UHF/VHF antennas with preamps on an AZ/EL rotor w/ controller.

Since the HL2 operates in DUPLEX, I assume all I need to get would be a transverter(s). Is it best to have separate VHF and UHF transverters, or would a dual-band unit work just as well?

[Clifford Heath]

I see no reason why a dual-band unit couldn't work, though obviously having band-switched filters will reduce aliasing, local-oscillator feed-through, and potential intermodulation. I had actually been thinking of designing a broad-coverage transverter using the RFFC5071 before my WilySDR design concept took a different path

On Tue, Apr 22, 2025 at 11:45 AM Elan Portnoy <elanp...@gmail.com> wrote:

Have an HL2 and love it. Would like to try working satellites. I have UHF/VHF antennas with preamps on an AZ/EL rotor w/ controller.

Since the HL2 operates in DUPLEX, I assume all I need to get would be a transverter(s). Is it best to have separate VHF and UHF transverters, or would a dual-band unit work just as well?

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[Elan Portnoy]

Thanks for the info. I'll give it a try and post my results.

[Charlie Rubenstein]

If you are planning to run satellites, while the HL2 operates in "duplex" mode, I am not sure it will allow for a different band on one VFO than the other, to hear your transmitted signal on the other band.

A dual-band transverter (like the Ukranian ones on eBay) clearly will not operate in duplex mode. They are EITHER VHF or UHF, switchable.  I have run full duplex with TWO HL2's each with a transverter, one for VHF, the other HL2 with a UHF transverter. It required running two instances of Thetis (or PiHPSDR) to accomplish full duplex.

Charlie KB8CR

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[Elan Portnoy]

Ah. Interesting point. What you say makes sense--will have to reconsider my plans. Thanks

[Clifford Heath]

While the HL2 gateware might not allow receive and/or transmit channels across bands, the hardware is perfectly capable of that. The actual receivers in the RTL are independent and could each run anywhere in the HF spectrum. However, you have to consider that the input to the HL2 should be filtered to just the frequencies that are in use, and the topology and switching of the filter board might not support that.

Clifford Heath

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[Luke Williams]

If you are using transverters for both satellite bands, it is most likely that you’d need the transmit and receive from the HL2 to both be on 10 meters.

Luke - AE5AU

Sent from my iPhone

On Apr 23, 2025, at 18:45, Clifford Heath <cliffor...@gmail.com> wrote:



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[Elan Portnoy]

So then, two separate transverters and one HL2 on 10 meters in duplex should work. 

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From: Luke Williams <lukeaw...@gmail.com>
Sent: Wednesday, April 23, 2025 7:07:40 PM
To: Clifford Heath <cliffor...@gmail.com>
Cc: Elan Portnoy <elanp...@gmail.com>; Charlie Rubenstein <charl...@gmail.com>; Hermes-Lite <herme...@googlegroups.com>
Subject: Re: HL2 for Satellite Communications: What do I Need to Get Rolling?

 

[Clifford Heath]

Two separate transverters (one up, one down, or two up) are what I had in mind with the RFFC5071

[Hamish Kellock OH2GAQ]

Hi,

I have been using a single HL2 plus a special 144/28 MHz full duplex "converter" (actually separate up and down converters using the same LO) together with several  microwave transverters for some time now. One of these microwave transverters is a full duplex  10GHz input/2.4GHz output with 144 MHz IF. The full duplex works well in the single HL2, have had many contacts on the QO100 satellite. I have separate filters in the Tx and Rx paths at 28 MHz, not using the HL2 filter board as it does not handle the full duplex. The common 116 MHz LO has good isolation between its two outputs (to the Rx and Tx converters) so there is no feedback path that way. I can monitor my 2.4 GHz transmitted signal by listening to the received 10 GHz from QO-100 .

So I can confirm that a single basic HL2 board works well in full duplex mode, but you have to keep the Rz and Tx paths separate. I use the low power tx port.

I have used both Quisk and piHPSDR as SW solutions, they both work very well. I published an article about this in the Finnish Radio Amateur magazine last year, I can make this available if anyone is interested.

73,

Hamish, OH2GAQ

[Probir]

Hi Hamish,

Would like to read your article. Could you make us available

73

Probir, VU2BQF

[Walter Holmes]

I used 2 HL2 units with transverters for years with excellent results.

Had to make a minor mod, to add a secondary receive jack on it. 

Running two instances of PowerSDr at the time was simple, but took a little to adjust to.

Walter/K5WH

[Elan Portnoy]

Walter: which transverters did you use?

[Hamish Kellock OH2GAQ]

Hi Probir,

I have updated my website on QSL.Net (OH2GAQ) with the article about the full duplex Microwave Transverter Controller. It is the V3 version. There is also some more detailled information about the full-duplex 144/28 MHz transverter under the material "Full duplex MTC". Both these are in the Projects page.

Hamish/OH2GAQ