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Re: [VHFcontesting] Sentry SDR transceiver...

To: vhfcontesting@contesting.com
Subject: Re: [VHFcontesting] Sentry SDR transceiver...
From: Roger Rehr <73w3sz@gmail.com>
Date: Mon, 20 Oct 2014 18:51:05 +1300
List-post: <vhfcontesting@contesting.com">mailto:vhfcontesting@contesting.com>
I am sad to hear this.

But, given their reasons for not going forward, maybe they will
consider open sourcing it so that interested hams can form a
cooperative to move forward, much like what has happened with HPSDR.

Very 73,

Roger Rehr
W3SZ

On Mon, Oct 20, 2014 at 12:36 PM, Tom <k8tb@bosscher.org> wrote:
> Remember how excited we all go when we heard about the Sentry SDR rig, going
> up to 1400 MHz?
>
> Some sad news:
>
>>After three long years development work resulting in a working prototype we
>> have reluctantly decided not to put the Sentry SDR transceiver into
>> production.
>
> We realize that without a major expansion of our company would not be able
> to meet the demand for the transceiver or provide adequate customer support.
>
> There is also an additional legal aspect to the decision. We have had
> inquiries from many potential users who may not use the proposed transceiver
> for amateur radio use and will use it for illegal purposes or detrimental
> activity.
>
> Thank you for all the support and feedback given during the development of
> the transceiver.
>
> Regards,
>
> Chris
>
>
>
> **************************************************************
> One of the original posts from Chris, G4HYG:
> *****************************************************
>>We are in the final development phase of the transceiver and are planning
>> to start a KickStarter project in about a month to put the transceiver into
>> production.
>
> To give you an idea of the technology used in the transceiver the RF front
> end device is a PGA-103+ low noise amplifier with a LTC5584 as a mixer. The
> PA stage uses the new BLP10H610 device from NXP. This NXP device is due to
> be released this month so it should be available when we are ready to start
> production.
>
> The transceiver will work at 222 and 902/903 MHz for U.S. customers. Our
> intention is to supply different firmware and filter options depending on
> the customers location. For example the E.U., U.S, and Japan have different
> frequency specifications for imported amateur radio equipment. For in-house
> testing and any potential military customers we do have wideband firmware
> but I wouldn't like to release that firmware for general use for obvious
> reasons.
>
> The approach we have taken with our existing SDR receivers is to try to
> design them so that they can use as many SDR programs as possible. The
> Sentry transceiver is somewhat different in that it doesn't divide the LO
> frequency by 4 to generate the 90 degree phase shift for the IQ LO
> injection. Programs will have to use the direct LO frequency without
> division. So far HDSDR and Quisk are the only programs I know of so far that
> will operate directly with the Sentry transceiver on both transmit and
> receive. SDR Radio and SDR Sharp work OK on receive. I'm in regular contact
> with most of the SDR software authors as I try to help them to add support
> for our products so I'll be in contact with them before launch to ask if
> they can add support for the Sentry transceiver.
>
> Regarding the question about bandwidth the internal sound card has a 48 kHz
> sampling rate so the span bandwidth is limited to 48 kHz, The transceiver
> will have a IQ output to drive external sound cards up to 192 kHz. The
> transceiver is designed as a near zero IF (typically 100 Hz to avoid the AM
> and FM carrier appearing at DC). This helps prevent hams unintentionally
> transmitting out of band. The transmitter IQ chain is filtered with a 8.5
> kHz filter to reduce the wideband noise that can be transmitted along with
> the wanted signal. We realize that many users will want to drive external
> high power amplifiers and transverters.
>
> Recently I've been testing one of the the prototype transceivers during the
> weekly Tuesday night 4, 6, 2 and 70cm contests run by the RSGB. My local
> club (Bolton Wireless Club) have around 25 members who take part in the
> contest and as they are line of sight with my station it's a tough test of
> any receiver or transmitter during the contest. The latest tests have even
> included using unmatched antennas such as a HF dipole as a VHF antenna to
> see how the RF filtering worked in extreme mismatch conditions. A lot of the
> development time over the last two years has been dedicated to ensuring that
> the receiver is as good as we can make it and that the transmitter is clean
> with regard to wideband noise. All these on-air tests confirmed what had
> already been proved in the lab tests and proved that the design is good and
> now ready for production.
>
> The original YouTube video and the photographs on the web page show an early
> prototype. The production version will have a different case more suited to
> fitting underneath a laptop PC. We are planning to add a new video showing a
> working prototype in action in a week or two.
>
> Thanks for your kind comments about the plan for a KickStarter project. I'll
> update the web page and the CCW Yahoo group forum with regular progress
> reports.
>
> Regards,
>
> Chris, G4HYG
> **************************************
>
> Tom K8TB
>
>
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