Get inline amplifier for feed/lna module

[theDarkLard]

The parts list addendum says to get the RCA VHD903 or equivalent, and to see SRT memo 10, which I have linked at the bottom of the page, along with amp links. Basically the memo details different inline amps to be used with the VSRT, which is the very small radio telescope. I can't find any memo's at all for the SRT so I'm assuming that this is the one they mean in the parts list. There is a nifty table in the memo that compares the amps listed and a schematic for how to connect them. The major issue is that I don't know if it is applicable to the SRT or not, and if it is, the schematic lists extra parts that are not present in the parts list addendum which we will also have to order. I'm hoping we can get away with just the one amp since that is all that is listed in the addendum. As far as I know, the only amplifiers from the list that are still available are the ACE 3107588, ZDS-5005, and the RadioShack 15-1170. I also found that pretty much all of the specs for these amps are different from what's listed in the memo. I also found Terk and RCA amplifiers that could be of use to us on amazon. I think the basic purpose of an inline amp is to boost a signal that may diminish when passing through a large length of cable, so our needs may also depend on telescope and telescope control locations.

MIT SRT MEMO 10

ACE 3107588

ZDS-5005

RadioShack 15-1170

Terk

RCA

[hcrowl]

From Alan Rogers:

The LNA, Feed is the same as in

http://www.haystack.mit.edu/edu/undergrad/srt/pdf%20files/SRT_Hardware_Manual.pdf

Sorry we didn't specify any particular inline amplifier, bias tee or wall wart. These are regular satellite TV parts which you can get from Amazon. I just took a look - the inline amp is

RCA VHD 903

as in

www.haystack.mit.edu/edu/undergrad/VSRT/VSRT_Memos/010.pdf‎

and bias tee is Channel Vision Power Injector by Channel Vision $14 from Amazon

and I can't easily see the 12v 1amp wall wart but any like Wall Adapter Power Supply - 12VDC 1A from Amazon $5.69 - should be O.k.

The best choices depend a bit on how far the dish will be from the PC. It is also possible to extend the USB but I don't recommend getting it close to the dish and the USB and dongle do generate some RFI. Depending on distance you will need some cable and adapters. I suggest LMR-240 or LMR-400 (for a really long run).

[hcrowl]

Take a look at the paper on the dongle:

http://www.haystack.mit.edu/edu/undergrad/srt/pdf%20files/2013_HigginsonRollinsPaper.pdf

[theDarkLard]

This is the only +15 dB amp I've found. All the others are 10, 12, 18, or 20 dB of gain. We would have a better idea of which one to get if we knew how much cable will be running between the dish and PC. If it's greater than 50' I say we go with the RCA amp, but I also think it's a safe bet to go with the Terk amp which provides +18 dB, since our cable will probably be around 50', and has the added benefit of being listed on amazon. I also saw that the dongle-based schematic has an extra bandpass filter between the the power inserter and dongle. From the paper, this needs to be a 1420 - 1470 MHz bpf which is the same bpf that's in the LNA, miniciruits model VBF-1445+.

[hcrowl]

Filters and amps ordered!

[hcrowl]

Filter is here (and on the back table next to the keyboard). Still waiting on the amps.

Do what we have what we need as far as cabling?

[theDarkLard]

I think we are still missing the lmr-240/lmr-400 to go from feed to power injector and then rg-6 quad shield cable to go from bpf (after line amp) to dongle. This is based off the parts list addendum listing the rg-6 quad shield cable, but that is the only place it is mentioned so maybe we could get away with just using the lmr cable.

On Mar 24, 2014, at 1:36 PM, hcrowl notifications@github.com wrote:

Filter is here (and on the back table next to the keyboard). Still waiting on the amps.

Do what we have what we need as far as cabling?

\ Reply to this email directly or view it on GitHub.

[hcrowl]

Amp is here and on the back bench. Still working on cabling.

[acencini]

is this safe to close?

[acencini]

^^^

[edaniszewski]

Yes.