Cheap way to access 1.2 GHz and above?

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by K3RW, Nov 19, 2015.

Tags:
ad: L-HROutlet
ad: l-rl
ad: L-MFJ
ad: Left-2
ad: Subscribe
ad: K5AB-Elect-1
ad: MessiPaoloni-1
  1. K3RW

    K3RW Ham Member QRZ Page

    I've been reading about SDR dongles and I'm a bit lost. Are these primarily receive-only?

    It seems pretty expensive to get into the SHF bands. A transverter is spendy and the base station rigs that can do it are spendier. I can get up to 440 on the ICOM 706. I saw that some guys hack a Asus or Linksys router, but I'm guessing the range is pretty short.

    I thought about hacking a r/c car transmitter just to get a signal out. Not sure if that is doable. Would definitely need an amplifier but I've actually seen some plans for that, just not plans how to hack the controller.

    So--looking for a budget friendly way to get on the SHF bands. I'll probably find out no one uses them here so not wanting to shell out $400+ just to find that out. Wish I could find a budget kit out there, but no luck there either.
     
  2. KC9ZHR

    KC9ZHR Ham Member QRZ Page

    most sdr stuff is receive except for flex or apache labs to name a few but those are geared towards hf......I would get on your local repeaters and clubs and see if anyone in the area is even doing shf before investing. Then in you decide to, a transverter is probobly the most economical way(trust me if thats what everyone is doing its probobly the most affordable way :eek:)
     
  3. K3RW

    K3RW Ham Member QRZ Page

    Ha--yup I agree with ya on all that. Its a spendy proposition, and even worse if no one is on the other side.
     
  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I'd first join the PNW VHF Society, a radio club focused almost entirely on weak signal VHF-UHF-SHF operations:http://www.pnwvhfs.org/

    Maybe attend a meeting or two or check into one of their 2m SSB nets on 144.240 to ask about local activity on 23cm. They would know.

    In my experience operating from both coasts on UHF-SHF as I have since the late 1960s (my first 1.2 GHz rig was on the air in '69, it was a varactor tripler driven by my 70cm rig and CW only, with a homebrew receiving converter from the RSGB VHF-UHF Handbook -- ran about 3W output to a pair of 23 element loop yagis), I'd say:

    -You may find local 1.2GHz FM/repeater activity, but it's as boring as any of the other bands.
    -The real fun and excitement is weak-signal work (CW-SSB and perhaps some WSJT digital modes), and people use high-gain, rotatable, very narrowly focused antennas for that so unless you also use those and know where other users are, you can hear a lot of nothing.
    -The antennas, antenna height above ground, and transmission line loss are all major factors at this frequency; so much so that a lot of "serious" 23cm ops (ditto for 13cm and the higher bands) put their "whole station" atop a tower next to the antenna system and just run power and baseband I.F. signals up and down from that. It's inconvenient packaging up the station to weatherproof it, but can save hundreds of dollars on hardline. Regular 'flexible" coax doesn't work well up here unless your run is very short -- and a very short run is only useful if you're portable on a mountaintop.

    But, after doing all the "right stuff," there is most certainly activity. Problem is, each area might only have a few workable 23cm stations, so you need good antennas to extend your range into "other" areas, to find more people. With 50W on 23cm SSB and decent antennas, making 250-300 mile contacts is quite common, and signals are about as strong as 144-222-432 MHz using equivalent "sized" (physically) antennas, since the 23cm antenna will have a lot more gain for any given boom length.
     
  5. KK4YWN

    KK4YWN Ham Member QRZ Page

    sdr dongles are receive only. any sdr that xmits is expensive... for now anyway.

    those dongles are really only for strong signals. i think the ADC is only 8-bits. the more bits the better.

    dynamic range is a term used to describe the range (in signal strength) that a receiver can recover (transmitters can have dynamic range too but i wont get into it). dynamic range is usally expressed in db, and you can find plenty of information about this elsewhere. for now i'll simplify, so you can avoid the pitfalls of trying to use an sdr dongle for real radio...

    in sdr world, where ADC's (analogue to digital converters) convert the incoming signal to digital numbers, the dynamic range can be simplified somewhat: the number of bits describe the ADC's dynamic range. More bits is better, up to a point (I wont get into this ). Keep in mind that this is a simplification of dynamic range in SDR.

    Say you have an 2-bit ADC. It will give only 4 possible variations (2^2). Bit 1 can be 0 or 1. Bit 2 can be 0 or 1. The four variations are:
    00
    01
    10
    11

    00 might be 0 s-units, while 11 is 20+ s-units. This leaves only two bits to describe the space between s-0 and s-20+.

    This would be very poor dynamic range.

    For reception of very strong signals, 8-bits is fine. But if you are interested in weak-signal work, you will need as many bits as you can get your hands on.
     
  6. KA2CZU

    KA2CZU XML Subscriber QRZ Page

  7. KV3D

    KV3D Ham Member QRZ Page

    Depends on what you want to do. If you just want repeater access, then you could get an Alinco DJ-G7 which covers 144/440/1.2 and can often be had for less than $250. Some repeaters are digital and so something like an Icom ID-1 would be required, which you can get for around $600 used. There's also the Icom IC-1271A, which does all modes for weak signal work, but it's around the same price as the ID-1.

    In general, if you want to do something "cheap" in ham radio, you're going to have to homebrew or at least have some good technical knowledge. There are small 1.2 GHz transverter kits out there for less than $150 and if you pair that with with a small homebrew or kit amplifier, you might be able to get on 23cm cheaply. I know that's still probably more expensive than you wanted, but that's just how things tend to be for 900 MHz and up. Hopefully the Chinese start making equipment for these bands so that more people could enjoy them--they have unique properties which can be quite useful at times.
     
  8. NC5P

    NC5P Ham Member QRZ Page

    They do make TX/RX dongles, but they are not clean enough to use for what you want to do. They are decent for home hotspot use, like your wifi router does only for D-Star, DMR, P25, Fusion, etc. You should find out about activity nights or nets with the weak signal group in your area. Since you have 432 capability you should try contacting them there and they can help you get on the higher bands. They might even loan you a transverter for contest weekends should they have a spare one. When I was in Colorado they had an awesome group there on weak signal. They had activity on a different band each night of the week.
     
  9. W9GB

    W9GB Ham Member QRZ Page

    Actually, the RAW parts for SHF usage (1 GHz and above) are all around you --
    and often end up in garbage/recycling.

    There are TWO Problems for the Newcomer/Novice.

    1.) The Communication is largely Line-of-Sight .... SO unless you are looking at Space Usage,
    LOCAL Radio Amateurs with Common interests (Frequency, Mode) dictate your access to technical talent (learn/mentor), enjoyment and operational usage (someone to communicate with).
    For Rural or Remote users, unless at High Elevations, have limited operational usage.
    Internet Forums have limited value -- outside of "Info Lookup".


    2.) "Plug-N-Play" equipment (appliance ops) for SHF amateur radio allocations can be $$$.
    When coupled with #1 (above) -- typical Novice says limited value for local communications.
    It is a GREAT Place for the DIY Builder/Electronics Experimenter with Knowledge (or learning) ----- they often only lack free time to design/build/experiment (and #1 above).

    It should come as no surprise that SHF operations are more popular in Europe and USA East/West Coast (due to high population density) as well area with significant elevation changes (mountains).
    ===
    Broadband-Hamnet // HSMM-MESH is a good starting point (cheap) for many newcomers.
    http://www.broadband-hamnet.org
    Hardware Shopping Guide
    http://www.broadband-hamnet.org/images/hsmm_docs/WRT54Shop.pdf

    FUNcube Dongle (UK project) has been popular for satellite / SDR reception.
    http://www.funcubedongle.com
     
    Last edited: Dec 8, 2015
    K6CLS likes this.
  10. W9GB

    W9GB Ham Member QRZ Page

    ANS-340 AMSAT News Service Weekly Bulletin
    ---
    AMSAT Ground Terminal Development Expands to Texas

    Hardware consisting of:
    Ettus Research USRP X300 SDR, USRP B210 SDR, UBX40 USRP Daughterboard, GPDSO Kits, and antennas have been ordered from National Instruments Corp. for delivery to Bill Reed NX5R in Dallas TX to equip a second community for development of the AMSAT Ground Terminals.

    These terminals will be used for the Phase 4B and other digital/microwave satellites being
    developed by AMSAT and in partnership with Virginia Tech.

    Michelle Thompson W5NYV has been leading the effort in the San Diego CA area, which started up when the P4B project was announced earlier this year.
    Amateur Radio operators in the Southern California area from AMSAT, Palomar Amateur Radio Club, and the San Diego Microwave Society have been implementing a terrestrial system to mimic the ground and space segments of a digital satellite communications link and developing code and hardware techniques for use in the P4B and future HEO opportunities that AMSAT is pursuing.

    Expanding the system to the Dallas area will allow more collaboration, development, and testing by AMSAT and North Texas Microwave Society amateurs with San Diego and other regions. The investment in equipment and community building will increase the number and quality of ideas in developing this next generation system of amateur radio satellite communications.

    Another development system is being planned for the East Coast.
    AMSAT is actively recruiting individuals and groups that want to work together to
    establish increased regional technical activity in support of satellite service goals.
    Rick Hambly, W2GPS has campaigned for the creation of this very type of activity on the east coast for many years. Successful east-coast expansion will add even more variability and expertise to the project.

    By involving amateurs who have expertise in both microwave and digital communications and in varying terrain and conditions, as well as including people with various backgrounds and experience, AMSAT plans to produce a ground terminal that will be useful with a variety of next generation satellites including Phase 4B, Phase 3E, the Heimdallr Lunar Cube Quest CubeSat, and an AMSAT developed HEO CubeSat. These are all projects currently being pursued by the AMSAT Engineering and ASCENT (Advanced Satellite Communications and Exploration of New Technology) Teams.

    "The development of a ground terminal along with satellite projects is part of a plan to offer a way for amateurs to buy, build, or access ideas to develop their own ground terminals which will be useful for many future AMSAT satellite mission for years to come" said AMSAT-NA Vice President of Engineering Jerry Buxton, N0JY.
    "The concept of common uplink (5 GHz) and downlink (10 GHz) frequencies with software defined transponders allows many different experimentation and communications opportunities ranging from simple texting to voice, streaming video, data exchange, and reliable EMCOMM access in remote areas, with bandwidths to support many satellites and users."

    If you are interested in supporting the effort please visit http://ww2.amsat.org/?page_id=1121 to submit a request. While those who live in the San Diego, Dallas, or Maryland areas may find it easier to participate, volunteers from other areas are welcome to join and contribute remotely.

    [ANS thanks Jerry, N0JY, for the above information]
     

Share This Page