Author Topic: Hello  (Read 4614 times)

Offline ekimike

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Hello
« on: January 31, 2008, 04:34:14 PM »
I recently found interest in phreaking, while researching phreaking i found this site and found the radio forum to be very interesting. i have read nearly every post on this forum and learned much from it as well as googled a couple thousand topics (slight over exaduration My own mediocre attempt at humor has been highly amusing to myself.) related to radio. Now i am looking to buy my own radio, it would be great if i could get some opinions/ advice so far i have found the Yaesu VX-7R (from the taco bell video) and the Kenwood TH-F6A. i am looking for a radio that will be able to receive and transmit over something like 1mhz to 1ghz+ over a pretty decent range and portable, i know the range part will most likely require more antennas. I have around a $350 spending range and i am able to mod i hope to learn some basics on radio threw this and hopefully in the future maybe set up my own broadcasting station or smthn.


I am very thankful for any help,
                                        Mike

Offline immabadspellor_

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Re: Hello
« Reply #1 on: January 31, 2008, 08:24:49 PM »
You're not going to find a radio, let alone a portable one under $350 that will receive AND transmit continuously from 1 MHz to 1 GHz or more.  Here's where the VX7 really receives and transmits:

RX Range (all in MHz):

0.5 - 728.990
758 - 773.990
803 - 823.990
849 - 868.990
894 - 914.990
944 - 959.990
989 - 998.990

steps 5, 10, 12.5, 15, 20, 25, 50, 100 kHz except above 580MHz 5kHz steps aren't available.  Modes AM, N-FM and W-FM.  The 758-999 band is all broken up because the radio blocks cellular frequencies AND frequencies you could hear images of cell signals on, something that some other ham radios don't do (i.e. the IC-T8A only blocks the cell band, you could still hear cell phones by tuning the frequency on the other side of the IF frequency, in other words just taking the cell freq and adding 47.25MHz)

TX Range:

40 - 221.995
222 - 224.995 TX (300mW)
300 - ~556 TX
~556 - 579.995 PLL won't lock

All other frequencies show TX ERROR.  Transmits in N-FM and AM modes only.  The further you get away from the designed transmit frequency ranges (50-54, 144-148, 222-225, 420-450) the lower the power output.  It will transmit on the FM broadcast band, but only in N-FM mode and since those frequencies are so far outside the designed operating range, the effective radiated power will be in the picowatts even with a proper antenna.  Translation: you'll transmit about 5 feet with it.  In the aircraft band the output is also quite low.  You can expect the same on any frequency too far from what the radio is designed for.  450-470 should be alright.  137-174 should be alright as well.  My guess is that those are your frequencies of interest anyway.  If so, you could accomplish this with cheaper with most run of the mill dual band HT's rather than a quad or tri band radio.  Take the Icom IC-T7H for example.  It'll transmit 118-174 & 400-470 modded and they cost around $150 new.  Anyway, you asked about the F6A so here's the stats on that Kenwood:

RX Range:
0.1 - 824
849 - 869
894 - 1300

TX Range:
137 - 174
216 - 235
410 - 470

While not as wide as the VX7, the VX7 isn't very effective at all outside of these ranges anyway with the exception of 50-54 of course.  Also, the F6A receives SSB which in my book is a big plus, but you could very well be uninterested in such capabilities.  Other such capabilities would be L band receive although the sensitivity there is probably quite poor.  Wouldn't so much matter if you were just using it to tune the output of an LNB or something similar.  Tell us what your prime frequencies of interest are, what modes, etc, and we can make a better reccommendation on a radio.  As for a "broadcasting station" none of these radios are really built for 100% duty cycle, especially at their highest power setting.  They're 2-way radios.  If you're trying to set up an LPFM station or something you'd best look into something completely different than a ham radio. 

Offline ekimike

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Re: Hello
« Reply #2 on: February 04, 2008, 02:40:22 PM »
first off sorry i took so long to post back, second thank you very much for your help and advice, very informational. I looked into the IC-T7H Sport Dual Band FM Transceiver looks real great but im looking for a little bit wider tx range. is there anything that you know about in my price range like the IC-T7H but in addition will tx around 30-100mhz and around 900mhz. i have no experience in using a radio for anything except listening to music so i am not sure of much, i am looking for a radio that will give me a good place start learning threw receiving and transmitting on as many interesting/populated frequency bands as possible. what about mobiles??

once again i thank you all for any input,
mike
« Last Edit: February 04, 2008, 04:26:06 PM by ekimike »

Offline immabadspellor_

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Re: Hello
« Reply #3 on: February 04, 2008, 08:10:01 PM »
is there anything that you know about in my price range like the IC-T7H but in addition will tx around 30-100mhz and around 900mhz?

No, and I doubt you'll find anything like that either.  30-100MHz you're covering VHF low business band, old cordless phones/baby monitors/walkie talkie frequencies, 6 meter ham, TV channels 2-6, RC toys, and part of the FM broadcast band.  Eliminating non-voice services, everything from 54 to 100MHz is wide FM.  Most 2 way radio services are narrow FM so that's a barrier there.  There are pirate FM broadcast band transmitters around if you search online that will do 87.5-108.0 generally, maybe some which are more wide banded.  RF modulators are easy to find for TV channels 3 and 4, although you can track down cable head ends for any TV channel.  With an amplifier and proper filtering they can be turned into a decent make shift TV transmitter.  From 30-54MHz is narrow FM.  Much of this range could be covered by a radio built for the VHF low business band.  These frequencies are commonly used for fire departments and red cross so used equipment is around for relatively cheap.  The minus side is that they are usually not keypad programmable and require special software and interfaces to program the limited amount of channels into the radio.  Many ham base/mobile radios which have HF+6 meter capabilities will cover 30-54 continuously and more (typically 1.8-54 continuous) but you won't find this in a handheld.  While 6 meter (50-54) coverage isn't that uncommon, anything below this is.  There was a 10m HT at one time that did the FM portion of the band (29.5-29.7) but that's all that it would do.  Handhelds capable of 6m operation when modified won't extend that much above or below it.  The lower the frequency, the less bandwidth you'll get out of a tuned circuit.  Compare 70cm radios running 420-450 without much difficulty on the same antenna even to transmitting on the 160m band where you have to retune the antenna/radio for a 0.05MHz change in frequency!

900MHz you won't find in any ham radio.  The 33cm band allocation is rather unique and not shared with the majority of the world so no commercial ham gear exists.  However, it is common in North America for business use and elsewhere for cellular use so equipment is easy to come by.  Business band stuff is usually narrow FM and sometimes trunked.  Unlicensed stuff is usually wide FM.  This would be cordless phones, drive through intercoms, baby monitors, wireless mics, etc.  For narrow FM, you can pick up a used radio but just like the VHF low stuff, you'll have to have a radio interface and special software to program a limited amount of channels.  The radios aren't keypad frequency agile.  For wide FM, I don't really have much of a suggestion.  Most everything is quite low powered to stay within FCC part 15 rules and none have removable antennas.  Many aren't frequency agile at all, those that are are set by the radio automatically after scanning for the clearest channel.  Also in 900MHz are studio to transmitter link systems which link radio station studios to their transmitters at a remote location where they could put up a giant tower.  Most modern STL's are digital but there are still analog links out there with many being sold used after upgrades.  There are some which are front panel frequency agile, but good luck finding one anywhere close to your price range or remotely portable.  If you're very technical, you could reverse engineer a cordless phone base and find a way to manually control what channel it was operating on.  Pair this up with an amplifier made for the European mobile phone band and you'd have something capable of causing trouble. 

Oh I see you also mentioned mobiles.  Here's some that'll work for some of what you mentioned, but they're out of your price range:
Yaesu FT-857
RX/TX 1.8 - 56MHz @ 100 watts, 137-164MHz @ 50 watts, 420-470MHz @ 20 watts  -- $700

Icom IC-706MKIIG
RX/TX 0.1 - 200MHz, 400 - 470MHz, maximum 100 watts, power varies depending on frequency -- $950
See this link for a plot of frequencies and output power after modification:
http://www.ham.dmz.ro/icom/ic706mk2g-range-expansion.php

Note that these types of radios do NOT come with antennas and there's no one antenna that will do all of those frequencies.  They're more expensive but they do so much more.  Every mode and plenty of power.  If all you're interested in is screwing around it'd be a huge waste of money, but if you're really interested in radio and get a licence it's useful and worth the money.   

Offline ekimike

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Re: Hello
« Reply #4 on: February 05, 2008, 01:49:35 PM »
It is a goal of mine to obtain a radio license, maybe over February vacation i could try for one. If i have understood you correctly it seems that there is alot of interesting stuff going on here """Unlicensed stuff is usually wide FM.  This would be cordless phones, drive through intercoms, baby monitors, wireless mics, etc.""" you said that wide fm is 54 to 100MHz right? ive heard that allot of wireless mics etc. are around 100-180 and 400-480mhz, are they here too? Right now the Kenwood F6A is my 1# choice because it has a very nice range, """Also, the F6A receives SSB which in my book is a big plus"""" I tried to wikipedia SSB but it didnt clear much up for me, could you explain this? Any idea how far the Kenwood F6A would transmit with the standard antenna i know it has 5watts on all bands but i have no idea what relation that gives me to transmit distance. I really want to rx and tx cordless phones but only the real old ones operate around 49mhz right? I was in staples the other day and took a look at the cordless phones section and everything for sale uses above 1.3ghz, are there any other more reachable common frequencies? I have an alright background in electronics but intern with a man that could prbly help me reverse engineer a cordless phone, i have done some research on this but come up with little do you know of any good resources for cordless phone hacks ect. Once again thank you for all the help, i am doing my best to research as many of my questions on my own as possible and so far i have learned allot but it is very nice to have a some expert help when i get stuck.

Mike
« Last Edit: February 05, 2008, 02:00:05 PM by ekimike »

Offline immabadspellor_

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Re: Hello
« Reply #5 on: February 05, 2008, 05:26:15 PM »
...it seems that there is alot of interesting stuff going on here """Unlicensed stuff is usually wide FM.  This would be cordless phones, drive through intercoms, baby monitors, wireless mics, etc.""" you said that wide fm is 54 to 100MHz right?

Wide FM (as a mode of transmission) is used many places, some of which would fall between 54 and 108MHz for the aural carriers of TV stations and FM broadcast stations.  There are also some professional wireless mics which share spectrum with TV stations on unused channels in a particular area.  The sentence you quoted me on about cordless phones, drive thru coms, etc, being wide FM was in reference to their use in the 900MHz band.   These services are often narrow FM in the 46-49MHz band.  While the old 49MHz 25 channel cordless phones aren't sold (or at least very rarely sold) anymore, there's still some around.  I still hear many baby monitors around 49.86.  Kids walkie talkies used to run 49.86 AM (not narrow FM) but FRS radios rule the streets these days.  The difference between N-FM and W-FM as the names would suggest is the bandwidth of the signal.  Ham radios use narrow FM to transmit so communicating with a wide FM device won't work well.  A N-FM signal on a W-FM receiver will sound very quiet.  A W-FM signal on a N-FM receiver will sound very loud and distorted.  Many ham radios will receive WFM but will not transmit it. 

ive heard that allot of wireless mics etc. are around 100-180 and 400-480mhz, are they here too?

Yes, there's some lower end wireless mic activity around 160-170.  As mentioned before, some professional wireless mics share spectrum with TV channels that aren't used in the area.  Most of these are UHF frequencies.

Right now the Kenwood F6A is my 1# choice because it has a very nice range, """Also, the F6A receives SSB which in my book is a big plus"""" I tried to wikipedia SSB but it didnt clear much up for me, could you explain this?

SSB = Single Side Band.  It's very common from 1.8 - 29.5MHz in the ham bands, CB (in both channels 1-40 but quite often in the illegal "freeband") some shortwave broadcast, transoceanic aircraft and ships with some telephone calls on occaision.  SSB is a type of AM (Amplitude Modulation) with the difference being that in SSB the carrier is removed along with one of the side bands (hence the name SINGLE side band) and regenerated at the receiving end.  This results in a signal that occupies less bandwidth than AM, uses less power and travels further given the same amount of power since the power isn't spread over as wide of bandwidth.  SSB isn't common at all at VHF in UHF frequencies except in extreme cases of EME (hams bouncing signals off the moon), ham long distance weak signal work and ham satellites.  I believe old troposcatter phone systems used in extremely isolated areas may have used it too.  Oh, and all SSB receivers can receive CW (morse code).  There are many data modes which use FSK (frequency shift keying) that an SSB receiver can receive.  Then you'd hook the radio up to a TNC or a computer soundcard with proper software to decode. Note that the antenna that the F6A comes with will do little for most of those things.  EME, weak signal, satellite all require an antenna with good gain away from obstructions (read outdoors and big).  The antennas that come with these radios generally have a loss of close to 3dB under isotropic.  This is because the antenna is shorter than a resonant fraction of the wavelength of the frequency it operates on.  The electrical length falls within those stipulation but the short physical length doesn't exhibit gain.  Worse yet, the antenna isn't built to be resonant on HF frequencies so it's a real poor performer there.  In other words, the antenna it comes with is just too short to be effective the lower in frequency you go.

Any idea how far the Kenwood F6A would transmit with the standard antenna i know it has 5watts on all bands but i have no idea what relation that gives me to transmit distance.

This is a difficult question to answer because it depends heavily on your environment, like terrain and obstructions between sender and receiver, what equipment the other end has, etc.  You could hit a repeater 50 miles away since many are on top of tall antenna towers in good locations with good antennas.  If you're trying to get to another handheld radio, you might only get a mile or two.  If you're trying to get into something like a cordless phone that's continuously transmitting then your signal is going to have to have a higher field strength at the receiver than the phone presents.  You can calculate this out with given output power of the handset, how far they are from the base, how far you are from their base and how much power you're transmitting.  Distance that will work is really all over the place because of all the variables but I'll tell you with the low power output of an HT you'd have to be pretty darn close and them pretty darn far from the base. 

I really want to rx and tx cordless phones but only the real old ones operate around 49mhz right? I was in staples the other day and took a look at the cordless phones section and everything for sale uses above 1.3ghz, are there any other more reachable common frequencies?

Yes, 46-49MHz phones are growing quite rare these days.  With Wal-Mart selling $10 cordless phones, most people tend to get a new phone rather than paying $10 or more to replace their dead battery in their old cordless.  40 channel 900MHz phones were the next ones out of the gate but these aren't nearly as common as they used to be.  2.4GHz phones are quite common and 5.8GHz phones are getting common as well.  DECT 6.0 phones (1.9GHz) are a new player in North America.  DECT phones are all digital only.  900MHz, 2.4 and 5.8GHz phones come in both analog and digital.  Digital you can't receive but analog you can with appropriate equipment.  I know you can get block downconverters that were used for wireless cable TV that will allow you to receive at least 2.4GHz but transmitting there is a different story.  Wireless A/V senders work at these frequencies so perhaps there's a possibility there if you tinkered around with it.  It helps that these are Wide FM for audio since the phones also use Wide FM.  Also, in a pinch remember that radio transmissions have harmonics so a transmitter at 450MHz also transmits at 900MHz, 1350MHz, 1800MHz, etc but the further you get from the primary frequency (first order harmonic) the weaker the signals are.  Filtering alone in the output will bring down any spurious emissions -60dB, or 1000000x weaker so 5 watts becomes 5 microwatts!  Developing an external frequency multiplier circuit using the radio to supply the intermediate frequency could yield some possibilities. 


I have an alright background in electronics but intern with a man that could prbly help me reverse engineer a cordless phone, i have done some research on this but come up with little do you know of any good resources for cordless phone hacks ect. Once again thank you for all the help, i am doing my best to research as many of my questions on my own as possible and so far i have learned allot but it is very nice to have a some expert help when i get stuck.

I've never read about anyone doing that but it's certainly possible.  You might be breaking new ground.  Be sure to write up some good documentation on it!  I'd just pop one open and try to gather as many specs on the IC's on it as I could round up.  An oscilloscope and a meter would help too.  Good luck!
« Last Edit: February 07, 2008, 04:36:44 PM by immabadspellor_ »

Offline ekimike

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Re: Hello
« Reply #6 on: February 07, 2008, 02:12:23 PM »
After much debate I have decided to go with the Yaesu VX-7R because i am a sailing man and the water proof up to 30ft won me over. also it is around $30 cheaper. About the having a higher field strength than the head set... i know that it is possible to hookup an amplifier between the antenna and the radio to boost the transmit power(will this also boost receive? im guessing it does) but i also know that you can fry your radio if not done right, i was looking at the PLA taco bell takeover video and there are 2 wires running from his radio im guessing 1 is one of the antennas on the car and the other an amp? do you have any advice on the amplification issue?

thanks again,

Mike

also ive been trying to use FCC to find registered wireless communications/ interesting radio broadcasts in my area but theres so many diff search types any other resources you know of for searching for local frequencies?
« Last Edit: February 07, 2008, 02:14:31 PM by ekimike »

Offline immabadspellor_

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Re: Hello
« Reply #7 on: February 07, 2008, 04:35:30 PM »
After much debate I have decided to go with the Yaesu VX-7R because i am a sailing man and the water proof up to 30ft won me over. also it is around $30 cheaper.

I believe this radio also has the marine channels built in rather than having to use up your memory locations and program them yourself so if you're a boater, that's an added plus. 

About the having a higher field strength than the head set... i know that it is possible to hookup an amplifier between the antenna and the radio to boost the transmit power(will this also boost receive? im guessing it does) but i also know that you can fry your radio if not done right, i was looking at the PLA taco bell takeover video and there are 2 wires running from his radio im guessing 1 is one of the antennas on the car and the other an amp? do you have any advice on the amplification issue?

I took a look at the video and I saw that it was hooked up to something.  The video never showed where the wire went to so you'll have to ask the creator.  It either went to an antenna or an amplifier then an antenna.  The other wire looked like it went to the side so it was probably DC in for running it off of a power supply, or it could also have been the supplied hand strap.  When using an amplifier, it goes between the antenna and the radio.  Not all amplifiers amplify on receive.  You have to look for an amp that also has a preamp built in.  You can also buy preamplifiers separate but it's much more convenient having one built into your amp because you don't have to worry about T/R relays, supplying power to the preamp, etc.  However, mast mount preamps are more effective so you rob Peter to pay Paul on that one.  Amplifiers are typically built for one band.  Not all drive through systems are on the same band.  Dual band ham amplifiers are available for 2m and 70cm and that would do the trick in most cases.  You just won't have any receive preamplification on systems using the 30 MHz band as an output.  A proper dual band amp will make you transmit as effectively on those frequencies as a mobile radio ... or better depending on how powerful of an amp you get.  Note that most of these things are too powerful to run through a cigarette lighter so if you're going to be in your car, you'll have to run a line directly to the battery (via a fuse of course).  Also, you don't necessarily have to have a stronger signal at the drive through repeater's receiver, since the drive through operator doesn't transmit continuously like a cordless phone does.  They only transmit when they talk.  If they're experiencing interference, they may hold down the button for the duration of their communications with the customer and in that case to overcome their transmission you'd have to have a stronger signal at their input. 

also ive been trying to use FCC to find registered wireless communications/ interesting radio broadcasts in my area but theres so many diff search types any other resources you know of for searching for local frequencies?

Just use the FCC WTB ULS search.  That will find most interesting things.  Other than that, Google for scanner frequencies and the name of your town.  There's a lot of frequency lists floating around on the internet. 
« Last Edit: February 07, 2008, 05:01:16 PM by immabadspellor_ »

Offline Lestan Gregor

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Re: Hello
« Reply #8 on: February 07, 2008, 09:37:21 PM »
I think ive learned more random ham radio facts from you than from the 40 odd hams in my area.

BTW: I finally have stable internet access and echolink in stalled on all my computers.

Offline ekimike

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Re: Hello
« Reply #9 on: February 09, 2008, 07:08:11 PM »
just as "Lestan Gregor" said very very helpful thank you so much for all the help and tips i will let you know as soon as i get my VX-7R, prbly bout a week or 2 cuz im a round $50 short but with all of the wonderful scams outlined on this site it could be much shorter My own mediocre attempt at humor has been highly amusing to myself.. n thnx for the tip on the FCC search i found cozy cabs registrations so that should be alot of fun once my beautiful radio arrives :)