View Full Version : Looking to expand HT's use as Mobile/Base
07-27-2005, 05:59 AM
I'm just getting into radio. I have to admit, I've been licensed for about 14 years...got Tech class when I was about 14, then found other things (girls/cars) to spend my time and money on.
So...now that I'm an old married guy, I've got some time and a little $ to put into a hobby I've always been interested in. I just ordered a VX-5R and am anxiously awaiting it's arrival.
For the time being I see this being the core of my radio setup. I'll be spending a lot of time just listening once I get my radio, but I'd like to get my vehicle setup with at lease an external magmount antenna. Any suggestions there? Will probably spend most time on 2M in the car.
Also, is the antenna that comes with the VX-5R really ideal or should I look at getting a replacement/backup right away?
What about using this HT as a base unit with maybe a 2M amp and a decent 1/2 wave dipole?
I'm probably looking for too much out of a little HT like this, but this is what I have to work with....for now http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif Thanks for any input on brands/models to look for or suggestions on getting the most out of this little tribander.
I'm pretty green and have some brushing up to do before I go on-air, but I'm excited to get involved in the ham community again.
07-27-2005, 06:21 AM
I've used an HT for a base several times with good results... Your best bet is a good antenna.. A 1/2 Wave Dipole is Ok.. but better antennas can be built for similar prices... I highly recommend a copper J-Pole antenna... I've had excellent results out of them.. If you can weld and have access to the equipment, 3/8" solid aluminum rod makes for an excellent J-pole which will last nearly forever... had one over 13 years now http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif
If you're just wanting to work the local repeaters I would say you could probably even skip the amplifier and just go for antenna height. That will get your range further because 2m signals are line of sight.
For my 2m mobile setup, I am currently using a converted trunk lip mount cb antenna which was made by valor.. I simply removed the coil and cut the antenna down to 19.25" and it works well.. Total cost one $1 yard sale CB antenna.
You needn't put a world of effort into this but a decent antenna and possibly more power would not hurt. Do not go overboard on antennas; HT's are very sensitive (because of their poor antennas) and often overload with a better one. Almost any antenna at a good height will work fine for home operation -- even a Radio Shack ground-plane scanner antenna, say, but you can BUILD as good -- and for mobile, a cheap magmount (http://www.mfjenterprises.com/products.php?prodid=MFJ-1724B) will do well.
Mirage has a dual band amplifier (http://www.mirageamp.com/products.php?prodid=BD-35) that can help mobile (a car roof is pretty low).
You'll want an external power cable/supply so you can run the radio fixed and mobile without running the battery down. A $pare battery is a good idea when you can. You'll also probably want a speaker-mike for mobile or fixed operation.
07-27-2005, 10:08 AM
I spent most of my first couple years on the air with just an old Kenwood TH-21 handheld and a Ringo up about 20'. I lived on top of a very large hill, and 5w routinely got me 45 miles into a repeater in Erie PA.
As KA5S mentioned, some HTs are prone to overloading with a high end antenna. I've found that its particularly true with newer, mid range HTs. Better HTs like the T-90A or TH-F6A (I've used both as excellent base stations) have attenuators you can turn on if a signal is overloading your receiver. I'm not familiar enough with your particular ht to tell you wether it is likely to be the same way.
As for your base antenna, it depends alot on your environment and just how far you want to get out. A 7 element quad can be built easily for less than $15 and can substantially increase your range, but requires a rotor. A copper Jpole is simple, dirt cheap and works pretty well, especially if you happen to live on a hill.
For mobile use I use a $30 Hustler 2m/440 mag mount. Its inexpensive, but difficult to tune. It has pretty close to its advertized 4.5dB gain on 440, and 2.5dB on 2m.
As for the HT antenna, I found that the stock antenna on my TH-F6A was reasonably good on 440, so-so on 2m, and one step up from a dummy load on 220. I replaced it immediately. Alot of people I talk to with multiband HTs say the same thing.
You can get 50w output pretty easily with a Mirage or similar amplifier, but for what you're going to pay for the amp, you might be better off finding an FT-1500 or some other mobile rig for $100 on the forum here or on ebay. If you feel adventurous, a 300w triode amplifier is remarkably simple to build, and with a GI-7B tube, can cost <$200. Such a project isnt really for the electrically inexperienced, or the faint of heart #http://www.qrz.com/iB_html/non-cgi/emoticons/biggrin.gif
Hope you hear you on the air sometime! Maybe catch you with your new HT on one of the easy sats.
07-27-2005, 01:50 PM
First of all welcome back to the hobby.
I used a VX-5 as a base for several months with success. There are a few things to be aware of. First off you will need an external power supply. The VX-5 will receive but not transmit using the just the wall wart. Rat Shack sells a unit that has a cigarette lighter output. Check the user’s manual for the amperage required by the VX-5. Another option is to buy a switching power. I have the Alinco DM-330MUT it costs around $150. Think of it as an investment for that future DC to Daylight rig you are looking at.
Since you will be operating FM a dual band j-pole should do nicely. I operate on a plumbers delight about 35 ft up with success. J-poles are easy to make and cost very little. Google “2m j-pole” there are numerous designs using everything from 450 Ohm ladder line to copper and aluminum. Consider a 6m vertical as well. Don’t know of the availability of 6 m repeaters in your area but you might just snag an opening on 6m FM.
You also want to purchase an adaptor to connect to the external antenna. The VX-5 uses a SMA connection for the rubber duck antenna. HRO has an adaptor to convert the SMA to a 259 coax connection. This is very important item. Using this adaptor will prevent strain and possible damage to the built-in SMA on the VX-5.
Another point to be aware of, the case of the VX-5 acts as a heat sink. You will find that the case heats up even on low power when transmitting. Nothing to be concerned about just be aware that it happens.
An external speaker mic is a plus. You might consider a headset instead. MFJ makes one with a mike plug wired for the VX-5. You can also find them a hamfests.
Don – KI4FON
07-27-2005, 02:48 PM
Copper Jpole works well. If you need a diagram for one, I have one up on my site listed in my signature. Works very well, just put it up 2 weeks ago and the improvement over a 1/4 wave antenna was amazing.
You shouldn't have to invest too much to do pretty well locally with an HT. You may even want to check into using it by itself first until you can afford a amp. A good antenna will help with this. Power is one thing, but power into a bad antenna won't do any good either. Get a good antenna with some good feedline and you'll be surprised at the results.
If you are going to be doing a lot of talking though, you may want to look at an amp. I would advise on trying to find one that can accept really low power in-if you like to ragchew and you have to have the radio up on high power to drive the amp properly, you may find the radio getting awfully warm. In this case I would try to make the amp do the work and take the heat instead of the HT-the HT will last much longer http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif
If it is just a 2m radio, you can probably get away with a single band magmount, and there are plenty out there. But if you ever think you may go multiband, you may want to spring the few extra $$ and get something that covers more than one band now. May save you money in the long run. Larsen makes a small mag mount that I use for APRS, and for mobile voice I use a glass mount. They have some mag mounts out there now that use a very small 'footprint' so less of your finish has the potential of being marred.
07-27-2005, 03:25 PM
Thanks for the input, I've got the "tinkering" but so it looks like I'll be building a J-pole this weekend (tks for the diagram KD6NIG). I've got some restrictive neighborhood covenants that I'll have to contend with for an antenna, but I'll see what I can get away with http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif Fortunately I'm on top of a hill, so my tx location is one of the higher points in this area.
I have read some about the weakness of the SMA antenna adapter, so I'll definitely pickup an adapter to relieve some of that, or at least be very careful. I'm glad to know that I'll be able to take this HT along camping with me and have a portable heat source when transmitting http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif "Hey honey, get out the frying pan and eggs, I'm gonna rag-chew for a bit"
I also didn't realist the portables could be picked up for such a reasonable price - time to browse the classifieds for a 2M or dualband mobile now!
Thanks all - I browsed a lot of ham forums in the last few weeks and the folks on QRZ always seem to jump in with friendly advice and great suggestions for newbies.
07-27-2005, 03:26 PM
J-pole calculators for a regular and a collinear J-Pole can be found here. I reccomend the super j since it will offer more gain compared to a regular j. the super j is built much like the Cushcraft ARX2B and performs as well as if not better than the commercially made antenna. The drawback to the j-pole is the fact you have to stand in line at Home Depot and carry $10 worth of copper parts home to make the antenna where as the commercially produced antenna will be there next week with assembly instructions in 4 languages for the low price of $59.95+s&h and you still have to put it together too. http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif Super J-Pole Calculator (http://users.marktwain.net/aschmitz/antennas/jpolecalc.html) Regular J-Pole calculator (http://www.hamuniverse.com/jpole.html)
07-28-2005, 09:42 PM
My copper J-pole is great on 2 meters, but it's inconvenient for me most of the time (camping and backpacking, moving about, etc.).
I recently got an MFJ-1720S rubber duck from MFJ corporation. #It seems to be a great tri-band antenna with gain on 2M and 440MHz. #No need to switch antennae, and your movement is not restricted.
I paid about $30 through the internet site, and shipping took several days.