| Author |
Message |
    
Radiodude
| | Posted on Tuesday, February 05, 2002 - 2:49 pm: | 
|
How should I hookup the following? Antenna,freq meter,Dosy meters,match box,amplifier? |
Radiodude
| | Posted on Monday, February 11, 2002 - 11:00 pm: |
|
I really need this help for a redo on my base setup >Anyone?? |
Bullshipper537
| | Posted on Tuesday, February 12, 2002 - 12:32 am: |
|
Radiodude: It goes radio,freq meter,amp,{match box? whats a match box,?} If ya gotta use amatch box, somthing's wrong. The meters are the last thing in line,before the antenna. Later bullshipper 537,Tex. |
707
| | Posted on Tuesday, February 12, 2002 - 2:08 am: |
|
Not knowing the power rating of your counter and match box, and whether you have a Tube or Solid state amp makes it difficult, but... Assuming you probably have a 100w max matchbox, and a 200w+ amp with Tune control, and some sort of decent antenna and feedline...try this...
If your radio has built in SWR metering and your Dosy is rated at least the output of the amp:
Radio>match box>freq>amp>Dosy>antenna
Unless your antenna feedline is wildly out of tune, then this setup should be OK. Just remember, if you put the match box AFTER the freq counter, and you plan on doing lots of adjusting, you run the risk of frying the sample circuit in the freq counter by a mismatch between radio and match box. If you have a pretty good antenna/coax match, then the amp input SWR should not exceed about 1.5:1 without using the match box to tune to the amp, and the counter sampler should be ok at 1.5:1. You may not even need the match box. REMEMBER- driving an amp into a bad antenna match will cause very high standing wave and can kill everything behind it. DO NOT PUT THE FREQ COUNTER BETWEEN AMP AND ANTENNA. It will smoke. DO NOT PUT A LOW RATED MATCHBOX AFTER THE AMP...it will short and smoke Everything. ALSO- spend the extra bucks on RG8x jumpers rather than RatShack crimped jumpers. You might pay 8 or 9 bucks for a 3' RG8x jumper at the local Ham Store or from Copper, but it's worth the money. Don't scrimp on your main feedline either. Cheap coax will transmit ok, but your receive will suffer.
Before you even attempt to use the amp, start with just the radio and the Dosy and adjust your antenna for lowest SWR. Add one item at a time into the mix and check it on the radio SWR meter.
1. With some amps, the output Tune control will greatly affect the input SWR(what the radio sees) Some amps have an adjustable Input tuning network, separate from the amp output tuning, which can eliminate the need for the matchbox between radio and amp.
2. For 11m/CB use, you should NOT need to constantly tune the matchbox if your antenna setup is decent, and tuned to the center of your most common band.
3. Certain freq counters are sensitive enough to trigger with only a small amount of power. You may consider driving the counter with an passive pickup, which can be a length of coax with connector on one end, strip about 1' of shield off, then wrap the center conductor tightly around the jumper coming out of the radio. If it works, this will eliminate a possible problem area by isolating the counter from direct RF output.
4. IF your amp has NO adjustments whatsoever, and your radio has no SWR meter built-in, then use the Dosy immediately after the radio. If you know the relative amp output already, then there is no point in wasting its(Dosy) monitoring capability and risking potential mismatches between radio and everything after it, by putting the Dosy last in line before the antenna. Use it instead to watch what the radio sees.
These are all suggestions based on my own personal experience and various different setups. Every setup is different, but there are certain common problems to watch for. Have fun. |
Scrapiron63
| | Posted on Tuesday, February 12, 2002 - 8:59 am: |
|
Radiodude: The less you have in line, the better.
Coming from the antenna:
Antenna, Dosy, amplifier, radio. If you gotta have the frequency counter in line, put it between the radio and Amp. If the counter will work without being in-line, thats the way to go.
I've left out the matchbox, because you don't need it just for CB, unless you have a problem with you antenna or coax. Fix that problem first, the cheaper matchboxs won't take any power and have a loss, really cause more problems than they help. For jumpers between the equipment, I've had better results with mini-8 or 8x, easier to work with and matches better at odd lengths. You don't need jumpers capable of 5000 watts for a 10 watt radio. From the amplifier, to the dosy, and on to the antenna, use the best RG-8 you can afford. |
Radiodude
| | Posted on Tuesday, February 12, 2002 - 10:02 am: |
|
Thanks you guys thats the way I have It set up and I have had no probs. I use the match box to get the lowest swr pos. The matchbox is rated at 500w and the amp is a Texas Star 350hd. Thanks again all |
|
