The 20m dipole will not work well at 2metres.Andy1845c said:I hooked it up to my 20 meter inverted V dipole that I have on my roof, just too see if I could hear anything. I could hear the local 2 meter net come in pretty good sunday night. Even made a weak contact using the 20 meter antenna.
Get yourself an SWR meter that works at 145Mhz, using the transciever output meter is a recipe for failure and burnt out PA transistors in your 7400.Andy1845c said:With the 20 meter dipole, I could get the output meter to read about a 6, with the 2 meter antenna, less then a 2! I tried moving the feedpoints, with no real change. I don't have a SWR meter for the 2 meter band, so I am just using the "output" meter and what I hear being recived to gauge my success (or lack of) The manual says the meter should read around a 9 with a good match.
GM3ZMAAndy1845c said:I'm hoping a fellow ham can answer a few questions so I can maybe understand this all better.
The correct antenna will always work better, and outside will always be better than inside, for a given height.Andy1845c said:Can I even expect this antenna to work at all inside a house? I know outside is always better, but I thought it would work better inside then a completly wrong antenna outside.
If I have the 2 meter antenna and a 20 meter antenna both outside at about the same hight, should the 2 meter greatly out preform the 20 meter for receiving? Our is most of the differance going to be noticed when I transmit?
I have no idea, I have never built or studied this antenna.Andy1845c said:Why do some of the 2 meter J pole designs have the center of the coax on the long element and the braid on the short element, and some are the other way around? Does it matter? I have tried both ways.
OK, lets hear them.Andy1845c said:I have some other questions too, but I'll wait and see if someone can help me first
Andy1845c said:I do want to get a VHF SWR meter, or possibly build one.
Yes but what sort of coax?Andy1845c said:I am using about 25 feet of 50 ohm coax to feed the J pole.
A good idea, but if you want to build your own, you really need a good 50ohm load to use when setting up the SWR meter.Andy1845c said:I do want to get a VHF SWR meter, or possibly build one.
Using the stripline is a good idea, but a bit fussy for a beginner project.Andy1845c said:I found this circuit.
https://www.scribd.com/doc/267448/PocketSize-VHF-SWR-Meter
I've never built one before though. I don't quite understand the 50hm: stripline.
You could try asking on QRZ.COM, but one or two of them on there can be a bit viscious sometimes.Andy1845c said:Most of the other questions I have are related to the J pole antenna and how it works. Maybe I will ask about it on the eham.com boards. Maybe sombody uses the same one.
Not as active as I would like to be, I listen a bit on 40 and 60metres, but very rarely do I put the microphone where my mouth is, so to speakAndy1845c said:Are you very active on the air waves? What bands do you work? I have mostly dabbled in 20 meters since I got my general ticket this spring.
Andy1845c said:I just got a 2 meter transciver a few weeks ago. Its a Kenwood TR-7400A I thought it would be fun to have some local contacts.
I hooked it up to my 20 meter inverted V dipole that I have on my roof, just too see if I could hear anything. I could hear the local 2 meter net come in pretty good sunday night. Even made a weak contact using the 20 meter antenna.
Well, I built a 2 meter J pole antenna. This one is the plan I used, but there seem to be about a hundred that all look very much alike.
https://www.n7qvc.com/copper.html
I finished it tonight, and I hooked it up inside, standing in a corner, and the results were pathetic. With the 20 meter dipole, I could get the output meter to read about a 6, with the 2 meter antenna, less then a 2! I tried moving the feedpoints, with no real change. I don't have a SWR meter for the 2 meter band, so I am just using the "output" meter and what I hear being recived to gauge my success (or lack of) The manual says the meter should read around a 9 with a good match.
I'm hoping a fellow ham can answer a few questions so I can maybe understand this all better.
Can I even expect this antenna to work at all inside a house? I know outside is always better, but I thought it would work better inside then a completly wrong antenna outside.
If I have the 2 meter antenna and a 20 meter antenna both outside at about the same hight, should the 2 meter greatly out preform the 20 meter for receiving? Our is most of the differance going to be noticed when I transmit?
Why do some of the 2 meter J pole designs have the center of the coax on the long element and the braid on the short element, and some are the other way around? Does it matter? I have tried both ways.
I have some other questions too, but I'll wait and see if someone can help me first
Anyone engaging in a technical hobby will be regarded as weird by the non-technical masses around him.Andy1845c said:Well, over the weekend I had a chance to half-ass get the antenna onto the roof of my porch. (the neighbors must think i'm nuts!)
Many antennas are greatly influenced by their surroundings, looks like this antenna is working properly now it is "in the clear".Andy1845c said:I got a huge improvment in preformance. I still don't have an SWR meter, so I don't know how much I am putting out, but it receives alot better and the power meter on the 7400 comes up to around 7 or 8 on the higher end of the band.
That all depends on what you have done to try and make contacts!Andy1845c said:I haven't been ablr to make any contacts yet though. kinda surprises me.
I think that radio is quite old now, it was probably never fitted with one from new.Andy1845c said:The 7400a has optional tone boards that can be added for tone burst. I didn't get one with my radio.
The tones are to prevent a distant station which is using another repeater on the same frequency, from "opening" your local repeater.Andy1845c said:The local repeaters all seem to use differn't tones.
Many years ago, amateur repeaters just required a tone burst at the beginning of the users transmission to open the repeater.Andy1845c said:The one I want to get into says it uses a 136.5 Hz tone. The manual for the tr-7400a shows the tone burst oscillator moduals ranging from 1800 Hz to 2550 Hz. It also has a tone squelch CTCS mode with filter modual freqs. ranging from 88.5 Hz to 156.7 Hz, with my 136.5 Hz also listed. I'm confused on what I actually am after here
Yes it is possible to build a tone generator. You will need a frequency counter to set it up though.Andy1845c said:Does anyone here know if it is possible to build a add on tone board that would plug into the radio and allow me to change the tone easier then having to open the radio and change moduals? I have googled with no luck yet.
JimB said:Many antennas are greatly influenced by their surroundings, looks like this antenna is working properly now it is "in the clear".
Alot of calling CQ on simplex freqs. 146.52 MHz is supposed to be the national calling frequency in the US as far as I can tell, but I have not made a contact on it yet. Maybe everyone just hangs out on the repeater output frequencys nowadays? Maybe I am only getting out a few miles for all I know. I'm so new to 2 meter I don't know.JimB said:That all depends on what you have done to try and make contacts!
It was an option. It talks about 2 different moduals in the manual, that were avalible in a bunch of freqs. I'll try and remember to post that page of the manual tonight when i get home.JimB said:I think that radio is quite old now, it was probably never fitted with one from new.
JimB said:Yes it is possible to build a tone generator. You will need a frequency counter to set it up though.
Andy1845c said:Thanks Ron! I'm glad to know there is a ready made option. Not even that bad of a price (around 30 bucks).
I'd kinda like to build one though.
I found this
http://www.ramseyelectronics.com/downloads/manuals/QT1.pdf
Can't seem to find the kit on the site, but the PDF has the parts list and PCB artwork. Being as its so simple, I think I can follow it well enough to make one on stripboard.
I can't find the IC though! MX165CP Datasheet:http://www.datasheetcatalog.com/datasheets_pdf/M/X/1/6/MX165C.shtml
You wouldn't happen to know where I could get 1 or 2 of these would you? Or if there is somthing it cross referances to?
Andy1845c said:I realize CTCSS is built into modern rigs, but i'm still a little surprised it dosn't seem to be more of a common thing to add it to an older rig. Isn't that part of what ham radio is all about? Building stuff yourself?
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